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      Volume 42,2021 Issue 4
        國家青年/地區科學基金項目專欄(約稿)
      • HUANG Xiaoting, YANG Kun, MAO Haikuan, LYU Hui

        2021,42(4):319-326, DOI: 10.7535/hbkd.2021yx04001

        Abstract:

        In order to deal with the complex situation that parametric uncertainty and correlation coexist in the automotive powertrain mounting system (PMS),an uncertainty analysis method for calculating the natural frequency and decoupling rate of PMS was proposed.In the proposed method,the multi-dimensional parallelepiped model was firstly constructed to describe the PMS parameters with uncertainty and correlation.Then,the uncertain responses of the natural frequency and decoupling rate were calculated by integrating the regulation technique,Taylor series expansion and central difference method.Next,the analysis procedure of the proposed method was presented.Finally,the Monte Carlo method was used as a reference method for comparison and verification.The numerical analysis results show that the correlation of uncertain parameters of PMS has a certain influence on the inherent characteristics of the system.The method presents acceptable computational accuracy and higher computational efficiency in solving the uncertain response of PMS,which provides important reference for the calculation,evaluation and optimization design of the inherent characteristics of automotive PMS.

      • LU Ying, LIU Yufa, SHU Yu, JI Xiaojie

        2021,42(4):327-333, DOI: 10.7535/hbkd.2021yx04002

        Abstract:

        In order to improve the rescue efficiency of the advanced automatic crash notification (AACN) system,a driver injury prediction algorithm was proposed,and the overall design of the AACN system terminal was conducted based on this algorithm.First,the amount of speed change,the direction of the accident,the driver′s age,gender,whether to wear the seat belt,and whether the driver′s side airbag inflated were selected as the influencing factors of the driver′s injury.Next,a Logistic regression model was analyzed and developed based on traffic accident data.The effectiveness of the model was verified by using the Hosmer-Lemeshow test table,and the best trigger threshold was obtained through sensitivity analysis.Then,the AACN system terminal was designed.Finally,an actual case was used to test the accuracy of the injury prediction algorithm and the effectiveness of AACN system terminal.The results of the case study show that the proposed driver injury prediction algorithm and the AACN system are highly accurate,which can effectively predict the driver′s injury and help the rescue center work out an active rescue plan.The research results can be used to solve the problem that existing centralized AACN systems′ efficiency is not high and their accuracy is greatly affected by human factors.Consequently,they provide a reference for the design of driver injury prediction algorithm in the decentralized AACN system.

      • NIE Mengwen, YANG Kun, WANG Jie, MA Chao, XIAO Jinzhao, TAN Shuliang

        2021,42(4):334-344, DOI: 10.7535/hbkd.2021yx04003

        Abstract:

        In order to improve the serious problem of "[KG-*2]collision" when the retarder is installed in the transmission system of a semi-trailer vehicle,and to improve the braking energy recovery rate during retarding conditions,a scheme of energy recovery type retarder installed in the hub on both sides of the front axle of semi-trailer was proposed.According to the regulation of retarder braking performance in GB/T 32692-2016,the retarder parameters were matched,and the corresponding retarder control strategy was proposed.According to the quality requirements of the electric semitrailer train in the control strategy,the quality estimation algorithm was studied,and based on the particle swarm algorithm,the braking torque distribution at low braking intensity was studied.A joint simulation platform was built through Matlab/Simulink and TruckSim to simulate and verify the quality estimation algorithm,the economy of electric semitrailer trains and braking safety.The simulation results show that the quality estimation algorithm can accurately estimate the quality of electric semitrailer trains; the energy recovery retarder can meet the retardation requirements of electric semi-trailer vehicles,improve the braking energy recovery rate,and can effectively improve the "[KG-*2]collision" problem of the electric semi-trailer train during slow braking.Related research provides new ideas for improving the braking energy recovery rate of electric semi-trailer vehicles during slow braking,and can improve the "[KG-*2]collision" problem and improve braking safety.

      • XIE Fang, ZHAI Changsheng, YAN Songshan, HU Rui, XU Chunxia

        2021,42(4):345-351, DOI: 10.7535/hbkd.2021yx04004

        Abstract:

        In order to improve the microstructure and properties of hot spraying coating for bearing of high speed rolling mill,induction remelting was carried out on the Ni60A coating which was prepared on the surface of GCr15 Bearing Steel by high energy flame spraying.The porosity,microstructure and microhardness of the coating before and after induction remelting were analyzed comparatively by metallographic microscope,scanning electron microscope,X-ray diffractometer and microhardness tester.The effect of induction remelting on the microstructure and microhardness of the coating and interface was investigated.The results show that the porosity of nickel based coating prepared by high energy flame spraying is as high as 509%,and there are many surface pore defects,as well as there are obvious interface cracks and pore defects at the interface between the coating and the substrate,showing typical mechanical bonding and poor interface bonding properties.However,after the induction remelting,the microstructure of the coating is dense,the porosity is only 027%,the defects of the coating are obviously reduced,and the bonding interface between the coating and the substrate shows strong metallurgical fusion characteristics.Additionally,the amount of hard phase in the coating increases significantly,and the microhardness of the coating and interface is greatly improved.Therefore,the induction remelting process can not only improve the surface quality of hot spraying coating for high-speed rolling mill bearings,but also improve the interface bonding characteristics of the coating.The application of induction remelting technology can improve the coating surface structure property,and it may be used in the surface strenthening of high-speed rolling mill bearings for some point.

      • 數學
      • YU Changlong, HAN Huode, WANG Jufang, XING Houmin

        2021,42(4):352-359, DOI: 10.7535/hbkd.2021yx04005

        Abstract:

        In order to improve the basic theory of boundary value problems for nonlinear quantum difference equations,in this paper,we study the solvability of nonlocal problems for second order three-point nonlinear (p,q)-difference equations.Firstly,the Green function of the boundary value problem of linear (p,q)-difference equation is calculated and the property of Green function is studied.Secondly,we obtain the existence and uniqueness of the positive solution for the problem by the Banach contraction mapping principle and the Guo-Krasnoselskii fixed point theorem in a cone.Next,we get the Lyapunov inequality for nonlocal problems of linear (p,q)-difference equations.Finally,two examples are given to illustrate the validity of the results.The results show that the existence and uniqueness of positive solutions for nonlocal problems of nonlinear (p,q)-difference equations are obtained,under the condition of nonlinear term f certain growth.The research results enrich the theory of solvability of quantum difference equations and provide important theoretical basis for the application of(p,q)-difference equation in mathematics,physics and other fields.

      • WEI Wenying, JI Yude, GUO Yanping

        2021,42(4):360-368, DOI: 10.7535/hbkd.2021yx04006

        Abstract:

        In order to extend the basic theory of nonlinear discrete boundary value problems,this paper studied the sufficient conditions for the existence of positive solutions for a class of nonlinear second-order difference equations with three-point boundary value problems.Firstly,the expressions of the solutions for the corresponding three-point boundary value problems for second-order difference equations were given and their properties were proved; Secondly,by constructing suitable cone and integral operator in Banach space and utilizing Krasnoselskii's fixed point theorem in cones,the sufficient conditions for the existence of positive solutions of three-point boundary value problems for nonlinear second-order difference equations were obtained under the condition that the nonlinear term was allowed to change sign.Finally,two examples were given to illustrate the validity of the main theorems and results.The results show that the conditions of the theorem are proved and the discrete boundary value problems satisfies the existence condition of positive solutions.The method is effective in the theoretical proof of the second-order discrete boundary value problem,and has reference for the study of the nonlinear high-order multi-point discrete boundary value problems.

      • Mechanical, Electronics and Information Science
      • GUO Jinyu, LI Tao, LI Yuan

        2021,42(4):369-379, DOI: 10.7535/hbkd.2021yx04007

        Abstract:

        In order to effectively improve the fault detection and monitoring performance of support vector machine (SVM) algorithm,a new fault detection algorithm of industrial process based on DW-ICA-SVM was proposed.Firstly,the training data was normalized.The independent component analysis (ICA) was used to obtain the independent component matrix of the data and extract the hidden non-Gaussian information.Then the Durbin-Watson (DW) criterion was used to calculate the DW values of the independent components (ICs).The DW method was used to effectively extract important noise information and select the important ICs.The ICs containing important information were used as the input of the SVM model to obtain the discriminant classification function.The ICs of test data were input to the model for fault detection and monitoring.Finally,the method was applied to the nonlinear numerical example and the Tennessee-Eastman industrial process,and compared with PCA,LPP,ICA,SVM and ICA-SVM methods.The results show that the proposed method reduces the autocorrelation among samples and effectively improves the fault detection rate.The proposed method strengthens the extraction and recognition of hidden non-Gaussian information to a certain extent,and provides a reference for improving the performance of SVM algorithm in fault detection of industrial process.

      • LYU Meiyuan, ZHANG Yongjian, ZHANG Yongqiang, SUN Shengjuan

        2021,42(4):380-388, DOI: 10.7535/hbkd.2021yx04008

        Abstract:

        In order to solve the problem of low accuracy of sentiment classification caused by neglecting the sentiment information of words in distributed word representation method,an improved sentiment analysis method incorporating weighted word vectors of sentiment information was proposed.According to the exclusive domain sentiment dictionary,combined with the dictionary and semantic rules,the sentiment information is integrated into the TF-IDF algorithm,and the weighted word vector representation method is obtained by using word2vec model.The method is used to compare the collected comments of tourist attractions in Hebei Province with the control group.The results show that compared with the sentiment analysis method based on distributed word vector representation,the accuracy and recall rate of positive text are increased by 61% and 66%,and the F value reached 903%,the accuracy and recall rate of negative text are increased by 60% and 72%,and the F value reached 896% by using the improved method of sentiment analysis integrated with sentiment information weighted word vector.Therefore,the improved method of sentiment analysis integrated with sentiment information weighted word vector can effectively improve the accuracy of sentiment analysis of comment text,and provide valuable reference for users to obtain more accurate comments.

      • Chemistry and Chemical Industry
      • ZHANG Xinxin, XU Jie, JIANG Yan, ZHAO Liyan, ZHANG Wanming

        2021,42(4):389-399, DOI: 10.7535/hbkd.2021yx04009

        Abstract:

        In order to enhance the aqueous solubility and stability of etoposide preparation,the central composite design-response surface method was used to optimize the prescription technology of etoposide nano-mixed micelles (ETP mPEG-PLA/P123).Based on the results of single factor test,central composite design-response surface method of three factors and five levels was carried out to optimize the prescription technology with drug dosage,the mass ratio of mPEG-PLA and hydration volume as independent variables,and the entrapment efficiency,drug loading and particle size as dependent variables.The critical micelle concentration (CMC) was determined by fluorescence probe method,and the physicochemical properties and release behavior of the prepared micelle preparations were evaluated.The results showed that the optimal prescription of ETP mPEG-PLA/P123 micelle preparation was that mPEG-PLA∶P123=38∶62,the drug dosage was 5 mg,and the hydration volume was 6 mL.After optimization,the entrapment efficiency and drug loading were 874% and 419%,the particle size was 1156 nm,PDI was 0216,and Zeta potential was -163 mV.The CMC value was 17×10-3 g/L,so mPEG-PLA/P123 micelles had high stability.In vitro release experiments,etoposide could be released from micelles slowly and continuously,up to 80% within 48 h.The optimized ETP mPEG-PLA/P123 nano-mixed micelles were able to enormously improve the aqueous solubility of etoposide,and the micelle preparation had good stability and a certain slow-release effect.The results of this study could provide theoretical guidance for further broadening the range of application of new etoposide preparations.

      • SU Xiaomei, ZHANG Danshen

        2021,42(4):400-409, DOI: 10.7535/hbkd.2021yx04010

        Abstract:

        Ischemic stroke is a common acute cerebrovascular disease in the middle-aged and elderly,and one of the most fatal diseases in the world.There are limited treatment options that currently exist and only apply to a small proportion of stroke patients,so developing effective treatments to reduce brain damage is critical.Astrocytes are the core components of the central nervous system.Mitochondrial dysfunction is the initial event of ischemic stroke and plays an important role in neuronal survival and neurological function improvement.In this paper,based on the role of astrocytic mitochondria in the pathogenesis of ischemic stroke,the changes of the biological energy and dynamics of astrocytic mitochondria,the functional transfer to neurons and the regulation of astrocytic mitochondria on cerebral blood flow by astrocytic mitochondrice were discussed.Emphasized that astrocytic mitochondria can be used as one of the targets for the treatment of ischemic stroke,so as to better understand the role of astrocytic mitochondria in the process of ischemia-induced neuronal death,and to provide a theoretical basis for the new treatment of ischemic stroke.

      • Material Science
      • ZHANG Zhibin, ZHOU Zhidan

        2021,42(4):410-414, DOI: 10.7535/hbkd.2021yx04011

        Abstract:

        In order to solve the problem that the glass forming ability of Al-based amorphous alloy is not easy to be evaluated because of the easy precipitation of α-Al crystal in the glass forming process,a simple and feasible glass forming ability evaluation scheme was designedto optimize the composition of amorphous AlNiZr alloy.Firstly,nine kinds of AlNiZr alloy ingots with different compositions were prepared; Then,under the same preparation conditions,the alloy ribbons with different compositions were prepared by single-roll strip casting method; Finally,the ribbons were characterized by XRD,and the amorphous content of alloy ribbon was calculated based on the XRD results.The results show that the glass-forming ability of Al100-x-yNixZry increases with the increase of Ni content and decreases with the increase of Zr content; When the Zr content is 3% and the Ni content is further increased to 20% and 25%,[JP2]the glass-forming ability of the alloy is reduced,and Al82Ni15Zr3[JP] alloy has better glass-forming ability.By optimizing the compositions of amorphous AlNiZr alloy,a new evaluation scheme of glass-forming ability can be provided for the Al-based alloy without rare earth elements,and its application space in the field of equipment protection can be expanded.

      • Civil and Architectural Engineering
      • SUN Jishu, QIU Bochao, XIAO Tian

        2021,42(4):415-423, DOI: 10.7535/hbkd.2021yx04012

        Abstract:

        In order to clarify the influence of rainfall on the seepage field and stability of embankment slope,the mechanism of embankment slope water failure and its main influencing factors were studied.Under the specific control conditions of soil quality,compaction degree and erosion infiltration time,this study explored the erosion damage of subgrade slope under rainfall through slope model test,and then combined with GeoStudio program to find out the seepage field and stability change law of subgrade slope during rainfall.The results show that in the process of rainfall,the slope surface is scoured by rain water and the external structure is damaged,while the internal stability of the slope is reduced by the seepage action of rain water.The two effects from the outside to the inside simultaneously lead to the overall damage of the slope.With the increase of compaction degree of two kinds of soil slopes from 85% to 95%,the erosion amount of sandy soil slopes decreased by 4618%,and the slope safety factor increased by 1374%,while the erosion amount of cohesive soil slopes decreased by 3370%,and the safety factor increased by 1021%.With the increase of rainfall time,the scouring depth of cohesive soil slope tends to be stable in the later stage,while the scouring depth of sandy soil slope tends to increase; Under the same control conditions,the change of safety factor of cohesive soil slope before and after rainfall is smaller than that of sandy soil slope.Under the same control conditions,the water damage resistance and overall stability of the clay soil slope are stronger than that of the sandy soil slope.The research results are helpful for more comprehensive understanding of the water-damage mechanism of the embankment slope and the influence laws of the main factors in the process of rainfall,and improve the stability of the road support.

      • Special Column: New Energy Resources, Energy Conservation and Environmental Protection
      • CUI Haiting, HUANG Xiajie, ZHANG Xinyue, ZHANG Liangrui

        2021,42(4):424-430, DOI: 10.7535/hbkd.2021yx04013

        Abstract:

        In order to solve the problems that the irreversible loss existing in the gas cooler has a great influence on its heat transfer performance,in order to improve the thermal performance of the straight tube tube-in-tube gas cooler,the heat transfer process between carbon dioxide and cooling water in supercritical carbon dioxide tube-in-tube gas cooler was studied.By using Fluent software and entropy generation analysis method,the temperature distribution of carbon dioxide and cooling water along the pipe length was obtained throught changing the operating pressure,carbon dioxide mass flow,cooling water mass flow and inlet temperature;according to the entropy generation analysis method of the second law of thermodynamics,the thermodynamic process in the straight pipe casing was calculated,and the entropy generation distribution along the tube length was obtained.The results show that the entropy production along the tube length increases with the increase of pressure;with the increase of carbon dioxide mass flow,the entropy production gradually decreases;with the increase of cooling water mass flow rate,the increase of entropy production is not obvious;with the increase of cooling water inlet temperature,entropy production decreases.The research result may provide some reference for the operation parameters and structure design of CO2 heat pump gas cooler,as well as for the engineering application of CO2 heat pump.

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      Volume 42,2021 Issue 4
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      Volume 42,2021 Issue 4
        Special Column: Data Analysis and Calculation
      • ZHANG Chunhui, WANG Laigui, ZHAO Quansheng, LI Weilong

        2015,36(1):90-99, DOI: 10.7535/hbkd.2015yx01016

        Abstract:

        How to quantitatively evaluate the permeability change of coalbed subjected to liquid nitrogen cooling is a key issue of enhanced-permeability technology of coalbed. To analyze the evolution process of permeability of coupled coal deformation, failure and liquid introgen cooling, the coal is supposed as elastic, brittle and plastic material. Its deformation process includes elastic deformation stage, brittle strength degradation stage and residual plastic flow stage. Combined with strength degradation index, dilatancy index of the element and Mohr-Column strength criterion, the element scale constitutive model with the effects of confining pressure on peak-post mechanical behaviors is built. Based on the deformation process of coal rock, there exist two stages of permeability evolution of the element including decrease of permeability due to elastic contraction and increase due to coal rock element's failure. The relationships between the permeability and elastic deformation, shear failure and tension failure for coal are studied. The permeability will be influenced by the change of pore space due to elastic contraction or tension of element. Conjugate shear zones appear during the shear failure of the element, in which the flow follows so-called cubic law between smooth parallel plates. The calculation formulas of the permeability and the aperture of the fractures are given out based on the volumetric strain. When tension failure criterion is satisfied with the rock element fails and two orthogonal fractures appear. The calculation formulas of the permeability and the width of the fractures are given out based on the volumetric strain. Further, combined with the thermal conduction theory the permeability evolution model of coupled coal deformation, failure and liquid nitrogen cooling is presented. Then Fish function method in FLAC is employed to perform the model. The permeability's evolution process for coal bed cryogenically stimulated by flowing liquid nitrogen through gas production well in Wangyingzi mine, Liaoning province, is simulated and the results include: 1) When liquid nitrogen(LN2) is injected into a rock at warm reservoir temperature, heat from the rock will quickly transfer to the liquid nitrogen resulting in rapid cooling and contraction of coal bed. The nearer the position is to bore hole, the bigger the shrinkage deformation and thermal stress and coal fail when tension stress sufficiently built up. In this paper the tension failure band after 10 days' LN2 cooling is 0.65 m. 2) In tension failure area the cracks from cooling stimulation lead to the significant growth of permeability. The maximum permeability for element is 1.97×105 times more than that before cooling. 3) Apart from the bore hole, the thermal tensile stress leads to the growth of permeability at a rate of 1%~14%, far less than that in the tension failure area. 4) With increasing time the failure area gradually slowly grows up. It indicates that the longer cooling time does not mean better effects. 5) The cooling fracturing area is found to have a 1.0 m band. In practical engineering the pressure in hole bore and phase transition of water also influences the deformation and failure of coal, which leads to much more failure zone of cooling. 6) The evolution process of permeability of coupled coal deformation, failure and liquid introgen cooling can be better reflected by the model in this paper. This study is hoped to provide a simple but reasonable description of the permeability evolution of rocks subject to liquid nitrogen cooling.

      • Material Science
      • MA Jing, WANG Ruiyang, WEN Ning

        2021,42(1):75-81, DOI: 10.7535/hbkd.2021yx01010

        Abstract:

        In order to improve the oxidation resistance of 304 stainless steel, SiO2 thin film was prepared on the surface of stainless steel by sol-gel method with tetraethyl orthosilicate (TEOS) as raw material. The effect of film layers on the high temperature oxidation resistance of stainless steel at 900 ℃ was studied by means of oxidation kinetics, XRD, SEM and EDS. The results show that the adhesion of SiO2 film to stainless steel matrix is good, which promotes the selective oxidation on the stainless steel surface and the formation of protective Cr2O3 and NiCr2O4 oxide layers. The high temperature oxidation resistance of stainless steel is improved remarkably. The oxidation resistance of the sample coated with three layers of SiO2 film proforms the best, and the oxidation weight gain and oxidation spalling of the sample are only 58.1% and 41.4% of the uncoated sample after 100 hours of cyclic oxidation at 900 ℃. The high temperature oxidation resistance of stainless steel is effectively improved through SiO2 film coating, which is another attempt of surface treatment method applied to high temperature environment, and provides reference for other thin films prepared by sol-gel method.

      • Mechanical, Electronics and Information Science
      • WANG Jianxia, LIU Menglin, XU Yunfeng, ZHANG Yan

        2021,42(1):48-59, DOI: 10.7535/hbkd.2021yx01007

        Abstract:

        Most of the real-life networks are heterogeneous networks that contain multiple types of nodes and edges, and heterogeneous networks integrate more information and contain richer semantic information than homogeneous networks. Heterogeneous network representation learning to have powerful modeling capabilities, enables to solve the heterogeneity of heterogeneous networks effectively, and to embed the rich structure information and semantic information of heterogeneous networks into low-dimensional node representations to facilitate downstream task applications. Through sorting out and classifying the current heterogeneous network representation learning methods at home and abroad, reviewed the current research status of heterogeneous network representation learning methods, compared the characteristics of each category model , introduced the related applications of heterogeneous network representation learning, and summarized and prospected the development trend of heterogeneous network representation learning methods. It is proposed that in-depth discussion can be carried out in the following aspects in future: First, avoid predefined meta-paths and fully release the automatic learning capabilities of the model; Second, design heterogeneous network representation learning method suitable for dynamic and large-scale networks.

      • CHEN Qi, ZHANG Renhui, HE Zhongyi, XIONG Liping

        2021,42(1):1-7, DOI: 10.7535/hbkd.2021yx01001

        Abstract:

        In order to explore the lubrication performance of alcohols under high loads and high speeds conditions, especially the relationship between carbon-chain length and hydroxyl number and lubrication performance, the effects of carbon-chain length and hydroxyl number on the lubrication performance were well studied. The tribological properties of a series of alcohols were investigated by a four-ball tribological machine, and the effects of the carbon-chain length and the hydroxyl number on their lubricating properties were investigated by means of viscometer, transmission electron microscopy (TEM) and Raman. Experiments show that with the increasing of the carbon-chain length, the run-in period and the time for achieving stable friction coefficient were shorted, and the wear was reduced; with the increasing of the hydroxyl number, the wear decreased with no obvious run-in period and consistent fluctuation of friction coefficient for ethylene glycol and continuous decrease of friction coefficient for glycerol. It is found that friction-induced graphene is superior to amorphous carbon in effectively promoting the tribosystem to achieve the stable friction coefficient and shorten run-in period, which provides reference for the application of alcohols in the field of mechanical equipment.

      • SUI Bingdong, ZHANG Pai, WANG Xiaojun

        2021,42(1):22-29, DOI: 10.7535/hbkd.2021yx01004

        Abstract:

        In order to solve the problems of low recognition accuracy and easily affected by illumination conditions in the gesture recognition, an improved YOLOv3 gesture recognition algorithm was proposed. Firstly, a smaller detection scale was added to the original three detection scales to improve the detection ability of small targets; secondly, DIoU was used instead of the original mean square error loss function as the coordinate error loss function, the improved focal loss function was used as the confidence loss function of the boundary frame, and the cross entropy was used as the loss function of the target classification loss function. The results show that when the improved YOLOv3 gesture recognition algorithm is applied to gesture detection, the map index reaches 90.38%, which is 6.62% higher than that before the improvement, and FPS is nearly twice as high as before. After the new model is trained by the improved YOLOv3 method, the gesture recognition accuracy is higher, the detection speed is faster, the overall recognition efficiency is greatly improved, the loss weights of simple samples and difficult samples are balanced, and the training quality and generalization ability of the model are effectively improved.

      • Food Science and Biological Science
      • JIA Yanli, QIU Yan

        2021,42(1):67-74, DOI: 10.7535/hbkd.2021yx01009

        Abstract:

        As the side effects of antibiotics are becoming increasingly prominent and the number of approvals is declining year by year, it is urgent to develop other active substances that are similar in functions and not easy to develop drug resistance. Antimicrobial peptides (AMPs) have broad-spectrum antibacterial activities, thermal stability and unique mechanism of action. They can not only play the role of anti-bacterial infection in vivo and promote apoptosis of cancer cells, but also be used as chemotherapeutic agents against virus and antibacterial materials for hospital settings. In this paper, developments related to antimicrobial mechanisms and activities of antimicrobial peptides against drug-resistant bacteria, anticancer and antiviral infection in the field of medicine are systematically reviewed. The problems of stability, hemolytic and toxicity of antimicrobial peptides are elucidated and the development prospects of AMPs in medicine are provided. Further research on AMPs can be carried out in the following aspects in the future. 1) Antibacterial mechanism in vivo are studied to promote the development and application of antimicrobial peptides;2)Structures of AMPs are optimized by replacing and modifying amino acid residues and hybrid peptides are synthesized to improve their activities, reduce side effects and prevent drug resistance; 3)Application of delivery systems for AMPs or combination of AMPs with green natural extracts is investigated to improve their antibacterial activity and bioavailability.

      • Mechanical, Electronics and Information Science
      • WANG Qing, YU Baoguo

        2021,42(1):8-14, DOI: 10.7535/hbkd.2021yx01002

        Abstract:

        In order to improve the positioning ability of ultra wideband network in non-cooperative indoor environment, the theory of centreless positioning algorithm was used to solve and analyze the output distance information of ultra-wideband ranging, and the relative positioning results were obtained. The positioning results of the system were compared with the results of the photoelectric calibration system, and the accuracy was evaluated. The results show that, compared with the traditional ultra-wideband positioning model, the combination of ultra-wideband ranging and centreless positioning algorithm can realize the centreless positioning and the relative positions among nodes, and finally determine the relative positions among nodes. The combination of UWB ranging and centreless positioning algorithm has good stability and accuracy in relative positioning, and can be widely used in various indoor and outdoor scenes.

      • WANG Xiaojun, XUE Linbo, WANG Yanpeng

        2021,42(1):15-21, DOI: 10.7535/hbkd.2021yx01003

        Abstract:

        In order to solve the problem that the impulse interference near the service frequency band of aviation radio navigation affects the receiver, and further improve the anti-jamming ability of GNSS system, a impulse interference suppression method based on STFRFT (short time fractional Fourier transform) was proposed. The optimal rotation order of the received signal was determined, and STFRFT was applied to the signal to obtain the two-dimensional distribution of time-frequency surface through coordinate rotation. Under the optimal order, the adaptive time-varying filter was used to separate the interference and the signal, so as to suppress the interference. The simulation results show that the adaptive filtering algorithm based on STFRFT has the best effect of eliminating interference compared with several traditional methods, and retains more useful signals while suppressing impulse interference. By combining STFRFT and adaptive time-varying filtering technology, the ability of suppressing impulse interference is improved, which provides some reference for the impulse anti-jamming technology of aviation radio navigation service.

      • YIN Yanan, ZHEN Ran, WU Xiaojing, ZHANG Chunyue, WU Xueli

        2021,42(1):38-47, DOI: 10.7535/hbkd.2021yx01006

        Abstract:

        In order to solve the problem that ant colony algorithm is easy to fall into local optimum in UAV route planning, an improved ant colony algorithm was proposed. The upper and lower limits of pheromone volatilization factor and pheromone were set to prevent ants from falling into local optimum because pheromone on short path was too high or pheromone on long path was too low. At the same time, under the influence of multiple heuristic factors, the overall length of the path was taken as an adaptive heuristic function factor to determine the state transition probability. When the path length was large, the adaptive heuristic function factor was small, which reduced the probability of choosing the path by the ant colony. The experimental results show that the improved algorithm reduces the path length by 6.4% and the variance of the optimal path length by 85.78%, which increases the consideration of environmental integrity, shortens the path length, reduces the number of iterations, and jumps out of the local optimum. In the case of increasing environmental complexity, the algorithm can effectively choose a better path and provide a theoretical basis for UAV route planning after introducing the adaptive heuristic function factor.

      • LI Chunhua, QIN Yunfan, LIU Yukun

        2021,42(1):30-37, DOI: 10.7535/hbkd.2021yx01005

        Abstract:

        Aiming at the problem of poor precision performance of traditional Bayesian model saliency detection algorithm, a Bayesian model saliency detection algorithm based on improved convex hull was proposed. Firstly, the foreground of the image was extracted by the manifold ranking algorithm, which was used as the prior probability in Bayesian model. Secondly, Harris corner detection algorithm based on color enhancement was used to detect the feature points of the image in three color spaces of RGB, HSV and CIELab; the convex hulls in RGB, HSV and CIELab spaces were constructed respectively; and the intersection of convex hulls were obtained. Thirdly, the saliency region map was calculated by Bayesian model according to the prior probability and the observed likelihood probability obtained by combining convex hulls and color histograms. Finally, the proposed algorithm was tested in two public data sets MSRA and ECSSD. The experimental results show that the proposed algorithm can suppress the background noise effectively and detect the salient areas completely. The test results of F-measure value in MSRA and ECSSD databases are 0.87 and 0.71 respectively, and the accuracy-recall rate curve is higher than that of traditional classical algorithms in complex image databases. The proposed algorithm improves the detection effect of the traditional classical algorithm and the accuracy of saliency map detection.

      • Chemistry and Chemical Industry
      • XIE Yinghua, LIU Zhaoxia, ZHANG Meimei, ZHANG Dongmei

        2021,42(1):60-66, DOI: 10.7535/hbkd.2021yx01008

        Abstract:

        In order to avoid the irritation of metformin hydrochloride to the stomach and realize its release in the intestine, with metformin hydrochloride as the main drug and chitosan/sodium alginate as the composite support, the optimal formulation and preparation technology of metformin hydrochloride loaded pH-sensitive hydrogel microspheres were selected, and the pH-sensitivity and in vitro drug release characteristics were investigated. The formulation and process were optimized by single factor test and orthogonal test. The morphology was characterized by SEM. The entrapment efficiency and drug-loaded amount were determined by UV. The release degree was studied by rotating basket method. The results show that the optimized prescription is as following: chitosan and sodium alginate with a total concentration of 2%(mass-volume ratio), mass ratio of sodium alginate to chitosan =1∶1, mass ratio of drug to sodium alginate=2∶5, and 3.5% CaCl2(mass-volume ratio). The cumulative release rate is less than 4% in artificial gastric juice within 6 h, and up to 96.4% in artificial intestinal juice within 6 h. The formulation and process are stable and reliable, and the hydrogel microspheres have high mechanical strength, good biodegradability and stability. So it is a new metformin hydrochloride delivery system.

      • Material Science
      • MENG Zhian, LU Suling, YAN Huajun, HAN Pengbiao, HU Xilei, WANG Tonghui, WANG Hao

        2021,42(1):82-90, DOI: 10.7535/hbkd.2021yx01011

        Abstract:

        In order to solve the problems of backward production technology, long processing cycle and low material utilization rate in traditional U-shaped steel tie rods, an integrated steel tie rod forming process was proposed. Taking the preform forming of 35 steel tie rod U-shaped head as the research object, a three-pass heating upsetting method was designed. The DEFORM-3D finite element software was used to analyze the simulation results of the temperature field and stress field after upsetting under different process conditions. The hot forming process parameters with better forming effect were discussed, and the feasibility of forming was verified through experiments. The results show that the optimum hot forming process parameters of each pass are as follows: the initial forging temperature of the first pass is 1 150 ℃, while the punch speed is 20 mm/s; the initial forging temperature of the second pass is 1 150 ℃, while the punch speed is 30 mm /s; the initial forging temperature of the third pass is 1 100 ℃, while the punch speed is 20 mm/s. Under the hot forming process parameters, the forming forces of each pass are 1 520, 2 090, 5 290 kN, and the expansion forces of each pass are 5 870, 6 710, 8 830 kN, respectively. After upsetting, the metal streamline distribution is reasonable, there is no crossover and folding phenomenon, and the forming effect is good. The equivalent stress distribution inside the part is relatively uniform while preparing the preform in the three-pass hot upsetting method, which can form a good quality part. It provides a certain reference for the upsetting aggregate process design and equipment selection of the U-shaped head perform of 35 steel tie rod.

      • Special Column: Data Analysis and Calculation
      • LIU Qing, LIU Bin, WANG Guan, ZHANG Chen, LIANG Zhixing, ZHANG Peng

        2019,40(1):68-78, DOI: 10.7535/hbkd.2019yx01011

        Abstract:

        In recent years, the research on Digital Twin is in the ascendant. As a new paradigm or concept, it shows great potential. However, the connotation and scope of the Digital Twin concept is still uncertain, especially the Digital Twin Model definition is not clear.According to the pattern category, the Digital Twin Model can be divided into general model and special model, in which the special model is still the focus of current research, and the research content is mainly embodied in the use of Digital Twin method to model specific projects. It also includes concept for developing specialized models. These specific projects in addition to the traditional manufacturing related to parts measurement and quality control, manufacturing, design and work processes, as well as system management, but also in the field of biomedical applications and applications for petroleum engineering and so on. There are many tools and techniques for developing special models, such as general industrial software, special industrial software, simulation platform and self-developed secondary development tools, etc.The research object of the Digital Twin general model is not specific to a specific project, but how to represent the controlled elements of the model as a group of common objects and the relationships between these objects. This provides a consistent approach to the management and communication of controlled elements between different environments. The research on the general model is mainly divided into the conceptual research and the model implementation method; the research heat of the two directions is almost the same. Conceptual research ranges from product lifecycle management to system behavior description, such as general system behavior and system reconfiguration, and to product configuration management, to specific workflow, such as design methods, manufacturing systems and manufacturing processes. The research content is relatively divergent, and there is no particularly prominent hot spot. The research of Digital Twin general model implementation is mainly reflected in the modeling language construction, the model development methods exploration, the specific tools usage, the Meta-model concept implantation and the model algorithm exploration.Digital Twin Model is one of the core areas of Digital Twin research. Its future research focuses on how to integrate the external features and intrinsic properties from different Digital Twin artifacts into a model with interoperability, interactivity and scalability for more efficiently realizing the information flow between the physical world and the digital world, thus achieving the universal Digital Twin application, and then supporting the CPS (Cyber Physical Space) and CPPS (Cyber Physical Production System) construction. To this end, the next problem in the Digital Twin Model needing to be solved first is how to dock the standard reference architecture, such as the RAMI4.0 (Reference Architecture Model Industrial 4.0) proposed by Germany and the IMSA (Intelligent Manufacturing System Architecture) by China, etc. Secondly, the Digital Twin Model needs a unified method to describe and it also needs consistent conclusions, in order to standardize the models established by independent development, thus improving the interoperability and scalability of the model. Otherwise, the performance of the model will decrease significantly as the system scales raise. Thirdly, the research on China's Digital Twin Model requires the support of domestic professional industrial software and modeling software, so that the Chinese scholars can carry out in-depth research that is more in line with national conditions.

      • Special Column: National Young Scholar/Local Science Foundation
      • WEN Juan, LI Fu, DING Junjun, LI Gang

        2015,36(1):1-8, DOI: 10.7535/hbkd.2015yx01001

        Abstract:

        Urban rail transit vehicles have been more and more attractive to people as a kind of fast, comfortable, energy-saving, environmental protection and safe transportation. But because of the vehicle noise and vibration, urban rail vehicles also face severe challenges. The research of resilient wheels has been continuously developed and improved. Based on the review of development background and structure sorts of resilient wheels, the advantages of resilient wheels are described, and the research status of noise and vibration reducing, infinite element strength analysis, vehicle dynamic analysis and the wheel-rail wear of resilient wheels are discussed. Taking the low-floor LRVs (light rail vehicles) in domestic and overseas as example, the development and application of the resilient wheels in city rail transit is described, and the application prospects of the resilient wheels in LRVs in domestic and the future research direction of elastic wheel are discussed.

      • 機械、電子與計算機
      • CUI Hai-ting, ZHANG Gai, JIANG Jing-zhi

        2012,33(5):453-458, DOI: 10.7535/hbkd.2012yx05016

        Abstract:

        By using the solidification/melting model of FLUENT software, the melting and solidification process of the aluminum-silicon alloy in a cylinder heat storage with double wall were simulated numerically. Considering the third kind of boundary condition, the dynamic temperature field distribution and the position of the phase interface change moving with time are obtained. And the melting and solidification duration time is also calculated. The results have important reference value for the numerical simulation of the phase change problem and the design of phase change energy storage device.

      • QIN Si-liang, WANG Qing-guo, QU Zhao-ming, LEI Yi-san

        2012,33(4):309-312, DOI: 10.7535/hbkd.2012yx04007

        Abstract:

        The permittivity of carbon fibers in different composites is calculated and discussed by using M-G equations, Bruggeman equations and generalized M-G equation. Results show that for high draw ratio fibers, all the three equations can calculate out the permittivity with the same numerical level and variation trend. Generalized M-G equation and M-G equation have a similar result but Bruggeman''s result is smaller. All three equations become invalidation when fibers'' concentration reaches its percolation threshold, which means that all three equations are useful at low concentration.

      • 〖CM5-3〗機械與計算機技術
      • ZHANG Fu-xiang, WANG Shu-guo

        2008,29(4):299-304, DOI: 10.7535/hbkd.2008yx04010

        Abstract:

        Based on the developed rehabilitation manipulator, study on the control system is carried out, such as embedded system platform with the ARM microprocessor S3C2410as its core, motor control module and data acquisition module based on serial peripheral interface (SPI) bus, control software and graphical user interfaces (GUI) etc. According to the mechanical system, a sensor system is also designed to realize the function of acquisition of rehabilitation dada during rehabilitation motion. The test proves the feasibility of the system which can be used in clinic in future.

      Editor in chief:孫鶴旭

      Inauguration:

      International standard number:ISSN 1008-1542

      Unified domestic issue:CN 13-1225/TS

      Domestic postal code:

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