摘要：The fore claws of the nymph of Cryptotympana atrata have excellent ability to cut and dig soil. Inspired by this, we designed a biomimetic stubble cutter to reduce the cutting resistance. Reverse engineering and 3D print technology were applied to design the biomimetic stubble cutter. Two types of biomimetic corn stubble cutters with different tooth heights （5 mm and 2.5 mm） were designed. The cutting ability of biomimetic corn stubble cutters was compared to the conventional design by the quadratic regression orthogonal test. Tooth height, dip angle of cutting edge, and cutting velocity were chosen as orthogonal test factors. The biomimetic stubble cutters show lower cutting resistance than the conventional one. Cutting velocity exerts the least effect on cutting resistance, followed by tooth height and dip angle of cutting edge. Optimal combination with the least cutting resistance is tooth height of 2.5 mm and dip angle of cutting edge of 40° while the cutting resistance does not vary remarkably with cutting velocity. Test results indicate the serrated structure design as a principal factor for cutting resistance reduction. The biomimetic stubble cutter design, inspired by the soil-cutting mechanism of Cryptotympana atrata nymph, remarkably improves the performance of stubble cutter.

摘要：Bone screws are devices used to fix implants or bones to ***,conventional screws are mechanically fixed with thread and often face long-term failure due to poor *** improve osseointegration,screws are evolving from solid and smooth to porous and *** manufacturing(AM)offers a high degree of manufacturing freedom,enabling the preparation of predesigned screws that are porous and *** paper provides an overview of the problems currently faced by bone screws:long-term loosening and screw ***,advances in osseointegrated screws are summarized hierarchically(sub-micro,micro,and macro).At the sub-microscale level,we describe surface-modification techniques for enhancing *** the micro level,we summarize the micro-design parameters that affect the mechanical and biological properties of porous osseointegrated screws,including porosity,pore size,and pore *** addition,we highlight three promising pore shapes:triply periodic minimal surface,auxetic structure with negative Poisson ratio,and the Voronoi *** the macro level,we outline the strategies of graded design,gradient design,and topology optimization design to improve the mechanical strength of porous osseointegrated ***,this paper outlines advances in AM technology for enhancing the mechanical properties of porous osseointegrated *** osseointegrated screws with hierarchical design are expected to provide excellent long-term fixation and the required mechanical strength.

摘要：Fugitive dust has been recognized as an important contributor to air pollution,and artificial porous fence is one of the most effective management strategies to reduce fugitive dust in open *** improve the shelter effects and efficiency of Particulate Matter(PM)reduction of traditional fences,this study proposed five bionic fences and their capability was evaluated through wind tunnel *** results indicated that all of bionic fences presented better efficiency in reducing wind speed and PM concentrations compared with traditional fences,and they were more efficient in capturing *** the bionic fences,the non-woven cloth material with four-leave opening presented the best capability both in wind speed and PM *** proposed bionic fences may be further developed and studied for future application in capturing fine PM and adapting to the wind.

摘要：Designing bio-inspired flow fields holds great potential in improving the performance of Proton Exchange Membrane Fuel Cell(PEMFC).Two kinds of biological prototypes are widely used:plant prototype and animal *** remains a question which one of these prototypes is more appropriate for the scenario of ***,a comparative study was conducted to compare bionic flow fields based on animal and plant ***,a Corn Leaf Vein Mathematical Model(CLMM)was established by extracting structural parameters from corn leaves of two growth *** the obtained CLMM and well-known Murray’s law were employed to design bionic flow fields corresponding to the plant and animal prototypes,respectively,which have been subsequently compared by numerical *** results demonstrate that the flow field guided by Murray’s law outperforms the counterpart based on the structural parameters of CLMM in terms of PEMFC net output power,mass transport,water management and pressure drop,suggesting that animal circulation system is more suitable to the bionic flow field design of PEMFC than plant leaf *** work may also offer valuable insights into the design of other flow fields related to electrochemical energy conversion.

摘要：With the growing demand and working complexity of corn precision planter,it becomes more important to monitor the working performance through intelligent systems.A new fault monitoring system for corn precision planters was designed and *** system consisted of the information acquisition module,controller module,alarm module,input module and display module.A capacitive sensor was utilized to monitor the seed flow without changing the track of a precision *** system can monitor the whole sowing process of a seed-metering device in *** sowing status,fault type and fault location can be displayed on liquid crystal display(LCD).Warning light on the LCD reminds the operator of abnormal *** tests and field tests showed that the minimum monitoring accuracies of missing sowing and total sowing number were 92.11%and 94.28%,respectively,and the seed level sensor and the opener sensor worked *** system can accurately prompt the seed-metering mechanism in real-time.

摘要：Biomimetic blades for soil-rototilling and stubble-breaking were designed learning from the geometrical structure of the tips of toes of mole rat （Scaptochirus moschatus）. The orientation, the number and the central angle of the biomimetic structure were taken as the testing factors. The optimal structure of the biomimetic blade was determined through the tests of soil-rototilling and stubble-breaking operation in an indoor soil bin. The optimal combination of the biomimetic structure pa- rameters is that three arc concave teeth are equally arranged on the front cutting edge with a central angle of 60°. The results of comparative tests between the optimal biomimetic blade and a conventional universal blade show the torque acting on the biomimetic blade is lower during soil-rototilling and stubble-breaking operations. The results of field tests show that the working quality of the biomimetic blades meets the requirements of the national standard of China. Tests of soil-rototilling show that, when the orientation of the biomimetic structure was at low and middle levels, the torque ofbiomimetic blades decreased from 34.17 N·m to 31.03 N·m. The torque also decreased with the increase of the number of biomimetic structure. The average torques were 34.57 N·m, 33.44 N·m and 31.37 N·m, respectively. The maximum different value between two levels of central angle was 0.41 N·m. Tests in field indicate that for soil-rototilling operation, the tillage depth is deeper than 80 mm, the soil-crushing rate （length of soil block less than 40 mm） is over 50 %, and the vegetation coverage rate is over 55 %. For stubble-breaking operation, the stubble-breaking depth is deeper than 70 ram, the stubble-breaking rate （length of stubble less than 40 mm） is over 60%, and the stubble coverage rate is over 80%, which can meet the stubble-breaking requirement of corn.

摘要：The serrated incisors of grasshopper [Chondracris rosea rosea （De Geer）] possess an advantageous capacity for cutting plant fiber. Inspired by this special geometrical structure of incisors, bionic saw blade was designed and manufactured. MATLAB software digital image processing technology was used to obtain outer margin profile from stereomicroscope pho- tograph of the serrated incisors. The outer margin profile of incisors was fitted and expressed by six-order polynomial function. To compare the cutting capacity of bionic and traditional saw blades, the internodes of dry corn stalks were cut perpendicularly. Cutting force-deformation characteristics were obtained by universal testing machine. The results of cutting experiments show that the maximum cutting force of bionic saw blade was 128.26 N, which is 15.87% lower than 152.45 N of traditional saw blade; the average cutting force of bionic saw blade was 51.56 N, which is 28.17% less than 71.78 N of traditional saw blade. Meanwhile, the cutting energy consumption of bionic saw blade was 8.95 J, which is 12.85% less than 10.27 J of traditional saw blade. Overall, the bionic saw blade can lead to noticeable reduction of the cutting force and energy. These results will be helpful for designing cutting elements of corn stalk harvesting, biomass size reduction and other processing machinery.

摘要：Mole rat （Scaptochirus moschatus）, a soil-burrowing mammal, can efficiently dig soil using its fore claws. The profile curves of its claw toe provide excellent structure for digging. In this paper, a biomimetic stubble-cutting disc was designed by learning from the geometrical characteristics of the mole rat claw toes. To compare the structural strength and working eff^- ciency of the biomimetic disc and the conventional stubble-cutting disc, three-dimensional （3D） models of the discs were built and numerical analyzed in ABAQUS. In the dynamic soil cutting model, soil was modeled as an elastic-plastic material with elastic parameters, including Young＇s modulus, Poisson＇s ratio and Drucker-Prager criterion, which were obtained from triaxial tests. A general contact algorithm was used to simulate the interaction between rotary disc and soil. In FEA models, for the combined action of normal and friction stresses, the stress on the biomimetic disc is 34.33% lower than that of the conventional disc. For only the normal stress, the stress on the biomimetic disc is 22.64% lower than that on the conventional one. The magnitude of soil stress in biomimetie disc cutting model is 6.87% higher than that in conventional disc. The FEA results indicate that the biomimetic disc performs better in structural strength and cutting efficiency.

摘要：Molecular simulations are widely used to model molecularly imprinted polymers(MIPs)in order to enliance their adsorption and *** this study,chloramphenicol(CAP)and acrylamide(AM)were used as the template and flinctional monomer,respectively,and pentaenlhritol triacrylate(PETA),ethylene glycol dimethacrylate(EGDMA),and trimethvlolpropane trimethvlacrylate(TRIM)were used as cross-linking *** 6oB97XD/6-31 density functional theory method was employed to simulate binding sites,binding energy,the number of hydrogen bonds,the imprinted molar ratio,which produced the most stable complex,and the interaction *** cross-linking agent was optimized based on the binding *** atoms in molecules theory were used to study the nature of the imprinting *** theoretical calculations revealed that CAP and AM fonned ordered complexes via hydrogen bonding interactions when the molar ratio between CAP and AM was 1:7 using TRIM as the cross-linking *** CAP-AM complex(molar ratio 1:7)had the most stable structure,the largest number of hydrogen bonds,and the smallest *** experimental results indicate that the CAP-MIPs ionncd perfect microspheres with an average particle size of 314 *** chard plot analysis showed that the CAP-MIPs had only one type of binding site over thestudied concentration *** dissociation equilibriinn constant and maximum apparent adsorption capacities were 1887.35 mg/L(5.84 mmol/L)and 155.56 mg/g(0.482 mmol/g),respectively.

摘要：The blocking between two snapping rollers will seriously constrict the harvesting efficiency for corn harvester.A variable screw pitch rib snapping roller was developed to solve this *** comparative experiment between fixed screw pitch rib snapping rollers and variable screw pitch rib snapping rollers illustrated that variable screw pitch ribs can avoid corn-stalk blocking effectively,and it can improve working efficiency by 56.7%.Conservation tillage with standing corn residue was testified that it had a strong control of soil wind *** order to implement this mode of conservation tillage at a production scale,a cutter was developed in this ***,two experiments were conducted,one was to test the cutting ratio(defined as the totally cut off stalk population divided by total stalk population),and the other one was to test standing-residue *** experiment results showed that the mean cutting ratio increased significantly(p<0.05)along with increasing height of cutter-head above the ground(cutting height);the cutting ratio’s mean value increased significantly(p<0.05)along with the decreasing angle between the cutter-head and the ground(cutting angle).The average standing-residue height increased along with the increase of cutting height from 300 mm to 500 *** average standing-residue height increased significantly(p<0.05)along with the decrease of cutting angle from 15°to 0°.Therefore,the newly designed snapping roller can improve the harvesting efficiency and prolong the working life of the cutting table;and the cutter can promote the popularization of the conservation tillage with standing corn residue in Northeast China.