Mn,P共掺杂MoS_(2)微米花的制备及其电解水析氢性能

提出一种阴、阳离子共掺杂策略,采用一步水热法成功制备Mn,P共掺杂的MoS_(2)微米花(Mn,P)-MoS_(2)析氢电催化剂。通过X射线衍射、拉曼光谱、扫描电子显微镜、X射线能谱和X射线光电子能谱等方法对(Mn,P)-MoS_(2)的结构、形貌、成分及化合价态进行表征,并使用电化学工作站对其电解水析氢性能进行测试。结果表明:Mn,P原子被成功掺入MoS_(2)晶格中;(Mn,P)-MoS_(2)在电流密度为10 mA·cm^(-2)时的析氢过电位为235 mV,塔菲尔斜率为61.2 mV·dec^(-1),远低于纯MoS_(2)及单一的Mn或P掺杂MoS_(2),具备良好的析氢稳定性。(Mn,P)-MoS_(2)具有优异的析氢性能可归因于:Mn,P的掺入激活MoS_(2)的惰性基面,优化MoS_(2)的电子结构,提升其电导率,且Mn,P的协同作用实现单一阴离子或阳离子掺杂的互补优势,增加面内析氢活性位点的数目,加快Volmer电化学吸附步骤的进行。

Resonance and Bifurcation of Fractional Nonlinear Systems with Power Damping Term for Robot Grinding

A fractional nonlinear system with power damping term is introduced to study the forced vibration system in order to solve the resonance and bifurcation problems between grinding wheel and steel bar during robot grinding.The robot,grinding wheel and steel bar are reduced to a spring-damping second-order system model.The implicit function equations of vibration amplitude of the dynamic system with coulomb friction damping,linear damping,square damping and cubic damping are obtained by average method.The stability of the system is analyzed and explained,and the stability condition of the system is proposed.Then,the amplitude-frequency characteristic curves of the system under different fractional differential orders,nonlinear stiffness parameters,fractional differential term coefficients and external excitation amplitude are analyzed.It is shown that the fractional differential term in the dynamic system is the damping characteristic.Then the influence of four kinds of damping on the vibration amplitude of the system under the same parameter is investigated and it is proved that the cubic damping suppresses the vibration of the system to the maximum extent.Finally,based on the idea that the equilibrium point of the system is the constant part of the Fourier series expansion term,the bifurcation behavior caused by the change of damping parameters in linear damping,square damping and cubic damping systems with different values of fractional differential order is investigated.

Dynamic Analysis and Dimensional Synthesis of Easy-to-Protect Large-Load Robot for Extracting Fermented Grains

To improve the operation situation of difficulty and low efficiency in the extraction of fermented grains(FG),a high-load and large-workspace reclaiming robot for ceramic cylinder fermentation is designed,and a reclaiming effector is designed according to the operating characteristics.Firstly,the kinematics and singularity of the mechanism are analyzed.A multi-domain polar coordinate search method is proposed to obtain the workspace and the volume of the mechanism.Secondly,the dynamic modeling is completed and the example simulation is carried out.Thirdly,the motion-force transmission index of the mechanism is established.And based on the global transmissibility and the good-transmission workspace,the dimensional synthesis of the driving mechanism is completed by using the performance atlas-based method.Finally,aiming at the regular workspace size,stiffness and loading capacity,the Pareto optimal solution set of the executive mechanism dimension is obtained by using the multi-objective particle swarm optimization(MOPSO)algorithm.This paper can provide a theoretical basis for the optimal design and control of FG reclaiming robot.

MobileNetV3-CenterNet:A Target Recognition Method for Avoiding Missed Detection Effectively Based on a Lightweight Network

To solve the problems in online target detection on the embedded platform,such as high missed detection rate,low accuracy,and slow speed,a lightweight target recognition method of MobileNetV3-CenterNet is proposed.This method combines the anchor-free Centernet network with the MobileNetV3 small network and is trained on the University at Albany Detection and Tracking(UA-DETRAC)and the Pattern Analysis,Statical Modeling and Computational Learn-ing Visual Object Classes(PASCAL VOC)07+12 standard datasets.While reducing the scale of the network model,the MobileNetV3-CenterNet model shows a good balance in the accuracy and speed of target recognition and effectively solves the problems of missing detection of dense and small targets in online detection.To verify the recognition performance of the model,it is tested on 2683 images of the UA-DETRAC and PASCAL VOC 07+12 datasets,and compared with the analysis results of CenterNet-Deep Layer Aggregation(DLA)34,CenterNet-Residual Network(ResNet)18,CenterNet-MobileNetV3-large,You Only Look Once vision 3(YOLOv3),MobileNetV2-YOLOv3,Single Shot Multibox Detector(SSD),MobileNetV2-SSD and Faster region convolutional neural network(RCNN)models.The results show that the MobileNetV3-CenterNet model accurately rec-ognized the dense targets and small targets missed by other methods,and obtained a recognition accuracy of 99.4%with a running speed at 53(on a server)and 14(on an ipad)frame/s,respectively.The MobileNetV3-CenterNet lightweight target recognition method will provide effective technical support for the target recognition of deep learning networks in embedded platforms and online detection.

Contrast Enhancement Using Weighted Coupled Histogram Equalization with Laplace Transform

Histogram equalization is a traditional algorithm improving the image contrast,but it comes at the cost of mean brightness shift and details loss.In order to solve these problems,a novel approach to processing foreground pixels and background pixels independently is proposed and investigated.Since details are mainly contained in the foreground,the weighted coupling of histogram equalization and Laplace transform were adopted to balance contrast enhancement and details preservation.The weighting factors of image foreground and background were determined by the amount of their respective information.The proposed method was conducted to images acquired from CVG⁃UGR and US⁃SIPI image databases and then compared with other methods such as clipping histogram spikes,histogram addition,and non⁃linear transformation to verify its validity.Results show that the proposed algorithm can effectively enhance the contrast without introducing distortions,and preserve the mean brightness and details well at the same time.

Comparative Analysis on Policy Realization of Old and New Rural Social Endowment Insurance System

Based on the perspective of"political potential"and"incentive mechanism",this paper compares the different effects of the old rural social endowment insurance system and the new rural social endowment insurance system,so as to explain the policy realization degree of the old and new rural social endowment insurance system.According to the analysis,the new rural social endowment insurance system has greatly improved the implementation of policies,the implementation of policies,the overall planning ability between departments,and the enthusiasm of individual farmers to participate in the insurance.Compared with the old rural social endowment insurance system,the policy realization ability of the new rural social endowment insurance system has been significantly enhanced,and the effect of the policy realization has been significantly improved.

Research on Bionic Jumping and Soft Landing of Single Leg System in Quadruped Robot

This paper proposed a novel multi-motion wheel-leg-separated quadruped robot that can adapt to both the structured and unstructured grounds.The models of the positive/inverse position,velocity,acceleration,and workspace of the single leg mechanism in the quadruped robot were established.A single leg complex dynamic model of the quadruped robot is derived,considering the mass and inertial force of all the components in the mechanical leg.Combined with the human jumping law in situ,the jumping trajectory of the single leg was planned.To reduce landing impact,a soft landing strategy based on motion planning was proposed by simulating human knee bending and buffering action.The change law of the kinetic energy and momentum of all the links in the single leg mechanism during the jump process was studied,and the influencing factors of jump height were analyzed to realize the height control of the jump.Single leg jumping dynamics model was established,and a dynamic control strategy for trajectory tracking with foot force compensation was proposed.In Adams and MATLAB/Simulink software,the jump simulation of single leg mechanism was carried out.The prototype of quadruped robot was developed,and the jumping experiment of the single leg mechanism was tested.The robot's single leg bionic jumping and soft landing control are realized.

IRVAN全视网膜光凝后视网膜有髓神经纤维渐进性消退一例

患者,女,37岁,因右眼视力下降1个月,于2017年7月13日来南昌大学第二附属医院就诊,眼科检查:右眼视力0.6,左眼视力0.8,双眼矫正视力无提高;右眼眼压15 mmHg(1 mmHg=0.133 kPa),左眼眼压16 mmHg,裂隙灯显微镜检查双眼前节未见明显异常,右眼下方见絮状玻璃体积血,左眼玻璃体未见异常。眼底镜检查示双眼视盘轻度充血,边界欠清,后极部视网膜动脉见多个动脉瘤,其中右眼颞下方见大片视网膜前出血;左眼视盘上、下方可见羽状视网膜有髓神经纤维(见图1)。眼底荧光血管造影(FFA)显示双眼视盘表面血管扩张并荧光素渗漏,视网膜动脉管径细窄,多处视网膜动脉瘤样扩张,中周部视网膜血管闭塞,中周部交界处毛细血管扩张并荧光素渗漏。