An aqueous BiI_(3)-Zn battery with dual mechanisms of Zn^(2+)(de)intercalation and I^(-)/I_(2)redox

The development of aqueous battery with dual mechanisms is now arousing more and more interest.The dual mechanisms of Zn^(2+)(de)intercalation and I^(-)/I_(2)redox bring unexpected effects.Herein,differing from previous studies using Zn I_(2)additive,this work designs an aqueous Bi I_(3)-Zn battery with selfsupplied I^(-).Ex situ tests reveal the conversion of Bi I_(3)into Bi(discharge)and Bi OI(charge)at the 1st cycle and the dissolved I^(-)in electrolyte.The active I^(-)species enhances the specific capacity and discharge medium voltage of electrode as well as improves the generation of Zn dendrite and by-product.Furthermore,the porous hard carbon is introduced to enhance the electronic/ionic conductivity and adsorb iodine species,proven by experimental and theoretical studies.Accordingly,the well-designed Bi I_(3)-Zn battery delivers a high reversible capacity of 182 m A h g^(-1)at 0.2 A g^(-1),an excellent rate capability with 88 m A h g^(-1)at 10 A g^(-1),and an impressive cyclability with 63%capacity retention over 20 K cycles at 10 A g^(-1).An excellent electrochemical performance is obtained even at a high mass loading of 6 mg cm^(-2).Moreover,a flexible quasi-solid-state Bi I_(3)-Zn battery exhibits satisfactory battery performances.This work provides a new idea for designing high-performance aqueous battery with dual mechanisms.

Kinematics and dynamics analysis of a 3-7R parallel decoupling mechanism

One kind of movable-pair analysis method is adopted to analyze the configuration of a 3-7R （revolute-pair） parallel decoupling mechanism, and the mechanism＇s characteristics are summarized. The mechanism has three orthogonal distributional branch-chains, and all movable pairs are rotational joints. The movable platform of the mechanism has x, y, z translational decoupling directions. Furthermore, in order to verify the mechanism＇s decoupling characteristics, the mechanism＇s kinematics analysis is solved, and the mechanism＇s direct/inverse kinematics model, input/output velocities and accelerations are deduced, which confirm its decoupling movement characteristics. Finally, one kind of mechanism link decomposed-integrated approach is adopted, and the mechanism＇s dynamics model is completed with the Lagrange method, which also proves its decoupling force characteristics. All of these works provide significant theory for the further study of the mechanism＇s control strategy, design, path planning etc.

基于SimMechanics的高速3-RRR并联机构动力学分析与控制

为了满足3-RRR并联机构在工业应用中高速操作,研究其在高速运动中的动力学行为和控制。采用SimMechanics建立3-RRR并联机构的动力学模型,基于该模型对其进行动力学分析。分析结果表明,速度越大,驱动力矩也越大;机构高速运行过程中驱动力矩变化大,且在某些时刻产生突变致使机构产生较大冲击。为了实现高速运动跟踪控制,利用PID控制的鲁棒性,设计PID控制器。仿真结果表明,动平台能较好地实现期望的轨迹,但在初始阶段,存在一定的跟踪误差。

Theoretical Study on the Reaction Mechanism of 2-Methoxybenzaldehyde,4-Bromo-indanone,Malononitrile and Ammonium Acetate One-pot to Form 6-(2-Methoxyphenyl)-2-amino-6-bromo-5H-indeno[1,2-b]pyridine-3-carbonitrile

The reaction mechanism of 2-methoxybenzaldehyde, 4-bromo-indanone, malononitrile and ammonium acetate one-pot to form 6-（2-methoxyphenyl）-2-amino-6-bromo-5 Hindeno[1,2-b]pyridine-3-carbonitrile was studied by density functional theory. The geometries of the reactants, transition states, intermediates and products were optimized at the PW91/DNP level. Vibration analysis was carried out to confirm the transition state structure. Reaction pathways were investigated in this study. The result indicates that the reaction Re→ TSB1→IMB1→ TSB2→ IMB2→TSB3→IMB3→TSB4→IMB4→TSB5→IMB5→TSB6→IMB6→TSB7→IMB7→ TSB8→IMB8→TSB9→IMB9→P2 is the main pathway, the activation energy of which is the lowest. The dominant product predicted theoretically is in agreement with the experiment results.

基于正交试验的平面3-RRR机构输出灵敏度分析

轻型、高速、高精度平面柔性并联机构,被广泛应用于精密加工与测量及航天航空领域。通过对平面并联3-RRR机构进行逆运动学建模,以机构的基本构件参数为因素,建立了构件参数与输出参数的灵敏度函数关系模型。应用MATLAB软件对灵敏度函数关系模型进行了正交仿真分析,通过大量实验得到两组模拟结果。分析结果表明,构件参数对输出参数的影响方向及灵敏度方向具有一致性,有效验证了该灵敏度函数模型的正确性,为3-RRR机构的参数设计及误差补偿提供有效的参考依据。

3-RRR平面并联机构模糊PID控制虚拟仪器设计

平面3-RRR机构的运动精度问题严重制约着它在工程领域的应用.为有效提高该机构运动精度,基于模糊PID控制算法建立3-RRR平面并联机构运动误差实时控制系统,搭建机构运动误差控制实验平台,研制模糊PID控制系统的LabVIEW虚拟仪器软件以开展机构运动误差实时控制实验研究.结果表明:该系统可以实时控制机构运动误差,提高机构运动精度,且算法较为简单;开发的测控虚拟仪器软件具有界面友好、操作简单、灵活性强、功能易于扩展、智能化程度高等优点.

3-RRR平面并联机构模糊PID控制系统研究

平面并联机构以其优异的性能在工程领域得到广泛应用,为有效提高机构运动精度,提出了基于模糊PID控制算法的3-RRR平面并联机构实时控制方法。在分析模糊PID控制原理的基础上,建立3-RRR平面并联机构模糊PID控制系统模型,搭建机构控制实验装置,实验研究了机构运动精度的实时控制。结果表明,对3-RRR平面并联机构施加模糊PID控制后,机构角位移误差最大值为2.1°,降幅达53%以上;建立的模糊PID控制系统能够用于机构运动精度实时控制,有效降低机构角位移误差,算法简单,实时性较好。

3-RRR型并联机构运动学研究

针对3-RRR型并联机构的输入及输出构件间的位置关系展开研究.基于运动螺旋理论,分析了该机构的自由度性质,并确定了主动副的位置;建立了机构的逆运动学方程及正运动学方程,并对给定运动平台的位姿进行了数值计算,以验证所建立方程的正确性;研究了机构的运动解耦性以及运动平台的工作空间大小与连杆长度变化的关系;最后,对给定运动平台的运动方程下主动副的输出转角进行了数值仿真.

基于绝对节点坐标法的平面3-RRR并联机构动态特性研究

平面3-R R R并联机构的柔性杆在运动过程中产生的柔性变形会影响机构的输出精度。基于绝对节点坐标法,建立含有柔性杆、刚性动平台的平面3-R R R并联机构刚柔耦合模型,对并联机构的动态特性进行研究,获得并联机构各时刻的位姿和动平台质心运动轨迹。结果表明,柔性杆的弹性变形使动平台不能按照预期的轨迹运行。建立柔性杆局部坐标系,得到了柔性杆中点处挠度值,发现主动杆的弯曲变形远大于从动杆,柔性杆对机构输出精度的影响主要由主动杆产生。仿真结果可以为机构的设计和优化提供理论依据。

六自由度3-RRRS并联机器人机构位姿正逆解

提出一种六自由度 3RRRS并联机器人机构 ,建立了位姿正逆解的解析表达式 ,其中位姿正解有 4组 ,位姿逆解有 8组 .

基于3-RRRS机构的新型并联机床构型及运动建模

提出了一种基于3-RRRS机构的并联机床构型。RRRS是由3个R副和1个S副组成的支链。3-RRRS机构在上下平台之间连接移动平台,实现移动平台相对于下平台的六维运动;安装在移动平台上的动力头完成机床的加工操作。RRRS运动支链的每个R副配备1个驱动动力,共有3个驱动;整个运动支链系统有9个驱动,具有从属驱动特性,使并联机床具有较大的工作空间和较好的运动动态特性。首先,介绍了新型机床的模块化结构;其次,对基于3-RRRS机构的机床进行建模分析,给出了机床操作中各机构变量的运动和控制模型;最后,给出计算实例,并用运动仿真对计算结果进行了验证。相关工作为后续设备的实际使用提供了理论依据。

可重构单驱动3-RRR平面并联机构连杆曲线与姿态的数值解法

针对3自由度3-RRR平面并联机构驱动与控制复杂、能耗大的问题,利用平行四边形运动链将其约束为单驱动3-RRR平面并联机构。通过数值解法计算单驱动3-RRR平面并联机构的连杆曲线与姿态,并分析重构对连杆曲线与姿态的影响。基于Freudenstein方程推导该机构的输入-输出方程;采用迭代算法建立方程的数值求解方法;通过改变机构的初始输入角,提出一种机构构型的可重构方法。给出一组机构参数作为数值算例,求解得到机构的两种构型,称为构型Ⅰ和构型Ⅱ,以构型Ⅰ为算例,计算得到构型Ⅰ重构前后的连杆曲线与姿态随输入角变化的规律。结果表明:理论曲线与仿真曲线相吻合,验证了求解方法的正确性;重构能够显著改变构型Ⅰ连杆曲线与姿态。

平面3-■RR并联机构过约束分析及自调结构设计

分析了平面3-RRR三自由度并联机构中存在的过约束及其有害影响,详细讨论了在保证3-RRR并联机构平面运动特性的情况下无过约束自调结构的设计问题,得出了几种新的平面三自由度并联机构运动副配置方案,深入分析了2-RCS-RRR结构的自调特性。

Electron beam welding of Ti-15-3 titanium alloy to 304 stainless steel with copper interlayer sheet

Electron beam welding of Ti-15-3 titanium alloy to 304 stainless steel with a copper sheet as interlayer was carried out.Microstructures of the joint were studied by optical microscopy(OM),scanning electron microscopy(SEM) and X-ray diffractometry(XRD).In addition,the mechanical properties of the joint were evaluated by tensile test and the microhardness was measured.These two alloys were successfully welded by adding copper transition layer into the weld.Solid solution with a certain thickness was located at the interfaces between weld and base metal in both sides.Regions inside the weld and near the stainless steel were characterized by solid solution of copper with TiFe2 intermetallics dispersedly distributed in it.While weld near titanium alloy contained Ti-Cu and Ti-Fe-Cu intermetallics layer,in which the hardness of weld came to the highest value.Brittle fracture occurred in the intermetallics layer when the joint was stretched.

Numerical analysis of the failure process of soil-rock mixtures through computed tomography and PFC3D models

Soil-rock mixture （SRM） is a unique type of geomaterial characterized by a heterogeneous composition and a complicated structure. It is intractable for the continuum-based soil and rock mechanics theories to accurately characterize and predict the SRM＇s mechanical properties. This study reports a novel numerical method incorporating microfocus computed tomography and PFC3D codes to probe the deformation and failure processes of SRM. The three-dimensional （3D） PFC models that represent the SRM＇s complex structures were built. By simulating the entire failure process in PFC3D, the SRM＇s strength, elastic modulus and crack growth were obtained. The influence of rock ratios on the SRM＇s strength, deformation and failure processes, as well as its internal mesoscale mechanism, were analyzed. By comparing simulation results with experimental data, it was verified that the 3D PFC models were in good agreement with SRM＇s real structure and the SRM＇s compression process, deformation and failure patterns; its intrinsic mesomechanism can be effectively analyzed based on such 3D PFC models.

lncRNA-SNHG15 accelerates the development of hepatocellular carcinoma by targeting mi R-490-3p/histone deacetylase 2 axis

BACKGROUND Hepatocellular carcinoma(HCC)has become a great threat for people’s health.Many long noncoding RNAs are involved in the pathogenesis of HCC.SNHG15,as a tissue specific long noncoding RNAs,has been studied in many human cancers,except HCC.AIM To explore the regulatory mechanism of SNHG15 in HCC.METHODS In the present research,101 HCC patient samples,two HCC cell lines and one normal liver cell line were used.RT-qPCR and Western blot analysis were applied to detect SNHG15,miR-490-3p and histone deacetylase 2(HDAC2)expression.The regulatory mechanism of SNHG15 was investigated using CCK-8,Transwell and luciferase reporter assays.RESULTS Our research showed that up-regulation of SNHG15 was found in HCC and was related to aggressive behaviors in HCC patients.Moreover,knockdown of SNHG15 restrained HCC cell proliferation,migration and invasion.In addition,SNHG15 served as a molecular sponge for miR-490-3p.Further,miR-490-3p directly targets HDAC2.HDAC2 was involved in HCC progression by interacting with the SNHG15/miR-490-3p axis.CONCLUSION In conclusion,long noncoding RNA SNHG15 promotes HCC progression by mediating the miR-490-3p/HDAC2 axis in HCC.

DFT Thermodynamic Research of the Pyrolysis Mechanism of the Carbon Matrix PrecursorTol uene for Carbon Material

Based on the experiments, the standard enthalpy△H■of the possible pyrolysis reactions of the carbon matrix precursor toluene was investigated by means of DFT method UB3LYP/ 3-21G *(based on semi-empirical method UAM1 and ab initio method UHF/3-21G*). The com- putation results with UB3LYP/3-21G* coincide with the experimental values well. Then, the mechanism for all types of the pyrolysis reactions of toluene was studied by UB3LYP/3-21G * The geometries of the reactant and the product radicals were optimized, meanwhile, the standard thermodynamic parameters of the pyrolysis reaction at different temperatures (298, 773, 843, 963 and 1 073 K) were calculated. The thermodynamic computation result shows that when the pyrolysis temperature of toluene is lower than 963 K, the reaction path supported by thermody- namics is that the C-H bond of the methyl on the benzene ring breaks and bitoluene form, while the temperature increases (about 1 073 K), the thermodynamic calculation result turns to support the reaction path producing phenyl radicals and methyl radicals. This mechanism is in accord with the experiments.

WINDOWS和MATLAB7环境下平面3RRR并联机构位置姿态仿真

简单推导了一种平面3RRR并联机构输入和输出参数关系的理论公式,采用MATLAB编程语言编写了合理的该并联机构位置姿态参数的分析仿真程序,得出了求解该并联机构运动平台上位置输出点在可达工作空间内的灵活度的方法,提出了采用数据库管理方法来处理并联机构的位置姿态参数信息的可行性,充分的展现了W INDOW S编程的优势。

PREPARATION,CHARACTERIZATION AND HYDROGENATION PROPERTY OF POLYMER-SUPPORTED Pd-Fe_2O_3 COMPOSITE CATALYSTS

A series of polymer- supported Pd -Fe2O3 composite catalysts were prepared and their hydrogenation property mas investigated. It was found that the above catalysts have good catalytic hydrogenation activity for carbon - carbon double bonds systems and reusability. Furthermore, XPS and IR spectra shouted that active component in the composite catalysts is atomic Pd(0). An addition of a small amount of Fe2O3 has a promotive action upon hydrogenation activity of the catalysts, which indicated that there are some strong interactions (electron transfer) between Pd(0) and Fe(Ⅲ) species. Based on these results, a possible catalytic hydrogenation mechanism was also suggested.

Residue Upgrading in Slurry Phase over Ultra-fine NiMo/γ-Al_2O_3 Catalyst

In this article, residual oil hydroconversion was studied in slurry phase in the presence of fine solid Ni Mo/γ-Al2O3 catalyst and the effects of operating conditions were carefully studied. The results showed that residue conversion was only affected by the reaction temperature and reaction time. The coke yield increased with a higher reaction temperature, a bigger catalyst particle size, a longer reaction time, a lower initial hydrogen pressure and a lower catalyst concentration. Heteroatoms removal rate increased with a higher reaction temperature, a longer reaction time, a higher initial hydrogen pressure, a higher catalyst concentration, and a smaller catalyst particle size. The role of catalyst in the slurry bed technology was discussed and its function could be stated as follows: the metal was applied to activate the hydrogen atoms for removing heteroatoms and saturating aromatics, while the support of the catalyst was used to prevent the mesophase coalescence for reducing coke formation.