Study on Microstructures and Properties of Electro Brush-plating Composite Coatings

In this paper, composite coatings were prepared using improved electro brush-plating, and the possibility and feasibility of obtaining of composite coatings with various hard dispersion paticles (C^Os. SiC, ZrO, A^Ojetc.) were studied.The microstructure, constitution, microhardness and wear resistance were examined. The results show that.electro brush-plating composite coatings have finner microstructures and higher microhardness and wear-resistance than ordinary electro brush-plating coatings.The research results can be used in repairing and surface strengthening of worn machine parts,and have practical uses.

Research on the Development of Fibroin and Nano-Fiber from Silk Cocoons for Regenerated Tissue Engineering Applications by Electro-Spinning

In this paper, the main goal is to prepare silk fibroin nano-fiber, which is used for regenerated tissue applications. Silk scaffold nano-fibers made by electro-spinning technology can be used in regenerated tissue applications. The purpose of the research is to prepare a silk-fibroin nano-fiber solution for potential applications in tissue engineering. Using a degumming process, pure silk fibroin protein is extracted from silk cocoons. The protein solution for fibroin is purified, and the protein content is determined. The precise chemical composition, exact temperature, time, voltage, distance, ratio, and humidity all have a huge impact on degumming, solubility, and electro-spinning nano-fibers. The SEM investigates the morphology of silk fibroin nano-fibres at different magnifications. It also reveals the surface condition, fiber orientation, and fiber thickness of the silk fibroin nano-fiber. The results show that regenerated silk fibroin and nano-fiber can be used in silk fibroin scaffolds for various tissue engineering applications.

Preclinical Verification of Modulated Electro-Hyperthermia —Part I. In Vitro Research

Modulated electro-hyperthermia (mEHT) targets tissue’s natural electric and thermal heterogeneities to heat the cancer cells selectively. The applied 13.56 MHz radiofrequency (RF) is a carrier of the low-frequency modulation. The high-frequency part was chosen to select the malignant lesion using the specialties of the tumor: the higher conductivity and dielectric constant of the tumor than its host. The electric field selects the tumor, and the low-frequency amplitude modulation polarizes and excites the transmembrane proteins of the malignant cells. The dominant absorption of the energy by the microscopic clusters of the membrane rafts acts like nanoparticle heating. Exciting the membrane produces various apoptotic signals. The processes were modeled using silico and phantom experiments, which proved the concept. The preclinical verification was made in vitro and in vivo, and in the end, clinical proofs validated the method. Our objective is to follow all the development steps from the laboratory to the clinics in a trilogy of articles. This present is the first part, which deals with in silico, phantom, and in vitro research.

Multiscale Finite Element Method for Coupling Analysis of Heterogeneous Magneto-Electro-Elastic Structures in Thermal Environment

Magneto-electro-elastic (MEE) materials, a new type of composite intelligent materials, exhibit excellent multifield coupling effects. Due to the heterogeneity of the materials, it is challenging to use the traditional finite element method (FEM) for mechanical analysis. Additionally, the MEE materials are often in a complex service environment, especially under the influence of the thermal field with thermoelectric and thermomagnetic effects, which affect its mechanical properties. Therefore, this paper proposes the efficient multiscale computational method for the multifield coupling problem of heterogeneous MEE structures under the thermal environment. The method constructs a multi-physics field with numerical base functions (the displacement, electric potential, and magnetic potential multiscale base functions). It equates a single cell of heterogeneous MEE materials to a macroscopic unit and supplements the macroscopic model with a microscopic model. This allows the problem to be solved directly on a macroscopic scale. Finally, the numerical simulation results demonstrate that compared with the traditional FEM, the multiscale finite element method (MsFEM) can achieve the purpose of ensuring accuracy and reducing the degree of freedom, and significantly improving the calculation efficiency.

Morphology and tribological properties of Ni/n-SiO_2 composite coatings by pulse-reverse current brush-plating

Ni/n-SiO2 composite coating was electrodeposited by brush-plating with pulse-reverse current（RC）. The morphology, hardness, and tribological properties of the coating were investigated and compared with those of Ni and composite coatings electrodeposited with direct current（DC）. The results indicate that Ni/n-SiO2 composite coating electrodeposited by RC, because of RC and the nano powders, has denser coating, finer crystal grains, higher hardness（HV650.0, nearly 1.5 times higher than that of Ni coating electrodeposited by DC） and lower friction coefficient（nearly 0.62）, as a result, in the wearing experiment, the Ni/n-SiO2 composite coating electrodeposited by RC has the least worn loss. So this kind of coating has better wear resistance. And RC electro brush-plating can be used as a new technology of brush-plating in the area of wear resistance.

Automatic brush-plating technology for component remanufacturing

An automatic brush-plating system was developed for component remanufacturing. With this system, Ni/nano-alumina composite coatings from an electrolyte containing 20g/L nano-alumina particles were prepared. Microstructure, surface morphology, microhardness and wear resistance of automatically plated coatings and manually plated coatings were investigated comparatively. The results show that the automatically plated coatings are relatively dense and uniform and have lower friction coefficient of 0.089 under lubricant condition, when compared with manually plated coatings with friction coefficient of 0.14.

Noncovalent interactions on the electrocatalytic oxidation of ethanol on a Pt/C electrocatalyst

Due to their environmentally friendly nature and high energy density,direct ethanol fuel cells have attracted extensive research attention in recent decades.However,the actual Faraday efficiency of the ethanol oxidation reaction(EOR)is much lower than its theoretical value and the reaction kinetics of the EOR is sluggish due to insufficient active sites on the electrocatalyst surface.Pt/C is recognized as one of the most promising electrocatalysts for the EOR.Thus,the microscopic interfacial reaction mechanisms of the EOR on Pt/C were systematically studied in this work.In metal hydroxide solutions,hydrated alkali cations were found to bind with OH_(ad)through noncovalent interactions to form clusters and occupy the active sites on the Pt/C electrocatalyst surface,thus resulting in low Faraday efficiency and sluggish kinetics of the EOR.To reduce the negative effect of the noncovalent interactions on the EOR,a shield was made on the electrocatalyst surface using 4-trifluoromethylphenyl,resulting in twice the EOR catalytic reactivity of Pt/C.

STUDY ON THE WEAR CHARACTERISTICS OF Ni-P BRUSH-PLATING COATING

This paper studied the wear characteristics as well as the wear mechanism of the Ni-P alloy brush-plating coating by means of sliding-wear tests, SEM and X Ray analyses. The results show that Ni-Palloy coating has excellent wear-ability in high temperature, and the wear mechanism of the coating is that both the adhesive wear and abrasive wear exist in a boundary lubrication condition. The wear model was built up.

Improved Electro Search Algorithm with Intelligent Controller Control System:ESPID Algorithm

Studies have established that hybrid models outperform single models.The particle swarm algorithm(PSO)-based PID(proportional-integral-derivative)controller control system is used in this study to determine the parameters that directly impact the speed and performance of the Electro Search(ESO)algorithm to obtain the global optimum point.ESPID algorithm was created by integrating this system with the ESO algorithm.The improved ESPID algorithm has been applied to 7 multi-modal benchmark test functions.The acquired results were compared to those derived using the ESO,PSO,Atom Search Optimization(ASO),and Vector Space Model(VSM)algorithms.As a consequence,it was determined that the ESPID algorithm’s mean score was superior in all functions.Additionally,while comparing the mean duration value and standard deviations,it is observed that it is faster than the ESO algorithm and produces more accurate results than other algorithms.ESPID algorithm has been used for the least cost problem in the production of pressure vessels,which is one of the real-life pro-blems.Statistical results were compared with ESO,Genetic algorithm and ASO.ESPID was found to be superior to other methods with the least production cost value of 5885.452.

The decisive role of adsorbed OH^(*)in low‐potential CO electro‐oxidation on single‐atom catalytic sites

CO impurity-induced catalyst deactivation has long been one of the biggest challenges in proton-exchange membrane fuel cells,with the poisoning phenomenon mainly attributed to the overly strong adsorption on the catalytic site.Here,we present a mechanistic study that overturns this understanding by using Rh-based single-atom catalysis centers as model catalysts.We precisely modulated the chelation structure of the Rh catalyst by coordinating Rh with C or N atoms,and probed the reaction mechanism by surface-enhanced Raman spectroscopy.Direct spectroscopic evidence for intermediates indicates that the reactivity of adsorbed OH^(*),rather than the adsorption strength of CO^(*),dictates the CO electrocatalytic oxidation behavior.The RhN_(4)sites,which adsorb the OH^(*)intermediate more weakly than RhC4 sites,showed prominent CO oxidation activity that not only far exceeded the traditional Pt/C but also the RhC4 sites with similar CO adsorption strength.From this study,it is clear that a paradigm shift in future research should be considered to rationally design high-performance CO electro-oxidation reaction catalysts by sufficiently considering the water-related reaction intermediate during catalysis.

滚仰式光电吊舱地理导引实现与误差分析

为了提升地理导引精度和成功率,根据滚仰式光电吊舱的结构特点,通过建立坐标系统、目标坐标求解和框架角解算三个步骤,完整构建了地理导引的数学模型,并在此基础上引入了速度前馈和小区域搜索模式。同时,对受惯导测量误差和目标距离影响的框架角解算误差进行了数据仿真。结果表明:经纬误差和航向角误差对俯仰角的解算误差影响较大;而高程误差和水平姿态角误差则对横滚角的解算误差影响较大。提升惯导的定位精度,可进一步减小框架角解算误差,从而提升地理导引精度,而当航向角<0.1°,水平姿态角<0.05°时,姿态角误差的影响权重会变小,再通过减小姿态角误差提升导引精度的作用已不明显。随着目标距离的增大,框架角解算误差会急剧减小。最后进行了导引试验,其俯仰、横滚角均方差均小于0.12°,表明了算法的准确性和仿真分析的有效性。

基于DDS的数字脉冲电火花沉积电源研究

在电火花沉积加工中,脉冲电源的放电参数对沉积效果和加工效率有重要影响。针对传统电火花沉积电源放电参数可控性差的问题,基于直接数字频率合成(DDS)技术全数字化调制、输出稳定的特性,设计了一种数字脉冲电火花沉积电源。以单片机和DDS芯片为核心来控制斩波电路输出加工脉冲,可实现放电电压、频率等参数的较精确控制以及宽范围内的无极调节。经测试,控制及驱动模块输出信号稳定、准确且频率误差在1 Hz以内,放电电压波形可控性好,满足电火花沉积加工的要求,可用于电火花沉积加工基础研究。

三维Electro-Hydrodynamics方程组光滑解的延拓准则

研究了三维Electro-Hydrodynamics方程组局部光滑解的延拓准则,利用负指标Besov空间中的对数Sobolev不等式和Kato-Ponce交换子估计方法,在Besov空间中获得了只涉及速度场水平分量的最优延拓准则,改进和推广了已有关于Electro-Hydrodynamics方程组正则性准则的部分结论,是Electro-Hydrodynamics方程组正则性理论的有益补充。

BDD电催化耦合电解析处理载人航天器中冷凝废水的研究

为解决在硼掺杂的金刚石电极(BDD)电催化处理冷凝废水中,由于冷凝废水电导率低而导致处理能耗较高的问题,提出了BDD电催化耦合电解析的新方法处理冷凝废水。在BDD反应器内填充吸附有无机盐的混合阴阳离子交换树脂,电催化处理冷凝废水时吸附在树脂上的离子在电场作用下解析下来进入废水中,并进行交替的吸附、解析及定向运动,从而改善废水的导电性,电极两端电压显著降低,停止加电后,离子又能重新交换吸附在树脂上。以Na_(2)SO_(4),Na_(3)PO_(4)以及NaNO_(3)作为电解质时,对总有机碳(TOC)去除没有影响;而以NaCl作为电解质时,TOC去除率随着NaCl添加量的增加而降低。

负载型三维电极-电Fenton法处理活性艳橙X-GN废水

三维电极-电Fenton法是一种在电Fenton的基础上引入三维电极电催化技术的新型高级氧化法,在水处理中得到了广泛的应用。用过量浸渍煅烧法制备负载型三维电极,以采用该电极的三维电极-Fenton法处理活性艳橙X-GN废水。通过试验研究了pH、电压、Na_(2)SO_(4)投加量、Fe^(2+)投加量对处理效果的影响,并采用响应曲面法最优化实验条件。结果表明,当试验pH=4.7,电压为20.39 V,Na_(2)SO_(4)投加量为2.13 g/L,Fe^(2+)投加量为2.5 mmol/L时,COD和色度去除率可以达到85.41%和92.18%。负载型三维电极-电Fenton法对活性艳橙X-GN废水的色度和COD均具有较理想的处理效果。

电针对硝酸甘油致偏头痛小鼠疼痛行为及三叉神经血管系统的影响

目的观察电针对硝酸甘油致偏头痛小鼠疼痛行为及三叉神经血管功能的影响,探讨其可能作用机制。方法将20只C57BL/6雄性小鼠随机分为对照组、模型组、假针组、电针组,每组5只。除对照组外,其余组小鼠于实验第1,3,5,7,9,11,13天给予10 mg/kg硝酸甘油腹腔注射建立慢性偏头痛模型。在每次注射后30 min,电针组和假针组进行电针干预。实验当天(第0天)注射前及实验第2,4,6,8,10,12,14天分别检测小鼠眶周机械痛阈及后足机械痛阈、热痛痛阈;实验第14天,采用ELISA法检测血清一氧化氮(NO)和降钙素基因相关肽(CGRP)水平,采用免疫荧光和Western blot法检测三叉神经节中c-Fos蛋白表达情况。结果实验第6,8,10,12,14天,模型组小鼠的眶周机械刺激反应评分均明显高于同期对照组(P均<0.05);实验第10,12,14天,电针组小鼠的眶周机械刺激反应评分均明显低于同期模型组(P均<0.05),且电针组小鼠实验第12,14天的眶周机械刺激反应评分均明显低于同期假针组(P均<0.05)。实验第8,10,12,14天,模型组小鼠的后足50%撤退阈值均明显低于同期对照组(P均<0.05),后足热痛撤退潜伏期均明显短于同期对照组(P均<0.05);实验第10,12,14天,电针组小鼠的后足50%撤退阈值均明显高于同期模型组(P均<0.05),后足热痛撤退潜伏期均明显长于同期模型组(P均<0.05),且电针组小鼠实验第12,14天的后足50%撤退阈值明显高于同期假针组(P均<0.05),后足热痛撤退潜伏期均明显长于同期假针组(P均<0.05)。模型组小鼠血清NO、CGRP水平和三叉神经节中c-Fos阳性表达平均光密度、c-Fos蛋白相对表达量均明显高于对照组(P均<0.05),而电针组各指标均明显低于模型组(P均<0.05)。结论电针能明显改善硝酸甘油致慢性偏头痛小鼠的疼痛行为,其可能是通过降低血清NO、CGRP水平及三叉神经敏化蛋白c-Fos的表达,从而改善三叉神经血管功能障碍实现的。

环境化学条件对软土电渗排水影响的试验研究

电渗排水在软土地基加固方面具有较大的应用前景。为研究土体环境化学条件对软黏土电渗排水过程的影响,开展了一系列室内试验,从电渗系数、排水量、排水速率、含水率分布等方面进行了对比分析,深入探讨土体pH值和盐度对电渗排水过程的影响机理。试验结果表明:土体pH值对土体的电渗系数和zeta电位均有明显影响,电渗系数随着pH值的升高而升高,通过测量zeta电位可以准确获取电渗系数;随着土体初始pH值的升高,电渗排水试验后阳极附近土体的含水率逐渐降低,阴极附近土体的含水率逐渐升高;在对较酸性土体的电渗试验中则出现了阴极附近土体排水固结较快的现象,对土体的整体排水过程产生不利影响;随着土体盐度的升高,电渗系数和电渗总排水量降低,能耗增大。低盐度、偏碱性的环境有利于提高电渗加固效果。

基于改进EMD和ARMA的MEMS陀螺仪随机误差补偿方法

微机电系统(Micro-Electro-Mechanical System,MEMS)陀螺仪的随机误差限制了其测量精度。为了降低MEMS陀螺仪的随机误差,提出一种基于改进的经验模态分解(Empirical Mode Decomposition,EMD)和优化的自回归滑动平均(Autoregressive Moving Average,ARMA)模型的方法。该方法在传统EMD的基础上,结合Hausdorff距离和累积标准化模态均值以提取信号中的噪声和趋势项,对剩余信号进行ARMA建模和滤波。采用沙猫群优化算法优化建模的定阶过程,采用改进的自适应滤波补偿随机误差。试验结果表明:相较于传统EMD和传统ARMA方法,新方法在静态试验中得到的均方根误差分别降低52.5%和34.4%,在动态试验中得到的均方根误差分别降低50%和32.35%;新方法有效抑制了随机误差,提升了MEMS陀螺仪的使用精度。

电缆终端应力锥错位缺陷对界面温度及应力分布的影响

电缆终端内部缺陷会造成终端内部电场分布不均、局部温度升高与应力分布变化,可能引发局部放电造成绝缘击穿。为研究终端应力锥错位缺陷对电缆界面温度及应力分布的影响,分别建立了电缆终端安装不足与安装过盈情况下的电缆终端错位缺陷模型,并进行电-热-力多物理场耦合仿真分析。结果表明:电缆终端绝缘屏蔽层截断处是电缆终端的薄弱部位,终端界面温度和界面压力都会在绝缘屏蔽层截断处发生突变。当电缆终端存在安装不足缺陷时,终端屏蔽层截断处与应力锥根部之间会出现电场升高区域,在安装位置为-7.5 mm时界面温度最高,绝缘界面压力值升高,且安装位置为-2.5mm时绝缘承受的压力值最大;当电缆终端存在安装过盈缺陷时,绝缘屏蔽层截断处会发生电场畸变,电场突变量随着偏移量的增加而增大,在安装位置为+5.0mm时绝缘界面压力值最大,且界面压力突变量增加发生畸变。因此,在电缆终端实际设计安装与运行维护中,额外注意应力锥错位缺陷对终端内部应力分布的影响十分必要。

基于可逆固体氧化物电池的电氢耦合微电网全生命周期规划-运营研究

为促进实现“双碳”目标,新能源将成为未来能源供应的主体。考虑到高比例新能源对电力系统容量规划和调度运营带来的巨大挑战以及电氢能源需求量的持续增长对电力系统的影响,以微电网为研究对象,设计基于可逆固体氧化物电池的考虑源荷不确定性的电氢耦合微电网全生命周期规划-运营优化模型及其求解算法。首先,针对风光产电、电氢负荷等多种不确定因素,设计包含微电网全生命周期内各年份不同典型日的数据,以构成随机场景。其次,对电氢耦合微电网容量规划成本、全生命周期调度运营成本以及新能源年均渗透率等多个优化目标进行数学表达,并对各发电机组、可逆固体氧化物电池以及储氢库的规划-运营约束进行线性描述。然后,设计一种改进的增广ε约束算法求解模型的Pareto解集,并提出一种平衡决策方法从解集中获取最佳规划-调度方案。最后,仿真结果表明,所提方法能均衡各优化目标,在保证新能源高渗透率的同时提升电氢耦合微电网的可靠性以及规划-运营经济性。