Nanomaterials possess distinct properties, including surface effect, volume effect, and quantum size effect, which present vast prospects for their application in the tribology field of resin matrix composites. To improve the comprehensive performance of 3D printed acrylic matrix composites, the modified zirconia nanoparticles (mZrO2) and boron nitride nanosheets (mBNNs) were assembled through the coordination bonding of lanthanum ions to prepare mBNNs-La-mZrO2 multidimensional nanoceramic reinforcements. The microscopic morphology and surface chemical properties of mBNNs-La-mZrO2 underwent characterization and testing through the utilization of transmission electron microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectrometry. Furthermore, the preparation mechanism was studied. The research delved into the examination of the friction and wear behavior of acrylic resin and its composites. Additionally, the friction mechanism of different samples was proposed. The study revealed that the multidimensional nanoceramic reinforcement exhibited high surface chemical activity and effectively synergized mZrO2 and mBNNs, resulting in enhanced antifriction and wear resistance of its composite. The composite reinforced by mBNNs-La-mZrO2 yielded superior outcomes compared to pure acrylic resin with a 20.62% reduction in friction coefficient and a 65.75% decrease in wear rate. Combined with the flexibility offered by 3D printing technology, the study presents a novel approach for creating acrylic resin as a material for denture frameworks.

This article studied the mechanism of the influence of light-curing 3D forming parameters of acrylic resin on its tribological and mechanical properties. A three-factor hybrid orthogonal table was designed, that is, the three key process parameters of printing monolayer thickness (P), heat treatment (H), and ultraviolet curing treatment (U). The priority of three process parameters affecting tribological performance was studied based on Gray Correlation Theory. The results showed that the order of priority was P, U, and H. The tribological and mechanical properties of acrylic resin decreased with the increase of printing monolayer thickness, while the printing efficiency increased with the increase of the printing monolayer thickness. Based on Gray Correlation Theory, the "Wear Resistance Efficiency " (WRE) parameter was defined to comprehensively evaluate the wear resistance and printing efficiency of the samples. When the thickness of the printing monolayer was 30 mu m, the comprehensive properties of the material reached the optimal value. The U increased the cross-linking degree of the acrylic interlayer molecules, and the H reduced the residual stress generated during the printing of the samples. The research results provided data support for the application of 3D printing acrylic resin and its nanocomposites in the field of tribology.

The objective of this systematic review was to learn the current state of Ergonomic/human factors researches in agricultural machinery and to draw implications for future efforts. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) was selected to conduct this review. The literature search was carried out in Web of Science, Engineering Village, and Science Direct for articles published between 1950 and 2021. After two rounds screening and discussions, 107 studies were identified, and another 16 relevant studies were added after author recommendation and discussion, so there were 123 selected studies for further analysis. According to the objective of each comparative study, they were classified into two categories, studies on human in H-M system and on ergonomic application in design or evaluation, and the summary of extracted data from each study was provided. Based on the review and analysis, some conclusions and further directions were put forward.

Three-dimensional printing (3DP) has high flexibility and controllability, and has attracted extensive attention in the biomedical field. However, the scaffolds prepared only by 3D bioprinting have poor mechanical properties, and they cannot effectively carry the required drugs. At the same time, compared with the size of cells, the pore size of 3D printed scaffolds is relatively large, and the efficiency of cell inoculation and tissue formation are still limited by the pore resolution of scaffolds. Therefore, a new method of forming 3D printing trachea composites is proposed. When combined, 3D bioprinting and electrospinning (ESP) can overcome the issues associated with scaffolds prepared by 3D bioprinting alone. Nanofibers create a suitable environment for cell growth. In terms of material use, Polycaprolactone (PCL) is commonly used as an ideal material source for 3D printing, but its biomechanical properties are insufficient. Cellulose nanocrystals (CNC) can effectively improve the properties of polymers such as PCL. Therefore, the inner layer of the scaffold used in tracheal surgery is created from PCL/CNC composite by 3D bioprinting, and the outer nano-cellulose film is deposited on the inner surface by electrospinning. Mechanical properties and cell adhesion/growth of scaffolds prepared by 3D bioprinting combined with electrospinning were found to be superior to those of scaffolds prepared by 3D bioprinting.

针对目前挂轨巡检机器人升降机构的特点和不足,从运动稳定性和展开性能出发,设计了一种绳索式剪叉升降机构.对比分析了剪叉升降机构不同驱动方式的优、缺点,给出了剪叉升降机构具体的结构设计方案,对所设计的剪叉升降机构进行了运动学仿真分析,验证了方案的可行性.试制样机试验结果证明所设计的剪叉升降机构运动平稳,展开性能优异,能够满足巡检机器人的工作需求.

针对高校实验室废液在储运过程中废液存储桶搬运存在劳动效率低、强度大,且在搬运和倾倒过程中废液的跑冒滴漏会对人体和环境造成危害等问题,设计了一种废液桶搬运机器人,用于代替人完成废液储运工作.首先对搬运机器人的剪叉式升降机构建立力学模型,利用虚功原理得出驱动力与负载之间的关系;其次以液压缸最大推力为目标函数,利用MATLAB局部优化函数进行优化,确定升降机构的合理结构;最后应用ADAMS对升降机构进行动力学仿真,分析升降平台运动特性和驱动力变化规律,为搬运机器人整机的合理配置提供设计依据.

背景:在现有的组织工程支架评价体系中,需要在多个方面测试支架的力学强度以保证其可以满足临床应用的要求,但由于生物复合材料的力学性能测量是一个微小变形的测量,目前市面上很难有专业的测量仪器满足测试的精度要求,常用的硬度仪或拉伸实验仪也难以达到支架力学性能的要求.目的:开发研究一款具有自动检测硬度和韧性的测试系统来检测生物支架的力学性能.方法:研发的测试系统采用两组差动电桥分别实现应力和应变的输出,在恒定的温度、湿度及应变速度下进行不同方式的力学实验,获取材料的各项力学性能.针对复合生物材料的特殊性,通过对纳米纤维素和聚己内酯组成的生物复合材料进行设备的测试来验证该测试系统能否满足要求.结果 与结论:实验开发研究的测试系统能够准确测量生物材料支架的力学性能,将被测支架的"力-位移"加载曲线斜率作为支架的韧性/硬度的表征,能够直观反映支架力学性能的好坏,同时该测试系统的精度能够达到0.1μm,这对3D生物打印技术运用到组织修复的建立具有理论依据和应用价值.

建立管翅式机油冷却器的三维模型,利用有限体积法对油冷器进行全局数值模拟,并结合风冷油试验研究了翅片密度、工作环境温度以及进风口风速对油冷器换热性能的影响.结果 表明,仿真模型所得结果与试验结果相差不大,在工程所允许的偏差范围之内.

针对实验废液处理设备运行状态和现场环境的检测、监控问题,研制了一种用于实验废液处理工作过程监测的轨道式巡检机器人系统;介绍了轨道巡检机器人系统的总体方案设计、结构设计及控制系统设计;利用该巡检机器人系统搭载的环境检测传感器和高清相机可对废液处理工作现场状况进行全天候全方位监测,提高了废液处理工作过程的安全管理能力.

随着国家生态文明建设的持续推进和环境监督管理的不断深入,对实验室环境污染的治理已成为高校实验室管理工作所面临的现实问题.探索实验室环境污染治理的相关理论与技术方法,提出了对实验室废液(水)处理的集成工艺技术方法和对实验室废气净化处理的组合工艺技术体系.经过在相关高校几年的应用实践表明,该技术体系具有良好的社会与经济效益.在此基础上,提出了对高校实验室环境污染治理技术推广应用的几点思考.

In recent years, 3D printing has received increasing attention from researchers. This technology overcomes the limitations of traditional technologies by printing precise and personalized scaffold with arbitrary shapes, pore structures, and porosities for the applications in various tissues. The cellulose nanocrystal (CNC) is extracted from Humulus Japonicus (HJS) and mixed with poly(ε-caprolactone) (PCL) to prepare a series of CNC/PCL composites for printing. Based on the analysis of the physical and chemical properties of the series of the CNC/PCL composites, an optimal mass ratio of CNC to PCL was obtained. The Solidworks was used to simulate the stretching and compression process of the scaffolds with three different patterns under an external force. The flow of nutrient solution in the scaffolds with different patterns was simulated by ANSYS FLUENT, and then a new optimization scaffold pattern with a concave hexagon shape was advised based on the simulation results. Collectively, the mechanical test results of the material and scaffold confirmed that the optimal filling amount of the CNC was 5%, and the scaffold pattern with concave hexagon shape exhibited better mechanical properties and suitable for the transport of cells and nutrients, which is expected to be more widely used in 3D printing.

按照实验室通风及废气净化需求,须对实验室环境进行实时监测,为此基于云平台设计了一套实验室环境智能监测系统,其监测数据包括实验室环境温湿度、实验室多种废气浓度、酒精、一氧化碳、可燃性气体(甲烷、液化气等)、粉尘等.该系统选用STM32F103C8T6作为微处理芯片,采用监测指标传感器实时获取实验室环境数据并基于OLED屏显示;无线传输模块ATK-ESP8266进行数据上传;原子云平台进行实时储存及显示;基于阈值设定法启动环境异常的支援服务,如蜂鸣器警示、温湿度调节、换气风扇开启等.该系统可用于高校实验室环境监测与支援服务,具有多地多主机实时监测、无人值守、海量数据储存等优点.

针对长型管材存储的特点和出入库运行要求,设计了一种适用于长型管材存储的自动化立体仓库.新型立体仓库采用了悬臂梁搭配料框的储存结构,在出入库装置的设计上摒弃了传统仓储业所采用的堆垛机存取货物的模式,利用卷扬机搭配行走机构和抓取机构的方式实现长型管材的升降以及出入库运输.同时应用有限元方法对货架的强度和刚度进行了模拟分析,进一步验证了设计的可行性,为长型管材存储的自动化立体仓库设计提供一定的参考价值.

针对高校实验室在环境污染防治方面普遍存在操作规范和管理保障制度等方面缺失的现状,通过实验室建设前环境污染防治工作的规范、实验过程中产生的废液处理工作规范、废气处理工作规范、实验动物尸体处理工作规范、实验试剂瓶处理规范等来解决高校实验室主要污染源的处理问题,并通过构建各环节污染防治处理过程工作规范体系,发挥现有的污染防护硬件和渠道的作用.

Recently, the CNC/GEL (cellulose nanocrystals/gelatin) composite hydrogel has been used as a biomaterial for 3D printing of tissue engineering scaffolds. Rheological properties of hydrogel have been regarded as one of the most important factors affecting printing quality, especially the viscosity recover time. However, there is still a lack of comprehensive research on the rheology property of the CNC/GEL hydrogel in the process of 3D printing. In this study, the CNC was isolated from Humulus japonicus , and a CNC/GEL hydrogel system was prepared. The rheological properties of CNC/GEL hydrogel were evaluated using a rotary rheometer. The viscosity recovery time of the CNC/GEL hydrogel was measured using a special method. The optimal ratio of hydrogel was obtained by rheology experiment and mechanical test. The flow field distribution of the hydrogel in the flow passage of 3D printer was analyzed using fluent simulation. The rheological parameters of a hydrogel can be adjusted by changing the printing conditions. Thus, the effect of printing conditions on the formation of CNC/GEL filaments was also investigated. Finally, the biocompatibility of the printed CNC/GEL scaffold after crosslinking treatment was verified using CCK-8 and Hoechst 33342/PI double-staining assays. The present study shows a new approach for the analysis of rheological properties of CNC/GEL and also provides some suggestions for 3D printing of CNC/GEL scaffolds.

基于实验室废液处理工艺的需求,对实验废液处理工艺装备结构组成进行了分析,应用模块化设计分析方法,进行实验废液处理装备的模块化设计.采用SolidWorks建立了废液处理装备模块支承结构的三维模型,在ANSYSWorkbench有限元环境下获得各模块的应力云图和位移云图,为模块化设计提供理论依据,提高装备模块化结构性能.分析结果表明,该模块化结构设计方案合理,满足要求.

高校实验室危险化学品管理信息化建设是基于物联网的智慧校园信息化建设的重要组成部分,是高校教学、科研实验有序开展的重要保障.在剖析目前实验室危险化学品的管理中存在的问题和物联网背景下实验室危险化学品管理优势的基础上,提出了提高再认识、加大投入、促进信息化网络化发展和提高人员素质的改革要点.分析和展望了基于物联网环境下的实验室安全教育、危险化学品申购和危险化学品过程管理的工作举措,对提高高校实验室管理水平,实现实验室危险化学品管理规范化、信息化、精准化有一定的促进作用.

基于超速离心技术的油液自动净化处理装置是一种多用途的可移动式油液净化设备.采用超速离心技术使不同密度的液体、杂质和油液分离,达到油液净化的目的.在对油液自动净化处理过程分析的基础上,进行了装置的总体结构设计,运用PLC控制技术,通过对液压控制装置、电气控制装置和程序控制的设计实现了装置的自动化运行.

In the biomedicine field, three-dimensional (3-D) printing of biomaterials can construct complex 3-D biological structures such as personalized implants, biodegradable tissue scaffolds, artificial organs, etc. Therefore, nanocellulose/gelatin composite hydrogels are often selected as bio-printing materials in the 3-D printing of biological scaffolds. Process parameters of 3-D printed bio-scaffolds were studied in this work because formation accuracy of scaffolds is an important part of the molding process. Firstly, the mixing proportion of nanocellulose and gelatin was explored, and the optimum proportion was selected. Then, the printing effects of different printing pressures, temperatures, speeds, and nozzle diameters were used in the 3-D printing. The filament widths were used to evaluate the molding effects. Finally, through the calculation and analysis of the grey correlation coefficient and grey correlation degree, the multi-objective optimization of the parameters was carried out. The combined effects of the process parameters and the influence degree order on the evaluation index were obtained. Using these parameters, the 3-D porous biological scaffolds were printed with high precision. Furthermore, using a microscope, the morphologies of CCK-8 cells were observed and the cell proliferation were analyzed. The results demonstrated that the printed bio-scaffolds had good biocompatibility.

Tissue scaffolds need to have anisotropic mechanical properties and a porous structure to meet the needs of different tissues and organs. This report presents results of a study on an especially-designed 3D printing method with oxidized nanocellulose and gelatin, analyzes the servo principle of pneumatic condensing extrusion 3D printer, and proposes a hexagonal algorithm. For the purpose of this study, a printing process file was written by G code, physical and mechanical performance of the 3D scaffolds was evaluated with Solidworks simulation, the porous structure and pressure-pull performance of the printed 3D scaffolds was observed by SEM, and experiments were conducted to measure their bio-compatibility. The study draws the conclusion that scaffolds thus printed have a highly porous structure and anisotropic mechanical properties.