Structural damage detection using improved particle swarm optimization

An approach based on an improved particle swarm optimization (PSO) algorithm is proposed for structural damage detection in this study. A disturbance is introduced in the evolution process to avoid the occurrence of premature. The present algorithm focuses on the mutation of global or individual best known positions to guide the swarm to escape from the local minimum. The feasibility and robustness of the modified PSO are verified by three different structures, including a beam, a truss and a plate. The results show that the method is efficient and effective for structural damage identification when measurement noise is considered.     

热变形对ZK60镁合金组织及性能的影响

对ZK60镁合金进行了平面应变等温压缩试验,并对不同变形条件下压缩试样的微观组织、拉伸性能进行分析.结果表明,ZK60合金热变形后力学性能得到提高,尤其是塑性得到较大改善,伸长率最高达到38％,断口形貌由河流状变为韧窝状,这主要是由于变形过程中产生动态再结晶,使晶粒明显细化；均匀态组织中个别未溶的共晶组织呈点状断续分布于晶界上,这些点状裂纹在变形过程中不易扩展还可能愈合；在300～380℃对均匀态ZK60合金进行平面压缩后,可获得较优的综合力学性能.     

基于LabVIEW的油库油情监测系统

介绍了一种基于LabVIEW软件的油库油位监测系统，包括系统的构成原理、特点，以及系统通讯功能的实现和采集数据的显示等关键设计技术。该系统的现场智能仪表为精确度高的磁致伸缩液位仪可自动采集数据。在Windows系统下，利用LabVIEW软件实现系统数据处理、实时数据高速存储和数据库管理等功能。该系统与传统的手工检尺和人工计量相比，具有测量精确、性情稳定、安全高效和管理方便等优点。     

塑料模用锌基合金的特点与展望

阐述了锌基合和塑料模具的优势和存在的问题，今后应当在合金材料配比，制作工艺和后期处理方法努力。随着市场对多品种小批量的塑料件的需求，锌基合金塑料模具获得极大的发展。     

机械振动对ZL101消失模铸造组织及性能的影响

将自制变频三维振动台应用于ZL101铝合金消失模铸造中,研究了不同频率、不同振动方向的机械低频振动对ZL101组织及性能的影响.试验结果表明,在ZL101铝合金消失模铸造凝固过程中进行机械振动能有效细化铸件组织,降低针孔率,提高铸件抗拉强度和伸长率.对比分析表明,振动频率为20～60 Hz且采用垂直方向振动时,铸件的组织较好,抗拉强度和伸长率可达180 MPa和2.7%.     

Properties of sodium silicate bonded sand hardened by microwave heating

The sodium silicate bonded sand hardened by microwave heating has many advantages,such as low sodium silicate adding quantity,fast hardening speed,high room temperature strength,good collapsibility and certain surface stability. However,it has big moisture absorbability in the air,which would lead to the compression strength and the surface stability of the sand molds being sharply reduced. In this study,the moisture absorbability of the sodium silicate bonded sand hardened by microwave heating in different humidity conditions and the effect factors were investigated. Meanwhile,the reasons for the big moisture absorbability of the sand were analyzed.Some measures to overcome the problems of high moisture absorbability,bad surface stability and sharply reducing strength in the air were discussed. The results of this study establish the foundation of green and clean foundry technology based on the microwave heating hardening sodium silicate sand process.     

镁合金真空低压消失模铸造的技术特征与实践

介绍了镁合金在真空低压消失模铸造下的技术特征。研究表明：真空低压消失模铸造的流动性受充型气体的流量与压力、浇注温度、涂层厚度、泡沫密度、真空度等多方面的因素影响；在低充型速度和低真空度的条件下，液态镁合金在真空低压消失模铸造过程中的充型形貌均呈现以内浇道为中心的拱形层状推进流动，如充型速度加快金属液流动前沿拱形形貌更加突出。而真空度增加会出现明显的“附壁效应”；与重力消失模铸造比较，真空低压消失模铸造镁合金铸件凝固更呈现“同时凝固”特征；由于快速充型、压力下凝固，镁合金真空低压消失模铸造零件的铸态抗拉强度（σh=180．8MPa）、屈服强度（σ0.2=113．2MPa）、伸长率（δ=4．4％），高于重力消失模铸造、树脂砂空型铸造的铸态性能，达到了金属型铸造的铸态性能，经热处理达到了压铸镁合金的性能范围。浇注实践表明，真空低压消失模铸造对液态镁合金，具有良好的抗氧化保护能力、优良的浇注充型性能和力学性能，可铸造出高精度的、薄壁复杂的镁合金消失模铸件，是一种极有潜力和优势的镁（铝）合金精密铸造技术。     

惠安女服装结构及其舒适性解析

惠安女服饰极具文化特色,但日渐消失。它可分为崇武城外、山霞和小岞、净峰两个类型,选取对极具代表性的崇武地区的服装进行相关研究。区别于美学角度,从惠安女服装结构舒适性的角度入手,分别对惠安女上装和下装的结构进行解构,分析其结构设计的原理,并对惠安女服装的开口形成的"烟囱效应"和"风箱效应"进行分析。从而得知,惠安女的服装结构设计符合着装舒适性需求和劳作需求,具有良好的结构合理性。     

A Bioinspired Capillary Force-Induced Driving Strategy for Constructing Ultra-Low-Pressure Separation Membranes

The development of low-pressure or pressureless self-driven membranes is important for saving energy and overcoming the critical trade-off effect in membrane separation processes. However, conventional self-driven membranes rely on gravity, which is effective in the separation of large-sized materials but is still ineffective in the fine separation of small molecules. Herein, inspired by the capillary effect that exists in nature, a capillary force-induced membrane-driving strategy for fine separation at ultra-low pressures is demonstrated. Hydrophilic nanoparticles are prepared by a cross-linking reaction between tannic acid and 3-aminopropyltriethoxysilane and then introduce them into membrane pores to simulate sand accumulation with an aim to generate the capillary force. The membrane is then used in ultra-low pressure membrane separation. Interestingly, it is found that the membrane has excellent performance in the separation of dye/salt mixtures (dye rejection > 99%, salt rejection < 10%) and a high permeate flux (160 L m⁻² h⁻¹) under near “zero pressure” conditions. Moreover, the structural stability of the membrane is verified. Introducing capillary forces into membranes as an autonomous driving force can be a promising universal approach that can be added up to the toolbox for the efficient preparation of separation membranes.     

Ultrathin Hydrogel Films toward Breathable Skin-Integrated Electronics

On-skin electronics that offer revolutionary capabilities in personalized diagnosis, therapeutics, and human–machine interfaces require seamless integration between the skin and electronics. A common question remains whether an ideal interface can be introduced to directly bridge thin-film electronics with the soft skin, allowing the skin to breathe freely and the skin-integrated electronics to function stably. Here, an ever-thinnest hydrogel is reported that is compliant to the glyphic lines and subtle minutiae on the skin without forming air gaps, produced by a facile cold-lamination method. The hydrogels exhibit high water-vapor permeability, allowing nearly unimpeded transepidermal water loss and free breathing of the skin underneath. Hydrogel-interfaced flexible (opto)electronics without causing skin irritation or accelerated device performance deterioration are demonstrated. The long-term applicability is recorded for over one week. With combined features of extreme mechanical compliance, high permeability, and biocompatibility, the ultrathin hydrogel interface promotes the general applicability of skin-integrated electronics.