磁控溅射CuCrMo薄膜耐126kV 20kA电弧烧蚀性能

提升真空断路器CuCr触头的抗电弧烧蚀能力是决定其能否应用于高压真空灭弧室的核心关键,尚未见有效触头材料或表面涂层改性技术使CuCr触头应用于126kV以上真空灭弧室的报道。基于CuCrMo薄膜的优异电气性能,对沉积CuCrMo薄膜的真空灭弧室触头进行126kV下的抗电弧烧蚀研究,并进行开断寿命的工程验证。采用磁控溅射技术在CuCr50真空触头片表面沉积5μm厚的CuCrMo薄膜,对其进行126kV 20kA电流下23次的电寿命试验。利用XRD、SEM和3D共聚焦显微镜研究电弧烧蚀后表面形貌。研究结果表明：沉积CuCrMo薄膜的触头片,在纵向磁场和126kV 20kA条件下可有效分散电弧,较未镀膜触头片有更小电弧电流密度;经过23次电寿命试验后,表面烧蚀程度比未镀膜的触头片轻,表面粗糙度降低,提高了触头的开断寿命。为表面改性真空断路器CuCr触头在高电压大电流真空灭弧室的应用提供了有效工程依据。     

含Zn2+的金属有机骨架材料对碳酸二苯酯与1,4-丁二醇酯交换反应的催化性能

采用溶剂热法制备了Zn2+和对苯二甲酸组合形成的金属有机骨架材料(MOF),并用X射线衍射(XRD)和红外光谱(FT-IR)对其进行了表征。研究了MOF对碳酸二苯酯(DPC)与1,4-丁二醇(1,4-BD)酯交换反应合成聚碳酸酯二醇(PCDL)的催化活性,并与乙酰丙酮氧钛(TiO(acac)2)、乙酰丙酮锌(Zn(acac)2)和锌铝类水滑石(Zn-A-lCO3LDH)等催化剂进行了比较。结果显示,MOF是该酯交换反应的良好催化剂。在优化的反应条件下,获得了数均分子量为3470,羟基值为35.2mg KOH/g的PCDL。     

Core–shell porphyrin·multi-walled carbon nanotube hybrids linked by multiple hydrogen bonds: nanostructure and electronic communication

In this paper, multiple hydrogen bonding interaction of ureidopyrimidinone (UPM) was employed as the linking bridge for the formation of a novel porphyrin·multi-walled carbon nanotube (MWNT) hybrid, which was then used to fabricate a layer-by-layer (LbL) film composed of porphyrin-UPM·MWNT-UPM. Both in the assembled hybrid and the LbL film, porphyrin was closely attached to the surface of the MWNT under the strong multiple hydrogen bonding interaction, forming the core–shell structure. In addition, strong electronic communication was observed between porphyrin and MWNT. The hydrogen bonding association behavior between porphyrin-UPM and MWNT-UPM was attentively analyzed by UV–Vis spectra, fluorescent spectra and transmission electron microscope experiments. It was found that the hydrogen bonding interactions were crucial for the formation of the supramolecular hybrid and the LbL film as well as the occurrence of interfacial electronic communication. This result indicated that the introduction of strong noncovalent bonding interaction between donor and acceptor is an appropriate way to control the material structure and facilitate the interfacial electronic communication in the hybrids which lay the groundwork for their application in electrochemical sensors or photovoltaic devices.     

一种模压代木包装材料的制备工艺及性能研究

利用速生杨树木材加工剩余物,制备了一种用于运输包装的代木材料,并研究其物理、机械性能。采用正交试验设计方法制备了不同代木包装材料试样,并利用极差分析方法分析了不同工艺参数对代木包装材料物理、机械性能的影响。试验结果表明,制备代木包装材料的较佳模压工艺参数如下:热压温度为120~125℃、热压时间为10 min、热压压力为10 MPa、胶黏剂的添加质量分数为10%,在此工艺条件下制备的代木包装材料,其静曲强度、内结合强度、吸水厚度膨胀率、密度分别为17.7 MPa,1.61 MPa,6.1%,0.73 g/cm3。所制备的代木包装材料满足国家标准(GB/T4897—1992)的A类刨花板一等品物理力学性能要求,是一种绿色环保的包装材料。     

稀土掺杂双钙钛矿结构红色荧光粉的制备及其发光性能

采用高温固相反应法制备了Sr_(2-x)BaxMgMoO_6∶Eu~(3+)(x=0~1)双钙钛矿结构红色荧光粉。探讨了预处理及煅烧制度、Ba取代量对Sr_(2-x)BaxMgMoO_6∶Eu~(3+)荧光粉的相结构和发光性能的影响。Sr_2Mg_(0.94)Eu_(0.06)MoO_6荧光粉最佳制备工艺为:在700℃下预处理1h再升温至1050℃预处理1h并随炉降温后研细,再在1300℃煅烧4h,所得样品主相为双钙钛矿结构的Sr2MgMoO6四方相。其最强发光峰位于617nm附近,对应于Eu3+的5D0→7F2电偶极跃迁。随着Ba2+对Sr2+的取代量的增加晶体对称性提高,晶体结构由四方相变为立方相,样品的激发峰强度显著提高。由于晶体对称性的提高,抑制了荧光粉在617nm处5D0→7F2红光发射,其发光由电偶极跃迁占主导转变为磁偶极跃迁占主导。     

基于社区的北京环境满意度研究

目的编制《北京社区环境满意度问卷》并进行调查,以充分了解北京居民对社区环境满意度现状。方法首先,随机选取社区进行预测和再测,确定《北京社区环境满意度问卷》的信效度和结构模型。然后,从北京7个城区中随机选取12个社区进行实地调查。结果编制的问卷的信度为0.919、结构效度为0.700。社区环境满意度的总体情况为42.85±8.833,7个城区中石景山区、东城区、朝阳区的环境满意度位于前3位。生活北京、服务北京、人文北京、自然北京4个维度中,居民最为满意的服务北京,最不满意的是自然环境维度。结论编制的《北京社区环境满意度问卷》具有较好地信效度,而且通过该问卷真实系统的地反映了北京社区环境满意度状况。     

Chemical-assisted bonding of thermoplastics/elastomer for fabricating microfluidic valves

Thermoplastics such as cyclic olefin copolymer (COC) and polymethylmethacrylate (PMMA) have been increasingly used in fabricating microfluidic devices. However, the state-of-the-art microvalve technology is a polydimethylsiloxane (PDMS)-based three-layer structure. In order to integrate such a valve with a thermoplastics-based microfluidic device, a bonding method for thermoplastics/PDMS must be developed. We report here a method to bond COC with PDMS through surface activation by corona discharge, surface modification using 3-(trimethoxysilyl)propyl methacrylate (TMSPMA), and thermal annealing. The method is also applicable to PMMA. The bonding strength between thermoplastics and PDMS was represented by the peeling force, which was measured using a method established by the International Organization for Standardization (ISO). The bonding strength measurement offered an objective and quantitative indicator for protocol optimization, as well as comparison with other PDMS-associated bonding methods. Using optimized bonding conditions, two valve arrays were fabricated in a COC/PDMS/COC device and cyclic operations of valve closing/opening were successfully demonstrated. The valve-containing devices withstood 100 psi (～689 KPa) without delamination. Further, we integrated such valve arrays in a device for protein separation and demonstrated isoelectric focusing in the presence of valves.     

基于PSO优化BP的冷水机组故障诊断研究

本文将PSO(粒子群算法)优化BP(误差反向传播神经网络)应用于离心式冷水机组的故障诊断,针对7种典型故障,包括4种局部故障与3种系统故障,建立了PSO优化BP的诊断模型。结果表明:PSO优化后的BP神经网络(包括单隐层与双隐层)故障诊断性能显著提高,神经网络结构简化,较少的隐含层节点即可获得较优的诊断性能。单隐层神经网络优化后最佳隐含层节点数从18降至10,诊断正确率从89. 42%提升至95. 30%;双隐层神经网络优化后最佳隐含层节点数从25降至12,诊断正确率从97. 87%提升至98. 11%,诊断用时仅为优化前的23%。故障诊断虚警率(假报及漏报)降低,且显著改善了系统故障尤其制冷剂泄漏故障的诊断性能,对正常情况的识别率亦极大提高。PSO优化有助于BP网络跳出局部极小值,较好地改善了故障诊断性能。     

All‐Polymer Solar Cells Based on a Conjugated Polymer Containing Siloxane‐Functionalized Side Chains with Efficiency over 10%

A novel wide‐bandgap conjugated copolymer based on an imide‐functionalized benzotriazole building block containing a siloxane‐terminated side‐chain is developed. This copolymer is successfully used to fabricate highly efficient all‐polymer solar cells (all‐PSCs) processed at room temperature with the green‐solvent 2‐methyl‐tetrahydrofuran. When paired with a naphthalene diimide‐based polymer electron‐acceptor, the all‐PSC exhibits a maximum power conversion efficiency (PCE) of 10.1%, which is the highest value so far reported for an all‐PSC. Of particular interest is that the PCE remains 9.4% after thermal annealing at 80 °C for 24 h. The resulting high efficiency is attributed to a combination of high and balanced bulky charge carrier mobility, favorable face‐on orientation, and high crystallinity. These observations indicate that the resulting copolymer can be a promising candidate toward high‐performance all‐PSCs for practical applications.     

A nano- and micro- integrated protein chip based on quantum dot probes and a microfluidic network

A novel nano- and micro-integrated protein chip (NMIPC) that can detect proteins with ultrahigh sensitivity has been fabricated. A microfluidic network (μFN) was used to construct the protein chips, which allowed facile patterning of proteins and subsequent biomolecular recognition. Aqueous phase-synthesized, water-soluble fluorescent CdTe/CdS core-shell quantum dots (aqQDs), having high quantum yield and high photostability, were used as the signaling probe. Importantly, it was found that aqQDs were compatible with microfluidic format assays, which afforded highly sensitive protein chips for cancer biomarker assays. Electronic Supplementary Material  Supplementary material is available for this article at and is accessible for authorized users.