会议中心中庭分层空调的节能改进策略 ——以景观与主被动式节能设计相结合并模拟验证

文章从跨专业视角基于复合设计原理探讨了会议中心中庭设计对建筑和暖通空调能耗的影响。采用CFD软件模拟了主、被动式节能设计的效果,结果表明建筑与暖通空调复合设计可以实现两个主要功能：建筑室内景观与暖通空调设计的有机结合、分层供冷与上部空间自然通风的有效结合。通过实例分析表明,采用复合设计方法,在实现中庭建筑节能的同时保持了夏季室内的舒适度。     

新型混凝土-碎石串联组合桩承载力计算

针对碎石桩容易在桩顶1～3倍桩径高度范围内发生鼓胀破坏现象,提出一种新型碎石桩复合地基:混凝土-碎石散体材料串联组合桩复合地基,并阐述了该新型复合地基的施工工艺。基于计算深基础承载力Meyerhof法,采用多滑块破坏模型,建立了混凝土-碎石散体材料串联组合桩深层鼓胀破坏计算模型,通过随机优化算法寻找临界滑动面,计算得到其单桩极限承载力。将该新型组合桩的承载力理论计算值与数值仿真计算结果、传统碎石桩承载力试验结果进行对比分析,结果表明:提出的多滑块解析计算方法准确性较好;新型桩的承载力比传统碎石桩承载力有了明显提高,相较于传统碎石桩,新型组合桩在混凝土桩段长度1 m时承载力计算值提高了32.76%,在混凝土桩段长度2 m时,承载力计算值提高了54.74%。     

基于多小波包样本熵的轴承损伤程度识别方法

为了自动辨识不同尺度下的轴承故障,建立了一种基于多小波包系数样本熵和BP神经网络的模式判别方法。针对5种尺度下的轴承外圈故障信号,分别采用GHM多小波包完成三层分解。为了充分利用多小波包的分析优势,将分解后的16个频段信号分别求系数样本熵,并将其作为神经网络的输入向量。通过三层BP神经网络的训练、学习,并与dB10小波包神经网络做了对比研究。结果表明,多小波包样本熵可以区别不同损伤程度的故障信号,且多小波包样本熵与神经网络结合,其辨识精度更高,分类效果明显优于传统单小波,便于轴承损伤程度的自动识别。     

动态反应池-电感耦合等离子体质谱法测定烟草中的铬

用微波消解法处理样品,利用氧气作为反应气的动态反应池模式,采用电感耦合等离子体质谱(ICPMS)对烟草中的重金属铬进行测定。考察了前处理中双氧水加入量以及仪器测定条件对方法的影响。方法的线性良好(R2=0.9999),检出限为0.042μg/L,加标回收率为96.4~105.2%,相对标准偏差小于5%。证明该方法准确、稳定,可用于烟草样品中铬含量的准确测定。     

2-丙基庚醇装置设备及管道清洗研究

根据某石化公司二期扩建2-丙基庚醇装置生产工艺及设备特点,说明了设备及管道中杂质污垢的存在对化工生产过程的影响,介绍了2-丙基庚醇装置设备及管道进行化学清洗的意义和清洗工艺过程。通过对装置设备及管道实施化学清洗,使之符合化工生产要求及化工行业的质量标准。     

Monel合金表面激光熔覆Ni基稀土合金空蚀性能

采用激光熔覆技术在Monel 400合金表面制备Ni基稀土合金熔覆层。利用SEM、EDS、XRD、显微硬度计及超声波金属材料空蚀仪等设备对熔覆层的组织形貌、相结构、硬度、空蚀性能及失效机制进行了系统研究。结果表明:Y_2O_3细化了熔覆层的组织,其组织主要由γ-Ni固溶体、Ni_3B和高硬度的Cr_(23)C_6和Cr_7C_3组成,熔覆层平均硬度可达9040MPa,抗空蚀性能是Monel400合金的8.7倍,熔覆层空蚀过程失效机制主要为枝晶干的冲蚀剥落,Ni基稀土合金熔覆层的细晶强化及空蚀过程中产生阻断晶界网状结构是提高其耐空蚀性能的关键。     

Aliphatic–aromatic poly(butylene carbonate‐co‐terephthalate) random copolymers: Synthesis,cocrystallization, and composition‐dependent properties

A series of aliphatic–aromatic poly(carbonate‐co‐ester)s poly(butylene carbonate‐co‐terephthalate)s (PBCTs), with weight‐average molecular weight of 113,000 to 146,000 g/mol, were synthesized from dimethyl carbonate, dimethyl terephthalate, and 1,4‐butanediol via a two‐step polycondensation process using tetrabutyl titanate as the catalyst. The PBCTs, being statistically random copolymers, show a single T_g over the entire composition range. The thermal stability of PBCTs strongly depends on the molar composition. Melting temperatures vary from 113 to 213°C for copolymers with butylene terephthalate (BT) unit content higher than 40 mol %. The copolymers have a eutectic melting point when about 10 mol % BT units are included. Crystal lattice structure shifts from the poly(butylene carbonate) to the poly(butylene terephthalate) type crystal phase with increasing BT unit content. DSC and WAXD results indicate that the PBCT copolymers show isodimorphic cocrystallization. The tensile modulus and strength decrease first and then increase according to copolymer composition. The enzymatic degradation of the PBCT copolymers was also studied. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41952.     

Antimicrobial polyethylene wax emulsion and its application on active paper‐based packaging material

Antimicrobial polyethylene wax (PEW) emulsions, prepared by emulsifying polyethylene wax grafted with polyhexamethylene guanidine hydrochloride (PEW‐g‐PHGH), were used as wet‐end additives or coating materials for fabricating hydrophobic and anti‐mold hand‐sheets or paper. To obtain PEW‐g‐PHGH, maleic anhydride (MAH) was adopted as a bridging agent. The melt or solution grafting of MAH to PEW was performed to achieve the appropriate grafting degree and grafting efficiency. The resulting PEW‐g‐PHGH was emulsified using a homogenizer by means of surfactants, and the resulted emulsions were characterized in terms of particle size, zeta potential, charge density, minimal inhibitory concentration (MIC), and adsorption capacity. After that the hydrophobicity of emulsion treated hand‐sheets was determined by measuring water contact angle (WCA). The morphology of the hand‐sheets treated by the emulsion was revealed using scanning electron microscope (SEM) and atom force microscope (AFM). Finally, the antimicrobial properties of the emulsion treated hand‐sheets were investigated by anti‐mold tests against Aspergillus niger and Chaetomium globosum. Results indicated that the PEW‐g‐PHGH emulsions exhibited good stability, high fiber adsorption capacity, and antimicrobial activity. The WCAs of the treated hand‐sheets reached 82°–140° with 80%～99.9% growth inhibition against fungi. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42214.     

水性聚氨酯/纳米二氧化硅杂化材料的研究进展

介绍了制备水性聚氨酯(WPU)/纳米Si O2(二氧化硅)杂化材料的几种方法(如纳米Si O2表面改性法、溶胶-凝胶法和原位聚合法等),特别综述了采用化学接枝改性法制备纳米Si O2和溶胶-凝胶法制备共价键连接的杂化材料的研究进展。最后对WPU/纳米Si O2杂化材料的发展方向提出了建议。