用φ20mm离心萃取器两步法制取高纯钇

本文研究了中钇富镧稀土的氧化物溶液在环烷酸中的萃取行为，测定了镧钇组成、温度变化与分离系数的关系；在Ｐ＿（５０７）体系中研究了ｐＨ值与分配比的关系；提出用环烷酸、Ｐ＿（５０７）两种萃取剂制备高纯钇的工艺流程。用８４台φ２０ｍｍ离心萃取器进行了一个月的台架试验，结果证明两种萃取剂有很好的互补性，在满足钇的纯度要求下有较高收率。离心萃取器具有易分相、体系存留量少、液流密闭性好等优点，它更适宜于粘度大、级数多、产品纯度要求高的体系。     

Ideal-gas thermodynamic properties for natural-gas applications

Calculating caloric properties from a thermal equation of state requires information such as isobaric heat capacities in the ideal-gas state as a function of temperature. In this work, values for the parameters of thec _p ⁰ correlation proposed by Aly and Lee were newly determined for 21 pure gases which are compounds of natural gas mixtures. The values of the parameters were adjusted to selectedc _p ⁰ data calculated from spectroscopic data for temperatures ranging from 10 to 1000 K. The data sources used are discussed and compared with literature data deduced from theoretic models and caloric measurements. The parameters presented will be applied in a current GERG project for evaluating equations of state (e.g., the AGA 8 equation) for their suitability for calculating caloric properties.     

Encapsulation of PV modules using ethylene vinyl acetate copolymer as a pottant: A critical review

The primary purpose of this work is to review the literature about what is and is not known about using ethylene vinyl acetate (EVA0 copolymer as the encapsulant (or pottant) material in photovoltaic (PV) modules. Secondary purposes include elucidating the complexity of the encapsulation problem, providing an overview about encapsulation of PV cells and modules, providing a historical overview of the relevant research and development on EVA, summarizing performance losses reported for PV systems deployed since ca. 1981, and summarizing the general problems of polymer stability in a solar environment. We also provide a critical review of aspects of reported work for cases that we believe are important.Failure modes resolved in the early work to establish reliability of deployed modules and the purposes and properties of pottants, are summarized. Typical performance losses in large field-deployed, large-scale systems ranging from 1% to 10% per year are given quantitatively, and qualitative reports of EVA discoloration are summarized with respect to ultraviolet (UV), world-wide location and site dependence.The general stability of polymers and their desirable bulk properties for solar utilization are given. The stabilization formulation for EVA, its effectiveness, and changes in it during degradation are discussed. The degradation mechanisms for the base resin, e.g., unstabilized Elvax 150^TM, and stabilized EVA are indicated for literature dating to the early 1950s, and the role played by unsaturated chromophores is indicated. The limited number of studies relating discoloration and PV cell efficiency are summarized.Observed degradation of EVA or the unstabilized base resin in the laboratory and examples used to measure the degradation are summarized in sections entitled: (1) thermally-induced degradation; (2) photodegradation and photothermal degradation of EVA in different temperature regimes; (3) photobleaching and photodegradation of the UV absorber and cross-linking agent; (4) acetic acid and metal and metal-oxide catalyzed oxidative degradation; and (5) discolaration and PV cell efficiency losses.Processing effects/influences on EVA stability are discussed in sections entitled: (1) EVA raw materials and extruded, uncured films; (2) thermal encapsulation processes; (3) effects of lamination, curing, and curing peroxide on gel content and chromophores formed; and (4) incomplete shielding of curing-generated chromophores. A summary is given for the limited number of accelerated lifetime testing efforts and examples of erroneous service lifetime predictions for EVA are discussed. The known factors that effect the discoloration rate of several EVA formulations are discussed in which the reduction in rate by using UV-absorbing superstrates is a prime example. A summary is given of what is and is not known about EVA degradation mechanisms, degradation from exposures in field-deployed modeules and/or laboratory testing, and factors that contribute to EVA stability or degradation. Finally, conclusions about using Elvax 150 in EVA formulations are summarized, and future prospects for developing the next-generation pottant for encapsulating PV modules are discussed.     

管内含蜡原油降温过程中的放热问题

利用两种管段和两种原油，进行了降温过程自然对流放热参数的测试和研究。采用滞流点确定降温第二阶段中凝油边界的移动，区分管内的对流区与导热区。由实验数据回归得到适用于含蜡原油降温过程的自然对流放热准则方程式。用该方程式计算的自然对流放热系数值比按无限空间自然对流准则方程式计算值小20％～50％。     

应用在地下工程施工中的新技术（Ⅱ）

为有效保护地面上的生态环境，开发利用地下空间资源并营建新世纪的地下水城，在新的21世纪里将会建造更多的地下工程以满足人们生产生活的各种需要。文中介绍了地下工程施工中采用的逆作法、盾构法、新奥法、沉管隧道、顶管工程和大型沉井施工新技术，供同行们参考应用。     

化学束外延

本文介绍了化学束外延(CBE)的发明和发展,论述了CBE的原理和设备。文中还介绍了最近提出的一种生长机理。     

岩样自然伽玛能谱的数据库管理系统

本文阐述了岩样自然伽玛能谱数据库管理系统的功能、结构、特点以及它在研究自然伽玛能谱与岩性参数间关系中的应用，为自然伽玛能谱测井的资料解释奠定了理论基础。     

Synthesis and characterization of poly(siloxane-urethane)s

A series of polyurethane block copolymers based on hydroxy-terminated polydimethylsiloxane and poly(propylene glycol) soft segments of molecular weights 1818 and 2000, respectively, were synthesized. The hard segments consisted of 4,4′-diphenylnethane diisocyanate and 1,4-butanediol as the chain extender. Samples with different molar ratios were prepared. We tried to synthesize polydimethylsiloxane-based polyurethanes (PDMS-PU) containing a hard block as major fraction and a soft block as minor fraction for preparing toughened rigid systems. After a study of the pure polydimethylsiloxane-based polyurethane and poly(propylene glycol)-based polyurethane (PPG-PU), (mixed polyol)-based block copolymers and blends of PDMS-PU and PPG-PU were synthesized, and characterized by means of differential scanning calorimetry, tensile testing and scanning electron microscopy. In (mixed polyol)-based copolymers and lower hard-segment content blends, macro-phase separation occurred, but blends with higher hard-segment contents showed significant reduction in amounts of phase separation.