空调产品结构设计间隙检查系统开发

随着企业的产品日益向高档化、精致化发展,出于外观、运行平稳性、产品寿命等方面的考虑,对产品设计中的配合间隙控制提出了越来越高的要求。针对空调行业的应用,利用Pro/TOOLKIT二次开发技术,研发出一套高效的基于Pro/E平台的产品间隙控制系统,实现设计间隙检查表自动输出和更新,达到了减少设计重复工作、提高产品开发效率的目的。     

多层住宅不同结构体系的比较

本文结合江苏省南通市某多层住宅设计，通过多方面的比较，经PKPM系列软件计算，统计了各自结构工程量，分析得出了简要结果，可供建设单位做类似工程项目的参考。     

江西有色金属行业节能减排工作的若干思考

对江西有色金属行业节能减排工作存在的主要问题进行了分析，主要是：对节能减排的认识不足，责任落实不够；产业集中度低，经营粗放；企业“点多面广”，资质参差不齐；产品结构不合理；监管机制未到位。对做好节能减排工作进行了深入探讨：要提高认识，增强推动节能减排工作的自觉性；发展精深加工，优化产品结构；加快推进行业整合，形成规模经济；努力提高资源利用水平；抓好再生金属的回收利用；着力推进技术进步和自主创新，加快用先进生产力取代落后生产力；强化监管，依法推进节能减排。     

神府煤的液化性能及其重质产物结构表征

利用管式高压反应釜,以四氢萘为溶剂、FeS和S为催化剂,对神府煤进行了加氢液化研究,考察了催化剂、反应温度和反应气氛等因素对煤液化性能和产物组成分布的影响,同时对液化产物进行了红外光谱、元素分析以及酸性含氧官能团等结构表征。结果表明,FeS+S催化神府煤液化的最高四氢呋喃(THF)抽提率和油+气收率分别为69.5%和35.9%;未加催化剂时,神府煤液化THF抽提率和油+气收率都是最低的。     

保温墙模复合剪力墙结构体系的施工技术

从轻骨料免拆保温墙模复合剪力墙结构体系的特点出发，说明了其施工工艺的特殊性和复杂性，重点研究了本体系墙模砌筑主要工序内容，提出了施工工艺，并总结了本体系施工工艺中的施工难点，以期促进该结构体系的推广及应用。     

南京某工程地下室柱网及顶板结构布置方案研究

安全、适用、经济是设计的原则,其中经济性已经越来越受到建设者和设计者的重视。文章以南京河西某项目的地下室柱网及顶板结构布置方案分析比较过程为例,展示了方案优选的过程及重要性。     

Control of droplet transfer in consumable electrode welding with short circuiting of the arcing gap

We present the results of an experimental programme of fatigue tests carried out on two types of butt joints with thicknesses of 20 and 40 mm respectively, characterized by a significant gap between weld edges, not compliant with the requirements of construction specifications. The tests were conducted on specimens taken from the weld beads of joints typical of those produced at the site (butt joints between web and flanges) and made with the same procedures (welding process, welding position, welding filler, etc.). The test results were elaborated statistically to determine the fatigue resistance category in accordance with the requirements of standard EN 1993-1-9 and IIW recommendations. Calculations took into account both the thickness of the specimens (tests were carried out on both to-scale and true-thickness specimens for the purposes of validation) and also flexural stress components induced by the non-planarity of the specimens.     

Potential Barrier Heights and Phase Transition in Polyphenyls and Poly(p-Phenylene)

Abstract

The analysis from X-ray or neutron diffraction data, of the unusually high librational motion around the long molecular axis of the p-terphenyl central ring, reveals a doubly-peaked probability density function (p.d.f.), associated with a double-well potential function between two twisted conformations (φ = ± 13.3° on either side of the average molecular plane). This p.d.f. is the pretransitional effect of an order-disorder transition which takes place at low-temperature. With a simple model averaging the intermolecular interactions, it is possible to separate in the overall libration on each site, at the bottoms of the double well, the contribution of the torsional g mode (θ²) = 35 deg², responsible for the jumps above the barrier, from the contribution of the other modes (θ²) = 17.5 deg². Thus it becomes possible to determine the parameters of the model describing the intermolecular, as well as the intramolecular interactions and to specify the non-sinusoidal shape of the intramolecular potential between two adjacent phenyl rings. It is straightforward to extend the model to any p-polyphenyl molecule with any number of phenyl rings, by considering that the molecular packings are the same in all the family. The model gives an estimate of the reorientational potential barrier heights V = 4.57 kJ mol^?1 in p-terphenyl, V = 7.91 kJ mol^?1 in p-quaterphenyl, in good agreement with NMR results; the calculated p.d.f. are doubly peaked and V < kT at room temperature, which characterizes order-disorder transitions. On the other hand, the model gives a singly peaked p.d.f. and V = 1.25 kJ mol^?1 < kT in crystalline biphenyl, which agrees with the displacive nature of the phase transition. Combined with the features of the incommensurate phase of biphenyl at T = 20K, it gives an estimate of the interactions involved in the modulated phase, predicting a large increase of intermolecular interactions in biphenyl at low-temperature. Finally it is applied to poly(p-phenylene), predicting a twisted conformation in agreement with recent diffraction results and high reorientational barrier potentials.     

Impact of curing condition on pH and alkalinity/acidity of structural wood adhesives

Nine formulations were selected for evaluating the effect of different curing methods on pH and alkalinity or acidity of various structural wood adhesives. These included four phenol–formaldehyde (PF) resins with high pH, one phenol–resorcinol–formaldehyde (PRF) resin with intermediate pH, two melamine–urea–formaldehyde (MUF) resins, and two melamine–formaldehyde (MF) resins with low pH. The four curing methods used in the study were: (1) curing at 102–105°C for 1 h (based on CSA O112.6‐1977), (2) four‐hour curing at 66°C followed by 1‐hour curing at 150°C (based on ASTM D1583‐01), (3) curing at room temperature overnight (based on ASTM D 1583‐01), and (4) cured adhesive squeezed out from glue lines of bonded shear block samples. The effect of the different methods on pH and alkalinity/acidity of the cured adhesive depended strongly on the individual adhesives. For the PF, the alkalinity was different for the different formulations in the liquid form, while in the cured form, the difference in the alkalinity depended on the curing method used. The MF and the MUF were the adhesives most affected by the method used. In particular, the MUF showed much higher cured film pH values when cured by method 2 compared to the other three methods, while both the cured MF and MUF exhibited quite variable acidity values when cured with the different methods. The PRF showed reasonably uniform cured film pH but varying acidity values when cured with the different methods. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010