烷基糖苷的制备与性能

介绍了以对甲基苯磺酸为催化剂 ,以葡萄糖和醇为原料合成APG的方法。确定了较佳工艺条件为 :正丁醇与高碳醇之比为 1∶1(mol/mol) ,醇糖比为 3∶1(mol/mol) ,用H2 O2 脱色 ,反应温度为 110～ 115℃ ,反应时间为 1 5h ,葡萄糖的转化率达到 98% ,合成出的产品性能好 ,特别适用于餐具洗涤剂和洗发香波     

浅谈330E软泡通用聚醚多元醇的生产及质量

简述了我国330E软泡通用聚醚多元醇的生产状况,与国外同类产品牌号进行了质量比较,并探讨了内在质量对发泡的影响。     

Development of a 100 W rechargeable bipolar zinc/oxygen battery

A bipolar filter press-type electrically rechargeable Zn/O2 battery has been developed. Reticulated copper foam served as substrate for the zinc deposit on the anodic side, and La0.6Ca0.4CoO3-catalysed bifunctional oxygen electrodes were used on the cathodic side of the cells. The 100cm2 unit cell had an open circuit voltage of 1.4V (O2) in moderately alkaline electrolyte. The open circuit voltage and the peak power measured for a stack containing seven cells were sim 10V and sim 90W, respectively. The current-potential behaviour was determined as a function of the number of bipolar cells, and the maximum discharge capacity was determined at different discharge rates.     

压力式空气泡沫比例混合器的结构设计与计算

本文对压力式空气泡沫比例混合器的工作原理、结构进行了分析，提出了压力式空气泡沫比例混合器的结构设计与计算方法。     

氮气泡沫调驱提高稠油采收率实验——以秦皇岛32-6油田为例

为了改善秦皇岛32—6油田的水驱开发效果，开展了氮气泡沫调驱提高稠油呆收率室内实验研究。通过泡沫剂的静态性能和动态性能评价，筛选出泡沫剂及其配方。在此基础上，研究了氮气泡沫的驱油特点。研究结果表明，在气液比为1：2时，氮气泡沫的阻力因子大于160，泡沫剂的最佳质量分数为0．3％～0．5％。氮气泡沫调驱能够较好地改善水驱效果，在水驱的基础上提高原油采收率达26％。     

Improved performance of Pd electrocatalyst supported on three-dimensional nickel foam for direct ethanol fuel cells

To improve the performance of direct ethanol fuel cells (DEFCs), a three-dimensional (3D), hierarchically structured Pd electrode has been successfully fabricated by directly electrodepositing Pd nanoparticles on the nickel foam (referred as Pd/Nickel foam electrode hereinafter). The electrochemical properties of the as-prepared electrode for ethanol oxidation have been investigated by cyclic voltammetry (CV). The results show that the oxidation peak current density of the Pd/Nickel foam electrode is 107.7 mA cm⁻², above 8 times than that of Pd film electrode at the same Pd loading (0.11 mg cm⁻²), and a 90 mV negative shift of the onset potential is found on the Pd/Nickel foam electrode compared with the Pd film electrode. Furthermore, the peak current density of the 500th cycle remains 98.1% of the maximum value for the Pd/Nickel foam electrode after a 500-cycle test, whereas it is only 14.2% for the Pd film. The improved electrocatalytic activity and excellent stability of the Pd/Nickel foam electrode make it a favorable platform for direct ethanol fuel cell applications.     

New Bounds for Multidimensional Packing

Abstract. New upper and lower bounds are presented for a multidimensional generalization of bin packing called box packing. Several variants of this problem, including bounded space box packing, square packing, variable-sized box packing and resource augmented box packing are also studied. The main results, stated for d=2 , are as follows: a new upper bound of 2.66013 for online box packing, a new 14/9 + ɛ polynomial time offline approximation algorithm for square packing, a new upper bound of 2.43828 for online square packing, a new lower bound of 1.62176 for online square packing, a new lower bound of 2.28229 for bounded space online square packing and a new upper bound of 2.32571 for online two-sized box packing.     

LZH—6／900复合式拉丝机的加工

通过解决复合式拉丝机加工过程中的几个难点,加工质量及整机的精度得到保证,并达到了设计要求。     

A comparison of CFD‐simulations and measurements of the temperature stratification in a mixing box of an air‐handling unit

This paper presents a comparison between CFD‐simulations and measurements of the temperature stratification in a mixing box of an air‐handling unit. We have used data from field measurements during a period of over a year for different outside temperatures. We performed two‐dimensional CFD‐simulations for four different outside temperatures with commercially available software. The measurements as well as the simulations show that the temperature difference between the upper part and the lower part of the duct downstream of the mixing box is considerable. It increases, as the outside temperature decreases. However, the discrepancies between the measurements and the simulations are large. The reasons for this are uncertain boundary conditions and modelling errors leading to an inaccurate simulation result. The stratification downstream of the mixing box implies large sensor errors and the use of the mixed air temperature for control and fault detection must therefore be questioned. Averaging sensors, which take a mean value over the duct section, can be used but do not consider differences in velocities and are therefore not accurate either. In order to, for example, use CFD as a tool to decide the optimal sensor location a more accurate model and more information regarding the boundary conditions is needed. Copyright © 2001 John Wiley & Sons, Ltd.     

某地铁区间轨排井基坑围护结构变形过大的设计调整

介绍广州地铁二八号线石会区间轨排井的锚索围护结构的施工过程,在地质条件差,雨季地下水丰富,锚索体系部分预应力失效引起基坑变形过大的情况下,利用支护结构本身加强和设置环框梁,既满足了轨排施工需要预留较大孔洞的需要,也保证了基坑安全,为类似支护工程提供参考。