Study of impurity induced modifications in amorphous N-type (GeSe3·5)100−x Bi x using high pressure technique

The technique of high pressure is utilized to study the carrier transport behaviour in doped and undoped bulk amorphous (GeSe_3·5)_100−x Bi _x (x=0, 2, 4, 10) down to liquid nitrogen temperature to observe impurity induced modifications in amorphous semiconductors. It is observed that pressure induced effects in lightly doped (2 at % Bi) and heavily doped (x=4, 10) semiconductors are markedly different. Results are discussed in view of the incorporation behaviour of the bismuth impurity.     

Precision equipment for symmetrical bending— Part 1. The loading system

The design and performance of precision bending equipment for testing straight beams with constant rectangular section under a pure bending moment is described. Part 1 deals with the loading arrangements and Part 2 with the rig for measuring beam deflection. The methods for recording deflection of strain gauges applied on the beam have been described elsewhere.^1–4
The reactions to the deadweight gravity loads are taken via ball bearings. The total bending moment inaccuracy, i.e. the sum of estimated systematic errors and random errors, the latter expressed as the 2Ga confidence interval about the mean (2G_cim), is about ± 25 x. 10^-4%, for 23 tests with a steel beam with 15 mm × 75 mm cross sectional dimensions, loaded to 1-1.5 mm/m strain.
The measuring rig stands on the beam via hardened and polished spherical segment feet and uses a capacitive transducer system with less than 5nm resolution. Various application tasks are described. The total inaccuracy of the measured deflection, i.e. apart from bending moment inaccuracy, is about ± 35 times 10^4% for about 10 reproduced, not repeated, tests with the same steel beam. The deflection for such a beam is of the order of 2 to 4 mm.     

建设群力新区水系工程的初步设想

就水系工程水源的选择、规划设计要点,提出了初步设想。     

Random errors caused by temperature in magnitude of principal strains evaluated ith 3-element strain gauge rosettes

The effects of the uncertainties associated ith the apparent strain and gauge factor data, given by the manufacturer, in the evaluation of principal strains are examined. Principal strains are obtained by a reduction of the strains measured ith electrical resistance strain gauge rectangular or delta rosettes. The theoretical analysis points out the relevance of the effects caused.     

Electrical conductivity of ferroelectric sodium vanadate,rubidium vanadate,cesium vanadate and their solid solutions

The d.c. electrical conductivity of sodium vanadate, rubidium vanadate, cesium vanadate and their solid solutions sodium-rubidium vanadate and sodium-cesium vanadate were studied by a two-probe method in the temperature range covering their transition points. The electrical conductivity shows sharp change at the phase transition temperature of these materials. In NaVO₃, RbVO₃ and CsVO₃, increase in d.c. conductivity is observed in the ferroelectric region while nonlinearities are observed above transition temperatures. In solid solutions, the activation energy in the paraelectric state is higher than that in the ferroelectric state and depends upon sodium concentration.     

Study of liquid injection impact on the performance of new refrigerant mixtures

In this paper, the test results of liquid injection impact on the performance of new alternative refrigerant mixtures such as: R-410A, R-507, R-407C and R-404A are discussed, analysed and presented. The test results were obtained using an air-source heat pump set-up with enhanced surface tubing under various liquid injection ratios. Performance tests were conducted according to the ARI/ASHRAE standards. The performance data demonstrated that as liquid injection ratio increases, compressor head pressure and discharge temperature decrease. This has a positive effect in protecting the compressor. The effect of liquid injection on mixture behaviour varies from one mixture to another depending upon the mixture's composition. Furthermore, liquid injection appears to have a significant influence on R-410A behaviour compared to the other mixtures in question. Copyright © 2002 John Wiley & Sons, Ltd.     

碾压混凝土穿透型诱导缝不同扩展阶段的强度指标试验研究

在不同削弱度碾压混凝土轴拉试件的穿透型诱导缝周围粘贴了应变片，得到在不同应力状态下诱导缝应变发展规律为：在加载初期，离缝端不同距离的应变发展较为均匀，数值上相差不突出；随着荷载的增加，应变开始出现不均匀发展，离缝端越远，应变变化越缓慢；当接近最大荷载的阶段，缝端应变急速发展，试件瞬间断裂。应变从均匀发展变为不均匀发展，实质上隐含了诱导缝起裂、稳定发展、失稳断裂的整个过程，针对这一试验现象，结合断裂力学理论，建立了诱导缝不同开裂阶段的远场温度应力强度指标模型。     

Selectivity Enhancement to the Exclusive Formation of Ethyltoluenes and Hydrogen During Dehydroalkylation of Toluene with Ethane

The dehydroalkylation of toluene with ethane to the isomeric ethyltoluenes was studied on 0.4Pt/H-ZSM-5 at varying contact times (1/WHSV). At a high contact time of 1.0 h, toluene disproportionation and hydrogenolysis reactions dominate, resulting in low selectivity to the desired ethyltoluenes via the alkylation reaction. However, at a low contact time of 0.12 h side reactions are eliminated, resulting in maximum selectivities to the kinetically favored ethyltoluenes and hydrogen. Results at high selectivities to ethyltoluenes provide significant insight into reaction pathways.     

Production and structural features of a water-soluble polysaccharide from a mutant strain of Agrobacterium sp.

We have developed a mutant strain derived from Agrobacterium sp. ATCC 31750, which produces a water-soluble polysaccharide having potential utility to the food, feed, pharmaceutical and cosmetic industries. A high concentration of product (15 g/L) is obtained by 48 h cultivation of the mutant strain under optimized fermentation conditions. The water-soluble polysaccharide obtained from cultures of the mutant strain beta82 has Glc:Man:Gal in approximate molar ratios of 5.8:6.7:1.0. The molecular weight of the polysaccharide was determined to be approximately 1000 kDa by HPSEC analysis. Linkage analysis contained 3-Glcp, 3-Manp, terminal Glcp and terminal Manp, as well as a small proportion of 3- and 3,4-Galp, and 4,6-Manp residues. Based on analyses using FT-IR and ¹³C NMR spectrometers, most glycosidic bonds joining these sugar residues are of the α-type, and acetyl groups are apparently attached to the polymer chain at random.     

Comment on Greenwood (2007): Solving the puzzle of structure/function relations in the aging brain?

Neuroimaging experiments have shown that prefrontal regions of the brain, which have the most age-related volume loss, are also the regions most likely to be more active in older adults than in younger adults. In an attempt to solve this puzzle, P. M. Greenwood (see record 2007-15625-001) has proposed a cascade that flows from age-related atrophy in the brain to changed processing strategies that result in plastic changes in regions adjacent and contralateral to the atrophic areas, culminating in greater functional activity. This hypothesis should stimulate research into these mechanisms and hopefully will ultimately inform researchers' ability to rehabilitate cognitive disorders in the elderly. (PsycINFO Database Record (c) 2010 APA, all rights reserved)