并行计算应用程序开发（上）

当今的软件开发是由两个关键因素所促成的:其一是并行计算技术的广泛采用;其二是面向服务的体系结构的发展趋势。这两种理念都由来已久,但当前的CMT(Chip Multi- Threading,芯片多线程)处理器设计、平行扩展系统,延迟时间近乎于零的互连和新的Web服务标准都加速了两     

主板也饭“A” ATi Radeon X200系列芯片组主板导购

早在2004年11月，ATi就开始推出针对AMD平台的芯片组——Radeon Xpress 200系列，它包含绘图整合的Radeon Xpress 200和独立型Padeon Xpress 200P。这一芯片组具有高效能的绘图功能、高整合的系统传输连接及稳定可靠的软硬件支持。Padeon Xpress 200系列芯片组支持AMD Socket 754及959。在此之后，ATi不断地对AMD平台的Xpress 200系列芯片组推出新的芯片，目前已经包含PD480、RS480、RS482、RX480、RD580等多款芯片组．[编者按]     

离子表面活性剂和胶原间的相互作用

研究了二十烷基苯磺酸钠（SDBS）和溴化十六烷基吡啶翁（CPB）表面活性剂同胶原纤维（BAT）的反应。在酸性环境（pH＝3）和等电点条件（CrBATpH=6.5,SBAT PH=4)决定了吸附作用等温线。同时，研究了底物的膨胀变化（用αm表示膨胀度）。已经证实了离子表面活性剂对铬鞣和植物鞣胶原的吸收。发现SDBS对CrBAT的吸收与反应的pH值无关而取决于铬进一步吸收的活性位置的含量。在酸性区域，结合SDBS不使CrBAT纤维膨胀，而CrBAT在等电点条件下存在较轻微的膨胀。CPB与CrBAT的结合量较小，在同样的反应条件下，CPB在pH=6.5时的吸收实际与其对未鞣 的BAT的吸收相同。靠SBAT在高pH值下的稳定性，离子表面活性剂对SBAT的吸收要在pH=4时有效。预测SBDS的吸收更低，但等温线是S形相对于c.m.c.SDBS有一个滞后的段。CPB－SBAT和SDBS－BAT反应，当CPB对BAT吸收时纤维会发生轻微的膨胀。     

基于分形的从明暗恢复形状算法研究

从明暗恢复形状是计算机视觉领域中的经典病态问题，传统方法是通过引入光滑约束等条件来获得问题的解，但传统方法存在因过平滑而失真的缺点。针对传统方法恢复结果的局限性，提出了一种基于分形约束的从明暗恢复形状的新算法，该方法首先给出分形约束条件，之后结合反射图线性化与最小能量法来计算出曲面高度。该方法不仅克服了传统算法因基于光滑假设所造成的恢复结果过分平滑而失真的缺点，且不需要可积性的约束条件，也不需要对边界条件的假设，实验结果表明，该方法用于自然景物的三维表面重构，可获得比传统方法更好的恢复效果。     

利用土壤切片及数字图像研究低丘缓坡不同部位土壤的孔隙结构特征

利用土壤切片及数字图像技术 ,初步研究了葡萄种植园低丘缓坡不同部位 (坡顶、坡中和坡底 )土壤的孔隙结构特征。结果表明 :孔隙面积随着深度的增加而减小 ,孔隙构成以直径小于 1mm的小孔隙为主 ,且随着深度增加小孔隙比重增加 ,不同部位孔隙结构具有一定的差异 ,这也说明了采取水土保持措施的必要性     

配电线路无通道保护的实现与试验

提出了一种利用单端电气量的快速配电线路无通道保护新原理，该原理作为一个独立模块嵌入MiCOM P140系列继电器中予以实现；描绘了实现方案的硬件结构和软件流程。大量的实时仿真系统(RTDS)的结果显示：新方案能有效加速过电流保护对不对称故障的响应速度，能正确区分区内故障和区外故障，实现了配电网无通道保护的功能。     

Simulation of dike-break processes in the Yellow River

Although dike-break and dam-break processes have similar unsteady and discontinuous hydrodynamic characteristics, there are significant differences. In general, dam-break simulations focus on the flood discharge, whereas dike-break simulations are required to provide detailed information on the hydraulic and breach evolution processes, such as pit-scour and breach-expansion. In order to overcome the difficulties inherent in applying existing dam-break models to dike-breaks, this paper presents an integrated model that combines the shallow water, sediment transport, riverbed deformation and breach-expansion equations. A Godunov-type finite volume method is used for the flow simulation, based on a fixed quadtree grid system. The hydro-dynamic aspects of the model are validated for an idealized rectangular dam break. A representative reach in the Yellow River is selected at a location where there is a significant risk of a dike-break, and full-scale topographic and hydrologic data are available. Typical di     

Capillary electrokinetic chromatography with charged linear polymers as a nonmicellar pseudostationary phase: determination of capacity factors and characterization by solvation parameters

A permanent polycation, polydiallyldimethylammonium (PDADMA), is applied as a linear, polymeric, replaceable, and nonmicellar pseudostationary phase for the separation of neutral analytes by capillary electrokinetic chromatography. It is shown that this polymer used in the background electrolyte is able to separate the analytes even if it does not form micelles under the given conditions. The most favorable aspect for practical use lays in the simple replacement of the separation media after each run, thus generating highly reproducible conditions. To determine the capacity factors of the analytes, a new method, based on an isotachophoretic regime, has been introduced for the measurement of the electrophoretic mobility of the polymeric pseudo-stationary phase. The capacity factors in the separation system, derived from the mobilities of the polymer, the electroosmotic flow, and the mobilities of 15 individual aromatic analytes, range between 0.3 and 1.2 for the given separation media (aqueous solution of acetate buffer, pH 5.2, with 4% w/w PDADMA). The type of interaction in the pseudochromatographic system was clarified from solvation parameters based on the linear free energy relationship model. It was found that pi and n electron interactions and hydrogen-bond basicity of the polymer, as compared with the aqueous bulk phase, are the main cause of retention of the analytes.     

The community safety approach in Falun, Sweden--is it possible to characterise the most effective prevention endeavours and how long-lasting are the results?

The safe community concept was put into practice in order to reduce the number of unintentional injuries occurring in the Falun municipality. A community-based injury prevention programme was initiated in 1989 and has been gradually built up since that time. The prevention endeavours were based primarily on active intervention strategies through the provision of information, supervision, education and training. After 5 years of an active intervention programme, a significant effect was found as regards the injury rates for both outpatients as well as patients discharged from hospitals. The objectives of this study were: to examine whether the character of the prevention endeavours was a determining factor on the outcome (recorded as in-patient injury cases); to evaluate the effects of this programme, which is still in practice, compared to long-term historical trends; and to draw comparisons with other community-based programmes. A category of 'most targeted risks' was identified as being different with respect to how the injury mechanisms involved were targeted through the programme activities. The development within the injury rates for this group, comprised predominantly of injuries caused by falls at the same level, was significantly different than those for the groups categorized as 'less targeted' and 'non-targeted'. The general effect of the programme appeared to be a neutralization of an otherwise upward trend in the injury rates. A particular effect was demonstrated in the number of fall injuries, including femoral fractures. It was also noted that there was still a reduction in injuries after 7 years. However, it was possible to surmise a waning effect during the last 2 years of the programme while still in progress. This observation suggests that a community-based injury prevention programme must be continuously renewed and reinforced.     

Head restraints--the neglected countermeasure

In a rear-end crash, if an occupant's head is unsupported it lags behind as the torso is accelerated forward. This causes the neck to change shape, first taking an s-shape and then bending backward in a 'whiplash' motion. This sudden differential movement of the head and torso can cause 'whiplash' injuries to the neck. This paper reviews methods to minimize the differential head/torso movement and reduce the resulting injuries, focusing on the necessary first step for prevention, which is a head restraint that is behind and close to the back of an occupant's head during the crash. The history of head restraints since the 1950s is reviewed, with particular attention to advanced restraint designs that are proving effective in reducing whiplash injury risk in dynamic tests using a new crash test dummy neck and a new neck injury criterion.