Partitioning and mapping nested loops on multiprocessor systems

A method for executing nested loops with constant loop-carried dependencies in parallel on message-passing multiprocessor systems to reduce communication overhead is presented. In the partitioning phase, the nested loop is divided into blocks that reduce the interblock communication, without regard to the machine topology. The execution ordering of the iterations is defined by a given time function based on L. Lamport's (1974) hyperplane method. The iterations are then partitioned into blocks so that the execution ordering is not disturbed, and the amount of interblock communication is minimized. In the mapping phase, the partitioned blocks are mapped onto a fixed-size multiprocessor system in such a manner that the blocks that have to exchange data frequently are allocated to the same processor or neighboring processors. A heuristic mapping algorithm for hypercube machines is proposed     

耐高温绝缘GFRP管的真空辅助树脂传递成型工艺研究

阐述了耐高温绝缘GFRP管的成型工艺及原材料选择，并对影响成型工艺的主要因素作了理论分析及试验验证。研究表明，以TDE－85／DDS体系为为基体，以无碱无捻玻璃纤维方格布为增强材料，用VARTM工艺成型的石油勘探高性能平衡管完全满足技术要求。     

Hyperdynamic circulation of cirrhotic rats: role of substance P and its relationship to nitric oxide

BACKGROUND: It has been suggested that excessive formation of nitric oxide (NO) is responsible for the hyperdynamic circulation observed in portal hypertension. Substance P is a neuropeptide partly cleared by the liver and causes vasodilatation through the activation of the endothelial NO pathway. However, there are no previously published data concerning the plasma level of substance P in cirrhotic rats and its relationship to NO. METHODS: Plasma concentrations of substance P and nitrate/nitrite (an index of NO production) were determined in control rats and cirrhotic rats with or without ascites using an enzyme-linked immununosorbent assay and a colorimetric assay, respectively. In addition, systemic and portal hemodynamics were evaluated by a thermodilution technique and catheterization. RESULTS: Cirrhotic rats with and without ascites had a lower systemic vascular resistance (2.6 +/- 0.2 and 3.9 +/- 0.4 mmHg ml(-1) x min x 100 g body weight, respectively) and higher portal pressure (14.6 +/- 0.6 and 11.3 +/- 1.8 mmHg) than control rats (6.5 +/- 0.3 mmHg x ml(-1) x min x 100 g BW and 6.8 +/- 0.2 mmHg, respectively, P < 0.05), and cirrhotic rats with ascites had the lowest systemic vascular resistance. Plasma levels of nitrate/nitrite progressively increased in relation to the severity of liver dysfunction (control rats, 2.7 +/- 0.5 nmol/ml; cirrhotic rats without ascites, 5.6 +/- 1.3 nmol/ml; cirrhotic rats with ascites, 8.3 +/- 2.2 nmol/ml; P < 0.05). Cirrhotic rats with ascites displayed higher plasma values of substance P (57.7 +/- 5.9 pg/ml) than cirrhotic rats without ascites (37.9 +/- 3.1 pg/ml, P < 0.05) and control rats (30.1 +/- 1.0 pg/ml, P < 0.05). There was no significant difference in plasma substance P values between control rats and cirrhotic rats without ascites (P > 0.05). No correlation was found between plasma levels of substance P and nitrate/nitrite (r = 0.318, P > 0.05). CONCLUSIONS: Excessive formation of NO may be responsible, at least partly, for the hemodynamic derangements in cirrhosis. Although substance P may not participate in the initiation of a hyperdynamic circulation in cirrhosis, it may contribute to the maintenance of the hyperdynamic circulation observed in cirrhotic rats with ascites.     

A 2.2 W, 80 MHz superscalar RISC microprocessor

A 28 mW/MHz at 80 MHz structured-custom RISC microprocessor design is described. This 32-b implementation of the PowerPC architecture is fabricated in a 3.3 V, 0.5 μm, 4-level metal CMOS technology, resulting in 1.6 million transistors in a 7.4 mm by 11.5 mm chip size. Dual 8-kilobyte instruction and data caches coupled to a high performance 32/64-b system bus and separate execution units (float, integer, loadstore, and system units) result in peak instruction rates of three instructions per clock cycle. Low-power design techniques are used throughout the entire design, including dynamically powered down execution units. Typical power dissipation is kept under 2.2 W at 80 MHz. Three distinct levels of software-programmable, static, low-power operation-for system power management are offered, resulting in standby power dissipation from 2 mW to 350 mW. CPU to bus clock ratios of 1×, 2×, 3×, and 4× are implemented to allow control of system power while maintaining processor performance. As a result, workstation level performance is packed into a low-power, low-cost design ideal for notebooks and desktop computers     

基于媒体用户访问行为偏好模型的代理缓存算法

目前,代理缓存技术广泛应用于改善流媒体传输的服务质量.文章从实际用户日志文件的分析出发,利用发现的用户浏览流媒体对象时的行为分布模型,提出了一种新的视频流媒体缓存算法.仿真结果证明,该算法可以通过记录很少的用户访问信息获取较高的性能表现.     

内嵌RAM的液晶显示控制驱动器

讨论一种液晶控制驱动器的设计及使用方法。根据设计要求，阐述了每个分模块的设计思想与设计方法，并进行了数模混合仿真。     

Synthesis,Characterization and Luminescent Properties of Complexes of Rare Earth Nitrates with Tris{2-[N-(pyridine-methanoyl)amino]ethyl} amine

Duringthelastdecade ,thedesignandsynthesisoftripodalligandsandtheirmetalcomplexeshaveattractedconsiderableattentionduetotheirpotentialusesaslumi nescentprobesinmedicineandbiochemistry[1～ 7] ,ascatalysts[8] andelectrochemicalmaterials[9] .However ,thecomplexesofrareearthmetalwithtripodalligandshavefewreported[10 ] .Asanextensionofourstudiesoncomplexesofmetalwithtripodalligands ,anewtripodalligand (tris { 2 [N (pyridine methanoyl)amino]ethyl}amine ,L)anditscomplexeswithrareearthnitratesweresyn…     

膜控晶体生长及纳米微粒的形成

膜控晶体生长不同于一般在溶液中的沉淀与结晶，由膜形成的有机界面具有空间定位和空间约束、定域化学控制及成核过程和晶体生长的立体化学专一的特性，使得晶体的结构、形状和尺寸上得到控制，并具有良好的重现性，由此可获得具有光、电以及磁特性的纳米功能材料。研究膜控晶体生长不仅可以模拟生物体系内的生物矿化作用，而且对于材料科学也有着特别重要的意义和应用前景。