6通道后向散射仪

6通道后向散射仪是用于海洋光学调查的仪器,可用于测量海水的后向散射系数.本文详细介绍了该仪器的配置、技术参数和使用方法.初步分析了利用该仪器于2005-06在渤海海域进行调查获得的数据,结果显示该仪器可适用于我国近海二类水体的测量.这对于我国近岸水体的光学调查及研究具有极其重要的意义.     

一种皮带纠偏装置

带式输送机在各种物料搬运机械中具有结构简单、输送物料种类广泛,运输能力大,输送线路适应性强,运行平稳可靠、动力消耗低、使用寿命长、安装方便装卸料简便等优点已成为连续输送机的主力军,但是输送带跑偏是其常见的问题,影响了其安全生产,本文介绍一种简单实用的纠偏装置,可实时的纠正输送带跑偏。     

Molecular wire of urea in carbon nanotube: a molecular dynamics study

We perform molecular dynamics simulations of narrow single-walled carbon nanotubes (SWNTs) in aqueous urea to investigate the structure and dynamical behavior of urea molecules inside the SWNT. Even at low urea concentrations (e.g., 0.5 M), we have observed spontaneous and continuous filling of SWNT with a one-dimensional urea wire (leaving very few water molecules inside the SWNT). The urea wire is structurally ordered, both translationally and orientationally, with a contiguous hydrogen-bonded network and concerted urea's dipole orientations. Interestingly, despite the symmetric nature of the whole system, the potential energy profile of urea along the SWNT is asymmetric, arising from the ordering of asymmetric urea partial charge distribution (or dipole moment) in confined environment. Furthermore, we study the kinetics of confined urea and find that the permeation of urea molecules through the SWNT decreases significantly (by a factor of ～20) compared to that of water molecules, due to the stronger dispersion interaction of urea with SWNT than water, and a maximum in urea permeation happens around a concentration of 5 M. These findings might shed some light on the better understanding of unique properties of molecular wires (particularly the wires formed by polar organic small molecules) confined within both artificial and biological nanochannels, and are expected to have practical applications such as the electronic devices for signal transduction and multiplication at the nanoscale.     

芝麻素对肾性高血压伴高血脂大鼠主动脉舒张功能的影响

目的: 探讨芝麻素(Sesamin,Ses)改善肾性高血压伴高血脂大鼠(Rrenal hypertensive-hyperlipidemia rat,RHHR)主动脉舒张功能损伤的作用机制。方法: RHHR灌服不同剂量Ses(100、33、10 mg·kg^-1·d^-1)8周后,测定主动脉环对乙酰胆碱(Acetylcholine,ACh)和硝普钠(Sodium nitroprusside,SNP)的舒张反应;测定一氧化氮合酶抑制剂左旋硝基精氨酸甲酯(N-nitro-L-arginine-methyl-ester,L-NAME)孵育后,动脉环对ACh的反应并计算一氧化氮(Nitric oxide,NO)活性。结果: 与假手术组相比,RHHR主动脉Ach和SNP诱导的舒张反应显著降低,NO活性减少,Ses治疗8周后能逆转上述作用。结论: Ses降压作用与改善RHHR主动脉内皮依赖性和非内皮依赖性舒张功能损伤有关。     

WindowsXP下PCI设备驱动程序的设计

文章介绍了WindowsXP环境下PCI设备驱动程序的开发与实现方法,探讨了PCI设备的I/0端口访问、中断处理、DMA传输、驱动程序与应用程序之间的通信等主要问题,重点对编写驱动程序的过程进行了说明,并实现了驱动程序的安装与调试。     

Distribution and genesis of the anomalously high porosity zones in the middle-shallow horizons of the northern Songliao Basin

High-quality reservoirs occur in the middle-shallow horizons of the northern Songliao Basin. The distribution and genesis of their anomalously high porosity zones were studied using measured porosities, examination of ordinary thin sections and blue epoxy resin-impregnated thin sections and by SEM. The results show that there are three anomalously high porosity zones at the depth of 450–900 m, 1,300–1,900 m, 2,050–2,350 m respectively, named zone i, zone ii and zone iii from top to bottom. Horizontally, zone i and zone ii are distributed all over the basin except in the Southeastern Uplift, while zone iii is only distributed in the Central Depression. Zone i was formed by meteoric water leaching as well as organic acid dissolution. Zones ii and iii were dominantly formed by organic acid dissolution. Additionally, clay mineral transformation generating H⁺ and hydrocarbon emplacement retarding the cementation of sandstones are also important for the formation of zones ii and iii.     

A whole-genome scan to map quantitative trait loci for conformation and functional traits in Canadian Holstein bulls

Genetic improvement of livestock populations can be achieved through detection and mapping of genetic markers linked to quantitative trait loci (QTL). With the completion of the bovine genome sequence assembly, single nucleotide polymorphism (SNP) assays spanning the whole bovine genome and research work on large-scale identification, validation, and analysis of genotypic variation in cattle has become possible. A total of 462 Canadian Holstein Bulls were used to test the association between SNP and QTL. Single locus linkage disequilibrium regression model was implemented to perform a whole genome scan to identify and map QTL affecting conformation and functional traits. One thousand five hundred thirty-six SNP markers from introns and exons of potential QTL regions for economically important traits across the bovine genome were selected for association analysis. A total of 45 and 151 SNP were found to be associated with 17 conformation and functional traits at a genome- and chromosome-wise significance level, respectively. Among the 196 significant SNP, 169 of them are newly detected in this study, whereas 27 of them have been reported in previous literature and 161 of these were located in genes and are worth further investigating to potentially identify the causative mutations underlying the QTL. The single locus linkage disequilibrium regression method using SNP marker genotypes has proven to be a successful methodology for detecting and mapping QTL in dairy cattle populations.     

Data Driven Prediction of Sintering Burn-Through Point Based on Novel Genetic Programming

 The paper presents an empirical dynamic model of burn-through point (BTP) in sintering process. The model combines two stages of sintering process, cold processing stage and sintering stage. Fist, cold bed permeability measured by Gas velocity is introduced in the cold stage. Then, K-Means clustering is applied to partition the feed according to the permeability. Besides, for each clustering, a novel genetic programming (NGP) is proposed to construct the empirical model of the waste gas temperature and pressure drop through the bed in sintering stage. NGP adopts least square method (LSM) and M-estimator to improve the ability to compute and resist disturbance. Therefore, the paper constructs a model base of burn-through point and the simulation proves that the model base has a good performance.     

Productivity and carcass characteristics of pure and crossbred Chinese Yellow Cattle

The carcass characteristics of 334 Chinese Yellow Cattle, and their Simmental and Limousin crosses, were investigated in abattoirs in Hebei and Sandong provinces of China. The overall slaughter age was 4.8±2.2 years at a mean liveweight of 527.28±77.0 kg. Mean ages and liveweights for Yellow Cattle and its crosses were, respectively, 5.29±2.03 and 2.85±1.71 years and 519.43±78.7 and 563.13±56.8 kg. Carcass weights varied considerably and, consequently, so did subcutaneous fat depths and dressing percentages. Overall, mean carcass weights, subcutaneous fat depths and, dressing percentages and eyemuscle areas were 283.9±64.1 kg, 14.0±8.0 mm, 54.0±4.0%, and 62.7 ±13.3 cm², respectively. Compared with pure Yellow Cattle, the crosses were slaughtered at younger age, and had larger live and carcass weights, higher dressing percentages, less subcutaneous fat depth and bigger eyemuscle areas. It is concluded that crossbreeding can significantly improve Yellow Cattle' meat productivity, however feeding systems need to be improved and an appropriate grading system developed to improve beef production and quality in China.     

南昌市用水结构变化及驱动力分析

研究城市用水结构变化及其驱动力,对于城市可持续用水,科学合理配置水资源有重要意义.基于南昌市2005~2014年水资源公报的用水量数据,采用信息熵理论和均衡度方法分析用水结构演变规律,运用SPSS软件的主成因分析法分析南昌市用水结构驱动力因子.结果表明:南昌市用水结构体现在农业用水量较大,工业和生活用水量次之,生态用水量较小;用水结构信息熵和均衡度呈上升趋势;因子分析结果表明,社会经济因子为用水结构演变主要驱动力.