国际石油市场供求格局正在发生结构性变化

从供给和需求两个方面对国际石油市场格局变化进行了分析。在供给方面,探讨了石油探明储量、产能以及产油主体政策调整等因素的影响。主要观点是:石油储量虽然满足未来数10年的世界石油需求,但探明储量增速明显放缓;世界石油产能增长缓慢,导致剩余产能严重不足;产油主体政策调整进一步制约了产能的增长。在需求方面,探讨了世界经济形势、高油价、能源利用效率、替代能源等因素的影响。主要观点是:世界经济保持较快增长,特别是随着发展中国家工业化程度加深,导致石油需求增长迅速;高油价对世界经济的冲击明显减轻,难以改变石油需求快速增长的趋势;由于石油消费集中在运输领域,节能对减少世界石油需求效果有限;高油价虽能推动替代能源的发展,但石油仍将长期保持主体能源地位。通过供需两方面分析,指出当前世界市场石油供需格局正在发生结构性变化,油价将长期在高位波动。     

河道洪水演算方法之间参数关系的研究

本文根据累积量定理推导了马斯京根法与扩散模拟法、加里宁一米留柯夫法与扩散模拟法之间参数关系的表达式,并与参数关系的水动力学推导作了比较,结果表明两者完全一样,本文还给出了滞时演进法与扩散模拟法之间参数的关系、河道洪水演算方法之间参数关系的研究,对概念性流域地貌汇流模型的建立具有一定的理论价值,而且对于认识汇流参数的推移和坦化作用以及汇流模型之间的比较均具有一定的实用价值.     

Influences of Thermal Martensites and Grain Orientations on Strain-induced Martensites in High Manganese TRIP/TWIP Steels

Strain-induced martensites in high manganese TRIP/TWIP steels were investigated in the presence of thermal martensites and under the influence of austenitic grain orientation by X-ray diffraction(XRD),scanning electron microscopy(SEM) and electron backscattered diffraction(EBSD).Before deformation,the morphology of α’-M depended mainly on the number of variants and growing period.Regardless of martensite morphologies and deformation,the Kurdjumov-Sachs(K-S) orientation relationships always maintained.The 6 α-M variants formed from a plate of ε-M were of 3 pairs of twins with a common axis <110> α’ parallel to the normal of {111} γ habit plane to minimize transformation strain.When α’-M could be formed only by deformation,it nucleated at the intersection of ε-M variants and grew mainly in thick ε-M plates.Thick ε plates promoted significantly the α’-M and weakened the influence of grain orientations.During tension,the transformation in <100>-oriented grains was observed to be slower than that in <111>-oriented grains.Deformation twins promoted ε-M formation slightly and had no apparent effect on α’-M.Deformation increased the number of ε-M variants,but reduced that of α’-M variants.     

基于分割区域的SAR图像配准方法研究

合成孔径雷达(Synthetic Aperture Radar,简称SAR)图像受到斑点噪声影响以及成像条件的变化,使得同一场景的两幅SAR图像之间存在很大差异,利用基于边缘特征或灰度信息进行SAR图像配准,难以达到预期效果.基于此,本文提出一种基于分割区域的SAR图像配准方法,该方法首先利用主动轮廓方法对去噪后的SA...     

我国三网融合发展战略

随着国民经济的飞速发展以及相关网络技术的突破,三网融合的趋势已经越来越明显.我国政府对此高度重视并积极推进相关政策的制定,在国民经济和社会发展规划以及相关政府工作报告中都对三网融合作出了重要指示.基于我国"十一五"三网融合发展的现状和特点,对当前推进我国三网融合所面临的一些主要问题进行了详尽的分析和讨论,研究了未来我国...     

数据挖掘技术在客户关系管理中的应用研究

在电子商务环境下,客户对企业起着至关重要的影响。新客户的获取无疑对企业的生存和发展起到很重要的作用。客户关系管理系统中,通过分析海量数据之间的联系,建立规范全面的信息模型。为了解决新客户的获取问题,采用数据挖掘技术对客户类别进行预测。通过对数据挖掘各种算法的比较,做了决策树算法编程实验,获得客户类别的预测结果。结果表明,数据挖掘技术能有效提高客户预测的准确率,提高了数据利用率。     

Effect of human-animal relationship and management on udder health in Swiss dairy herds

In a cross-sectional study, we investigated the effects of human-animal interactions and management factors on udder health in 46 Swiss dairy herds living in loose-housing systems on farms that participated in the Swiss dairy farm network “pro-Q.” The human-animal relationship was measured by observing milkers’ behavior, cows’ behavior during milking, and cows’ avoidance distance in the barn. Management factors were assessed by questionnaire-guided interviews and observations. Udder health was evaluated using indicators that were calculated from milk recording data over a period of 1 yr before assessment: (1) average somatic cell scores (SCS) per herd and (2) incidence of new infections per herd (NEWINF); and indicators that were calculated from quarter milk samples of all lactating cows at the time of assessment: (3) prevalence of quarters with elevated somatic cell counts (>100,000 cells/mL; %Q>100) and (4) prevalence of mastitis quarters (>100,000 cells/mL and culturally positive; %Qmast). After univariate preselection of associated factors, multivariable linear regression models were calculated at the herd level and a multilevel regression model was calculated at the herd and cow levels for SCS. Among all of the human-animal relationship factors, the most dominant predictor for SCS, %Q>100, and %Qmast was the percentage of positive interactions of milkers with the cows in relation to all of their interactions during milking. Furthermore, a higher prevalence of fearful cows in the herd (with an avoidance distance >1 m) was associated with a higher %Q>100. In herds with a higher NEWINF, incidents of cows kicking during milking occurred more frequently. Concerning management as well as farm and herd characteristics, the following mastitis risk factors were found: (1) breed, especially Holstein with regard to SCS, NEWINF, and %Qmast; (2) high age in terms of lactation number with regard to SCS and %Qmast; (3) high amount of new infections of a cow over 1 yr with regard to SCS; (4) air-adsorption during application of teat-cups with regard to NEWINF; (5) lack of separation of diseased cows with regard to NEWINF; and (6) ample dimensions of lying places with regard to %Qmast. The results suggest that the human-animal relationship is relevant for udder health, especially for cows’ reactions to infections expressed as somatic cell count levels. Risk of infection itself appears to be mainly influenced by management factors. Hence, the human-animal relationship may be considered in extension concerning preventive mastitis control.     

QSAR-aided in silico approach in evaluation of food proteins as precursors of ACE inhibitory peptides

An increasing prevalence of hypertension in the world implies the necessity of further study of antihypertensive peptides as an alternative means for hypertension management. The purpose of this study was to evaluate systematically the potential of major food proteins as precursors of ACE inhibitory peptides using QSAR-aided in silico approach, and thus to establish the rationale for choosing the appropriate substrate proteins in preparing ACE inhibitory peptides. In silico digestion of proteins from 15 common food commodities by thermolysin generated 5709 peptides ranging from 2 to 6 amino acid residues. Peptides were divided into three categories based on the potency of their predicted activities. Our results showed that meat proteins from pork, beef and chicken contain the largest number of potent peptides (IC₅₀ < 10 ??M), followed by proteins from milk, egg, soybean and canola, whereas proteins from fish (with the exception of salmon) and cereals (oat and barley) contain the least number of potent peptides. This study demonstrated that proteins from livestock meat, milk, egg, soybean and canola are good sources of ACE inhibitory peptides.     

水泥-沥青胶凝材料动态力学行为的初步研究

研究了不同沥青含量（A/C）的水泥-沥青复合胶凝材料7d龄期的动态黏弹性力学行为。选择3种温度环境（？25℃、25℃和75℃）,采用动态黏弹谱仪测试了3种不同A/C的水泥-沥青胶凝材料（简称为CAB）在频率范围0.1Hz~100Hz的动态力学性能,获得了不同温度下储存模量、损耗模量及损耗角随加载频率变化的基本规律。基于...