稠油电加热最优PID参数自整定控制方法

稠油油井电加热是油田常用的稠油开采方式之一,针对稠油电加热系统,建立了加热对象的数学模型;通过仿真实验对不同最优准则下进行了比较研究,并给出了仿真波形及其分析,得出时间平方加权的误差平方积分(ISTTE)准则下的控制方法,该法可以缩短系统的调节时间,有效地抑制系统的超调,从而可以提高稠油电加热系统的加热效率.     

基于多层特征基参数融合的网络入侵检测算法

传统的网络入侵检测算法,使用的都是同一个或者相似的特征基作为入侵检测的衡量标准,但是在多层网络中,不同层次的特征基参数存在差异,检测结果误差较大。为此提出了一种基于多层特征基参数融合的网络入侵检测算法。通过提取多层网络操作差异特征基参数,利用非线性回归方式对每层特征基参数进行差异补偿,按照自适应融合方式对多层差异特征基进行融合处理,以此作为检测的基础。实验表明,该算法提高了检测的准确率,取得了理想的效果。     

早期宇宙再电离过程的宇宙学效应

利用再电离时期的高红移类星体的Lya光子的有效光学深度数据,对ACDM宇宙学模型下的宇宙学参数h,Ωm,ΩA和Ωb进行限制．这批数据是首次被用于这类限制宇宙学参数的工作．以Gunn—Peterson的Lya光子的光深公式为基础,在四种情况下对参数进行限制．结果发现,在非均匀星际介质的高红移化简情况下,所得到的大部分参数的最佳值及1σ不确定度非常理想,它们与WMAP-5的最新观测结果非常接近．此外,对理论值与观测值的比较,也说明了结果是令人满意的．得到的这些结果不但强烈支持了WMAP-5的观测,并且由于是首次利用这批高红移类星体的数据,所以也从另一个角度检验了ACDM宇宙学模型的自洽性．此外,还可将所得到的结果与其它观测如BAO、超新星的结果联合起来进行更多的讨论及限制．对于其他情况的结果,我们也进行了较深入的讨论．     

利用项目反应理论的正态双卵模型评估考试科目

文章采用项目反应理论中的两参数正态双卵模型,利用MCMC的方法,给出了Gibbs抽样估计项目参数的Matlab程序,根据该程序对某校本科生的期末成绩数据进行运算得出了项目参数,并加以分析。     

铝合金薄壁筒形零件车削与夹具

采取提高工艺系统刚度,进行多次工序间热处理,选择合理切削用量、充分冷却等措施,通过新设计的车削夹具及优化刀具角度等工艺方法的改进,提高了铝合金薄壁筒形零件的加工质量．以薄壁筒体车端面和精车内、外圆为例,结合典型夹具结构,分析和介绍改进后的工艺方法．     

中国女足赛前训练指标分析与机能评定研究

为了探讨中国女足赛前训练的生化指标特点及变化规律,利用多项指标对奥运备战冲刺阶段的中国女足国家队运动员进行了身体机能评定。结果显示:1)血红蛋白的测试值变化范围不大,始终保持相对较高的水平,奥运前一周的测试值为(127.82±7.08)g/L,离赛前的最适值有一定差距。2)血尿素的变化幅度较小,始终保持在相对稳定的水平,说明此阶段的训练量相对稳定。而血清肌酸激酶变化幅度相对较大,奥运前一周仍保持在较高水平,可能与此阶段的热身赛较多有一定关系,训练强度变化比较明显。3)血睾酮变化趋势呈先高后低,又升高再降低,最后一周又升高,变化比较频繁,但保持在相对较高的水平。     

Biochemical Effects of Lead Exposure on Systolic &; Diastolic Blood Pressure,Heme Biosynthesis and Hematological Parameters in Automobile Workers of North Karnataka (India)

The purpose of this study was to find out the effect of lead exposure on systolic and diastolic blood pressure, heme biosynthesis related and hematological parameters of automobile workers. For this study 30 automobile workers were selected and compared with 30 age matched healthy control subjects. Significantly increased blood lead (364%, P < 0.001) and urinary lead (176%, P < 0.001) levels were observed in automobile workers (study group) as compared to controls. Systolic blood pressure (5.32%, P < 0.05) and diastolic blood pressure (5.87%, P < 0.05) were significantly increased in the automobile workers as compared to controls. The significantly decreased non-activated erythrocyte δ-aminolevulinic acid dehydratase (δ-ALAD) (−18.51%, P < 0.01) and activated δ-ALAD (−13.29%, P < 0.05) levels were observed in automobile workers as compared to normal healthy control subjects. But the ratio of activated/non-activated δ-ALAD was significantly increased (43.83%, P < 0.001) in automobile workers as compared to controls. Excretions of δ-aminolevulinic acid (83.78%, P < 0.001) and porphobilinogen (37%, P < 0.001) in urine were significantly increased in the study group as compared to the controls. In automobile workers heamoglobin (−11.51%, P < 0.001), hematocrit (−4.06%, P < 0.05), mean corpuscle volume (−3.34%, P < 0.05), mean corpuscle hemoglobin (−5.66%, P < 0.01), mean corpuscle hemoglobin concentration (−7.67%, P < 0.001), red blood cell count (−14.6%, P < 0.001) were significantly decreased and total white blood cell count (11.44%, P < 0.05) increased as compared to the controls. The results of this study clearly indicate that the absorption of lead is more in automobile workers and it affects on blood pressure, heme biosynthesis and hematological parameters observed in this study group.     

Hierarchically structured porous materials: synthesis strategies and applications in energy storage

To address the growing energy demands of sustainable development, it is crucial to develop new materials that can improve the efficiency of energy storage systems. Hierarchically structured porous materials have shown their great potential for energy storage applications owing to their large accessible space, high surface area, low density, excellent accommodation capability with volume and thermal variation, variable chemical compositions and well controlled and interconnected hierarchical porosity at different length scales. Porous hierarchy benefits electron and ion transport, and mass diffusion and exchange. The electrochemical behavior of hierarchically structured porous materials varies with different pore parameters. Understanding their relationship can lead to the defined and accurate design of highly efficient hierarchically structured porous materials to enhance further their energy storage performance. In this review, we take the characteristic parameters of the hierarchical pores as the survey object to summarize the recent progress on hierarchically structured porous materials for energy storage. This is the first of this kind exclusively to survey the performance of hierarchically structured porous materials from different porous characteristics. For those who are not familiar with hierarchically structured porous materials, a series of very significant synthesis strategies of hierarchically structured porous materials are firstly and briefly reviewed. This will be beneficial for those who want to quickly obtain useful reference information about the synthesis strategies of new hierarchically structured porous materials to improve their performance in energy storage. The effect of different organizational, structural and geometric parameters of porous hierarchy on their electrochemical behavior is then deeply discussed. We outline the existing problems and development challenges of hierarchically structured porous materials that need to be addressed in renewable energy applications. We hope that this review can stimulate strong intuition into the design and application of new hierarchically structured porous materials in energy storage and other fields.     

Parameters for Software Piracy Research

Advances in Internet and other digital technologies have opened up new channels and methods for online business. They have also led to a situation where the same channels can be abused and misused. One of these forms of technology abuse, which is becoming increasingly prevalent these days, is the piracy of digital content. This article introduces a relatively comprehensive and unified theoretical framework for studying and understanding a major aspect of digital piracy: namely, software piracy. Based on Routine Activities Theory, Rational Choice Theory, and guardianship concepts, the framework identifies key parameters that can affect the incidence of software piracy. We apply the framework in conducting a systematic examination of 75 articles dealing with software piracy. The examination reveals that a considerable number of parameters have received little or no attention from software-piracy researchers. In addition to suggesting research opportunities, the framework furnishes a systematic approach for structuring the design of future research studies in the realm of software piracy. The insights furnished by this article contribute to future investigations of the software-piracy phenomenon that are needed to avert the economic and social damage caused by software piracy.     

双栅极空气计数管的工作电压研究

Based on analysis of the discharging course in double grid air counter(DGAC),the dischargin model is built up by applying the conception of average ionizaing free path.An effective algorithm is presented for the working voltage of DGAC using this model.The working voltage is nearly related to the geometric parameters of DGAC,the sensitivity of the circuitry and the number of discharges,computing results confirm that the working voltage increases with the ratio of the radius of the anode to that of the cathode.The number of discharges follows the similar rule.