送电线路跨越高速铁路迁移改造措施

随着国家扩大内需计划的深入开展,各地基础建设全面铺开,新建越来越多的高速铁路、高速公路或高等级公路,在这样的大环境下,无疑使得数量众多运行中的输电线路面临改造问题.这种输电线路的改造工作往往时间紧迫、数量众多,如若对改造中的一些相关影响因素考虑不周全,将会严重影响工期、制约整体工程的施工进度,甚至会影响到送电线路的安全...     

HULL GESTURE AND RESISTANCE PREDICTION OF HIGH-SPEED VESSELS

Since trim and sinkage are significant while vessels are advancing forward with high speed, the predicted vessel resistance based on restrained model theory or experiment may not be real resistance of vessels during voyage. It is necessary to take the influence of hull gesture into account for oredicting the resistance of high-speed ship. In the present work the resistance problem of high speed ship is treated with the viscous flow theory, and the dynamic mesh technique is adopted to coincide with variation of hull gesture of high speed vessel on voyage. The simulation of the models of S60 ship and a trimaran moving in towing tank with high speed are conducted by using the above theory and technique. The corresponding numerical results are in good agreement with the experimental data. It indicates that the resistance prediction for high speed vessels should take hull gesture into consideration and the dynamic mesh method proposed here is effective in calculating the resistance of high speed vessels.     

Codes based on BCK-algebras

The notion of a BCK-valued function on a set is introduced, and related properties are investigated. Codes generated by BCK-valued functions are established.     

投切电容器组专用真空断路器性能研究

真空断路器切除并联电容器组时,如果发生重燃可引起较高的操作过电压,对电容器组等设备危害严重。降低真空断路器的重燃率是限制切除电容器组过电压的根本措施。笔者在分析研究真空断路器重燃机理的基础上,提出采用带串联电阻真空断路器的方法,通过限制合闸涌流和断口恢复电压的幅值,达到降低真空断路器切电容器组重燃率的目的。     

海上油田含聚合物污水水质对储层保护技术的影响

研究含聚合物(含聚)污水水质对储层的伤害为确定含聚污水回注储层的可行性提供了依据。以渤海绥中36-1油田含聚污水为例,利用偏光显微镜、扫描电镜、核磁共振仪等,通过岩心动态损害实验分别对污水中的乳化油、悬浮物和产出聚合物浓度及粒径中值进行了评价,分析了含聚污水回注对储层的伤害机理。结果表明,含聚污水中油、悬浮物、聚合物三者的协同作用是主要伤害源,且对储层的伤害程度随着单一水质指标的增大而增加;由于聚合物分子的吸附聚集作用而形成高强度的可变形团状集合体,是造成岩心孔隙喉道堵塞的关键因素;含聚污水进入储层对孔喉的堵塞形式是优先堵塞大-中孔喉,并逐步由内滤饼向外滤饼的堵塞形式转化。优化含聚污水水处理工艺及现行加药方式,是解决含聚污水处理问题的关键。     

A review of metabolism of labeled glucoses for use in measuring glucose recycling

The fate of tritium from each carbon of D-glucose and the metabolism of L-glucose and 2-deoxy-D-glucose are known. Differences in metabolism of labeled glucoses can be used to quantify physical and chemical recycling of glucose. Only physical recycling is measured by [1-3H]-L-glucose, whereas [U-14C]-D-glucose measures total recycling. The difference between [1-3H]-L-glucose and [U-14C]-D-glucose, therefore, is chemical recycling. Recycling from extracellular binding sites and hepatic glucose 6-phosphate can be measured by difference between [1,2-3H]-2-deoxy-D-glucose and [1-3H]-L-glucose, and the difference in irreversible loss of the two will measure extrahepatic uptake of D-glucose. Recycling via Cori-alanine cycle plus CO2 is the difference in irreversible loss measured by using [6-3H]-glucose and [U-14C]-D-glucose. Recycling via the hexose monophosphate pathway can be determined by difference in irreversible loss between [1-3H]-D-glucose and [6-3H]-D-glucose. Recycling via CO2 and glycerol must be measured directly with [U-14C]glucose, bicarbonate, and glycerol. Recycling via hepatic glycogen can be estimated by subtracting all other measured chemical recycling from total chemical recycling. This review describes means to quantify glucose recycling in vivo, enabling studies of mechanisms for conservation and utilization of glucose.     

Perovskite‐Induced Ultrasensitive and Highly Stable Humidity Sensor Systems Prepared by Aerosol Deposition at Room Temperature

A new capacitive‐type humidity sensor is proposed using novel materials and fabrication process for practical applications in sensitive environments and cost‐effective functional devices that require ultrasensing performances. Metal halide perovskites (CsPbBr₃ and CsPb₂Br₅) combined with diverse ceramics (Al₂O₃, TiO₂, and BaTiO₃) are selected as sensing materials for the first time, and nanocomposite powders are deposited by aerosol deposition (AD) process. A state‐of‐the‐art CsPb₂Br₅/BaTiO₃ nanocomposite humidity sensor prepared by AD process exhibits a significant increase in humidity sensing compared with CsPbBr₃/Al₂O₃ and CsPbBr₃/TiO₂ sensors. An outstanding humidity sensitivity (21426 pF RH%^?1) with superior linearity (0.991), fast response/recovery time (5 s), low hysteresis of 1.7%, and excellent stability in a wide range of relative humidity is obtained owing to a highly porous structure, effective charge separation, and water‐resistant characteristics of CsPb₂Br₅. Notably, this unprecedented result is obtained via a simple one‐step AD process within a few minutes at room temperature without any auxiliary treatment. The synergetic combination of AD technique and perovskite‐based nanocomposite can be potentially applied toward the development of multifunctional sensing devices.     

Plasmon‐Induced Hot Carrier Separation across Dual Interface in Gold–Nickel Phosphide Heterojunction for Photocatalytic Water Splitting

Precise control of the topology of metal nanocrystals and appropriate modulation of the metal–semiconductor heterostructure is an important way to understand the relationship between structure and material properties for plasmon‐induced solar‐to‐chemical energy conversion. Here, a bottom‐up wet chemical approach to synthesize Au/Ni₂P heterostructures via Pt‐catalyzed quasi‐epitaxial overgrowth of Ni on Au nanorods (NR) is presented. The structural motif of the Ni₂P is controlled using the aspect ratio of the Au NR and the effective micelle concentration of the C₁₆TAB capping agent. Highly ordered Au/Pt/Ni₂P nanostructures are employed as the photoelectrocatalytic anode system for water splitting. Electrochemical and ultrafast absorption spectroscopy characterization indicates that the structural motif of the Ni₂P (controlled by the outer‐shell deposition of Ni) helps to manipulate hot electron transfer during surface plasmon decay. With optimized Ni₂P thickness, Pt‐tipped Au NR with an aspect ratio of 5.2 exhibits a geometric current density of 10 mA cm^?2 with an overpotential of 140 mV. The photoanode displays unprecedented long‐term stability with continuous chronoamperometric performance of 50 h at an input potential of 1.5 V with over 30 days. This work provides definitive guidance for designing plasmonic–catalytic nanomaterials for enhanced solar‐to‐chemical energy conversion.     

基于柱坐标抛物方程的海上雷达覆盖范围研究

为预测雷达波在海面的全向传播特性,提出了基于柱坐标抛物方程(parabolic equation,PE)的电波传播模型,用于海上雷达覆盖范围的研究.从亥姆霍兹方程出发,推导出柱坐标系下的前向PE形式.再利用PE通解中三角函数的正交性,求解各电波传播模式的激励系数,结合分步傅里叶变换实现柱坐标PE的步进迭代算法,以预测电...     

PFM开关电源集成电路的抗电磁干扰设计

针对脉冲频率调制(PFM)开关电源(SMPS)集成电路,提出了抗电磁干扰(EMI)设计的两种方法.通过采用零电流检测电路,控制开关电源集成电路中的开关金属氧化物半导体场效应晶体管(MOSFET)在第一个谷底导通,从而降低导通电流的尖峰值.通过采用恒压和恒流设计技术,使开关电源集成电路中的电压和电流得到限制,有助于降低电流纹波.采用CSMC lμm 40 V高压工艺设计了PFM开关电源集成电路SX1618,将以上两种抗电磁干扰设计方法应用在该电路的设计中,并设计了针对性的保护结构.完成SX1618整体仿真和版图设计后进行了流片和封装,并将其应用在实际的开关电源中,经测试,开关电源的抗电磁干扰能力符合标准.