2000—2019年西北地区云水资源时空特征研究

为认识西北地区的云水资源(Cloud Water Resource,简称CWR)特征以及科学规划人工增雨开发空中水资源作业布局,利用2000—2019年中国1°×1°CWR观测诊断评估数据集,采用线性拟合和经验正交函数分解(EOF)等方法,统计分析了西北地区CWR的分布及演变气候特征。结果表明:(1)从全区整体看,CWR的相关物理量(状态量、平流量、总量和降水效率)主要表现为夏季最高,春、秋季次之,冬季最低的季节变化特征。其中,春季CWR总量约为1736亿t(折合柱水量约为51.2 mm),仅次于夏季;春季水凝物降水效率为48.7%,相较于秋季,春季的CWR开发潜力更大。(2)从区域内1°×1°网格的计算结果得到空间分布,受地势与环流的影响,近20年CWR年总量及水汽年总量、水凝物年总量的多年平均空间分布呈“两高一低”的特征,高值位于西风急流区与季风影响边缘区,低值区主要位于高原气候区。(3)近20年,西北地区格点的CWR年总量平均以23.6 mm/a速率增加,其中春季的增加趋势最显著,增速为8.5 mm/a。季节分布上,CWR夏季最多,春、秋季次之,冬季最少;水凝物降水效率夏季高,秋、春季较低,冬季最低。(4)CWR年总量的EOF分解第一模态(EOF1)贡献率为78.2%,分布特征为区域东部较高,在2008年出现年际转折,开始转变为CWR东部多、西部少的分布格局。(5)在西北地区典型区域中,天山区域年平均及格点平均后的CWR年总量以及水凝物降水效率均高于祁连山区,年际变化上祁连山区的CWR在增多,天山区的在减少。

Constructing long-cycling crystalline C_(3)N_(4)-based carbonaceous anodes for sodium-ion battery via N configuration control

Carbon nitrides with two-dimensional layered structures and high theoretical capacities are attractive as anode materials for sodium-ion batteries while their low crystallinity and insufficient structural stability strongly restrict their practical applications.Coupling carbon nitrides with conductive carbon may relieve these issues.However,little is known about the influence of nitrogen(N)configurations on the interactions between carbon and C_(3)N_(4),which is fundamentally critical for guiding the precise design of advanced C_(3)N_(4)-related electrodes.Herein,highly crystalline C_(3)N_(4)(poly(triazine imide),PTI)based all-carbon composites were developed by molten salt strategy.More importantly,the vital role of pyrrolic-N for enhancing charge transfer and boosting Na+storage of C_(3)N_(4)-based composites,which was confirmed by both theoretical and experimental evidence,was spot-highlighted for the first time.By elaborately controlling the salt composition,the composite with high pyrrolic-N and minimized graphitic-N content was obtained.Profiting from the formation of highly crystalline PTI and electrochemically favorable pyrrolic-N configurations,the composite delivered an unusual reverse growth and record-level cycling stability even after 5000 cycles along with high reversible capacity and outstanding full-cell capacity retention.This work broadens the energy storage applications of C_(3)N_(4) and provides new prospects for the design of advanced all-carbon electrodes.

钢轨纵向位移快速测量系统的方法与应用

钢轨纵向位移是无缝线路状态演变的典型表现,监测钢轨纵向位移情况成为无缝线路养护维修的重点工作。然而,目前常用的无缝线路状态监测方法均基于固定式设备,大多存在成本高、精度差的弊端,且较难实现快速监测。开发设计一种动态的无缝线路钢轨爬行快速测量系统,基于机器视觉技术,对轨标和道旁基标图像进行特征提取,并通过对轨道场景进行还原和追踪,实现对无缝线路状态的监测。通过系统在现场的应用测试验证了该监测方法良好的适用性,在现场试验中钢轨纵向位移的测量精度可控制在±1 mm范围内,满足监测要求。该系统提高了无缝线路养护维修作业效率,降低了人工劳动强度,可为无缝线路科学精细化管理提供借鉴。

稳定沉默Rictor表达的前列腺癌CWR22RV1的构建

目的应用RNA沉默技术下调前列腺癌CWR22RV1细胞株的Rictor基因表达,并筛选具有稳定转染Rictor-shRNA的细胞株,为进一步研究Rictor在前列腺癌中的作用打下基础。方法针对Rictor基因设计合成siRNA序列;鉴定、测序并转染293T细胞观察基因表达情况;构建Rictor-shRNA慢病毒载体;进行Rictor-shRNA慢病毒包装及滴度测定;筛选稳定表达Rictor-shRNA的前列腺癌CWR22RV1细胞株;Western blot检测稳定转染前列腺癌CWR22RV1细胞株Rictor的表达水平。结果 Rictor-shRNA慢病毒成功包装后转染前列腺癌CWR22RV1细胞,进行嘌呤霉素筛选,获得沉默Rictor基因的前列腺癌CWR22RV1细胞株,Western blot检测显示该细胞株Rictor水平明显降低(P<0.01)。结论成功构建了稳定沉默Rictor表达的前列腺癌CWR22RV1细胞株,为后续的实验了打下坚实的基础。

比卡鲁胺抑制CWR22Rv1细胞移植裸鼠前列腺癌的机制研究

目的:探讨比卡鲁胺抗CWR22Rv1细胞移植裸鼠前列腺癌的作用机制。方法:采用瘤块接种的方法制作裸小鼠前列腺癌模型,观察比卡鲁胺治疗后的移植瘤重量和体积,并计算抑瘤率,收集移植瘤标本,使用光镜观察法、免疫组化法、基因芯片法和实时定量RT-PCR法比较比卡鲁胺组和阴性对照组肿瘤相关指标的差异。结果:①比卡鲁胺低、中、高剂量组抑瘤率分别为10.77%、37.32%和63.28%(P<0.01)。②光镜观察:对照组肿瘤内癌细胞生长旺盛,移植癌细胞保持原有异型性。而比卡鲁胺低、中和高剂量组呈腺癌典型表现,癌细胞出现不同程度的退变。③免疫组化:低、中、高剂量组增殖细胞核抗原增殖指数同阴性对照组相比明显减小(P<0.01)。对照组每200个细胞中平均有180±8个细胞雄激素受体(androgen receptor,AR)呈阳性表达,而高剂量组中AR阳性细胞数较对照组明显减少(P<0.01)。④基因芯片:高剂量组在前列腺癌相关基因表达丰度上明显低于对照组,主要为AR和关联蛋白、细胞黏附分子和细胞周期相关基因,并且实时定量RT-PCR结果与基因芯片结果基本一致。结论:比卡鲁胺抗22Rv1细胞移植裸鼠前列腺癌效果显著,主要通过降低细胞核AR表达、减少细胞黏附、调控细胞周期和抑制细胞增殖等发挥作用。

基于调整护轨轨向不平顺的无缝线路稳定性提高方法

为使护轨充分发挥作用,采用有限元方法建立无缝线路稳定性分析模型,研究了护轨初始弯曲方向对无缝线路稳定性的影响;基于轨道不平顺和护轨与基本轨头部之间净距限值要求,提出了一种通过调整护轨轨向不平顺来提高无缝线路稳定性的方法,并进行了仿真验证。结果表明:当护轨初始弯曲方向与基本轨相反时,可提高无缝线路的稳定性,且提高程度随曲线半径增大而增加;以轨道不平顺作为钢轨初始弯曲,利用本文方法调整护轨轨向不平顺后,外侧基本轨横向位移大幅降低,钢轨容许温升大幅提高;曲线半径为3000 m时,按护轨无缝化的最不利工况考虑,采用本文方法可使无缝线路钢轨容许温升提高31.9℃。本文方法适用于不同曲线半径条件,对曲线半径较大无缝线路的稳定性提高效果更为显著。

Possibility of the Application of the Ultra-long Electromagnetic Wave Remote Sensor to Marine Geological Exploration

The ultra-long electromagnetic wave remote sensing technique developed by Peking University is one of new future techniques, which can detect the submarine geological information from the depth of 20 to 10000 m below the surface by receiving natural ultra-long electromagnetic waves (n Hz to n 100 Hz). The new remote sensor is composed of three parts: a main instrument with a portable computer, an antenna with an amplifier and an external power.

Enhanced photocatalytic properties of ultra-long nanofiber synthesized from pure titanium powders

Using Ti powder as reagent,ultra-long TiO2 nanofibers were prepared via hydrothermal method in NaOH solution.The samples were char-acterized respectively by means of field emission scanning electron microscopy (FESEM),transmission electron microscopy (TEM) with selected area electron diffraction (SAED),and X-ray diffraction (XRD).The diameter and the length of the ultra-long TiO2 nanofiber were ～100 nm and >200μm,respectively.The ultra-long TiO2 nanofibers were anatase after heat treatment at 450 ?C for 1 h.Moreover,the optical properties of the products were investigated by UV-visible light absorption spectrum.Furthermore,methyl orange was used as a target molecule to estimate the photocatalytic activity of the specimens.Under the same testing conditions,the photocatalytic activity of the ultra-long TiO2 nanofibers was higher than that of P25.Direct electrical pathway and improved light-harvesting efficiency were crucial for the superior photocatalytic activity of the ultra-long TiO2 nanofibers.

Nonlinear Ultra-Long Wave and Its Stability

A stability of a nonlinear ultra-long wave and its solution are discussed in this paper by employing Burger model which is subject to heat resource. It is of interest noted that the wave solution can be described by an equation of KDV or MKDV and that conditions for the existence of the solution are related to characteristic divergences. In addition, a wave velocity expression for nonlinear ultra-long waves and some diagnostic correlations among wave parameters have been obtained.

Synthesis of Ordered Ultra-long Manganite Nanowires via Electrospinning Method

We develop a new electrospinning method to prepare ultra-long ordered La1-xSrxMnO3 （LSMO） nanowires. The length is up to several centimeters and is only limited by the size of the collector. The well-ordered straight-line structure ensures the transport measurement, which is impossible to be carried out for the random nanowires fabricated by the traditional electrospinning method. Magnetic and transport measurements indicate that the physical properties of the LSMO nanowires depend sensitively on the doping concentration. At the optimum doping, the LSMO wires are ferromagnetic at room temperature with a metal-insulator transition temperature close to room temperature. Magnetic force microscopy studies are also performed to provide a microscopic view of these ultra-long nanowires.

New insight into the ultra-long lifetime of excitons in organic-inorganic perovskite： Reverse intersystem crossing

Recently, an effective exciton diffusion length L exceeding 100μm has been reported for organic- inorganic halide perovskites owing to both the high mobility and ultra-long lifetime of the excitons; however, the origin of ultra-long L is still unclear in nature. In some photoelectric materials, reverse intersystem crossing （RISC） from the triplet to the singlet state can enhance the quantum yield of pho- toluminescence greatly. In this study, our theoretical investigation indicated that the energy difference △E_st between the singlet state and the triplet state of CH_3NH_3Pbl_3 was less than 0.1 eV, which represents one crucial prerequisite for the occurrence of RISC. Meanwhile, the experimental results showed that the photoluminescence lifetime increased with the increasing temperature, a typical feature of RISC. Based on this study, we put forward the hypothesis that the ultra-long lifetime of excitons in organic-inorganic halide perovskite might be caused by the RISC process. This may provide a new insight into the important photophysical properties of such novel photovoltaic materials.

高原大日温差环境下跨区间无缝线路研究

研究目的:本文利用无缝道岔稳定性公式和有限元方法对高原大日温差某车站无缝道岔的稳定性和力学性能进行理论计算,分析在年温差70℃左右、日温差40℃左右局部温度骤变的高原环境下铺设跨区间无缝线路的可能性,并对该车站及两端区间轨道进行跨区间无缝线路设计。采用胶冻结接头的方式消灭道岔和缓冲区有缝钢轨接头,在西藏地区第一次铺设桥上无缝道岔,一站两区间实现了跨区间无缝线路。通过一年时间在线监测和安全运营,积累了大量高原大日温差跨区间无缝线路可靠数据和运营经验。研究结论:(1)验证了在年温差70℃左右、日温差40℃左右局部温度骤变的高原环境下铺设跨区间无缝线路是可行的;(2)胶冻结接头作为跨区间无缝线路钢轨连接方式是可行的,可为既有非无缝线路无缝化提供又一个技术方向;(3)在大日差局部温度骤变的高原环境下,跨区间无缝线路养护关键是无缝道岔,一定要注意道岔的轨道几何形位状态和尖轨、心轨的位移,出现不良状态时及时加强养护。

The Use of Tamping Machine for Diagnosising the Longitudinal Forces in Rails of CWR Track

In the novel approach to the diagnostic tests of continuous welded rail （CWR） track by the use of the tamping machine, the fundamental statement related to the recording of the curvature with a definite value of the lateral displacement being subjected to verification, can provide a basis for the determination of the longitudinal axial force in the rail. An attempt has also been made to define an alternative factor which by means of the measured signals, could be used for the determination of the axial forces in the rail sections. A power engineering approach has been adopted to this concept. Within the framework of the experimental investigations, measurements were carried out in the track test section. The investigations were based on stretching the rail sections by stretchers and on lateral displacements of the track by the tamping machine. The operation of the measuring apparatus was also tested in the experimental railway track section while carrying out the geometrical adjustments by the tamping machine. As a result of next series of the investigation carried out in 2006-2007, the authors worked out a procedure of estimating the longitudinal forces in rails of CWR track.

CWR——跨国公司实现全面质量管理的光明之路

介绍了一种新的质量管理模式——全公司注册(CWR)的产生、发展及其所取得的实际效果。

基于车致振动响应的无缝线路温度力识别研究

无缝线路温度力过大会导致胀轨或断轨,现场需实时监测钢轨温度力。以钢轨在温度力作用下受到的车致振动加速度为研究对象,提出一种利用多元回归算法拟合温度力特征指标反向识别钢轨温度力的新方法。通过对温度力作用下车致钢轨振动加速度进行希尔伯特黄变换,提取钢轨加速度的HHT灰度时频直方图方差和边际谱在1300~1500 Hz内的瞬时幅值变化率作为温度力特征指标,将2指标分别输入到回归算法和灰色算法中,对比钢轨温度力识别误差。结果表明,钢轨所受温度力越大,识别结果的相对误差越小;利用多元回归算法识别温度力的平均识别误差可达到3.24%,相比于灰色预测模型降低了3.54%,为现场实时监测钢轨温度力提供借鉴。

WJ-8型小阻力扣件纵向阻力温变特性研究

为评估高速铁路桥上无缝线路扣件对服役环境的适应性,以WJ-8型小阻力扣件为例,开展一系列室内纵向阻力试验。设置-30~60℃的环境温度和90~120 N·m的螺栓扭矩,在标准组装状态下按照10 kN/min的恒定速率加载,实时记录纵向力值及钢轨纵向位移值,每个工况加载4次。试验获得了4个不同扭矩和10个不同温度组合工况下的扣件纵向阻力-位移变化特征,分析得到温度、扭矩和纵向滑移阻力三者之间的映射关系。研究结果表明:1)不同工况下,扣件纵向阻力随位移的增大呈幂指型函数递增关系;不同扭矩作用下,扣件纵向滑移阻力随温度升高呈指数型函数递增关系;不同温度作用下,扣件纵向滑移阻力随扭矩增大呈线性递增关系。2)扭矩作用和温度作用对小阻力扣件纵向阻力均有影响,但扭矩作用基本不影响扣件阻力对温度变化的敏感性,反之亦然。3)当温度上升至40℃以后,在规范建议的90~120 N·m扭矩下,纵向滑移阻力均不再满足4±1 kN的要求。建议高温环境下适当减小螺栓扭矩,以便于桥上无缝线路附加力的释放。研究成果对于优化轨道结构设计、验证和完善无缝线路扣件纵向阻力取值计算理论具有参考意义。

桥梁新型多功能支座对无缝线路纵向力影响研究

提出一种桥梁新型多功能支座,重点探讨此支座对桥上无缝线路纵向受力与变形的影响规律,以杭温铁路义乌特大桥为工点,对比研究桥梁采用固定墩设计方案及中墩更换为多功能支座后的桥上无缝线路力学特性,并在此基础上提出支座优化建议。研究得到以下结论:多功能支座方案可将桥梁的伸缩位移零点调整到桥梁主跨中点,从而减小桥梁温度跨度,解决义乌特大桥不适合做刚构桥的地形限值条件;当多功能支座摩擦系数小于0.005时,多功能支座方案相比传统支座方案的无缝线路受力优化幅度较小,摩擦系数大于0.005时,支座摩擦力可完全抵消列车制动力,无缝线路受力将得到大幅优化;随着摩擦系数的增加,钢轨伸缩力小幅增加,钢轨制动力较大幅度减小,摩擦系数为0.005时,制动力最小;建议多功能支座后续的优化方向为增大支座摩擦系数。

桥跨布置对连续梁桥上轨道地震响应影响规律研究

为探讨桥跨结构布置关键参数对梁轨系统地震相互作用影响规律,基于梁轨相互作用原理,采用地震碰撞大质量法建立非线性约束的桥梁与轨道相互作用有限元模型,分析地震碰撞作用下连续梁桥上无缝线路受力,研究线路纵向阻力、相邻简支梁桥跨数以及支座非顺序布置形式等关键设计参数的桥跨结构布置方式对结构地震响应的影响。研究结果表明:大跨度连续梁上设计钢轨强度检算困难时需采用小阻力扣件方案,地震影响下建议采用仅连续梁范围铺设小阻力扣件,使结构受力及位移均保持在较小限度内。钢轨伸缩调节器是无缝线路中薄弱环节,会引起轨道不平顺,应尽量减少钢轨伸缩调节器的使用,确需设置调节器时,建议仅在连续梁活动端设置,必要时可在对侧边跨及相邻一孔跨简支梁同时铺设小阻力扣件。地震分析时可按连续梁两侧接8跨简支梁进行地震作用简化计算,随着连续梁跨度的增大,钢轨受力大幅增加,两侧相邻一孔跨简支梁落梁几率增加。桥台路基填筑优良时,可将相邻简支梁固定支座靠近连续梁布置,通过减小温度跨度均衡梁轨结构受力与变形。当桥台路基地质不良时,可将简支梁活动支座设置在桥台处,以大幅减小桥台受力。