Diagnosis of indirectly driven double shell targets with point-projection hard x-ray radiography

We present an application of short-pulse laser-generated hard x rays for the diagnosis of indirectly driven double shell targets. Coneinserted double shell targets were imploded through an indirect drive approach on the upgraded SG-II laser facility. Then, based on thepoint-projection hard x-ray radiography technique, time-resolved radiography of the double shell targets, including that of their near-peakcompression, were obtained. The backlighter source was created by the interactions of a high-intensity short pulsed laser with a metalmicrowire target. Images of the target near peak compression were obtained with an Au microwire. In addition, radiation hydrodynamicsimulations were performed, and the target evolution obtained agrees well with the experimental results. Using the radiographic images, arealdensities of the targets were evaluated.

Endoscopic retrograde cholangiopancretography in modified double tracks anastomosis with anastomotic stenosis

A 63-year-old man presented at our hospital with right upper abdomen pain and fever for 4 d.The patient's magnetic resonance cholangiopancreatography revealed dilated common bile duct and choledocholithiasis.In his past history,he received proximal gastrectomy and modified double tracks anastomosis.Endoscopic retrograde cholangiopancretography in modified double tracks anastomosis,especially accompanied with anastomotic stenosis,has been rarely reported.In the present case,the duodenoscope was successfully introduced over the guidewire and the stone taken out using a basket.The patient had good palliation of his symptoms after removal of the stone.

Linear Track Estimation Using Double Pulse Sources for Near-Field Underwater Moving Target

The double pulse sources （DPS） method is presented for linear track estimation in this work. In the field of noise identification of underwater moving target, the Doppler will distort the frequency and amplitude of the radiated noise. To eliminate this, the track estimation is necessary. In the DPS method, we first estimate bearings of two sinusoidal pulse sources installed in the moving target through baseline positioning method. Meanwhile, the emitted and recorded time of each pulse are also acquired. Then the linear track parameters will be achieved based on the geometry pattern with the help of double sources spacing. The simulated results confirm that the DPS improves the performance of the previous double source spacing method. The simulated experiments were carried out using a moving battery car to further evaluate its performance. When the target is 40-60m away, the experiment results show that biases of track azimuth and abeam distance of DPS are under 0.6° and 3.4m, respectively. And the average deviation of estimated velocity is around 0.25m/s.

Automatic Assessment of Fabric Smoothness Grade Using Double CCD Grating Projection

Automatically assessing fabric smoothness grade is very important in the evaluation of fabric appearance.A system for objectively evaluating the fabric smoothness grade based on a grating projection unit and double colored CCD(short form of charge coupled device) was constructed in this paper.Two images captured by different CCD compensated each other which reduced the influence of noises.The application of the four-step phase-shifting method enabled the calculation of the exact phase in a point easy and quick.A large amount of 3D points with three coordinates X,Y and Z were obtained precisely making the definition and calculation of fabric smoothness characters easy.Then four parameters which intuitively denoted the fabric smoothness degree were obtained.Finally,a proper neural network was built,which successfully performed the fabric smoothness classification.The experimental results show that the system is applicable for all the fabric whatever pattern or color.The experimental grades provided by this grating projection system are also highly consistent with the subjective results.

Teaching Reform for Mobile Application Development with Industrial Projects,Double Instructors,and Automatic Assessments

Mobile Application Development is a well-known undergraduate specialized course majoring in Computer Science and Software Engineering.Since it is a rapid developing technique and requires extensive project samples to help understand,current teaching mechanism has still limitations in rare real project examples,outdated course contents,and lack of automatic assessment platforms.In order to improve the teaching effects and cultivate students’practical ability,we employ this teaching reform with industrial projects,double instructors,and automatic assessment platform to allow students participating in every course process.We aim to improve students’practical and collaboration ability during conducting the project spontaneously,and cultivate their awareness of self-learning and lifelong learning.Our classroom feedback has demonstrated that this teaching reform is effective on improving students’practical abilities,learning initiatives and comprehensive qualities.

The Double Projecting Neuron of the Cat Spinal Dorsal Horn——A Study with Double Retrograde Fluorescent Tracing Technique

The new double projecting neurons were found in the cat spinal dorsal horn by the double retrograde fluorescent tracing technique.Fast Blue(FB)was injected into unilateral dorsal column nucleus(DCN)of adult cats anesthetized with pentobarbital.Nuclear Yellow(NY)was injected ipsilaterally into the lateral cervical nucleus(LCN)8-9 days later.After an additional 18-30 hrs.

The Optimizing Model and Its Solution for Making Train Working Graph with Computer on Separative Division of Double－Track Lines

The authoros specialize in the field of optunization and automatic programme oftrain working graph. In this peper, at frist, a mixed 0-1 integer progranimingmodel about this problem for duuble-track lines is set up, then the principle andProcess of selution are stated, with an application exaiiiple put forward.

Multi-model Projection of July–August Climate Extreme Changes over China under CO_2 Doubling. Part I: Precipitation

Potential changes in precipitation extremes in July–August over China in response to CO 2 doubling are analyzed based on the output of 24 coupled climate models from the Twentieth-Century Climate in Coupled Models （20C3M） experiment and the 1% per year CO 2 increase experiment （to doubling） （1pctto2x） of phase 3 of the Coupled Model Inter-comparison Project （CMIP3）. Evaluation of the models’ performance in simulating the mean state shows that the majority of models fairly reproduce the broad spatial pattern of observed precipitation. However, all the models underestimate extreme precipitation by ～50%. The spread among the models over the Tibetan Plateau is ～2–3 times larger than that over the other areas. Models with higher resolution generally perform better than those with lower resolutions in terms of spatial pattern and precipitation amount. Under the 1pctto2x scenario, the ratio between the absolute value of MME extreme precipitation change and model spread is larger than that of total precipitation, indicating a relatively robust change of extremes. The change of extreme precipitation is more homogeneous than the total precipitation. Analysis on the output of Geophysical Fluid Dynamics Laboratory coupled climate model version 2.1 （GFDL-CM2.1） indicates that the spatially consistent increase of surface temperature and water vapor content contribute to the large increase of extreme precipitation over contiguous China, which follows the Clausius–Clapeyron relationship. Whereas, the meridionally tri-polar pattern of mean precipitation change over eastern China is dominated by the change of water vapor convergence, which is determined by the response of monsoon circulation to global warming.

Multi-Model Projection of July–August Climate Extreme Changes over China under CO_2 Doubling. Part II: Temperature

This is the second part of the authors’ analysis on the output of 24 coupled climate models from the Twentieth-Century Climate in Coupled Models （20C3M） experiment and 1% per year CO 2 increase experiment （to doubling） （1pctto2x） of phase 3 of the Coupled Model Inter-comparison Project （CMIP3）. The study focuses on the potential changes of July–August temperature extremes over China. The pattern correlation coefficients of the simulated temperature with the observations are 0.6–0.9, which are higher than the results for precipitation. However, most models have cold bias compared to observation, with a larger cold bias over western China （5°C） than over eastern China （2°C）. The multi-model ensemble （MME） exhibits a significant increase of temperature under the 1pctto2x scenario. The amplitude of the MME warming shows a northwest–southeast decreasing gradient. The warming spread among the models （～1°C– 2°C） is less than MME warming （～2°C–4°C）, indicating a relatively robust temperature change under CO 2 doubling. Further analysis of Geophysical Fluid Dynamics Laboratory coupled climate model version 2.1 （GFDL-CM2.1） simulations suggests that the warming pattern may be related to heat transport by summer monsoons. The contrast of cloud effects also has contributions. The different vertical structures of warming over northwestern China and southeastern China may be attributed to the different natures of vertical circulations. The deep, moist convection over southeastern China is an effective mechanism for ＂transporting＂ the warming upward, leading to more upper-level warming. In northwestern China, the warming is more surface-orientated, possibly due to the shallow, dry convection.

A BRIEF INTRODUCTION TO GEOSPACE DOUBLE STAR PROGRAM

The Geospace Double Star Exploration Project (DSP) contains two small satel lites operating in the near-earth equatorial and polar regions respectively. The tasks of DSP are: (1) to provide high-resolution field, particle and wave mea surements in several important near-earth active regions which have not been covered by existing ISTP missions, such as the near-earth plasma sheet and its boundary layer, the ring current, the radiation belts, the dayside magnetopause boundary layer, and the polar region; (2) to investigate he trigger mechanisms of magnetic storms, magnetospheric substorms, and magnetospheric particle storms, as well as the responses of geospace storms to solar activities and in terplanetary disturbances; (3) to set up the models describing the spatial and temporal variations of the near-earth space environment.To complete the mission, there are eight instruments on board the equatorial satellite and the polar satellite, respectively. The orbit of the equatorial satellite is proposed with a perigee at 550km and an apogee at 60 000km, and the inclination is about 28.5°; while the orbit of the polar satellite with a perigee at 700 km and an apogee at 40 000 km, as well as an inclination about 90°. The equatorial and polar satellites are planed to be launched into orbits in June 2003 and December 2003 respectively to take coordinating measurements with Cluster Ⅱ and other missions.

A Brief Introduction and Recent Progress of the Geospace Double Star Program

The Geospace Double Star Project (DSP) consists of two small satellites operating in the near-earth equatorial and polar regions, respectively. The goals of DSP are: (1) to provide high-resolution field, particle, and wave measurements in some important near-earth active regions which have not been covered by current ISTP missions, such as the near-earth plasma sheet and its boundary layer, the ring current, the radiation belts, the dayside magnetopause boundary layer, and the polar region; (2) to investigate the trigger mechanisms of magnetic storms, magnetospheric substorms, and magnetospheric particle events,as well as the responses of geospace storms to solar activities and interplanetary disturbances; (3) to set up the models describing the spatial and temporal variations of the near-earth space environment.To realize the above goals, the equatorial satellite TC-1 and the polar satellite TC-2 will accommodate, respectively, eight instruments on board. TC-1was launched successfully in December 2003 while the polar satellite (TC-2)will be launched in July 2004. The orbit of the equatorial satellite TC-1 consists of a perigee at 550 km, an apogee at 60 000 km, and an inclination of about 28.5; while the orbit of the polar satellite will have a perigee of 700 km, an apogee of 40 000 km, and an inclination of about 90. The two satellites will take coordinated measurements with Cluster Ⅱ and will first form a "six-point exploration" in geospace.The operational status of TC-1 are introduced in this paper.

An object tracking and global localization method using the cylindrical projection of omnidirectional image

We present an omnidirectional vision system we have implemented to provide our mobile robot with a fast tracking and robust localization capability. An algorithm is proposed to do reconstruction of the environment from the omnidirectional image and global localization of the robot in the context of the Middle Size League RoboCup field. This is accomplished by learning a set of visual landmarks such as the goals and the corner posts. Due to the dynamic changing environment and the partially observable landmarks, four localization cases are discussed in order to get robust localization performance. Localization is performed using a method that matches the observed landmarks, i.e. color blobs, which are extracted from the environment. The advantages of the cylindrical projection are discussed giving special consideration to the characteristics of the visual landmark and the meaning of the blob extraction. The analysis is established based on real time experiments with our omnidirectional vision system and the actual mobile robot. The comparative studies are presented and the feasibility of the method is shown.

Analysis and Comparison of Electric Drive System Projects of Military Tracked Vehicles

The electric drive system characteristics of different projects for tracked vehicles are analyzed.For the two most typical projects,the parameters of power,torque and rotating speed and others of drive motor are figured out under the condition of satisfying adequate steering performance of the tracked vehicles.General opinions on the two projects are brought forward and conclusions are drawn.

Design Consideration and Reconstruction Method for Double-source Double-multislice Spiral CT

To accelerate the scan speed and improve the image quality, a new type of CT configuration, "double-source double-multislice spiral CT" (DSDMS-CT), which is based on two sets of single-source multislice spiral CT was proposed with a special reconstruction algorithm. Simulation results using the fan-beam filtered backprojection algorithm with a special interpolation method were presented for both single-source multislice spiral CT and DSDMS-CT. The results of new CT model show that it scans faster than the traditional spiral CT and has a better slice sensitivity profile (SSP) with larger pitch value.

钢管混凝土双块式轨枕无砟轨道结构疲劳性能试验研究

新型钢管混凝土(CFT)双块式轨枕克服了桁架钢筋双块式轨枕存在的生产制造复杂、存放易锈蚀、运营阶段易开裂等问题,可广泛应用于高速铁路和城市轨道交通无砟轨道结构。为检验CFT双块式轨枕无砟轨道结构的疲劳性能,采用11根预制CFT双块式轨枕现浇制作足尺无砟轨道结构节段模型,开展橡胶隔振垫式减振轨道和现浇整体式轨道节段的疲劳试验,揭示其疲劳损伤特性,分析典型疲劳加载循环次数后静载作用下轨道结构应变和变形分布及其演化规律。研究结果表明:1.5倍静轴重的疲劳荷载累计作用500万次后,减振节段及整浇节段CFT双块式轨枕无砟轨道结构混凝土均未出现肉眼可见的裂缝,轨枕与现浇道床整体工作性能良好,疲劳性能满足规范要求;停机开展静载试验过程中轨道结构各测点混凝土横向应变值随荷载增大而近似线性增大,最大拉压应变值均远小于混凝土的极限应变值,工作状态良好;轨道整浇节段道床板中处于整体受拉的状态,可见设置层间连接钢筋实现了道床与底座的共同工作;疲劳试验过程中轨道结构测点竖向位移值总体随着静载的增大而逐渐增大,位移量级较小,满足规范要求,减振轨道节段竖向位移值及其变化率大于整浇轨道节段。研究结果可供类似研究及钢管混凝土双块式轨枕无砟轨道结构工程应用参考。

面向“双碳”目标人才培养的工业化学课程教学改革探索与实践

为培养“双碳”目标高等教育紧缺专业人才,过程装备与控制工程专业工业化学课程“教”与“学”的模式需要与时俱进,改变以教师为中心的教学模式,建立以学生为中心的教学模式势在必行。该文针对工业化学课程教学过程中存在的“双碳”目标教育内容不足问题,初步探索通过增加绿色工程教育内容、实施项目驱动教学、建设跨学科的工业化学师资队伍和建立与“双碳”目标人才培养相适应的教学评价方法等措施来提高教学质量,并提出“双碳”目标下工业化学课程体系改革建议,为培养“双碳”目标紧缺人才提供参考和应用实践。

能源技术进步与区域专业化——特高压输电工程的视角

基于2003—2020年中国285个地级市数据,以特高压输电工程为切入点,研究能源技术进步对区域专业化的影响及作用机制。结果显示:以特高压输电技术为代表的能源技术进步显著提升了区域专业化水平,具体而言,较没有特高压输电项目城市,配备特高压输电工程城市的专业化水平提升约1.09%,且该效应在中小城市、资源丰富城市和内陆地区更强;在考虑样本选择偏差、基期分工水平、调整指标测度、剔除极端值并进行安慰剂检验和倾向得分匹配后,该结果依然稳健;进一步的机制分析表明,特高压建设所表征的能源技术进步通过激发资源禀赋的比较优势、生产的集聚效应来促进地区专业化。继续扩大特高压输电规模,合理实施区域专业化,互通有无、取长补短,对促进区域协调发展具有重要意义。

“双一流”大学教师国际学术影响力研究——结构、评价指标及影响因素

构建大学教师国际学术影响力的三维评价指标和量表,对中国37所“双一流”大学教师进行了国际学术影响力抽样调查和测评。通过结构方程模型方法,拟合验证了所构建的大学教师国际学术影响力的三维结构,即国际人才培养、国际科学研究和国际社会服务。研究结果表明,大学教师的国际学术影响力平均水平偏低,存在较大的个体差异,同时,还会受到大学教师的学科领域、职称、访学时长、访学次数等因素的显著影响。

重载列车编组与运行对双线桥动力响应的影响

研究目的:为研究重载列车编组与运行对双线桥梁动力响应的影响,以朔黄重载铁路线上一座32 m预应力混凝土双线简支T梁为研究对象,建立重载列车-轨道-桥梁耦合有限元模型,并通过现场试验验证有限元模型的准确性,研究重载列车通过双线桥梁时的动力响应,分析重载列车不同编组方式、重载列车双线对开运行等因素对双线桥梁动力响应的影响规律。研究结论:(1)动力响应计算结果与实测值吻合较好,表明所建立的重载列车-轨道-桥梁耦合有限元模型的可靠性高;(2)重车编组对桥梁的位移响应和动应变影响最大,对加速度的影响最小;空车编组对桥梁的加速度响应最大;空重混编次之,其中重车在前空车在后的混合编组对空车的位移响应影响较大,可能引起空车脱轨;(3)重车空车双线对开运行下桥梁的动力响应随着车速的提高而增加,与重车单线运行下桥梁的动力响应规律相似;在相同车速下,双线对开运行下桥梁的跨中竖向动力响应峰值均比重车单线运行下略大,而横向动力响应峰值比重车单线运行下小;(4)当重车与空车入桥距离差值为车体长度的整数倍时,桥梁的动力响应峰值与重车空车同时上桥时基本相等;当入桥距离差值为车体长度一半的整数倍时,桥梁的动力响应峰值有所降低;(5)本研究成果可为新建重载铁路双线桥梁的设计提供参考。