Thermodynamic Analysis of Inclusions of Low Melting Point Area in Spring Steel

The activity data of each component of a CaO–SiO2–Al2O3 system were calculated by thermodynamic software Factsage. The composition of low melting point inclusions in a CaO–SiO2–Al2O3–MgO system was analyzed by thermodynamic calculation. The results show that the area of low melting point inclusions first increases then decreases with accumulating the alumina and magnesium oxide contents, respectively; the low melting area of CaO–SiO2–Al2O3–MgO inclusion is the biggest when the content of MgO and Al2O3 is 15%. To obtain low melting point inclusions, the alumina and magnesium contents should be approximately controlled to be 15%, and the CaO should be 40%.

Discussion on the Green Tax Stimulation Measure of Nitrogen Fertilizer Non-Point Source Pollution Control-Taking the Dongting Lake Area in China as a Case

A study on designing the tax of nitrogen fertilizer can provide a new method for controlling nitrogen fertilizer non-point source pollution. The tax design of nitrogen fertilizer was discussed by utilizing the external theory and the demand elasticity theory. The results indicated that the coefficient of price elasticity of nitrogen fertilizer demand is -0.21, which instructed that the market demand is in lack of elasticity in the short period and the impact of nitrogen fertilizer manufacturers is subtle. The 11 counties （cities and boroughs） in the Dongting Lake area in China, where the farmland nitrogen application surpassed the average ecological fertilization dosage, is listed to the taxation scope of nitrogen fertilizer tax. The environment loss will reduce 0.07 hundred million RMB yuan and the revenue will increase 0.89 hundred million RMB yuan in the country after levying on nitrogen fertilizer. The loss, which was brought by the decreasing food supplies production, will be 0.58 hundred million RMB yuan and the net social benefit will be 0.38 hundred million RMB yuan following revenue collection. The variation scope of the increasing expenditure of farmers will range from 0.95 to 1.49%. The variation scope of the income of farmers will range from -8.41 to 6.44%. The 5 areas, Yunxi Borough, Junshan Borough, Hanshou County, Jinshi City, and Ziyang Borough, had an increase in food supplies production after the revenue collection. The environment loss will reduce 0.01 hundred million RMB yuan and the revenue will increase 0.16 hundred million RMB yuan in the country after levying on nitrogen fertilizer. The economic benefits, which was brought by the increasing cereals production, will be 0.67 hundred million RMB yuan and the net social benefit will be 0.84 hundred million RMB yuan after revenue collection. The variation scope of the increasing expenditure of farmers will range from 0.95 to 1.06%. The variation scope of the increasing income of farmers will range from 0.69 to 6.44%. Considering the entire social welfare, taxation of nitrogen fertilizer will have more advantages than disadvantages in the Dongting Lake area.

Acupuncture at Waiguan(SJ5) and sham points influences activation of functional brain areas of ischemic stroke patients: a functional magnetic resonance imaging study

Most studies addressing the specificity of meridians and acupuncture points have focused mainly on the different neural effects of acupuncture at different points in healthy individuals. This study examined the effects of acupuncture on brain function in a pathological context. Sixteen patients with ischemic stroke were randomly assigned to true point group （true acupuncture at right Waiguan （SJ5）） and sham point group （sham acupuncture）. Results of functional magnetic resonance imaging revealed activation in right parietal lobe （Brodmann areas 7 and 19）, the right temporal lobe （Brodmann area 39）, the right limbic lobe （Brodmann area 23） and bilateral oc-cipital lobes （Brodmann area 18）. Furthermore, inhibition of bilateral frontal lobes （Brodmann area 4, 6, and 45）, right parietal lobe （Brodmann areas 1 and 5） and left temporal lobe （Brodmann area 21 ） were observed in the true point group. Activation in the precuneus of right parietal lobe （Brodmann area 7） and inhibition of the left superior frontal gyrus （Brodmann area 10） was observed in the sham group. Compared with sham acupuncture, acupuncture at Waiguan in stroke patients inhibited Brodmann area 5 on the healthy side. Results indicated that the altered specificity of sensation-associated cortex （Brodmann area 5） is possibly associated with a central mechanism of acupuncture at Waiguan for stroke patients.

Reductions in non-point source pollution through different management practices for an agricultural watershed in the Three Gorges Reservoir Area

Non-point source water pollution generated by agricultural production is considered a major environmental issue in the Three Gorges Reservoir Area （TGRA） of China. The Annualised Agricultural Non-Point Source Pollution （AnnAGNPS） model was selected to assess the impact of the application of various management treats, including seven crops, five fertilizer levels and three-group management practice scenarios, on water quality from Heigou River Watershed in TGRA. The scenario subsets include conservation tillage practice （CTP）, conservation reserve program （CRP） and conversion of cropland into forestland program （CCFP）. Results indicated that tea can not be replaced by other crops because comparatively tea resulted in a higher sediment yield. CTP with no-tillage was more effective to reduce sediment yield, but could increased nutrient loss. CRP reduced sediment yield significantly, but slightly benefited on nutrient loss. CCFP reduced not only sediment yield but also the nutrient loss significantly. The conversion of cropland with a slope greater than 10° into forestland was found to be the best scenario as the sediment yield export is less than 5 tons/ha and nutrient loss is within the permissible limit.

Research on Monitoring Area Division of Quality Grade Changes in County Cultivated Land and Technology of Deploying Monitoring Point

It is an important means in management of improving both the quality and quantity of cultivated land to monitor grade changes in cultivated land quality. How to deploy monitoring network system and its point reasonably and roundly are the key to the technology of monitoring grade changes in cultivated land quality by monitoring grade changes in cultivated land quality dynamically in order to obtain the information to the index of cultivated land quality and its changes based on the existing achievements of farmland classification and grading. Spatial analysis method is used to demarcate monitoring area and deploy monitoring point according to ARCGIS,of which the result can meet the demand for monitoring grade changes in cultivated land.

Fractal Analysis on the Spatial Structure of Land Use Patterns in a Non-Point Source Polluted Area in Southern China

Based on the TM remote sensing interpretation of land use data of a non-point source polluted area in southern China in 2015, supported by ArcGIS and the fractal theory, this paper established the perimeter-area fractal equation of the spatial structure of land use types, quantitatively calculated the fractal dimension and stability index of various land use types in this non-point source polluted area in 2015, and analyzed the spatial structure characteristics of land use types. The results showed that the fractal dimension values of the different land use types in the research area ranged 1.141–1.657, and the whole fractal dimension of the research area was 1.206. To be specific, the fractal dimension values of unused land, grass land and rural residential land were high, and the fractal dimension values of dry land, paddy filed and waters were low, and the fractal dimension values of urban land, industrial traffic construction land and forest land were moderate. The area of the land use types whose stability index values were 0.2–0.4 accounted for 89.5% of total area, suggesting that the stability of the spatial structure of land use types of Beibei District in 2015 was not high generally. The rural residential land and urban land of the research area should be planned and managed more properly from now on.

Combination Operation for Neutral Point of 35 kV Power Grids in Mountainous Area

Based on a lot of measurement and analysis,this paper find that the unbalanced nature of 35 kV grids due to unsymmetrical capacitance values gives difficulty in neutral point operation in mountainous area.Improving compensation of Petersen coil can rectify imbalance of voltage but bring up new problem that Petersen coil can not extinguish grounding arc effectively in fault.To put down contradiction mentioned above,this paper proposes a combination operation for neutral point of 35 kV grids as neutral point insulated in routine operation and grounding through Petersen coil in fault,then EMTP simulation is carried out.Simulation indicates that new neutral operation method can improve lightning withstand level and decrease trip-out rate of grids.

秦岭南麓小流域乡村聚落空间集聚PSR评价研究——以乾佑河流域柞水段为例

小流域是山地区域乡村聚落广泛存在的空间载体,随着新型城镇化建设、乡村振兴战略的实施,这里的聚落也开始发生剧烈变动,开始了更为集约的收缩型集聚。为了更好地发现其变化集聚的状态与趋势,对聚落发展提出合理的优化建议与引导,急需合适的评价工具与方法。因此,针对秦岭南麓小流域内聚落斑块零散存在的现实情况,借助“压力-状态-响应”评价模型,提出了聚焦小流域乡村聚落社会-生态健康发展的PSR评价方法以及聚焦关键问题的研究思路;进而以乾佑河柞水段的七条典型小流域为对象,借助核密度估算工具,进行内部聚落空间集聚特征的总结,建构起可进行比较的核点集聚区域、点轴集中区概念;并通过评价参数的筛选,明确了小流域、核点集聚区域双层级PSR评价体系,结合实践提出相关优化建议,也为小流域乡村聚落合理建设探索更科学的研究基础。

小型玉米收获机车身调平系统研究

为了提高小型两行轮式玉米收获机在复杂地形的作业能力,设计了一种三点调平装置,建立了调平模型并对其进行了理论分析,并设计了调平控制系统。在此基础上,设计并制造了试验用车,对倾角信号进行滤波处理后,进行了调平试验。试验结果表明:车身左倾最大调平角度是15°,右倾最大调平角度是17.5°,前倾最大调平角度是12.5°,后倾最大调平角度是17.5°,验证了自动调平机构和控制系统的可靠性和实用性。设计的针对4YZ-2玉米收获机的三点调平装置和调平控制系统可为玉米收获机自适应调平提供了研究基础,并为其他行走农业机械的调平设计提供了新思路。

基于黄金分割搜索的电压暂降域快速识别方法

针对大型复杂电网中敏感负荷的电压暂降域难以准确识别的问题,提出一种基于黄金分割搜索的电压暂降域快速识别方法。首先,求得网络中发生各类短路故障时敏感负荷节点的电压暂降幅值解析式,并引入节点判定向量和线路关联向量,以及相应的判定准则,实现对所有线路临界点的快速分类计算;接着详细阐述了传统插值法存在的问题,并提出一种由黄金分割搜索改进的插值法,以期为正割迭代提供更优的初值点,提高临界点计算的准确度;因考虑到拟合的二次曲线难免存在偏差,故使用故障点法作为补充算法,用以计算有求解困难的线路;最后,以IEEE30节点标准测试系统为例,验证了该方法能在保证计算精度的前提下,简化电压暂降域的求解过程,提高算法的收敛速度,并广泛适用于大型复杂电网。

多无人车协同规划及突发情况下应急响应与恢复方法

面对环境突变、车辆故障等突发情况,传统集中式协同规划方法无法快速应急响应、实现系统冲突消解和有序恢复。针对以上问题,提出一种运动学约束下多无人车协同规划及突发情况下应急响应与恢复方法。首先,采用集中式搜索架构构建运动学约束下的协同路径规划模型,引入车身约束树以消解连续空间内多无人车碰撞。其次,为确保受突发情况影响的无人车能够安全快速停靠并降低对系统的干扰,提出一种基于预警区域的应急规划起始点选取方法,基于紧急事件发生时无人车状态生成的随机搜索树进行分层搜索,将随机搜索树、系统内部时空约束、无人车运动稳定性需求相结合,确保无人车能平稳过渡到应急停靠点。最后,在系统恢复过程中,针对不同无人车到达应急响应停靠点的时间差异,采用异步规划策略,将未受突发事件影响的车辆轨迹纳入协同规划的时空约束,最终生成应急响应后的恢复轨迹簇。仿真测试中,最优应急响应轨迹生成平均时长0.324 s,应急响应模块将规划成功率由28.7%提高到87.6%,异步模块在突发障碍物高达15个时将运行效率提升接近93%。

高原地区四点源诱偏系统抗ARM防护性能仿真分析

针对传统反辐射导弹(ARM)攻击仿真模型难以评价高原复杂地形下雷达诱饵的防护效能问题,对传统雷达诱饵诱偏模型进行了改进.首先建立了ARM攻击有源诱偏系统的运动模型,分析了有源诱偏系统对ARM的影响;然后在此基础上,模拟仿真了高原条件下最佳四点源诱偏系统分布模型的抗毁效能.仿真结果表明,通过增大各辐射源高度差可以有效弥补因间距缩短导致的防护概率下降的问题;利用前三角形布站形式,当各辐射源部署间距为100m和高度差为60m时,雷达的防护概率可以达到99.1%,基本满足雷达有源诱偏系统对雷达的防护要求.

结合载客热点和POI的出租车停车位划定方法

针对出租车随意停靠造成城市交通拥堵甚至交通事故的问题,利用成都实际区域的出租车GPS(Global Position System)数据和爬取的POI(Point of Interest)数据,使用DBSCAN(Density-Based Spatial Clustering of Application with Noise)聚类算法对上下客点进行聚类,得到出租车的载客热点,根据POI的类型划定载客热点区域的类型,对出租车不同时间的出行需求进行分析,进而划分出出租车的固定停车区域。研究结果表明,出租车固定停车区域的设定与出行者的出行需求有关,即将固定停车区域设置在出行者出行需求多的区域,可以满足出行者的不同出行需求。结合出租车载客热点和爬取POI数据划定固定停车区域的方法具有较高的实用性,可为城市交通安全方面提供理论和现实意义。

基于拐点密集区凹凸波动特性的直流配网故障检测方法

基于模块化多电平换流器(modular multilevel converter,MMC)的柔性直流配电网具有不存在换相失败等优点。但换流器存在低惯性、弱阻尼等特性,导致故障电流上升速度快且峰值高,对系统危害极大。针对直流配电网发生单极接地故障难以准确选择故障馈线的问题,提出了一种基于拐点密集区凹凸波动特性的直流配网故障检测方法。首先,利用变分模态分解算法对各馈线零模电流进行分解,选取特征分量。然后,计算特征分量的二阶导数,选择拐点密集区并进行归一化处理,得到各馈线的凹凸波动性。最后,判定凹凸波动性与其他馈线相异的线路为故障线路。仿真结果表明,所提方法能够快速识别故障馈线,且受过渡电阻、采样频率、数据窗和噪声等因素影响小。

Effect of Lumbar Spinal Point Injection on Sitting Function in Children with Cerebral Palsy

Objective: To observe the effect of lumbar spinal point injection on sitting function in children with cerebral palsy. Method: Sixty-two children with post-confirmed cerebral palsy were randomly divided into control group and treatment group, 31 each. The control group was given conventional rehabilitation treatment, and the treatment group was given lumbar chiropspinal acupoint injection on the basis of the treatment method of the control group. After 3 consecutive courses of treatment, the sitting score of the two groups before and after treatment (GMFM88) was used to evaluate the sitting score before and after treatment. Outcome: Before treatment, the two groups were evaluated and the differences were not statistically significant (p > 0.05), which was comparable. The two groups (GMFM88) after treatment had significantly increased the differential values, and the difference was statistically significant compared with the same group before treatment (p Conclusion: Conventional rehabilitation combined with lumbar spinal point injection can effectively improve the sitting motor function of children with cerebral palsy.

基于手机信令数据的贝叶斯优化出行链识别

为了克服手机信令数据定位信息的时空不确定性对出行识别的影响,分析手机信令数据的时空特性,在时空阈值识别停留点方法的基础上,引入兴趣面(AOI)信息和基站位置数据,提出可变参数滑动窗口的出行停留点识别方法.建立出行链模型,采用贝叶斯多目标优化获得模型的最佳参数,实现时空阈值的动态调整,提高识别的准确性.为了验证方法的有效性,组织志愿者采集真实出行GPS数据和出行信息标签作为验证数据,与应用模型于对应手机信令数据后的结果进行对比.研究结果表明,手机信令数据的采样在移动和静止状态下存在特性差异;相较于对比方法,提出的出行链识别方法在泛化性能和最优性能方面都表现出较小的误差和较高的识别率,尤其在识别率指标上,相比其他的最新算法改进了3%~26%.

新疆准噶尔盆地北部黄花沟铀异常点矿化特征及找矿方向

近年准噶尔盆地北缘铀矿勘查取得了较好的找矿成果,相继发现了顶山矿点、卡姆斯特矿产地等。黄花沟异常点的发现为盆地北缘“新地区、新层位、新类型”三新找矿提供了重要线索。文章通过对盆地北缘黄花沟铀异常点的地质调查和系统采样,总结了异常点的铀矿化特征,探讨了矿化成因。研究认为:1)黄花沟异常点矿化主要发育在红砾山背斜核部,吐丝托依拉断裂上盘;2)矿石岩性以细粒岩屑砂岩为主,其次为砾岩,发育褐铁矿化、黏土化蚀变;3)含矿层砂岩成分成熟度较低、结构成熟度中等,为近源冲积扇扇中辫状河道沉积成因;4)黄花沟地区下一步主攻层位为下白垩统吐谷鲁群,主要找矿类型以潜水氧化带型和潜水-层间氧化带型为主。准噶尔盆地北缘下一步找矿工作应重视对隆起与凹陷构造单元的边界及控凹断裂附近、目的层沉积环境与上覆地层具有继承性的位置的查证。

多点起爆下鼓形战斗部的威力特性

为调控对地弹药破片杀伤威力场,研究了一种鼓形战斗部在静爆和动爆下的威力特性。采用数值模拟研究了端面中心单点、中心单点两种起爆方式下,鼓形战斗部相较于同口径圆柱形战斗部在静爆下的破片威力特性及动爆下对地面装甲车辆目标的毁伤面积。在此基础上,调整鼓形战斗部起爆方式为偏心两线同时起爆、偏心两线序贯起爆及偏心两线同时-序贯起爆,计算了不同偏心起爆下鼓形战斗部静爆时的破片速度、飞散角和动爆时对车辆目标的毁伤面积及有效破片落地动能分布。研究表明,相比于同口径的圆柱形战斗部结构,鼓形战斗部的破片飞散角增大了55.98%,对地面军用车辆的毁伤面积最大增大了59.3%;相对于偏心两线同时起爆,偏心两线同时-序贯起爆的鼓形战斗部破片飞散角增大了18.0%,破片飞散的离散程度提高了11.48%;相对于装药中心单点起爆,偏心两线序贯起爆下鼓形战斗部的毁伤面积受炸高影响较小,在落角50°、落速200 m/s、炸高为9 m时的毁伤面积达47.15 m^(2)。通过调整战斗部的结构和起爆方式,可有效增大破片的飞散角,增大破片对目标的覆盖面积,提高战斗部的毁伤效能。

基于结构光场辅助的面阵定位投影标示技术研发

以一套数字光处理面阵投影装置和一个工业相机作为基本硬件平台,研发了三维定位标示原型系统i-Guider,阐述了i-Guider系统的工作原理和关键技术。在数字光处理投影仪中固化一组正弦相移条纹结构光图像,将投影仪作为逆成像装置,在结构光场的辅助下利用一块平面标定板实现相机–投影仪内外参数的精确标定。对于三维数模上的曲线轮廓、操作说明等操作信息,提出一种现场自动生成标示信息定位投影图像的方法,并通过HDMI端口将现场生成的标示信息投影图像传递给面阵投影仪,实现操作信息在三维工件实物上的精确定位标示。以一个机身蒙皮试验件为对象,开展了蒙皮定位钻铆三维标示试验,结果表明,i-Guider系统定位投影标示精度在0.25 mm以内,且具有良好的三维定位标示效果。