黑龙江省装备制造企业国际竞争力分析

在东北振兴的政策扶持下,如何提升黑龙江省装备制造企业国际竞争力成为亟须解决的重点问题。本文以黑龙江省装备制造企业为研究对象,对黑龙江省装备制造企业国际竞争力进行分析。在进行实地考察和问卷调查的基础上,构建了4个二级指标,又分解为15个三级指标,建立装备制造企业竞争力指标体系。通过层次分析法和模糊综合评价法构建AHP-FCE模型,对黑龙江省装备制造企业进行评价,对得出的结果进行分析,探究黑龙江省装备制造企业在国际市场竞争中所遇到的难题,提升黑龙江省装备制造企业在国际市场中的竞争力。

非均匀网格下的高阶精度中央差分格式:理论推导和理想试验

传统的高阶精度有限差分格式通常是在均匀网格的基础上推导得到的,在非均匀网格的情况下它会出现精度退化的问题。基于泰勒展开方法构造了一种适用于非均匀网格的2阶、4阶和6阶精度中央有限差分方案,利用Burgers方程和一维平流方程对新方案的性能进行测试,着重分析新方案对其误差大小及分布形态的改进效果。数值模拟结果表明:在非均匀网格下,提高差分方案的精度可明显减小数值解误差(降低了70%~88%),特别是当差分精度从2阶提高到4阶的时候。同时,高阶精度方案在梯度变化较大或者网格距较粗区域的模拟结果更有优势,4阶和6阶精度方案在以上区域的误差远小于2阶精度方案。方案可用于提高数值天气预报模式中非均匀分层模式的垂直差分计算精度。

乡村教师身份认同危机转化过程的多向——发展动力机制研究——基于X省D教师的个案考察

随着乡村振兴战略的推进,乡村教师作为“新乡贤”是乡村教育、乡村文化发展的重要主体。然而,当下乡村教师身份认同危机是影响其“去”与“留”的关键因素。采用质性研究方法,深入考察在乡村执教21年的骨干教师D教师身份认同危机转化的内部过程,可以发现:D教师身份认同危机转化过程经历了从生存型向生长型再到生命型的转变。在实现身份认同危机转化的过程中显现出两种力量的交织,一是家人支持、主动学习和使命感所组成的正向推动力,二是由教师文化和组织文化所形成的主要负向阻碍力。D教师身份认同危机转化过程构建了多向—发展动力机制,这对于有效促进乡村教师身份认同危机转化的启示是:情感沃土是乡村教师实现身份认同危机转化的保障;任务重塑能力是乡村教师实现身份认同危机转化的基石;与学生共同成长的价值感是乡村教师实现身份认同危机转化的原点;良好的学校文化是乡村教师实现身份认同危机转化的文化土壤。

A Review on GRAPES-TMM Operational Model System at Guangzhou Regional Meteorological Center

This review summarizes the general developments of the operational mesoscale model system based on the Global/Regional Assimilation and Prediction System-Tropical Monsoon Model (GRAPES-TMM) at the Guangzhou Regional Meteorological Center. GRAPES-TMM consists of the Tropical Regional Atmospheric Model System for the South China Sea (TRAMS, a typhoon model with a horizontal resolution of 9 km), the Mesoscale Atmospheric Regional Model System (MARS, 3km) and the fine-scale Rapid Update Cycling (RUC, 1km) forecasting system. The main advances of model dynamical core and physical processes are summarized, including the development of the 3D reference atmosphere scheme, the coupling scheme between dynamics and model physics, the calculation of nonlinear terms by fractional steps, the gravity wave drag scheme induced by sub-grid orography and a simplified model for landsurface scheme. The progress of model applications is reviewed and evaluated. The results show that the updated 9-3-1forecasting system provides an overall improved performance on the weather forecasting in south China, especially for typhoon-genesis and typhoon-track forecasting as well as short-range weather forecasting. Capabilities and limitations as well as the future development of the forecasting system are also discussed.

Development of 1km-Scale Operational Model in South China

To support short-range weather forecasts,a high-resolution model(1km)is developed and technically upgraded in the South China Regional Center,including the improvement of the 3D reference scheme and the predictor-corrector method for semi-implicit semi-Lagrangian(SISL)in model dynamical core,as well as the improvement of physical parameterization.Furthermore,the multi-process parallel I/O and parallel nudging techniques are developed and have facilitated rapid updating in the assimilation prediction system and fast-output post processing process.The experimental results show that the improved 3D reference scheme and upgraded physic schemes can effectively improve the prediction accuracy and stability with a longer integration time step.The batch test shows that the precipitation forecast performance of 1-km model is significantly better than that of 3-km model.The 1-km model is in operation with a rapidly updating cycle at 12-minute intervals,which can be applied to short-range forecasts and nowcasting.

Performance Evaluation of the GRAPES Model in Wind Simulations Over South China

In the present study,the performance of the GRAPES model in wind simulation over south China was assessed.The simulations were evaluated by using surface observations and two sounding stations in south China.The results show that the GRAPES model could provide a reliable simulation of the distribution and diurnal variation of the wind.It showed a generally overestimated southerly wind speed especially over the Pearl River Delta region and the south of Jiangxi Province as well as the coastal region over south China.GRAPES also exhibited a large number of stations with the opposite surface wind directions over the east of Guangxi and the south of Jiangxi during the nocturnalto-morning period,as well as an overall overestimation of surface wind over the coastal regions during the afternoon.Although GRAPES could simulate the general evolutional characteristics of vertical wind profile,it underestimated wind speed above 900 hPa and overestimated wind speed below 900 hPa.Though the parameterization scheme of gravity wave drag proved to be an effective method to alleviate the systematic deviation of wind simulation,GRAPES still exhibited large errors in wind simulation,especially in the lower and upper troposphere.

城市轨道交通列车开行方案和客流控制协同优化研究

针对城市轨道交通高峰期沿线部分车站的拥挤问题,提出列车开行方案和线路客流控制协同优化策略.以乘客总延误和站内控制节点控流强度最小化为目标,综合考虑行车条件、客流动态加载过程和设备设施安全约束等条件,构建了多目标规划模型.通过引入0-1变量对非凸约束条件处理以及利用评价函数对多目标函数处理,把模型转化为等价的单目标混合整数线性规划模型,利用通用代数建模系统编程调用求解器直接求解.算例结果表明,所建模型会有效降低站台乘客集聚程度、减少乘客总延误时间,从而保证运营安全的同时提高了系统效率.

基于“案例教学”的交通运输统计分析课程教学探索

文章提出基于“案例教学”的交通运输统计分析课程教学模式改革,以解决统计理论、软件应用和行业数据分析三个知识模块相互脱节的问题,并从案例库的构建、教学设计的选择、评价机制的完善等方面探讨实施过程中的关键环节,突出“目标导向、学生中心、持续改进”的架构,旨在实现由传授型课堂向研究型课堂的转变,以培养学生养成以探索、研究为本的学习意识,提高自主学习能力以及创新能力。

基于网络可控性的地铁客流控制站点识别研究

选择合适的站点进行客流控制有利于提高地铁高峰期客流时空分布均衡度和运力资源的利用效率.基于网络可控性判别原理提出客流控制站点选择优化策略,通过引入阈值,将初始状态连接矩阵转化为骨干矩阵,给出节点控制能力的概念,提出求最小驱动节点集的搜索算法.以某市地铁客流网络进行算例分析,结果表明:当限流车站达到23%以上时,系统处于可控状态,给出了路网在可控状态下的最小控流车站集合.

分光光度法测定玩具POM材料甲醛迁移量影响因素研究

根据欧盟标准EN 71-9:2005的测试要求,对新开封的玩具聚甲醛(POM)材料进行测试时,未检出甲醛,但在模拟儿童玩耍后,却检出了一定量的甲醛,发现POM材料的玩具与其他塑料玩具相比具有特殊性。因此,本文对玩具POM材料的甲醛迁移量测定的影响因素进行了研究,通过对迁移温度、迁移液pH、过滤方式、乙酰丙酮显色剂的用量和显色时间等因素进行分析,发现对测定POM材料的甲醛迁移量合适的迁移温度为40~60℃,迁移液的pH值在5.5~7.0之间,显色剂的用量为3.0~5.0 mL,显色时间为10~60 min。本研究通过对玩具POM材料中甲醛迁移量影响因素的优化研究,可有效避免产品假阴性现象,对完善相关标准具有一定的参考意义。