An Approach of Reducing Overall Level of Export Fluctuations of the Export-oriented Countries

Overall level of export fluctuations of the export-oriented countries with rising export volume partly stem from the market failure caused by free choice of export enterprises,some government intervention thus may be necessary.To reduce the level of fluctuations of the export growth rates in these countries,this paper,taking the significant differences of the exports among various markets into account and thus using a new index named relative variance to measure the export volatility risks,proposes a model of merchandise market portfolio,a modified version of Markowitz model,available to provide explicit guidelines for the firms,the industries and even the whole country to optimize the structure of their export markets.An application of this model to the case of China’s apple is then discussed.The results show that the market share of China’s apple in 7 sub-markets should be redistributed drastically.

HAS THE PEARL RIVER DELTA BEEN AN EXPORT-ORIENTED ECONOMY?

Ever since the introduction of the Open Door Policy, the Pearl River Delta (PRD) has enjoyed very phenomenal export and economic growth. As a result, many scholars have tried to associate the two phenomena and described the region as an,'export-oriented economy'.However, these studies, mostly based on the rapid export growth of the PRD and its status as the most important exporting area of the country,have not paid any heed to the actual export-orientation of the regional economy and, hence, cannot prove that the PRD has been a 'truly'export-oriented economy. in view of these shortcomings. the present paper attempts to re-examine the issue from the viewpoint of the PRD's local economy, at both the regional and county levels. The study period is from 1981 to 1990. Judging from the export-dependency indices and the relative importance of exports in accounting for the economic growth and industrialization of the PRD, this paper concludes that the region, though having signs of increasing export-orientation, cannot be categorized as a 'truly' export-oriented economy. In addition, it also shows that most of the 'evidences' or 'common beliefs' behind the notion of an export-oriented economy in the RD are illusionary, if not erroneous. Finally, the paper explores into the reasons behind the low export-orientation of the PRD and tries to sugyst some ways for boosting the export-orientation of the PRD and tries to suggest some ways for boosting the export-orientation of the region.

Current Situation and Problems of Export-oriented Tilapia Processing in Guangxi and Countermeasures

Guangxi Zhuang Autonomous Region is an excellent area for tilapia breeding in China,and the development of tilapia industry has received high attention of both the state and Guangxi government. The foreign exchange earning is an essential industrial form of tilapia industry in Guangxi. Thus,enhancing the competitiveness of export-oriented tilapia processing is of great significance to the development of tilapia industry. On the basis of field survey,this paper analyzed current situation of export-oriented tilapia processing in Guangxi. At present,tilapia processing industry in Guangxi has realized preliminary standardization,large-scale and grouping,but it is still faced with some problems and challenges,such as low industrialization level,no balanced marketing,and imperfect product quality safety monitoring measures. Therefore,it is required to create favorable environment for export-oriented tilapia processing industry in Guangxi through enhancing policy support,increasing financial input and supporting tilapia processing leading enterprises.

Export-Oriented Economy in Shenzhen

In the past 15 years Shenzhen has made great achievements in its export-oriented economy. According to customs’ statistics, the city’s export value stood at US $ 14.3 billion in 1993 and US $ 12.1 billion in the first three quarters of 1994. The total import and export value was US $ 23.8 billion in the first three quarters of 1994, a 1, 500-fold increase over 1979 and an average annual growth rate of 70%. Export trade held a small part in Shenzhen’s economy

Impetus for Export-Oriented Economy——Review of foreign capital utilization in Hunan during the Eighth Five-Year Plan period

Since its implementation of the openingpolicy,China has witnessed greatsuccess in foreign fund utilization.Hunan,situated in the hinterland,beganto introduce foreign capital a little later thanthe coastal areas.In 1979,Hunan began toconduct processing and assembling businessand compensation trade,but gained only afew million US dollars.A vast change wastook place in the Eighth Five-Year Planperiod,achieving a great quantitative andqualitative rise in foreign capital utilizationas compared with the sixth and seventh Five-Year Plan periods.In the past five years,Hunan has approved 4,001 foreign-fundedprojects,a 5,5-fold increase over the total forthe previous 12 years(1979-1990),including3,584 projects directly financed by

Zhangjiagang's Strategies for the Export-oriented Economy

Following its fast development over the past dozen years, especially the past three years, Zhangjiagang, a coastal city in Jiangsu Province has established conditions for the further advance of its export-oriented economy. An official of the city announced to the press in Beijing recently that with the aim of building Zhangjiagang into a modern port city by the end of the century, the following three strategies have been adopted:

Evaluation of a software positioning tool to support SMEs in adoption of big data analytics

Big data analytics has been widely adopted by large companies to achieve measurable benefits including increased profitability,customer demand forecasting,cheaper development of products,and improved stock control.Small and medium sized enterprises(SMEs)are the backbone of the global economy,comprising of 90%of businesses worldwide.However,only 10%SMEs have adopted big data analytics despite the competitive advantage they could achieve.Previous research has analysed the barriers to adoption and a strategic framework has been developed to help SMEs adopt big data analytics.The framework was converted into a scoring tool which has been applied to multiple case studies of SMEs in the UK.This paper documents the process of evaluating the framework based on the structured feedback from a focus group composed of experienced practitioners.The results of the evaluation are presented with a discussion on the results,and the paper concludes with recommendations to improve the scoring tool based on the proposed framework.The research demonstrates that this positioning tool is beneficial for SMEs to achieve competitive advantages by increasing the application of business intelligence and big data analytics.

The Application of Knowledge Management(KM)by Small and Medium-Sized Enterprises(SME)in Manufacturing Industry

To accelerate the digital transformation of small and medium-sized manufacturing enterprises(SMEs),this study delves into the primary challenges encountered in adopting knowledge management(KM)within these organizations and identifies the essential methods for successful implementation.The objective is to provide practical recommendations for the effective adoption of KM.This research suggests that enterprises should promote knowledge management through three key approaches:enhancing employees’cognitive understanding,standardizing knowledge systems,and tailoring business scenarios to meet diverse needs.These findings offer valuable insights into the digital transformation of SMEs in the manufacturing sector,ultimately helping these businesses to remain competitive and innovative in a rapidly changing market.By addressing the specific needs and challenges faced by SMEs,this study aims to contribute to a more comprehensive understanding of how knowledge management can be leveraged to drive digital transformation and improve overall business performance.

含风电-SMES的电力系统暂态稳定概率评估

大规模风电并网给电力系统的稳定运行带来了新的挑战,储能是应对这一挑战的技术之一。以超导磁储能(SMES)为例,提出了含风电-SMES储能的电力系统暂态稳定概率评估方法。首先搭建了一个含有风电和储能的仿真测试平台,其中:风电场采用双馈型风力发电机等值模拟,储能的模型采用SMES的三阶模型。在此基础上,研究了含风电和SMES的电力系统暂态稳定概率评估的方法,重点考虑了故障扰动和风速波动等随机因素,故障扰动包括故障位置、故障类型、故障持续时间以及重合闸成功与否等。基于二分法和蒙特卡罗仿真,量化了系统失稳的风险,建立了风电场的渗透率、储能容量和系统稳定性之间的定量关系。最后,结合SMES的技术经济性分析,给出了最优储能容量计算方法。

百千焦级高温超导环型SMES磁体设计研究

高温超导SMES磁体未来的发展方向是环型磁体,目前对高温超导环型SMES磁体的概念设计比较多,但储能量主要集中在兆焦级,真正制作完成并并网实验的储能量只有千焦级。文中立足高温超导环型SMES处于实验室研究阶段的现实,用遗传算法和有限元法结合的方法对百千焦级高温超导环型SMES磁体进行了设计研究,总结出了单元线圈数量n、单元线圈内直径d和环型磁体内直径D影响磁体储能量E的规律。

用于SMES的电压型换流器试验研究

为实现超导储能装置(SMES-Superconducting Magnetic Energy Storage)与输配电网之间的协调作用,达到提高电网输送容量、暂态稳定性和电压稳定性,提高配电网电能质量的目的。根据SMES的结构特点,结合目前大功率电力电子器件以及电路拓扑的发展趋势,设计了一台三单相H桥分立控制的电压型换流器(VSI-Voltage source inverter)及其控制系统平台。该电压型换流器采用三相器件独立运行结构,控制系统采用数字信号处理器(DSP-Digital Signal Processing)设计,在功能上实现了对串联于电力线路的注入电压幅值和相位的灵活控制,最后给出了一台20 kW电压型换流器原理样机对母线电压补偿功能的试验结果,试验结果表明,该电压型换流器可以满足超导储能系统的需要。

基于STATCOM/SMES系统的平滑风力发电机机端电压输出的研究

恒速异步风力发电机受快速扰动的风速影响其输出的功率和电压将会出现较大波动,含该风力发电机的系统电压稳定性也会受到较大影响。鉴于此现象,通过分析异步风力发电机的功率-电压特性,从理论上研究运行状态及线路阻抗特性对含分布式电源的微网系统电压稳定性的影响,提出一种有功、无功功率解耦控制的STATCOM/SME控制结构,同时首次提出使用指数平均数指标(EXPMA)作为有功功率控制指令信号,有效平滑了风力发电机功率输出,改善了系统的电压稳定性。仿真分析验证了所提出控制结构和策略的有效性。

基于托卡马克超导纵场线圈的SMES-UPS变流器设计及其控制策略

基于超导托卡马克纵场线圈构成的超导磁体储能不停电电源,可用来避免由于电网嬗变或秒级跳闸使低温和真空系统掉电导致的托卡马克装置中的超导磁体失超。文中为SMES-UPS设计的是电流型变流器系统,该系统既可用作为纵场磁体正常工作时的励磁电源又可用作电网故障时关键负载的备份电源。文章对该SMES-UPS变流器的不同工作条件下的原理和控制目标做了说明,对不同控制目标提出了相应的简单易实现的控制策略,并用Matlab进行了数字仿真,验证了控制策略的可行性。

旋转空间矢量算法在电压型SMES控制中的应用

研究了将旋转空间矢量算法应用于超导磁储能 (SMES)装置的可行性 ,比较分析了旋转空间矢量控制和传统矢量控制这两种控制算法在系统节点电压幅值或相位发生突变时的控制效果 ,讨论了旋转空间矢量算法在电压不对称条件下的适用性。旋转空间矢量的另一优点是可以减小计算量 ,为空间矢量控制、无差拍控制等复杂算法控制提供了条件。

模块化级联型SMES变流器及其总分式功率无源控制策略

为实现超导磁储能系统(SMES)的大规模可扩展式应用,提高控制系统的动态性能和鲁棒性,改进级联型SMES变流器的电路拓扑,并设计基于无源控制器的总分式功率控制策略。采用二阶广义积分构造虚拟轴,实现单相电路的坐标变换;证明了无源系统反馈互联后仍保持端口受控哈密尔顿模型结构的特征,分别在交、直流侧设计控制策略,降低了控制设计的复杂度;提出总分式功率控制策略,实现系统并网总功率和各级联模块分功率的独立控制;分别在交、直流侧设计无源控制器,提高了系统控制的动态性能和稳定性。仿真分析验证了模块化级联型SMES变流器及其总分式功率无源控制策略的有效性。系统具备模块化特征,可实现灵活扩展以及各超导磁体功率的独立控制,并具有更快的响应速度、更小的超调量和更好的并网电流质量。

高温超导SMES磁体的失超检测研究

失超保护是保证磁体安全运行的重要措施,而失超检测是失超保护正常动作的前提。由于SMES磁体运行工况的特殊性,现有失超检测方法在失超信号提取上遇到电磁噪声干扰严重的问题。文中针对高温超导SMES的运行工况,对电桥检测法进行了改进,通过对电桥信号的滤波设计解决电磁噪声干扰,设计了一套适用于高温超导SMES磁体在交变电流情况下的失超检测系统,同时进行了高温超导磁体的失超检测实验。实验结果表明,此系统能快速、准确地检测失超信号,并输出保护动作信号。

基于BPGM-SME和改进UKF的双星多目标跟踪算法

重点研究多传感器协同探测对多目标的跟踪问题。首先,根据观测几何分析双星协同探测的可观测性建立基于重力转弯模型的主动段状态方程和观测方程;其次,针对多目标跟踪情形中的航迹交叉跟踪异常问题,提出基于二元多项式思想的SME滤波算法;最后,为提高目标跟踪精度,提出基于迭代思想的改进无迹卡尔曼滤波算法。仿真结果表明:采用基于二元多项式思想的测量方程(BPGM-SME)算法对多个目标跟踪都能分别得到较好的跟踪效果,与扩展卡尔曼滤波(UKF)算法相比,改进算法能够取得更好的收敛性效果,跟踪精度也更高。

一种改善电力系统性能的SMES解耦控制策略及其仿真研究

在分析电压源型超导储能装置工作原理及控制策略的基础上,提出了一种在两相同步旋转坐标系下的电流解耦协调控制方法。该方法通过控制有功电流和无功电流实现了有功功率和无功功率的独立控制,对改善基于SMES电力系统实时性和稳定性有明显的效果。理论分析和仿真研究验证了此方法对改善电力系统性能的有效性和可行性,对以后超导储能装置的产品化和市场化具有很好的实用参考价值。

组织间网络、资源整合与SMEs战略适应能力

文章以组织间关系理论、资源基础理论、动态能力理论为基础,构建了组织间网络、资源整合与科技型中小企业战略适应能力的概念框架,通过大样本的数据调查,运用smart PLS和AMOS软件对概念框架进行信度及效度检验和结构方程模型分析。实证结果显示,组织间网络(组织间网络多样性和组织间网络依赖性)对资源整合(资源获取和资源利用)具有显著的正向影响;资源整合(资源获取和资源利用)与科技型中小企业战略适应能力之间具有显著正向相关关系。

时效和SME训练对Ti_(50)Ni_(50)合金丝记忆效应的影响

研究了不同时效热处理和形状记忆效应训练(SME)对Ti50Ni50合金丝的单程形状回复率ηs、双程回复率ηt的影响。结果表明:时效温度在300～500℃时,ηs保持在一个较高的状态,出现一个稳定的平台;时效温度从500℃升到600℃时,ηs急剧下降,550℃时下降了56.7%,600℃时下降了68.3%。时效温度在400～600℃时双程记忆效应最平稳也是最好的。随着训练次数的增加,单程记忆效应是减弱的,训练75次后的回复率仅为未经训练的60%。不同的时效温度,减弱的趋势是一致的。随着训练次数的增加,ηt显著增加,训练75次后基本稳定,回复率增加了200%,时效温度高于500℃后,训练对双程回复率影响不大。