Event triggering power sharing control for AC/DC microgrids based on P -F droop curve method

The power sharing of AC/DC micro-grids is researched in this paper. The proposed strategy mainly include two parts: the primary power event triggering control with secondary control and an adaptive quasi sliding mode voltage control in inner-loop. Firstly, a event triggering power sharing control (ETPSC) based on $P?F$ droop curve is developed to regulate the voltage and frequency of AC and voltage of DC with the aim of the proportional power sharing between AC and DC micro-grids. The triggered threshold of ETPSC can be chosen to decide the transmitted power between AC and DC micro-grids. When the difference power between AC and DC micro-grids is less than the triggered threshold of power flow, there is no power sharing between AC and DC micro-grids, which can less the number of switching the power flow direction and the transmitted line power loss. The ETPSC has a great robust for the disturbances of load and improve the stability of the system. An adaptive quasi-sliding-mode control,which is implemented easily and flexibly with small computational burden and only based on input/output (I/O) measurement data but not the model any more, is used to control voltage in inner-loop. The effectiveness of the proposed control schemes is demonstrated by some numerical simulations and experimental results.     

ON THE REE ACROSS THE PERMIANTRIASSIC BOUNDARY IN SOUTH CHINA

This paper discusses the INAA results of REE in clays atand near some Permian/Triassic boundaries of South China.It showsthat the REE patterns of boundary clays differ from those of non-boundary clays.One difference is that the boundary clays are moreenriched in LREE,with steeper slope of REE and a smaller Eu nega-tive anomaly than the non-boundary clays.Another difference is that theboundary clays show a small Ce negative anomaly,but no Ce anomalyoccurs in the non-boundary clays.From these REE patterns and some other experimental facts,it isproposed that the P/T boundary clay may be a mixed product consistingof the acidic-intermediate ash and the upper crust substance representingsputtering component,and the calculated fraction of the former andlatter is 7/3.     

浅谈高校普及型竞争情报教育

随着竞争情报的发展,专业竞争情报人才的培养规模不断扩大,一种为普及竞争情报知识的普及型竞争情报教育也在各个高校悄然兴起,并不断发展。文章就高校普及型竞争情报教育发表一些看法。     

我国的信息咨询业发展中的服务创新

本文针对目前我国信息咨询业的发展机遇和发展中的不足，提出了以服务创新带动咨询业发展的构想，并分析了服务创新的基本内容。     

网上信息资源的组织方法与管理策略

从网上信息资源组织的意义入手，分别阐述了网上信息组织的方法，原则与管理策略。     

基于大数据决策分析需求的图书馆大数据清洗系统设计

图书馆的大数据时代已经来临,大数据质量问题是影响图书馆大数据应用的重要因素,而大数据清洗则是提高图书馆大数据质量的主要手段。本文介绍了图书馆不清洁数据的类型与产生原因,设计了基于大数据决策分析需求的图书馆大数据清洗系统,该系统不仅可以提高大数据清洗的效率和精确度,而且大幅度降低了图书馆大数据决策分析的复杂度。     

中国岩蕨科植物研究(二)——成熟孢子体的比较形态解剖

本文报道了国产岩蕨科19个种l变种的比较形态解剖研究结果，其中10个种为我国 特有。  通过对根、根状茎、叶轴和叶柄关节的解剖，对叶、毛状体和孢子囊群的比较形态观察，及对20种孢子扫描电镜观察，扼要讨论了它们与系统发育和分类的关系。     

多药马兜铃亚属的分类修订

多药马兜钤亚属是马兜铃属目前已知3个亚属中最小的一个亚属，约9种，其中8种产于热带 非洲，1种产于热带亚洲(马来西亚)。  本工作从经典分类学角度对该亚属的系统进行了探讨，首次利用花药数目及其排列方式将其划分为三个组，并对其中所含的种类进行了分类学处理，本文承认9种及3个新异名。     

清代东北封禁政策下的旗民交往关系——以乾隆朝吉林珲春为例

清政府于康熙五十三年(1714)在珲春设置八旗驻防,该地由此形成了一个以旗人为主体的军事管制型社会。珲春原不准民人居住,至乾隆时期清政府开始将珲春有限地开放。民人进入该地后,与旗人在日常经济活动中结成雇佣关系与买卖关系,相互依赖、补充。在经济互惠基础之上,双方开始产生更深层次的情感认同,在日常社交活动中建立了跨旗民的社交网络。值得注意的是,珲春旗人的文化面貌并未因此产生明显流变,他们在长时间里较好地保持了以"国语骑射"为代表的"满洲旧俗"。     

任凤苞及《天春园方志目》稿本述论

文章以河北大学图书馆藏《天春园方志目》四种稿本为研究对象,全面介绍了《天春园方志目》四种稿本的版本年代、版式、内容、校改方式、校改特点以及各种稿本之间的联系和变化,并将其与传世刻本进行对比,分析该稿本具有的文物价值、文献价值和版本价值。