宋版《史记》的源流与系统新考(一):绍兴本、杏雨本与景德校订本

《史记》之刻始于北宋太宗淳化五年校刊“三史”,后经真宗景德、仁宗景祐覆校,形成了淳化本、景德校订本、景祐校订本三个系统。今存宋版《史记》达十多种,清代以来的藏书家做了不少著录和考订,近现代学者对各个具体版本多有研究。张玉春先生的《〈史记〉版本研究》则从版本源流的角度,梳理了宋元明清的大量《史记》刻本,勾画出《史记》的版本源流图。探讨宋版《史记》的源流与系统,应围绕两宋的官方监本,即“杏雨本”(日本杏雨书屋藏北宋刊北宋修十四行本)和它的覆刻本“绍兴本”,以及旧称“景祐本”“淮南本”(南宋淮南西路转运司刻本)。可行之方法是文本内容与版叶时代的结合校对,版本自身信息与文献书目记载的相互发明,版刻普遍规律以及官刻、坊刻书籍大背景的综合视野。以此方法分析各本的异文,可知杏雨本即景德校订本、绍兴本覆刻既有讹误也有校改,景祐本、淮南本共源景祐校订本,二家注本之耿本(张杅刊耿秉重修本)、蔡本(蔡梦弼刊本)共源蜀刻二家注本,此蜀本则出自景德校订本,此外,耿本、蔡本各有校改。

湖北省水稻资源加工转化业创新发展战略与对策

研究了湖北省水稻产品加工转化的现状、前景和主要制约因素,提出了湖北省水稻加工转化业创新发展的战略与对策。

Scarcity within Opulence:Water Management in the Karakoram Mountains Revisited

Water management in general and in the Indus Basin in particular is concerned with the energy-efficient transportation of hydrologically exploitable resources from the upper zone to climatically favourable areas where irrigation helps to supersede arid conditions for the cultivation of crops and watering of meadows.In other words:Human intervention sets the stage for the allocation of water from a wider catchment area in a smaller habitat where this resource is deficient.Emphasis on mountain irrigation practices is counteracted with developments in the forelands where different frame conditions prevail and peculiar development problems occur.In dealing with the importance of water from the mountain regions three dimensions have to be evaluated:1) natural factors and their validity for the environmental frame conditions and technological adaptation processes;2) social factors and their impact on culture,economy and equitability;3) institutional factors and their importance for sustainable growth and for the implementation of development projects.In the study of decentralized irrigation systems in high mountain regions of the Indus Basin a systems theoretical approach values the complexity of interrelationships between different systems elements.Human activities in arid mountain regions are restricted by limiting ecological factors and are characterized by certain utilization and adaptive strategies.

Optimal Power Flow Solution Using Particle Swarm Optimization Technique with Global-Local Best Parameters

This paper proposes an efficient method for optimal power flow solution （OPF） using particle swarm optimization （PSO） technique. The objective of the proposed method is to find the steady state operation point in a power system which minimizes the fuel cost, while maintaining an acceptable system performance in terms of limits on generator power, line flow limits and voltage limits. In order to improvise the performance of the conventional PSO （cPSO）, the fine tuning parameters- the inertia weight and acceleration coefficients are formulated in terms of global-local best values of the objective function. These global-local best inertia weight （GLBestlW） and global-local best acceleration coefficient （GLBestAC） are incorporated into PSO in order to compute the optimal power flow solution. The proposed method has been tested on the standard IEEE 30 bus test system to prove its efficacy. The results are compared with those obtained through cPSO. It is observed that the proposed algorithm is computationally faster, in terms of the number of load flows executed and provides better results than the conventional heuristic techniques.

Finite Set-Model Predictive Current Control of Three-Phase Voltage Source Inverter for RES （Renewable Energy Systems） Applications

This paper focuses on a combination of three-phase VSI （voltage source inverter） with a predictive current control to provide an optimized system for three-phase inverters that control the load current. A FS-MPC （finite set-model predictive control） strategy for a three-phase VSI for RES （renewable energy systems） applications is implemented. The renewable energy systems model is used in this paper to investigate the system performance when power is supplied to resistive-inductive load. With three different cases, the evaluation of the system is done. Firstly, the robustness of control strategy under variable DC-Link is done in terms of the THD （total harmonic distortion）. Secondly, with one prediction step, the system performance is tested using different sampling time, and lastly, the dynamic response of the system with step change in the amplitude of the reference is investigated. The simulations and result analyses are carried out using Matlab/Simulink to test the effectiveness and robustness of FS-MPC for two-level VSI with AC filter for resistive-inductive load supplied by a renewable energy system.

The concept, connotation and method of representation of watershed water environment carrying capacity （WWECC）

Based on the relationship between water environment system and human society, water environment carrying capacity （WECC） probes into supporting ability of complex water environment system to the human society. Recent years, due to the shortage of water resources and serious water pollution in several watersheds in China, the research of watershed water environment carrying capacity （WWECC） becomes very important. The conception, connotation and method of representation of WWECC are discussed deeply in this paper. It shows that WWECC is a kind of index that instructs whether the water environment system in watershed can continue to support the development of social economy and ecology, it is dimensionless number.

Overview of the Power Supply System on the HL-2A Tokamak

This paper shows the R＆D results of the power supply system in 2006, including the application of speed control assemblies of two 80 MVA MG sets, the modification of the exciting field system, the development of the new HV modulators in ECRH system, the update of several poloidal power supplies. It also presents the status of the power suppIy system in HL-2A experimental operation and foresees the power and energy requirements for new power supply system at HL-2M device.

Commissioning Status of NSLS-II Vacuum Control System

The NSLS-II （National Synchrotron Light Source II） is a state-of-the-art 3 GeV third generation light source currently under integrated testing and commissioning at Brook_haven National Laboratory. The vacuum systems are monitored by vacuum gauges and ion pump current. The gate valves are controlled by PLC （programmable logic controllers） using voting scheme. EPICS （Experimental Physics and Industrial Control System） application codes provide the high level monitoring and control through the input-output controllers. This paper will discuss the commissioning status of the various aspects of vacuum control system.

Difficulties in Parameters Identification of Traction Transformer Multi-port Equivalent Scheme with Hidden Construction Defect

While modeling a power supply system for an electric railway traction, knowing equivalent circuits of locomotives supplied this way is an essential issue. In alternating current traction, it is important to diagnose inter alia processes taking place in transformers installed on electric vehicles. This article presents specific phenomena occurring during the work of mono-phase, multi-winding, multisystem （systems AC： 50 Hz, 16.7 Hz） laboratory traction transformer. It also shows difficulties encountered during the process of identifying multi-port equivalent scheme＇s elements of the described device, in which a construction defect occurs.

Fraud in Businesses and Internal Control System

This study, based on the literature, stresses the effectiveness of internal control systems for the prevention, to a reasonable extent, of fraudulent practices that cause resource loss in business. In this context, the key concepts related to fraud and internal control systems are presented first. After the introduction, the relation between fraud and internal control systems is elaborated, and the method for establishing an effective internal control system which is needed to detect and prevent fraud is explained. As for the conclusion, the study connects the effectiveness of the internal control system with the effectiveness of the elements which compose the system, and provides some suggestions for increasing the efficacy of the elements which compose the system, such as control environment, risk analysis, information-communication, control activities, and monitoring.

Florida Springs--A Water-Budget Approach to Estimating Water Availability

Florida＇s artesian springs receive groundwater outflows from the Floridan Aquifer System and are concentrated north of I-4 and west to the Florida Panhandle. These springs and their resulting spring runs support a unique freshwater ecology dependent on perennial flows, constant temperature and chemistry, and high light transmissivity. Numerous observations indicate that Florida＇s springs flows are declining as a result of the increasing extraction of groundwater for human uses. North Florida＇s karst environment is especially susceptible to nitrogen pollution from agricultural and urban development. An empirical springs/aquifer water budget is needed to better understand these spring stressors. Discharge data from 393 of the state＇s 1,000＋ artesian springs are used to estimate trends in total spring discharge by decade since 1930-39. This analysis indicates that average spring flows have declined by about 32%. Large groundwater pumping centers are altering spring flows over the whole springs region. Existing groundwater pumping rates from the Floridan Aquifer in 2010 were more than 30% of average annual aquifer recharge, and allocated groundwater use in north-central Florida is nearly double current estimated uses. Based on biological research conducted in Florida springs, these flow reductions are from two to six times greater than declines known to result in significant harm to aquatic resources.

Eutrophication of Aquatic Ecosystems： A Viewpoint on the Environmental Impact of Climate Change

Environmental concerns associated with nutrient-oriented eutrophication phenomenon have become a serious issue and a major cause of water quality deficiency nowadays. This necessitated eutrophication to occupy a front seat in research accompanied with climate change. Climate change has revealed to be a key player and a main contributor in the occurrence of such phenomenon. This paper discusses the ever-growing concern about eutrophication as a cause of climate change. Climate change affects storms intensity, changing the precipitation regime and increasing temperature. These effects increase the nutrient loading diffusion and cause excessive nutrients accompanied with storm water runoff, domestic wastewaters, and agricultural discharges to pour into water bodies. Eutrophication conversely contributes in the global wanning by releasing greenhouse gases from deoxygenated waters and sediments. Some control and mitigation measures are needed to fight climate change and achieve desired water quality goals. These measures include mitigation of climate change causes, enhancement of natural ecohydrological processes, application of proper integrated water resource management and participation of communities and governments.

Development of a Renewable Energy Based DC Excitation System in a Micro Hydro Power Plant

MHPPs （micro hydro power plants） have become prominent in hydropower plants as a solution to provide the energy demands of the grid. In this study, a new hybrid renewable energy based DC excitation system for synchronous generator in the developed MHPP system is introduced. Proposed hybrid DC excitation system consists of solar ＆ hydrogen energy based power generating systems. Hybrid renewable energy based system is used for the excitation of the synchronous generator in the MHPP test system. The renewables are used as a secondary energy source to provide the excitation current to a synchronous generator that generates energy in MHPP. A PV （photovoltaic） array is used as the main source of excitation, and a FC （fuel cell） stack is used for DC excitation in the lack of sunshine. In the experimental setup, an electrical control card is developed, and a microcontroller is used to perform the proposed excitation system. All experimental results obtained from 5 kW rated power MHHP test system. Experimental results show that, the proposed method provides the continuous excitation current, and the operation of the synchronous generator is uninterrupted. The proposed method is also practical and easily implemented for MHPP systems.

Flexible HVDC Transformer for Next Generation Renewable Energy Industry

The growing demand on non-fossil fuel energy has escalated the desire for mega-scale renewable energy power generation, which can no longer be satisfied solely by relying on onshore renewable energy power plants. Outcomes from a recent project funded by the Sixth European Union Framework Programme （FP6）, Project ＂Upwind＂ concluded that larger offshore wind turbines （i.e., 〉 10 MW） are feasible and cost effective. It will be beneficial for such future large scale renewable energy power generators （i.e., large offshore turbines） and plant （i.e., large offshore wind farms） to have a dedicated high efficiency, robust, flexible and low cost power collection, transmission and distribution technology. Proposed in this paper is a compact and effective hybrid HVDC （high voltage direct current） transformer that allows realisation of a highly robust and financially rewarding next generation multi-terminal HVDC system for future offshore renewable energy power plant. This concept, potentially, allows the elimination or minimisation of the need for a centralised local offshore HVDC platform or substation in each wind farm, solar farm, or tidal farm. This paper discusses the study outcome of the proposed hybrid HVDC transformer and the application of a multi-terminal HVDC system in the renewable energy industry, compared to the existing HVAC and VSC （voltage source converters） type HVDC systems.

数字文献学的系统脉络与科学范式阐论

数字科技与文献研究的学术共通熔铸通常被指称为数字文献学,其学术旨趣在于运用数字科技的理念阐释文献学科的境遇疑难,或从时代主题来思辨文献思维形构数字图景的系统脉络。基于此,从系统科学视野纵向考探数字文献学的脉络缘起、本体内涵、外延定位、学术组织,同时在横向上对数字文献学的范式创新进行诠释,期冀能为数字文献学跻身于国际学术潮流之林提供一科学的建议参考。

Research on the control method for voltage-current source hybrid-HVDC system

The hybrid-HVDC topology,which consists of line-commutated-converter(LCC)and voltage source converter(VSC)and combines their advantages,has extensive application prospects.A hybrid-HVDC system,adopting VSC on rectifier side and LCC on inverter side,is investigated,and its mathematic model is deduced.The commutation failure issue of the LCC converter in the hybrid-HVDC system is considered,and a novel coordinated control method is proposed to enhance the system commutation failure immunity.A voltage dependent voltage order limiter(VDVOL)is designed based on the constant DC voltage control on the rectifier side,and constant extinction angle backup control is introduced based on the constant DC current control with voltage dependent current order limiter(VDCOL)on the inverter side.The hybrid-HVDC system performances under normal operation state and fault state are simulated in the PSCAD/EMTDC.Then,system transient state performances with or without the proposed control methods under fault condition are further compared and analyzed.It is concluded that the proposed control method has the ability to effectively reduce the probability of commutation failure and improve the fault recovery performance of the hybrid-HVDC system.

Periodic orbit model of diode rectifiers-synchronous machine system

Diode rectifiers-synchronous machine system has a wide range of applications in isolated power system,whose low frequency oscillation emerges under certain parameters.Considerable error is produced when the state space averaging model is used to analyze its small signal stability.Therefore,this paper has presented a periodic orbit model of diode rectifiers-synchronous machine system to solve these problems.Using trapezoidal integration method,it is possible to derive equation of periodic orbit and its Poincaré mapping.Jacobian matrix of the Poincaré mapping of periodic orbit can be calculated by chain derivative method.Besides,stability margin index and linearized Poincaré mapping model have also been proposed.Thus small signal stability of diode rectifiers-synchronous machine system can be assessed through orbitally asymptotical stability of its periodic orbit so as to lay a foundation for isolated power system analysis and its control design.Simulation test demonstrates that the proposed model and algorithm are effective and practicable.

Construction of a Comprehensive Observation Network for Natural-Resource Elements in Heihe River Basin,NW China

The construction of a comprehensive observation platform for natural-resource elements would provide data support for studies of dynamic changes in various natural resources,and could serve the needs of natural-resource management and the construction of ecological civilization during a period of global change.As the second-largest inland river basin in NW China,the Heihe River Basin(HRB)lies in the central part of the Silk Road Economic Belt,consequently,pilot studies of resource management in the basin are urgently needed.This paper describes the construction of a comprehensive natural-resource elements observation network in the HRB to meet requirements for natural-resource management,based on natural-resource and Earth-system science.Based on current observations and research,thirteen observation stations were established in different river basins through integration with existing stations,reconstruction and upgrading,and new construction.The main types of land-surface resources in the HRB(grassland,forests,rivers,lakes,deserts,wetlands,and farmland)were included in the observation network constructed for the monitoring of natural-resource elements.Long-term,continuous,and stable observation can yield key data concerning coupling processes,trends of change,and rates of change in natural resources.This is of great significance in improving cognitive ability,scientific management,and strategic decision-making regarding natural resources in the HRB,and can provide a reference paradigm for the observation of and research into natural resources in other basins.

Numerical modeling of regional groundwater flow in the Heihe River Basin,China:Advances and new insights

Numerical groundwater modeling is an effective tool to guide water resources management and explore complex groundwater-dependent ecosystems in arid regions.In the Heihe River Basin(HRB),China’s second largest inland river basin located in arid northwest China,a series of groundwater flow models have been developed for those purposes over the past 20 years.These models have elucidated the characteristics of groundwater flow systems and provided the scientific basis for a more sustainable management of groundwater resources and ecosystem services.The first part of this paper presents an overview of previous groundwater modeling studies and key lessons learned based on seven different groundwater models in the middle and lower HRB at sub-basin scales.The second part reviews the rationale for development of a regional basin-scale groundwater flow model that unifies previous sub-basin models.In addition,this paper discusses the opportunities and challenges in developing a regional groundwater flow model in an arid river basin such as the HRB.

Flow field optimization and design for a Spallation Neutron Source target cooling system

Cooling water is an important part in a Spallation Neutron Source target cooling system, but the unstable vortexes at the exits of the slits between every two tungsten target slices have a negative impact on the stable running of the target system. We apply the field synergy principle for fluid flow to obtain the optimal flow field, which has a uniform velocity distribution without eddy, and then, optimize the geometrical structure of the cooling water flow channel based on the optimal flow field. The results show that when the cooling water flows in the optimized channel, the eddy sizes decrease, the time fluctuations of velocity and pressure almost vanish, and the volume flow rates of the cooling water in each parallel slit are uniform. Therefore, it effectively improves the running stability of the target system with the premise of satisfying the target heat load.