Large Units, Large Plants -Major Thermal Power Sources

China’s electric power industry as a basic industry, plays an important role in the longterm, sustained and healthy development of the whole national economy. China’s electric power industry attained great achievement in technology and economical results during the past eight years from 1987-1995. The total national installed generating capacity increased from 102.897 GW in 1987 to more than 200 GW in March, 1995.

Xiangfan Coal-fired Power Plant - a matched large power plant for Three Gorges Project starts to construct

Xiangfan Coal-fired Power Plant, a key energy construction project matched with Three Gorges Project, approved by the State Council. formally started to build in the suburb of Xiangfan City, Hubei Province on November 29, 1996.

Development of Key Technologies of Large Hydro Unit in HEC

Introduction to HEC Harbin Electric Machinery Company Limited (HEC) is a pivotal company that produces large electric machinery and accessorial control equipment in China. The hydro units made by HEC have

Abdominal compartment syndrome:Often overlooked conditions in medical intensive care units

Intra-abdominal hypertension(IAH)and abdominal compartment syndrome are well recognized entities among surgical patients.Nevertheless,a number of prospective and retrospective observational studies have shown that IAH is prevalent in about half of the critically ill patients in the medical intensive care units(ICU)and has been widely recognized as an independent risk factor for mortality.It is alarming to note that many members of the critical care team in medical ICU are not aware of the consequences of untreated IAH and the delay in making the diagnosis leads to increased morbidity and mortality.Frequently it is underdiagnosed and undertreated in this patient population.Elevated intraabdominal pressure decreases the blood flow to the kidneys and other abdominal viscera and also results in reduced cardiac output and difficulties in ventilating the patient because of increased intrathoracic pressure.When intraabdominal hypertension is not promptly recognized and treated,it leads to abdominal compartment syndrome,multiorgan dysfunction syndrome and death.Large volume fluid resuscitation is very common in medical ICU patients presenting with sepsis,shock and other inflammatory conditions like pancreatitis and it is one of the major risk factors for the development of intra-abdominal hypertension.This article presents an overview of the epidemiology,definitions,risk factors,pathophysiology and management of IAH and abdominal compartment syndrome in critically ill medical ICU patients.

A novel carbon trap sampling system for coal-fired flue gas mercury measurement

A novel carbon trap sampling system for gas-phase mercury measurement in flue gas is developed, including the high efficient sorbents made of modified biomass cokes and high precision sorbent traps for measuring particle-bound and total vapor-phase mercury in flue gas. A dedusting device is installed to collect fine fly ash for reducing the measurement errors. The thorough comparison test of mercury concentration in flue gas is conducted between the novel sampling system and the Ontario hydro method （OHM） in a 6 kW circulating fluidized bed combustor. Mercury mass balance rates of the OHM range from 95.47% to 104.72%. The mercury breakthrough rates for the second section of the sorbent trap are all below 2%. The relative deviations in the two test cases are in the range of 15. 96% to 17. 56% under different conditions. The verified data suggest that this novel carbon trap sampling system can meet the standards of quality assurance and quality control required by EPA Method 30B and can be applied to the coal-fired flue gas mercury sampling system.

A GPU-Based Parallel Algorithm for 2D Large Deformation Contact Problems Using the Finite Particle Method

Large deformation contact problems generally involve highly nonlinear behaviors,which are very time-consuming and may lead to convergence issues.The finite particle method(FPM)effectively separates pure deformation from total motion in large deformation problems.In addition,the decoupled procedures of the FPM make it suitable for parallel computing,which may provide an approach to solve time-consuming issues.In this study,a graphics processing unit(GPU)-based parallel algorithm is proposed for two-dimensional large deformation contact problems.The fundamentals of the FPM for planar solids are first briefly introduced,including the equations of motion of particles and the internal forces of quadrilateral elements.Subsequently,a linked-list data structure suitable for parallel processing is built,and parallel global and local search algorithms are presented for contact detection.The contact forces are then derived and directly exerted on particles.The proposed method is implemented with main solution procedures executed in parallel on a GPU.Two verification problems comprising large deformation frictional contacts are presented,and the accuracy of the proposed algorithm is validated.Furthermore,the algorithm’s performance is investigated via a large-scale contact problem,and the maximum speedups of total computational time and contact calculation reach 28.5 and 77.4,respectively,relative to commercial finite element software Abaqus/Explicit running on a single-core central processing unit(CPU).The contact calculation time percentage of the total calculation time is only 18%with the FPM,much smaller than that(50%)with Abaqus/Explicit,demonstrating the efficiency of the proposed method.

Tempospacial energy-saving effect-based diagnosis in large coal-fired power units:Energy-saving benchmark state

The energy-saving analytics of coal-fired power units in China is confronting new challenges especially with even more complicated system structure, higher working medium parameters, time-dependent varying operation conditions and boundaries such as load rate, coal quality, ambient temperature and humidity. Compared with the traditional optimization of specific operating parameters, the idea of the energy-consumption benchmark state was proposed. The equivalent specific fuel consumption(ESFC) analytics was introduced to determine the energy-consumption benchmark state, with the minimum ESFC under varying operation boundaries. Models for the energy-consumption benchmark state were established, and the endogenous additional specific consumption(ASFC) and exogenous ASFC were calculated. By comparing the benchmark state with the actual state, the energy-saving tempospacial effect can be quantified. As a case study, the energy consumption model of a 1000 MW ultra supercritical power unit was built. The results show that system energy consumption can be mainly reduced by improving the performance of turbine subsystem. This nearly doubles the resultant by improving the boiler system. The energy saving effect of each component increases with the decrease of load and has a greater influence under a lower load rate. The heat and mass transfer process takes priority in energy saving diagnosis of related components and processes. This makes great reference for the design and operation optimization of coal-fired power units.

Distribution and exploration direction of medium-and large-sized marine carbonate gas fields in Sichuan Basin, SW China

Based on the analysis of the basic characteristics of medium-and large-sized marine gas fields in Sichuan Basin, combined with the division of major reservoir forming geological units in the marine craton stage and their control on key hydrocarbon accumulation factors, the distribution law of medium-and large-sized marine carbonate gas fields in the basin was examined and the exploration direction was pointed out. Through the analysis of the periodic stretching-uplifting background, it is concluded that five large scale paleo-rifts, three large scale paleo-uplifts, five large scale paleo erosion surfaces were formed in the marine craton stage of Sichuan Basin, and these geological units control the key reservoir forming factors of medium and large sized gas fields:(1) Large-scale paleo-rifts control the distribution of high-quality hydrocarbon generation centers.(2) The margin of large-scale paleo-rifts, high position of paleo-uplifts and paleo erosion surfaces control the distribution of high-quality reservoirs.(3) Large-scale paleo-rifts, paleo-uplifts, paleo erosion surfaces and present tectonic setting jointly control the formation of many types of large and medium-sized traps.(4) Natural gas accumulation is controlled by the inheritance evolution of traps in large geological units. Based on the comparative analysis of the distribution characteristics of medium-and large-sized gas fields and large geological units, it is proposed that the superimposition relationship between single or multiple geological units and the present structure controls the distribution of medium-and large-sized gas fields, and the "three paleo" superimposed area is the most advantageous. According to the above rules, the main exploration fields and directions of medium-and large-sized marine carbonate gas fields in Sichuan Basin include periphery of Deyang-Anyue paleo-rift, eastern margin of Longmenshan paleo-rift, margins of Kaijiang-Liangping oceanic trough and Chengkou-western Hubei oceanic trough, the high part of the subaqueous paleo-uplifts around Central Sichuan, paleo erosion surfaces of the top boundary of Maokou Formation in eastern and southern Sichuan Basin, paleo erosion surfaces of the top boundary of the Leikoupo Formation in central and western Sichuan Basin.

The Effects of SO_3 in Flue Gas on the Operation of Coalfired Units and Countermeasures

There exists a certain amount of SO_3 in flue gas discharged from coal-fired power plants. With the operation of the selective catalystic reduction( SCR) denitrification system,SO_3 concentration in the flue gas increases,which will lead to fouling,erosion and plugging of downstream equipment. In this study,the main effects of SO_3 on the safety,stability and efficiency of units were analyzed,and measures to control SO_3 were proposed.

从学习进阶到内容重构:基于情境链的体育与健康课程大单元的内部构建

情境链是体育与健康课程大单元教学内容重构的重要支撑,能有效解决中小学体育教学实践中的教学内容低级重复、情境创设连贯性较弱和延展性不够等问题。基于情境链的体育与健康课程大单元教学重视链式整合的课程样态,依托递进的情境进行专项运动技能的有效学练,通过情境链串联目标、任务、内容等课程元素,整体规划体育与健康课程大单元的学习路径。情境认知理论、境脉学习理论与学习进阶理论为情境链的深入理解提供了理论基石与实操框架。结合三大理论的基本要素探讨基于情境链的体育与健康课程大单元的构建流程,聚焦核心素养的整体性,通过水平二“篮球保护和控制球能力的提升”大单元主题案例,从“精准分析学情,确立大单元学习目标”“提取关键概念,规划大单元学习路径”“串联进阶元素,重构大单元学习内容”“基于真实情境,评价学生的学习表现”展现完整的情境链研究。

大单元视阈下体育与健康教学模式的经验汲取与应用策略

核心素养导向的体育与健康大单元教学亟需从专家的理念引领转化为教师的课堂实践。体育与健康大单元教学组织形式与教学模式均顺应教学专业化的要求,试图找寻能够指导基层课堂教学的规律、原理,教学模式着眼于结构程序与操作框架,教学组织形式立足于作用机制与环境特征。围绕体育与健康大单元教学的关键内核:多课时的教学单位是大单元教学整体规划的载体;结构化的教学设计是大单元教学内容整合的抓手;运动项目完整的体验与理解是大单元教学情境设计的依据,研究汲取了运动教育模式、领会教学模式、个人与社会责任教学模式等的教学组织经验,提出大单元视阈下体育与健康教学模式的应用策略:基于学习体验、任务拆解规划教学单元;围绕学习主题、概念原理整合教学内容;依循认知规律、活动架构创设学习情境。

学习中心视角下的大单元教学设计

大单元作为学习单位的本质规定,意味着大单元教学的重心不是教授内容而是组织和引导学习,也决定了其教学设计必须以学习为中心。学习中心视角下,大单元教学设计在任务设定、内容生成和时间安排方面分别遵循依学施教、因学而成和以学定时的理念。其内在逻辑表现为,以大观念为内核生成大单元,以大任务为起点驱动大单元,以大活动为过程展开大单元。大单元教学要在素养目标与现实材料的双向比对中提取大观念,在理论学习与经验学习的双层考量中构建大任务,在素养针对性与学科典型性的双重观照中设计大活动。其过程设计可按进阶式学习、平行式学习、迭代式学习等模式展开。

35 kV高压直挂大容量电池储能系统

为推动35 kV高压直挂电池储能系统(battery energy storage system,BESS)的实际应用,系统研究了35 kV高压直挂BESS的主电路参数设计、控制策略及相关控制参数的设计方法;并在MATLAB/Simulink中搭建了35 kV/10 MW/10 MWh系统的仿真模型,以验证所提设计方法及控制策略的正确性。研究结果表明:35 kV高压直挂BESS单机容量大,功率响应速度快,可对内部电池簇进行主动荷电状态均衡及故障冗余控制,系统效率和可靠性更高,能适应未来新能源大规模发展需求。

具身认知理论视域下语文大单元教学策略研究

大单元教学是《义务教育语文课程标准(2022年版)》和学习任务群的必然要求,但在教学开展过程中存在着困境。具身认知理论主张认知不仅仅依赖于大脑,更是身体和环境互动的产物,强调教学过程中“身心一体”与“主客融合”的教学范式。基于具身认知理论的大单元教学是在新课标背景下,以具身认知为指导,以大单元教学为依托,促进学生问题解决与迁移,思维提升与创造。为此,从学习目标、学习情境、学习任务、学习评价四个方面进行设计,发挥身体在学习中的作用,以更好地实现学生核心素养发展。

基于声纹监测技术的大型泵站机组振动特性研究

声音和振动是反映旋转机械设备运行状态信息的直接载体,根据声纹监测的原理,通过对数据进行采集、预处理、提取特征值,采用卷积神经网络深度学习识别模型,建立大型泵站机组运行状态声纹样本库和模型库,构建泵站机组振动状态的声纹监测系统,实现大型泵站机组运行状态的实时监测。

评大概念教学之争

“大概念”是2022年版义务教育课程方案和各科课程标准中颇具代表性的观念变化。然而,随着大概念教学在更大范围的实践推广,其诸多问题不断聚集起来,并由此引发了肯定与否定两种对立性观点的争议。考察对大概念教学的质疑或批判观点,主要集中于其前提假设是否成立、是否适应中国实践、是否适合所有学科。如何评判大概念教学之争,首先需要解决对大概念教学的认识确证问题,从中国课程改革的整体进程、理论与实践的转化过程以及学生发展立场来确证大概念教学的价值性、适应性与本质性。大概念教学的落地需要从理论与实践的角度同时解决好认知问题与操作问题,厘清相关核心概念及其关系,做好学校课程教学顶层设计,立足现实精准把脉关键问题,提供典型案例支撑,方能推动大概念教学真实有效地进入课堂。

教科版小学科学新教材的理念与特色

教科版小学科学新教材的编写原则是:坚持素养导向,突显科学思维,加强进阶贯通,丰富中国元素,重视地区普适。新教材继承了老教材大单元结构特点,通过强化情境设计等举措加强了单元内课文间的联系。各单元由“单元首页—单元内容—单元小结—科学阅读”四大部分构成,其中“单元小结”显性化地凝练出学科核心概念和跨学科概念。每一课由聚焦、探索、研讨、拓展四大板块构成,对应工程技术实践为主的课文则为明确任务、设计方案、实施方案、评价改进等板块。与教材配套的教参也进行了大幅度修订。使用新教材应注意充分利用教参功能,全面理解大单元结构,灵活应用四大板块,在理解教材的基础上鼓励因地制宜。

义务教育体育与健康大单元教学的底层逻辑与实现路径

为全面贯彻落实义务教育体育与健康大单元教学的要求,运用逻辑分析法、文献研究法等阐述了义务教育阶段体育与健康大单元教学概念内涵、底层逻辑、实现路径等。研究认为中小学体育与健康课程教学缺乏整体教学理念,碎片化、蜻蜓点水式的教学问题突出等是义务教育大单元教学的逻辑基点;运动技能形成规律、系统化教学等是义务教育大单元教学的底层逻辑;正确把握大单元的时代要求、从学校层面进行科学谋划等是义务教育体育与健康大单元教学的实现路径。