Three-Level Optimal Scheduling and Power Allocation Strategy for Power System ContainingWind-Storage Combined Unit

To mitigate the impact of wind power volatility on power system scheduling,this paper adopts the wind-storage combined unit to improve the dispatchability of wind energy.And a three-level optimal scheduling and power allocation strategy is proposed for the system containing the wind-storage combined unit.The strategy takes smoothing power output as themain objectives.The first level is the wind-storage joint scheduling,and the second and third levels carry out the unit combination optimization of thermal power and the power allocation of wind power cluster(WPC),respectively,according to the scheduling power of WPC and ESS obtained from the first level.This can ensure the stability,economy and environmental friendliness of the whole power system.Based on the roles of peak shaving-valley filling and fluctuation smoothing of the energy storage system(ESS),this paper decides the charging and discharging intervals of ESS,so that the energy storage and wind power output can be further coordinated.Considering the prediction error and the output uncertainty of wind power,the planned scheduling output of wind farms(WFs)is first optimized on a long timescale,and then the rolling correction optimization of the scheduling output of WFs is carried out on a short timescale.Finally,the effectiveness of the proposed optimal scheduling and power allocation strategy is verified through case analysis.

Short-Term Scheduling of Combined Cycle Units Using Mixed Integer Linear Programming Solution

Combined cycle plants (CCs) are broadly used all over the world. The inclusion of CCs into the optimal resource scheduling causes difficulties because they can be operated in different operating configuration modes based on the number of combustion and steam turbines. In this paper a model CCs based on a mixed integer linear programming approach to be included into an optimal short term resource optimization problem is presented. The proposed method allows modeling of CCs in different modes of operation taking into account the non convex operating costs for the different combined cycle mode of operation.

Dynamics Analysis of Square Unit and its Combined Mechanism with Joint Clearance

The deployable mechanisms consisting of square units are widely applied in aeronautics and astronautics,biomedicine, architecture and other fields, and joint clearance in such a mechanism is unavoidable. This study is carried out to accurately investigate the dynamic property of the mechanism.Firstly,a dynamics model was built by considering the motion characteristics between elements of joint with clearances. Secondly,based on Floures contact force model and LuGre friction force model,the tangential and normal contact force of revolute pair element with clearance were calculated respectively. Finally,square combined mechanisms' dynamic analytical method considering joint clearance was investigated, and constraint renege problem was resolved by adopting Baumgarte stable constraint method in integration process.Analytical result indicates that the impact of joint clearance on dynamic property of square combined mechanism should not be neglected.

Protective effect of borneol combined with safflower on neurovascular unit in rats with ischemic stroke

Background:Compatibility is a characteristic of the clinical application of traditional Chinese medicine,often leading to enhanced therapeutic effects.In the treatment of cerebral ischemia,blood-activating and open orifices herbs are frequently used individually;however,their combination is not commonly practiced.This study aims to investigate the impact of combining safflower and borneol as examples of open orifices herbs and blood-activating herbs on the neurovascular unit in rats with ischemic stroke.The objective is to determine whether this combination exhibits superior therapeutic efficacy compared to using borneol or safflower alone while exploring its underlying mechanism.These findings may provide novel insights for clinical treatments.Methods:SD male rats were randomly divided into 6 groups:sham operation group,model group,borneol group(0.1 g/kg),safflower group(5 g/kg),borneol combined with safflower group(0.1 g/kg+5 g/kg)and nimodipine group(0.01 g/kg).The middle cerebral artery cerebral ischemia(MCAO)model were prepared after continuous intragastric administration for 7 days in each group,the neurological function of each group were scored 24h after operation,and water content in brain tissue were measured by weighing method.The activity of superoxide dismutase(SOD)and the contents of nitric oxide(NO)and malondialdehyde(MDA)in brain tissue and serum were determined by spectrophotometry,and the mRNA expressions of matrix metalloproteinase 2(MMP-2),tight junction protein 1(ZO-1),vascular endothelial growth factor(VEGF)and brain-derived neurotrophic factor(BDNF)were detected by Real time PCR.Result:Compared with the model group,the group treated with borneol combined with safflower exhibited a significant decrease in the neural function score of MCAO rats(P<0.01).Additionally,it led to a reduction in brain tissue water content(P<0.01),elevated SOD activity,and reduced levels of NO and MDA in both serum and brain tissue(P<0.01 or P<0.05).Moreover,this treatment resulted in a decrease in the mRNA expression of MMP-2 and an increase in ZO-1 in brain tissue,along with an increase in the mRNA expression of VEGF and BDNF(P<0.01).Conclusion:Borneol combined with safflower demonstrates a protective effect on the neurovascular unit in rats with ischemic stroke.This effect is likely associated with increased SOD activity,reduced MDA and NO content in both serum and brain tissue of MCAO rats,and a decrease in MMP-2 mRNA expression in brain tissue,coupled with an increase in ZO-1,VEGF,and BDNF mRNA expression.These effects were superior to those observed with borneol or safflower administered alone.

Model Selection of Gas Turbine for Large Scale Gas-Fired Combined Cycle Power Plant

This paper briefs the configuration and performance of large size gas turbines and their composed combined cycle power plants designed and produced by four large renown gas turbine manufacturing firms in the world, providing reference for the relevant sectors and enterprises in importing advanced gas turbines and technologies.

Combined exercise improves gastrointestinal motility in psychiatric in patients

AIM To examine the effect of combined exercise on colonic transit time(CTT) in admitted psychiatric patients. METHODS Over a 6-mo period, consecutive in patients with mental illness were recruited from the Somang Hospital Psychiatry Unit. A combined exercise program that included 60 min per day of exercise 3 d per week for 12 wk was performed. Physical fitness and CTT of the patients were measured twice before and twice after the exercise program. CTT was measured using a multiple marker technique with a radio-opaque marker. Changes in the exercising patients' CTT and weight-,cardiovascular-and fitness-related parameters were statistically assessed.RESULTS After the 12-wk combined exercise intervention, decreased intestinal transit time was observed in all CTTs of the exercise group, including the right CTT(exercise: 15.6 ± 15.2 vs 9.2 ± 11.9, control: 13.1 ± 10.4 vs 10.9 ± 18.7), left CTT(exercise: 19.7 ± 23.5 vs 10.4 ± 13.2, control: 19.2 ± 19.0 vs 16.9 ± 19.8), recto-sigmoid CTT(exercise: 14.3 ± 16.7 vs 6.7 ± 7.9, control: 15.0 ± 14.4 vs 19.3 ± 30.3), and total colonic transit time(TCTT)(exercise: 50.2 ± 38.1 vs 27.1 ± 28.0, control: 47.4 ± 34.6 vs 47.3 ± 47.3). After the 12-wk combined exercise period, TCTT was significantly shortened in the exercise group compared with that in the control group. In addition to eating habits, water intake, and fiber intake, the increased physical activity level as a result of the 12-wk combined exercise program reduced the CTT.

Thermal-environment characteristics and comfort of combined radiant-floor (Korean heating system ondol) and convective cooling system

The thermal-environment characteristics of the existing forced-convection cooling system were compared with those of the convective cooling system, which combined the radiant-floor cooling system using floor-heating panel typically applied to apartments in South Korea with the forced-convection cooling system using improved fan coil unit. The subjective warm/cool-feeling responses to the combined radiant-floor and convective cooling system in the questionnaire survey conducted among the test subjects were analyzed to establish the basic data for the combined cooling system. The results show that in the thermal-equilibrium condition, the vertical air temperature difference in the model living room is larger in the forced-convection-cooling condition. Most of the subjects feel a proper warm/cool feeling on their entire body, but they feel colder on the foot and lower body in the combined-cooling condition.

On units combination and commitment optimization for electric power production

Electric power system is one of the most important and complex engineering in modern society, supplying main and general power for social production and social life. Meanwhile, since it is a productive system with both high input and output, it has an obvious economic significance to improve its operating efficiency. For an example, an unit is 10 GW scale, if its standard coal consumption can be decreased with 1 g/kW·h, it can save about 5 000 tons standard coal per year. It will be discussed mainly that how to establish optimization model and its numerical algorithm for operating management of the electric power system. The idea on establishing optimization model is how to dispatch work state of units or power plants, so that total cost of fuel consumption for generation is reduced to the minimum. Here the dispatch is to decide which unit or plant to operate, which unit or plant to stop running, how much power should be generated for those operating units or plants at each given time interval.

Bond population analysis on combination of favorable growth unit of Al(OH)_3 crystals

The quantum chemical calculation on four representative combination modes of the favorable growth unit Al6(OH)18(H2O)6 of Al(OH)3 crystals and the single unit were calculated. On the base of the prior investigation, and from the point of view of bond population and net atomic charge, the relationships between the combination mode of the favorable growth unit and the relative intensity of chemical bond of the systems were discussed. The quantum chemistry calculations were performed at RB3LYP/6-31G and RHF/6-31G levels by ab initio and DFT methods respectively. From the point of view of bond population, it can be preliminarily presumed that the interatomic bond force of the system with side-face-combination-B mode is weaker to a certain extent. From the point of view of the net charge, when the combination mode is obverse-face-combination-D, the interatomic bond force will be enhanced.

浅谈“UNIT”在艺术体操中的运用

以文献资料、专家访谈法为主要研究手段 ,就 2 0 0 3年艺术体操新规则中新出现的“UNIT”难度进行了理论上的界定 ,在探讨“UNIT”与联合难度之间的本质区别的基础上 ,着重对“UNIT”的运用进行了研究。结果表明 :“UNIT”的出现使艺术体操进一步向着竞技级别化的方向发展 ;“UNIT”的合理运用体现了教练员和运动员能力和水平。

Experimental Study of Air Conditioning Unit of Evaporative Cooling Assisted Mechanical Refrigeration

The evaporative cooling,which assists the refrigeration machinery air-conditioning systems test-rig,has been designed.Its structure and working principle were described,and the performance test was conducted and analyzed.The test shows that making full use of the evaporative cooling "free cooling" in Spring and Autumn seasons can fully meet the requirements of air-conditioned comfort through the switch of the function in different seasons.Taking into account the evaporative cooling fan and pump energy consumption,compared with the traditional mechanical refrigeration system,more than 80 percent of energy can be saved,and the energy efficiency ratio of the Unit(EER)is as high as 7.63.Using the two stages of indirect evaporative cooling to pre-cool the new wind in summer,under the conditions of the same air supply temperature requirements,0.83 kg/s chilled water saved can be equivalent to the traditional mechanical refrigeration system,and when the new wind ratio up to 50 percent,more than 10 percent load was reduced in mechanical refrigeration system.The overall EER increased about 35 percent.

Education Knowledge System Combination Model Based on the Components

Resources are the base and core of education information, but current web education resources have no structure and it is still difficult to reuse them and make them can be self assembled and developed continually. According to the knowledge structure of course and text, the relation among knowledge points, knowledge units from three levels of media material, we can build education resource components, and build TKCM （Teaching Knowledge Combination Model） based on resource components. Builders can build and assemble knowledge system structure and make knowledge units can be self assembled, thus we can develop and consummate them continually. Users can make knowledge units can be self assembled and renewed, and build education knowledge system to satisfy users＇ demand under the form of education knowledge system.

气体封隔器密封单元的增强方法与安全分析

气体封隔器胶筒是实现气井分层分段开采的关键部件。常规三胶筒结构在坐封时易发生初始破坏,导致胶筒整体应力水平降低,密封安全性储备不足。为此,提出一种多材料组合式密封单元的增强方法,用于HPHT105-232-V0型含硫化氢高温高压气体封隔器密封单元的设计;基于拉伸试验和Yeoh理论获得橡胶的本构模型参数;在温度204℃、坐封力200 kN和环空压力70 MPa下,分析了胶筒的应力和变形规律;试验测试了增强单元的密封安全性。分析结果表明:HPHT105-232-V0型封隔器密封单元胶筒的最大变形量为94.785 mm,最大接触应力为240 MPa,位于金属护环与套管接触区域。根据API标准,对HPHT105-232-V0型封隔器实物进行测试试验,坐封时胶筒未发生初始破坏,密封单元的整体应力水平提高;稳压过程胶筒压降幅度小于1%;整个试验测试过程中,密封单元无气泡溢出,封隔器卸载后胶筒结构无明显的塑性变形。研究结果表明,采用该增强方法所设计的多材料组合式密封单元具有良好的密封性能,满足极端环境下的密封安全性要求。

灵活性驱动下的热电联产机组多目标协同控制策略

灵活性提升会显著影响热电联产机组的热舒适性及运行经济性等性能,为实现机组大范围快速变负荷过程中的综合性能优化,提出了一种基于预测控制的机组多目标协同控制策略。首先,建立了一套考虑灵活性、热舒适性、经济性及平稳性的机组多目标评价指标体系,为实现多目标协同,设计了一种基于预测控制的机组电热协调控制策略,在滚动优化中引入煤耗指标实现经济优化,并给出了多目标控制律的求解方法;然后,以多目标评价指标作为粒子群优化的目标函数,基于仿真模型离线寻优,获得了控制策略中的最佳参数设定,实现了机组综合性能的优化;最后,以某300 MW机组为例进行了仿真测试。结果表明:该策略可提升热电联产机组的运行灵活性,并在较大程度上保证机组的热舒适性和运行经济性,为热电联产机组的多目标优化控制提供了依据。

风-火-储耦合系统储能容量配置优化对比

为提升风电富集区域风电消纳水平及燃煤机组的灵活性,提出了基于热电共蓄式压缩空气储能的风-火-储耦合系统及系统调度策略,建立了系统的容量配置优化框架,并对7种布局方案进行了多目标优化。优化结果表明:电锅炉将弃风电量转化为热量时,燃煤机组的运行点向电力负荷下限更低的区域移动,风电上网空间增大,燃煤机组出力水平降低;加入热电共蓄式压缩空气储能子系统,使得燃煤机组电功率水平降低;换热器废热的回收进一步降低了燃煤机组产热水平;通过调整燃煤机组热出力,抽汽蓄热子系统能够实现抽汽热的时空平移,促使燃煤机组运行点向电力负荷下限更低的区域移动,可间接促进风电的消纳。综合来看,3种子系统相组合的最佳耦合方案可实现燃煤机组的热电解耦,从而提升了其深度调峰能力,在更大程度消纳风电能力的同时提升了系统的效率和环保性。

考虑核电灵活参与调峰的多源联合运行低碳经济调度

在含高比例核电机组和新能源发电设备的沿海地区电网,系统调峰压力严峻。为了满足系统调峰需求,充分挖掘核电调峰潜力,建立核电灵活出力参与调峰的核-光-储-蓄-火联合运行优化调度模型。首先,针对核电灵活出力的非线性特性,采用0-1变量进行线性化有效约束;然后,充分考虑各电源的运行特性及成本,建立完整的系统运行约束;最后,在传统的以经济调度为优化目标的基础上,引入不同碳交易机制,并兼顾系统新能源消纳水平。算例分析验证了模型的有效性,结果表明,所提优化调度模型充分实现了核电的灵活出力,有效缓解了系统调峰压力,减少常规火电机组的频繁启停,并有效提高了新能源的消纳水平,使系统运行更加经济性和低碳性。

预制UHPC永久模板钢筋混凝土组合梁抗剪性能有限元分析

为了研究预制超高性能混凝土永久模板钢筋混凝土组合梁抗剪性能,选取合适的U型UHPC预制单元本构关系,建立了钢筋混凝土梁的有限元永久模型,并与已有的试验数据进行比较,验证了模型的可靠性,并分析配箍率、剪跨比等参数对超高性能混凝土组合梁抗剪性能的影响。结果显示:超高性能混凝土预制单元可显著提高斜向开裂荷载和极限荷载;预制单元会限制箍筋的作用,所以配箍率对组合梁影响小;剪跨比对组合梁抗剪性能影响大,但是和配箍率一样都会影响其延性。

咸淡水组合灌溉对土壤盐分和棉花生长的影响

为揭示不同微咸水(农田排水)与淡水在“先咸后淡”的组合灌溉模式下对土壤容重、盐分迁移和棉花生长的影响。以淡水灌溉为对照(CK),设置7种不同微咸水、淡水组合灌溉(微咸水∶淡水=1∶14(T1)、2∶13(T2)、3∶12(T3)、6∶9(T4)、9∶6(T5)、12∶3(T6)),T7处理采用全额微咸水灌溉,于2022年4-9月进行了棉花田间试验。结果表明,采用微咸水灌溉造成土壤表层盐分积累,0~40 cm土层出现积盐现象,棉花生育期结束后,各处理与淡水对照(CK)比较,T1~T6在0~40 cm土层的电导率分别增加1.16%~26.61%,T7处理电导率增加86.40%;与淡水对照相比,组合灌溉后各处理土层0~40 cm土壤容重明显增加,土壤孔隙度降低,以全额微咸水灌溉T7处理最为显著(容重增加10.24%);微咸水组合灌溉有效提高棉花株高、叶面积指数、茎粗。合理利用微咸水组合灌溉能够为棉花生长提供良好的水盐环境,提高棉花产量,能够为极端干旱区合理利用微咸水提供一种新的灌水模式,为灌区发展节水灌溉及农业可持续发展提供理论支撑。

低负荷下燃气‒蒸汽联合循环机组与煤气发电机组经济效益分析

马钢北区拥有1台燃气‒蒸汽联合循环发电机组和1台全烧煤气锅炉发电机组,用于平衡马钢北区高、焦、转炉煤气。为提高煤气综合利用效率,采集2台机组不同负荷下煤气消耗数据并进行分析,根据分析结果对2台机组的煤气资源进行最优分配,优化生产运行组织方式,最大可能实现有限煤气资源多发电。

基于CHP机组碳排放分析的综合能源系统低碳调度优化方法

针对现有研究对于热电联产(CHP)机组碳排放计算不符合实际物理特性的问题,提出了基于CHP碳排放分析的综合能源系统(IES)低碳调度优化方法。从CHP机组内部结构入手,分析CHP机组内部各部分之间能量的传递过程,绘制CHP机组功率与碳排流向图,列写各个部分的功率平衡方程,得到CHP机组排放废气的等效热功率;计及碳排放量与废气排放速率的关系,结合废气排放的热力学方程,得到CHP机组废气排放速率与输入气流量及输出功率的关系;提出基于CHP机组碳排放分析的IES低碳调度优化模型,以总运行成本最小为目标,求解IES低碳调度优化结果;通过算例分析不同CHP机组运行方式下的优化调度结果,并与现有方法进行对比,验证了所提模型在降低碳排放方面的有效性。