摘要：Due to its inherent safety feature, the modular high temperature gas-cooled reactor (MHTGR) has been seen as one of the best candidates in building next generation nuclear plants (NGNPs). Since the MHTGR dynamics has high nonlinearity, it is necessary to develop nonlinear power-level controller which is not only beneficial to the safe, stable, efficient and autonomous operation of the MHTGR but also easy to be implemented practically. In this paper, based on the concept of shiftedectropy and the physically-based control design approach, it is proved theoretically that the simple proportional-differential (PD) output-feedback power-level control can provide globally asymptotic closed-loop stability. Numerical simulation results verify the theoretical results and show the influence of the controller parameters to the dynamic response.

摘要：根据10MW高温气冷堆(HTR-10)蒸汽发生器传热小螺旋管的具体结构，提出了相应的计算模型；针对传热管振动的主要机理、流体弹性不稳定、旋涡脱落和湍流激励，依据目前所能够查阅到的文献资料中提供的半经验模型，做了详细分析和校核计算。分析结果表明， HTR- 10蒸汽发生器在设计工况下运行时，不会发生流体弹性不稳定所导致的大振幅振动，也不会产生旋涡脱落引起的联锁共振；湍流激励对小螺旋管振动的影响很小。它在避免流致振动方面的设计是安全、可靠的。

摘要：The design of a wireless water level control system is introduced and discussed in detail. In this system, the wireless Proportional Integral (PI) controller is developed using the LabVIEW graphical user programming language. Zigbee wireless technology is chosen for the wireless data transfer system. The experimental testbed was built and the system software and hardware were implemented. In order to compare the performance of the wired and wireless system, a corresponding wired water level control system was built. Experimental results show that under the same PI parameters, the settling time of the wired system is 3.3 times faster than the wireless system. However, the percent overshoot using the wireless controller is 4% smaller.

摘要：混合金属氧化物具有优异的电化学活性,在高性能超级电容电极领域具有广阔的应用前景.然而,电极内离子动力学和电子动力学的迟滞从根本上限制了其电化学性能的进一步提高.为了弥补这一不足,本文通过原位化学反应在自支撑碳纳米管薄膜(CNTF)表面生长四元过渡金属氧化物纳米片(Ni-Co-Mn-MoNS),并进一步在纳米片上沉积碳纳米管导电网络(CNTN),得到了具有"三明治"结构的多孔柔性电极薄膜(CNTF/Ni-Co-Mn-MoNS/CNTN).得益于高电化学活性四元金属氧化物纳米片和碳纳米管(CNT)的协同作用以及合理的分层设计,该柔性电极拥有出色的储能性能,在1molL^-1KOH中能达到15.39Fcm^-2(2243.42Fg^-1)的高比面积电容,优于大多数已报道的柔性电极.基于CNTF/Ni-CoMn-MoNS/CNTN电极的非对称柔性超级电容器拥有优异的电化学性能,其稳定的输出电压为1.5V,比电容可达3738.12mFcm^-2,对应于1.17mWhcm^-2的高能量密度.此外,超级电容器具有出色的柔韧性和稳定性,即使在180°弯曲下也能稳定工作,并且在高电流密度下经过10000次充放电循环后其比电容仍能保持87.87%.这种独特的设计为高性能柔性储能器件的发展开辟了新的方向.

摘要：合理设计高离子电导率和低活化能(Ea)的固态电解质(SSEs)对全固态电池至关重要.近年来,基于各种描述符的机器学习技术成功地预测了锂离子在SSEs中的传导特性.本文建立了一个通用的基于HECS描述符的机器学习预测无机SSEs材料Ea的框架,并且以立方相锂-硫银锗矿型SSEs材料作为模型体系进行实例研究,采用偏最小二乘方法(PLS)建立了高精度(训练集:R^(2),88.7%;RMSE,0.02 e V;测试集:R^(2),82.0%;RMSE,0.02 e V)预测E_(a)的模型.变量投影重要性(VIP)分析表明了全局及局域离子传导环境对E_(a)的联合作用,其中平均阴离子尺寸以及与阴离子位置无序密切相关的结构的改变对激活能值的贡献尤为突出,这一发现有助于进一步指导发现或设计新的无机固态电解质材料.同时,对该模型进行的知识提取表明,可以通过增大瓶颈尺寸、引发阴离子位置无序、激活离子协同迁移等优化和设计出具有高离子传导性能的新的无机固态电解质材料.

摘要：P2型钠离子电池正极材料中的阴离子氧化还原化学(O^2-→O^-)引起了广泛关注.但是如何调节阴离子氧化还原反应仍然是一个很大的挑战.本文通过一种集Li2SiO3包覆层、Li掺杂和Si掺杂三方优点的协同策略对正极材料Na0.67Mn0.5Fe0.5O2中阴、阳离子氧化还原反应的活性和可逆性进行了调控.改性后正极材料的初始容量、倍率性能和循环稳定性都得到了显著改善.通过中子衍射、同步辐射X射线吸收谱、原位X射线衍射、电子顺磁共振、第一性原理计算等手段深入揭示了调控机理.Li2SiO3包覆层减轻了电极表面的副反应,提高了循环稳定性.Si^4+掺杂扩大了钠层层间距,降低了Na^+扩散势垒.此外,Si^4+掺杂还增强了结构的稳定性以及氧的氧化还原活性和可逆性.Li^+在Na位的掺杂进一步提高了结构的稳定性.电子密度云图证实了改性样品中Na和O活性较高.核密度云图和键价能谱确定了Na^+从Nae向Naf的迁移途径.本文所揭示的阴/阳离子氧化还原反应调控机理对其他氧化物正极材料的设计也具有指导意义.

摘要：A supercritical CO2 gas turbine cycle can produce power at high efficiency and the gas turbine is compact compared with the steam turbine. Therefore, it is very advantageous power cycle for the medium temperature range less than 650 ℃. The purpose of this paper is to show how it can be effectively applied not only to the nuclear power but also to the fossil fired power plant. A design of 300 MWe plant has been carried out, where thermal energy of flue gas leaving a CO2 heater is utilized effectively by means of economizer and a high cycle thermal efficiency of 43.4 % has been achieved. Since the temperature and the pressure difference of the CO2 heater are very high, the structural design becomes very difficult. It is revealed that this problem can be effectively solved by introducing a double expansion turbine cycle. The component designs of the CO2 heater, the economizer, supercritical CO2 turbines, compressors and the recuperators are given and it is shown that these components have good performances and compact sizes.