Improving the operational stability of perovskite solar cells with cesium-doped graphene oxide interlayer

Perovskite solar cells(PSCs)have made great advances in terms of power conversion efficiency(PCE),yet their subpar stability continues to hinder their commercialization.The interface between the perovskite layer and the charge-carrier transporting layers plays a crucial role in undermining the stability of PSCs.In this work,we propose a strategy to stabilize high-performance PSCs with PCE over 23%by introducing a cesium-doped graphene oxide(GO-Cs)as an interlayer between the perovskite and hole-transporting material.The GO-Cs treated PSCs exhibit excellent operational stability with a projected T80(the time where the device PCE reduces to 80%of its initial value)of 2143 h of operation at the maximum powering point under one sun illumination.

Monitoring Study of Long-Term Land Subsidence during Subway Operation in High-Density Urban Areas Based on DInSAR-GPS-GIS Technology and Numerical Simulation

During subway operation,various factors will cause long-term land subsidence,such as the vibration subsidence of foundation soil caused by train vibration load,incomplete consolidation deformation of foundation soil during tunnel construction,dense buildings and structures in the vicinity of the tunnel,and changes in water level in the stratum where the tunnel is located.The monitoring of long-term land subsidence during subway operation in high-density urban areas differs from that in low-density urban construction areas.The former is the gathering point of the entire urban population.There are many complex buildings around the project,busy road traffic,high pedestrian flow,and less vegetation cover.Several existing items requiremonitoring.However,monitoring distance is long,and providing early warning is difficult.This study uses the 2.8 km operation line between Wulin Square station and Ding’an Road station of Hangzhou Subway Line 1 as an example to propose the integrated method of DInSAR-GPS-GIS technology and the key algorithm for long-term land subsidence deformation.Then,it selects multiscene image data to analyze long-termland subsidence of high-density urban areas during subway operation.Results show that long-term land subsidence caused by the operation of Wulin Square station to Ding’an Road station of Hangzhou Subway Line 1 is small,with maximumsubsidence of 30.64 mm,and minimumsubsidence of 11.45 mm,and average subsidence ranging from 19.27 to 21.33 mm.And FLAC3D software was used to verify the monitoring situation,using the geological conditions of the soil in the study area and the tunnel profile to simulate the settlement under vehicle load,and the simulation results tended to be consistent with the monitoring situation.

Voltage-dependent plasticity and image Boolean operations realized in a WOx-based memristive synapse

The development of electronic devices that possess the functionality of biological synapses is a crucial step towards neuromorphic computing.In this work,we present a WOx-based memristive device that can emulate voltage-dependent synaptic plasticity.By adjusting the amplitude of the applied voltage,we were able to reproduce short-term plasticity(STP)and the transition from STP to long-term potentiation.The stimulation with high intensity induced long-term enhancement of conductance without any decay process,thus representing a permanent memory behavior.Moreover,the image Boolean operations(including intersection,subtraction,and union)were also demonstrated in the memristive synapse array based on the above voltage-dependent plasticity.The experimental achievements of this study provide a new insight into the successful mimicry of essential characteristics of synaptic behaviors.

A Two-Stage Approach for Large-Scale Cascaded Hydropower System Operations

The paper presents a two-stage approach to cope with the long-term optimal operation of cascaded hydropower systems. This approach combines progressive optimality algorithm (POA) with quadratic programming (QP) to improve the optimization results. POA is used at the first stage to generate a local optimal result, which will be selected as the initial feasible solution of QP method employed at the second stage. Around the initial solution, a rational local search range for QP method is then determined, where the nonlinear water level function and tailrace level function can be linearized nearly with high accuracy. The simplified optimization problem is formulated as a QP model with a quadratic generation function and a linear set of constraints, and solved using the available mathematic optimization software package. Simulation is performed on the long term operation of Hongshui River hydropower system which is located in southwest China and consists of 9 built hydropower plants. Results obtained from the proposed approach show a significant increase in the total energy production compared to the results from POA.

Advancing immunosuppression in liver transplantation: A narrative review

Immunosuppression is essential to ensure recipient and graft survivals after liver transplantation(LT). However, our understanding and management of the immune system remain suboptimal. Current immunosuppressive therapy cannot selectively inhibit the graft-specific immune response and entails a significant risk of serious side effects, i.e., among others, de novo cancers, infections, cardiovascular events, renal failure, metabolic syndrome, and late graft fibrosis, with progressive loss of graft function. Pharmacological research, aimed to develop alternative immunosuppressive agents in LT, is behind other solidorgan transplantation subspecialties, and, therefore, the development of new compounds and strategies should get priority in LT. The research trajectories cover mechanisms to induce T-cell exhaustion, to inhibit co-stimulation, to mitigate non-antigen-specific inflammatory response, and, lastly, to minimize the development and action of donor-specific antibodies. Moreover, while cellular modulation techniques are complex, active research is underway to foster the action of T-regulatory cells, to induce tolerogenic dendritic cells, and to promote the function of B-regulatory cells. We herein discuss current lines of research in clinical immunosuppression, particularly focusing on possible applications in the LT setting.

深圳地区某近零能耗学校设计探讨

以深圳地区某学校项目为案例,对近零能耗建筑相关技术难点进行了分析论证,并提出多项运维、科普措施:采用分体空调的教室设置集中新风系统;利用EnergyPlus软件进行模拟计算,证实热回收装置在深圳地区不具有经济性,新风系统不设置热回收装置;编制近零能耗建筑运行管理手册和师生个人节能减排行为建议书,并结合课程进行知识科普,倡导师生行为节能。

ERROR ESTIMATE FOR INFLUENCE OF MODEL REDUCTION OF NONLINEAR DISSIPATIVE AUTONOMOUS DYNAMICAL SYSTEM ON LONG-TERM BEHAVIOURS

From viewpoint of nonlinear dynamics, the model reduction and its influence on the long-term behaviours of a class of nonlinear dissipative autonomous dynamical system with higher dimension are investigated theoretically under some assumptions. The system is analyzed in the state space with an introduction of a distance definition which can be used to describe the distance between the full system and the reduced system, and the solution of the full system is then projected onto the complete space spanned by the eigenvectors of the linear operator of the governing equations. As a result, the influence of mode series truncation on the long-term behaviours and the error estimate are derived, showing that the error is dependent on the first products of frequencies and damping ratios in the subspace spanned by the eigenvectors with higher modal damping. Furthermore, the fundamental understanding for the topological change of the solution due to the application of different model reduction is interpreted in a mathematically precise way, using the qualitative theory of nonlinear dynamics.

Research on the development mode of long-term nursing insurance ——taking Qingdao as an example

With the gradual development of society, scientific and technological progress, aging gradually aggravated, has become a hot topic of society. People to old age, self-care ability than in the past, not only suffer from disease, life has become difficult, coupled with the large number of empty nest family, the cost of care is also very high, whether it is to receive home care or professional institutions of care have great difficulties. Therefore, the community should be a large number of people with long-term care needs of the appropriate economic compensation, in this context, long-term care insurance is born. As a leading city in Shandong Province, Qingdao has introduced long-term care insurance and achieved good results. This paper analyzes the practical problems faced by Qingdao, that is, the development background of Qingdao long-term nursing insurance model, obtains the deficiency of Qingdao long-term nursing insurance, and then puts forward the corresponding countermeasures, and then ponders how to choose the long-term nursing insurance model of our country＇s future development.

直接蒸发冷却技术在渭南地区数据中心的应用

对渭南地区某数据中心机房的直接蒸发冷却设备进行实测,发现:若将制冷系统的机械制冷模式开启条件由室外空气湿球温度不低于18.0℃提高至不低于25.1℃,能够减少机械制冷模式的全年运行时间2 179 h,具有较大的节能潜力。该研究可以为陕西地区的数据中心采用直接蒸发冷却制冷系统提供参考。

北京大兴国际机场航站楼过渡季新风系统运行策略调适与优化

北京大兴国际机场航站楼核心区内区新风系统设计采用新风机组+全空气处理机组组合的方式进行新风供应。经实测发现,过渡季时室内新风量严重不足,室内效果无法达到设计预期。针对这一问题对机组运行方式展开调适优化并进行分组实测,验证不同运行模式下的室内CO_(2)浓度,分析结果表明,过渡季新风系统新风量不足是其设计策略导致的。同时根据分析结果对过渡季新风系统运行策略进行修正,并得到了不同区域变频新风机组(OAU)和空调机组(AHU)运行频率的搭配。在该运行模式下,过渡季新风系统既可以满足室内需求,又兼顾节能效果,为后续北京大兴国际机场过渡季OAU-AHU新风系统的实际运行提供了运行依据。

电缆户外终端绝缘老化状态自动监测技术优化

为解决电网设备出现绝缘老化故障问题,提出全生命周期下高压电缆户外终端绝缘老化状态自动监测方法。管理高压电缆户外终端设备的生命周期,在生产运营阶段,分析高压电缆户外终端绝缘老化状态温度损耗特性,构建终端绝缘老化评估模型,评估高压电缆户外终端的绝缘老化状态,设计老化状态监测标准,将评估的结果输入到监测标准中实现自动监测。实验结果表明,该方法能够有效分析老化状态下电缆户外终端设备在不同季节的电流泄露情况,分析不同使用年限设备的介质损耗,同时可以精准监测出多种类型的设备绝缘老化状态。

基于BIM与状态监测的车辆段室外管线智能管控设计及关键技术研究

针对车辆段室外综合管线运维中存在的隐蔽性强、交互错杂、信息割裂、管理效率低下等问题,提出一种基于BIM与状态监测的车辆段室外管线智能管控设计技术方案。首先,通过BIM技术建立车辆段管线地下管网三维模型,并将管线的各类信息(位置、材质、规格等)以数据化的形式存储在模型中,实现地下管线的三维可视化和管线数据信息化;然后,通过管线监测控制方案设计,在各类管线关键节点安装智能仪表,实时采集管线状态数据,经过后台数据处理和智能化分析,监测分析管线运行状态,开展管线故障预警及故障诊断,利用电动阀门实现故障情况下区域阀门的自动开启及闭合,实现管网状态的实时监测,降低管线故障对车辆段生产作业的影响危害;最后,搭建管线信息数据库和智能管控软件平台,数据库集成管线的运维、能耗、实时监测数据,软件平台将各管线专业信息相融合,形成一个各管线专业集中统一的管理和监视界面终端,集成管线三维展示、状态数据展示、故障报警提醒、智能派单等功能,减少人工作业,提高管线管理效率。研究成果可以为车辆段室外综合管线运维管理提供借鉴,给车辆段基础设施资源的建设、规划提供行之有效的管理手段和办法。

太阳能电池的电势诱导衰减研究进展

在户外长期运行中,不论是晶体硅太阳能电池还是薄膜太阳能电池,都会受到电势诱导衰减(PID)的影响,从而导致太阳能电池组件输出功率下降。尽管前人已经开展了许多研究,但对PID现象的理解及解决方案仍旧不完整。本文主要介绍了晶体硅太阳能电池、薄膜太阳能电池的PID现象成因及相关解决办法,以促进人们对太阳能电池PID现象的深入理解,以期对太阳能电池的稳定性研究提供指导性意见。

Development of a Long-Term Operational Optimization Model for a Building Energy System Supplied by a Geothermal Field

In order to reduce energy consumption and CO_(2) emissions in the building sector, more and more renewable energy sources are integrated into energy systems. Especially geothermal fields combined with heat pumps are able to supply buildings with heat and cold at low carbon emissions. However, using geothermal fields as heat and cold source influences the ground temperature. Consequently, the ground temperature can change dramatically over a building’s lifetime, leading to less efficient operation of the energy system. Therefore, a sustainable operation is required to ensure the long-term efficiency of geothermal fields. In this paper, we develop an optimization model to derive operating strategies for an efficient long-term operation of a building energy system coupled to a geothermal field. The investigated energy system is the main building of the E.ON Energy Research Center in Aachen, Germany, which includes a heat pump, two boilers, a combined heat, and power unit, a glycol cooler, and a geothermal field with 41 probes. For each component, we develop energy-based sub-models, which are connected to form the overall system. The geothermal field is modeled by using a g-functions approach as well as a simplified resistance-capacitance approach. To achieve short computing times and realize an optimization horizon of several years, the optimization problem is formulated as mixed-integer linear programming(MILP). The developed model is optimized regarding two different objectives: the minimization of energy costs and the minimization of long-term temperature changes in the ground. Conclusions for an efficient and sustainable operation of the field, especially for the cooling supply, can be derived from the optimization results. It is shown that a state of equilibrium should be aimed to achieve an energy-efficient operation, in which the temperature of the field is close to the initial ground temperature.

Recovery of Cu(Ⅱ) from aqueous solution by induced crystallization in a long-term operation

The feasibility of copper recovery by induced crystallization in a long period（174 days） was investigated in a seeded fluidized bed reactor（FBR）. The process was divided into 3 periods according to different influent conditions, and the period Ⅲ was separated into Ⅲ-a and Ⅲb due to the adjustment of the molar ratio of CO3^2- concentration to copper concentration（[CT]/[Cu^2＋]）. The removal efficiency could exceed 95% and the average effluent copper concentration decreased to 3.0 mg/L. The mean particle size of seed grains with copper crystals coating on, raised to 0.36 mm from initial 0.18 mm. During period Ⅲ-a, the supersaturation exceeded 2.88 × 104, the removal efficiency decreased to 60%–80% and the particle size dropped to 0.30 mm, due to the generation of fines by homogeneous crystallization and seeds breaking. And the morphology of the crystals on the seed grains changed from rod-like to spherical which lead to the particle size decreasing. In period Ⅲ-b,the supersaturation was modified by adjusting the molar ratio of [CT]/[Cu^2＋] to 1.2 from 2.The efficiency was back to 95% and the mean particle size grew to 0.36 mm at the end of Ⅲb, the crystals coating on the seeds turned back to rod-like products of good stability. This study illustrated that the copper salt crystal could keep on growing on the seed grains for over 150 days, the feasibility and controllability of copper recovery by induced crystallization process in FBR were satisfactory, even under the dramatic changes in influent conditions.

杭州某近零能耗居住建筑空调形式对比

暖通空调系统能耗约占建筑总能耗的50%,相比照明等其他建筑能耗具有较大的节能潜力。本文以杭州某近零能耗居住建筑为基础,运用DesignBuilder建立了3种适用于居住建筑的空调系统模型——分体空调+独立新风系统、多联机+独立新风系统及热泵型新风环境控制一体机系统,对比分析了其全年空调运行能耗。选取热泵型新风环境控制一体机系统进行了能耗实测对比,验证了模型的准确性。同时以全寿命周期成本为经济性指标,比较了3种空调系统的经济效益,为夏热冬冷地区近零能耗居住建筑空调系统形式的选择提供参考。

三相联动双断口户外高压隔离负荷开关的研究

为了解决目前农村电网和郊区电网广泛使用的高压柱上开关产品存在的问题,如容易受恶劣环境影响、SF_(6)气体排放等,设计了一种新型三相联动双断口户外高压隔离负荷开关。采用环氧树脂固体绝缘和硅橡胶外包绝缘技术,具有耐高低温、耐紫外线和耐老化等优势。同时,采用小型化弹簧操作机构和挂簧传输方式以提高设备可靠性。此外,该开关内嵌真空灭弧装置,无需使用SF_(6)气体绝缘,对环境更为友好。与传统设备相比,所设计的隔离负荷开关采用双真空开关和三相柱式倒装结构,具备无污染、安全可靠、长寿命和低成本等优点,为实现高压线路的有效管理和维护提供了一种新的解决方案。

严寒地区室内水上乐园全新风除湿设计与探索

结合某严寒地区大型室内水上乐园项目,通过除湿方案的对比分析,展示了严寒地区全新风除湿的节能优势;通过暖通空调系统概述,梳理了该项目的设计思路;通过模拟分析,验证了该除湿方案冬季室内供暖效果及末端系统气流组织对于防结露的效果。

A better long-term outcome in cardiac transplant recipient with a history of previous open heart operations

Objective To investigate the effect of previous open heart operations (POHO) on the outcome of heart transplantation (HTX). Methods Between November 1984 and May 1996, HTX was performed on 151 patients at Hartford Hospital. Among them, 61 patients had previous open heart operations (POHO) (group A), and 90 did not (group B). The average follow up period was 1615±1185 days for group A and 1330±1125 days for group B. The recipient age was 55±10 years for group A and 48±12 years for group B (P<0.01). There were 17 patients (26%) in group A and 14 (50%) in group B who were over 60 years of age. There was more coronary artery disease (74% versus 37%, P <0.001) as etiology, and more diabetics in group A (P<0.02). Results The time for cardiopulmonary bypass (133±20 min versus 106±18 min, P<0.01) and aortic clamp time (73±16 min versus 61±13 min, P<0.01) were longer in group A. The operative mortality (within 30 days) was 0 and 2.2%, and the cumulative deaths were 16 (26%) and 43 (48%) respectively for group A and group B (P<0.01). The causes of death were (group A vs group B): infection (31% vs 26%), rejection (13% vs 28%, P<0.05), malignancy (25% vs 16%), cardiac event (6% vs 14%) and others (25% vs 16%). In patients over 60, there were 4 deaths (24%) in group A and 7 (50%) in group B. The difference was not significant. No patients died of rejection in this subgroup. The actuarial survival rates in group A versus group B were: 1 year, 93% versus 83%; 2 years, 85% versus 74%; 3 years, 81% versus 71%; 5 years, 76% versus 58%; and 10 years, 57 % versus 24% (P<0.01). Conclusion The survival rate in patients who had POHO is much higher than that in patients who had HTX as their primary operation.

杭州某办公建筑内区利用气候条件供冷分析

以杭州某办公楼为例,提出了建筑内区在过渡季和冬季利用新风供冷和冷却塔供冷2种方案,对二者进行了技术要点分析和综合比对。对于新风供冷方案,分析了室内温度、新风温度、新风比之间的关联及供冷小时数的影响。对于冷却塔供冷方案,分析了不同室内温度、供回水温差下所对应的风机盘管最高供水温度,研究了冷却塔热工性能曲线、冷却塔流量比、供回水温差对冷却塔供水温度的影响,探讨了冷却塔供冷不同工况下运行水温、切换温度、供冷时长、水泵配置及供冷系统运行策略。最后,计算了新风供冷和冷却塔供冷系统的节能量及经济性。