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Enhanced photoelectrochemical water splitting with a donor-acceptor polyimide

《能源前沿(英文)》 doi: 10.1007/s11708-023-0910-8

摘要: Polyimide (PI) has emerged as a promising organic photocatalyst owing to its distinct advantages of high visible-light response, facile synthesis, molecularly tunable donor-acceptor structure, and excellent physicochemical stability. However, the synthesis of high-quality PI photoelectrode remains a challenge, and photoelectrochemical (PEC) water splitting for PI has been less studied. Herein, the synthesis of uniform PI photoelectrode films via a simple spin-coating method was reported, and their PEC properties were investigated using melamine as donor and various anhydrides as acceptors. The influence of the conjugate size of aromatic unit (phenyl, biphenyl, naphthalene, perylene) of electron acceptor on PEC performance were studied, where naphthalene-based PI photoelectrode exhibited the highest photocurrent response. This is resulted from the unification of wide-range light absorption, efficient charge separation and transport, and strong photooxidation capacity. This paper expands the material library of polymer films for PEC applications and contributes to the rational design of efficient polymer photoelectrodes.

关键词: polyimide (PI) film     photoelectrochemistry     band structure engineering     aromatic unit    

Energy conservation in China’s coal-fired power industry by installing advanced units and organized phasing out backward production

Weiliang WANG, Junfu LYU, Zheng LI, Hai ZHANG, Guangxi YUE, Weidou NI

《能源前沿(英文)》 2019年 第13卷 第4期   页码 798-807 doi: 10.1007/s11708-019-0633-z

摘要: Coal-fired power is the main power source and the biggest contributor to energy conservation in the past several decades in China. It is generally believed that advanced technology should be counted on for energy conservation. However, a review of the decline in the national average net coal consumption rate (NCCR) of China’s coal-fired power industry along with its development over the past few decades indicates that the up-gradation of the national unit capacity structure (including installing advanced production and phasing out backward production) plays a more important role. A quantitative study on the effect of the unit capacity structure up-gradation on the decline in the national average NCCR suggests that phasing out backward production is the leading factor for the decline in the NCCR in the past decade, followed by the new installation, whose sum contributes to approximately 80% of the decline in the national average NCCR. The new installation has an effective affecting period of about 8 years, during which it would gradually decline from a relatively high value. Since the effect of phasing out backward production may remain at a certain degree given a continual action of phasing out backward capacity, it is suggested that the organized action of phasing out backward production should be insisted on.

关键词: coal-fired power     energy conservation     net coal consumption rate     new installation     phasing out backward production     unit capacity structure    

Calculation of diagonal section and cross-section bending capacity for strengthening RC structure using

Shouping SHANG , Fangyuan ZHOU , Wei LIU ,

《结构与土木工程前沿(英文)》 2009年 第3卷 第3期   页码 330-338 doi: 10.1007/s11709-009-0046-x

摘要: Because there is a great demand of reinforcement and retrofitting of aged structures nationwide, as well as the rapid development of innovative building materials, the adoption of strengthening RC structures using new inorganic materials has become possible. High-performance ferrocement laminate (HPFL) is an effective method of strengthening concrete structure. High-performance ferrocement laminate is a new type of inorganic material with the advantages such as high strength, small contraction, good bonding properties, etc. This paper introduces the formula of cross-section bending capacity for strengthening concrete beams with HPEL. A comparative analysis of experimental data, as well as the calculation of diagonal section bearing capacity of concrete members, is given.

关键词: RC beams     high-performance ferrocement laminate (HPFL)     inorganic material     reinforcement    

三峡工程巨型水轮发电机组设计与实践

邵建雄,刘景旺,袁达夫

《中国工程科学》 2011年 第13卷 第7期   页码 104-110

摘要:

分析了三峡水轮发电机组设计中必须考虑的主要问题;总结了所进行的关键技术研究;通过关键技术问题研究,使得三峡水轮发电机组参数达到最优化。机组运行结果表明三峡水轮发电机组性能良好,能够长期安全、稳定、高效运行,从而有效地验证了对三峡巨型水轮发电机组的总体技术设计是科学合理的。

关键词: 三峡工程     700 MW级水电机组     单机容量     设计研究     运行稳定性     实践    

Structure improvement and strength finite element analysis of VHP welded rotor of 700°C USC steam turbine

Jinyuan SHI,Zhicheng DENG,Yong WANG,Yu YANG

《能源前沿(英文)》 2016年 第10卷 第1期   页码 88-104 doi: 10.1007/s11708-015-0387-1

摘要: The optimized structure strength design and finite element analysis method for very high pressure (VHP) rotors of the 700°C ultra-super-critical (USC) steam turbine are presented. The main parameters of steam and the steam thermal parameters of blade stages of VHP welded rotors as well as the start and shutdown curves of the steam turbine are determined. The structure design feature, the mechanical models and the typical position of stress analysis of the VHP welded rotors are introduced. The steady and transient finite element analysis are implemented for steady condition, start and shutdown process, including steady rated condition, 110% rated speed, 120% rated speed, cold start, warm start, hot start, very hot start, sliding-pressure shutdown, normal shutdown and emergency shutdown, to obtain the temperature and stress distribution as well as the stress ratio of the welded rotor. The strength design criteria and strength analysis results of the welded rotor are given. The results show that the strength design of improved structure of the VHP welded rotor of the 700°C USC steam turbine is safe at the steady condition and during the transient start or shutdown process.

关键词: 700°C ultra-super-critical unit     steam turbine     very high pressure rotor     structure strength design     strength design criteria     finite element analysis    

A solution to stochastic unit commitment problem for a wind-thermal system coordination

B. SARAVANAN,Shreya MISHRA,Debrupa NAG

《能源前沿(英文)》 2014年 第8卷 第2期   页码 192-200 doi: 10.1007/s11708-014-0306-x

摘要: Unit commitment (UC) problem is one of the most important decision making problems in power system. In this paper the UC problem is solved by considering it as a real time problem by adding stochasticity in the generation side because of wind-thermal co-ordination system as well as stochasticity in the load side by incorporating the randomness of the load. The most important issue that needs to be addressed is the achievement of an economic unit commitment solution after solving UC as a real time problem. This paper proposes a hybrid approach to solve the stochastic unit commitment problem considering the volatile nature of wind and formulating the UC problem as a chance constrained problem in which the load is met with high probability over the entire time period.

关键词: unit commitment (UC)     randomness     wind generation     univariate     chance constrained    

Solving unit commitment problem using a novel version of harmony search algorithm

Roozbeh MORSALI,Tohid JAFARI,Amirhossein GHODS,Mohammad KARIMI

《能源前沿(英文)》 2014年 第8卷 第3期   页码 297-304 doi: 10.1007/s11708-014-0309-7

摘要: In this context, a novel structure was proposed for improving harmony search (HS) algorithm to solve the unit comment (UC) problem. The HS algorithm obtained optimal solution for defined objective function by improvising, updating and checking operators. In the proposed improved self-adaptive HS (SGHS) algorithm, two important control parameters were adjusted to reach better solution from the simple HS algorithm. The objective function of this study consisted of operation, start-up and shut-down costs. To confirm the effectiveness, the SGHS algorithm was tested on systems with 10, 20, 40 and 60 generating units, and the obtained results were compared with those of the simple HS algorithm and other related works.

关键词: generation scheduling     harmony search (HS) algorithm     intelligent technique     unit commitment    

A solution to the unit commitment problem—a review

B. SARAVANAN, Siddharth DAS, Surbhi SIKRI, D. P. KOTHARI

《能源前沿(英文)》 2013年 第7卷 第2期   页码 223-236 doi: 10.1007/s11708-013-0240-3

摘要: Unit commitment (UC) is an optimization problem used to determine the operation schedule of the generating units at every hour interval with varying loads under different constraints and environments. Many algorithms have been invented in the past five decades for optimization of the UC problem, but still researchers are working in this field to find new hybrid algorithms to make the problem more realistic. The importance of UC is increasing with the constantly varying demands. Therefore, there is an urgent need in the power sector to keep track of the latest methodologies to further optimize the working criterions of the generating units. This paper focuses on providing a clear review of the latest techniques employed in optimizing UC problems for both stochastic and deterministic loads, which has been acquired from many peer reviewed published papers. It has been divided into many sections which include various constraints based on profit, security, emission and time. It emphasizes not only on deregulated and regulated environments but also on renewable energy and distributed generating systems. In terms of contributions, the detailed analysis of all the UC algorithms has been discussed for the benefit of new researchers interested in working in this field.

关键词: unit commitment (UC)     optimization     deterministic load     stochastic load     evolutionary programming (EP)     hybrid    

Industrial Structure Adjustment of Shaanxi Province under the Limited Water Resources Condition

Xiao-jun Liu,Zhen-yu Guo,Chao Ding,Han-liang Fu

《工程管理前沿(英文)》 2014年 第1卷 第4期   页码 378-384 doi: 10.15302/J-FEM-2014057

摘要: Shaanxi Province is a region poor of water resources in China, and the lack of water resources is becoming a key factor which restricts the social and economic development of Shaanxi Province. In the perspective of efficient utilization of water resources, Shaanxi Province is committed to the transformation of the economic growth and the industrial structure, and treats these measures as important guarantees for the future development of Shaanxi Province. This paper focuses on building multi-objective programming model of industrial structure optimization under the limited water resources condition, indicates the direction of the industrial transformation and water consumption structural adjustment by solving the model, and furthermore points out the key factors that affect the development of Shaanxi Province in the future. Finally, the authors give some advices of promoting the reasonable and effective utilization of water resources of Shaanxi Province.

关键词: water resources     capacity of water resources     industrial transformation     multi-objective programming    

我国草原生产力

侯扶江,王春梅,娄珊宁,侯向阳,呼天明

《中国工程科学》 2016年 第18卷 第1期   页码 80-93 doi: 10.15302/J-SSCAE-2016.01.011

摘要:

分析我国草原植物生产和动物生产,比较国内外草原生产力。结果表明,在过去的30余年中,我国一部分草原产草量下降,局部变化不显著。世界草原对畜产品生产的贡献率为40.08 %,中等收入国家为67.35 %。全球24.1 %的牛肉和31.9 %的羊肉来自草原,低收入国家草原载畜量分别高出高收入国家和中等收入国家87.4 %和66.4 %,畜产品生产分别只有两者的37.3 %和71.9 %。适宜的放牧利用,可使我国的草原生产能力达到6.35×109畜产品单位(APU);全国草原单纯依靠放牧每年可产肉2.959×106 t,占全国肉类总产量的3.5 %,占全国牛羊肉总产量的27.4 %。通过草原畜牧业的现代化转型可接近高收入国家水平,增产潜力约为50 %~200 %。

关键词: 草原生产力     产草量     放牧     载畜量     畜产品单位(APU)    

Energy saving design of the machining unit of hobbing machine tool with integrated optimization

《机械工程前沿(英文)》 2022年 第17卷 第3期 doi: 10.1007/s11465-022-0694-2

摘要: The machining unit of hobbing machine tool accounts for a large portion of the energy consumption during the operating phase. The optimization design is a practical means of energy saving and can reduce energy consumption essentially. However, this issue has rarely been discussed in depth in previous research. A comprehensive function of energy consumption of the machining unit is built to address this problem. Surrogate models are established by using effective fitting methods. An integrated optimization model for reducing tool displacement and energy consumption is developed on the basis of the energy consumption function and surrogate models, and the parameters of the motor and structure are considered simultaneously. Results show that the energy consumption and tool displacement of the machining unit are reduced, indicating that energy saving is achieved and the machining accuracy is guaranteed. The influence of optimization variables on the objectives is analyzed to inform the design.

关键词: energy saving design     energy consumption     machining unit     integrated optimization     machine tool    

Association between ICU quality and in-hospital mortality of V-V ECMO-supported patients—the ECMO quality improvement action (EQIA) study: a national cohort study in China from 2017 to 2019

《医学前沿(英文)》 doi: 10.1007/s11684-023-1014-x

摘要: This cohort study was performed to explore the influence of intensive care unit (ICU) quality on in-hospital mortality of veno-venous (V-V) extracorporeal membrane oxygenation (ECMO)-supported patients in China. The study involved all V-V ECMO-supported patients in 318 of 1700 tertiary hospitals from 2017 to 2019, using data from the National Clinical Improvement System and China National Critical Care Quality Control Center. ICU quality was assessed by quality control indicators and capacity parameters. Among the 2563 V-V ECMO-supported patients in 318 hospitals, a significant correlation was found between ECMO-related complications and prognosis. The reintubation rate within 48 hours after extubation and the total ICU mortality rate were independent risk factors for higher in-hospital mortality of V-V ECMO-supported patients (cutoff: 1.5% and 7.0%; 95% confidence interval: 1.05–1.48 and 1.04–1.45; odds ratios: 1.25 and 1.23; P = 0.012 and P = 0.015, respectively). Meanwhile, the V-V ECMO center volume was a protective factor (cutoff of ≥ 50 cases within the 3-year study period; 95% confidence interval: 0.57–0.83, odds ratio: 0.69, P = 0.0001). The subgroup analysis of 864 patients in 11 high-volume centers further strengthened these findings. Thus, ICU quality may play an important role in improving the prognosis of V-V ECMO-supported patients.

关键词: veno-venous extracorporeal membrane oxygenation     in-hospital mortality     high-volume centers     quality control     intensive care unit capacity parameters    

Low crosstalk switch unit for dense piezoelectric sensor networks

Lei QIU, Shenfang YUAN,

《机械工程前沿(英文)》 2009年 第4卷 第4期   页码 401-406 doi: 10.1007/s11465-009-0047-4

摘要: Structural health monitoring (SHM), on the basis of piezoelectric (PZT) sensors and lamb wave method, is efficient in estimating the state of monitored structures. Furthermore, to monitor large-scale structures, dense piezoelectric sensor networks are required, which usually contain many piezoelectric sensor pairs called actuator-sensor channels. In that case, considering the few data acquisition channels especially in the data acquisition board with a high sampling rate and limited quantity of signal amplifiers used in an integrated computer system, a switch unit is adopted to switch to different channels. Because of the high frequency and power of the lamb wave excitation signal, there exists a crosstalk signal in the switch unit. A large crosstalk signal is mixed into the response signal so that the on/off-line signal processing task is difficult to achieve. This paper first analyzes the crosstalk signal phenomenon, describes its production mechanism, and proposes a method to reduce it. Then a 24-switch channel low crosstalk switch unit based on a digital I/O board PCI7248 produced by Adlink technology is developed. An experiment is implemented to validate it. Its low crosstalk characteristics make it promote the real application of the SHM based active lamb wave method. Finally, a general software program based on LabVIEW software platform is developed to control this switch unit.

关键词: structural health monitoring (SHM)     piezoelectric (PZT) sensor networks     switch unit     crosstalk signal    

Ensemble unit and AI techniques for prediction of rock strain

Pradeep T; Pijush SAMUI; Navid KARDANI; Panagiotis G ASTERIS

《结构与土木工程前沿(英文)》 2022年 第16卷 第7期   页码 858-870 doi: 10.1007/s11709-022-0831-3

摘要: The behavior of rock masses is influenced by a variety of forces, with measurement of stress and strain playing the most critical roles in assessing deformation. The laboratory test for determining strain at each location within rock samples is expensive and difficult but rock strain data are important for predicting failure of rock material. Many researchers employ AI technology in order to solve these difficulties. AI algorithms such as gradient boosting machine (GBM), support vector regression (SVR), random forest (RF), and group method of data handling (GMDH) are used to efficiently estimate the strain at every point within a rock sample. Additionally, the ensemble unit (EnU) may be utilized to evaluate rock strain. In this study, 3000 experimental data are used for the purpose of prediction. The obtained strain values are then evaluated using various statistical parameters and compared to each other using EnU. Ranking analysis, stress-strain curve, Young’s modulus, Poisson’s ratio, actual vs. predicted curve, error matrix and the Akaike’s information criterion (AIC) values are used for comparing models. The GBM model achieved 98.16% and 99.98% prediction accuracy (in terms of values of R2) in the longitudinal and lateral dimensions, respectively, during the testing phase. The GBM model, based on the experimental data, has the potential to be a new option for engineers to use when assessing rock strain.

关键词: prediction     strain     ensemble unit     rank analysis     error matrix    

Performance design of a cryogenic air separation unit for variable working conditions using the lumped

Jinghua XU, Tiantian WANG, Qianyong CHEN, Shuyou ZHANG, Jianrong TAN

《机械工程前沿(英文)》 2020年 第15卷 第1期   页码 24-42 doi: 10.1007/s11465-019-0558-6

摘要: Large-scale cryogenic air separation units (ASUs), which are widely used in global petrochemical and semiconductor industries, are being developed with high operating elasticity under variable working conditions. Different from discrete processes in traditional machinery manufacturing, the ASU process is continuous and involves the compression, adsorption, cooling, condensation, liquefaction, evaporation, and distillation of multiple streams. This feature indicates that thousands of technical parameters in adsorption, heat transfer, and distillation processes are correlated and merged into a large-scale complex system. A lumped parameter model (LPM) of ASU is proposed by lumping the main factors together and simplifying the secondary ones to achieve accurate and fast performance design. On the basis of material and energy conservation laws, the piecewise-lumped parameters are extracted under variable working conditions by using LPM. Takagi–Sugeno (T–S) fuzzy interval detection is recursively utilized to determine whether the critical point is detected or not by using different thresholds. Compared with the traditional method, LPM is particularly suitable for “rough first then precise” modeling by expanding the feasible domain using fuzzy intervals. With LPM, the performance of the air compressor, molecular sieve adsorber, turbo expander, main plate-fin heat exchangers, and packing column of a 100000 Nm O /h large-scale ASU is enhanced to adapt to variable working conditions. The designed value of net power consumption per unit of oxygen production (kW/(Nm O )) is reduced by 6.45%.

关键词: performance design     air separation unit (ASU)     lumped parameter model (LPM)     variable working conditions     T–S fuzzy interval detection    

标题 作者 时间 类型 操作

Enhanced photoelectrochemical water splitting with a donor-acceptor polyimide

期刊论文

Energy conservation in China’s coal-fired power industry by installing advanced units and organized phasing out backward production

Weiliang WANG, Junfu LYU, Zheng LI, Hai ZHANG, Guangxi YUE, Weidou NI

期刊论文

Calculation of diagonal section and cross-section bending capacity for strengthening RC structure using

Shouping SHANG , Fangyuan ZHOU , Wei LIU ,

期刊论文

三峡工程巨型水轮发电机组设计与实践

邵建雄,刘景旺,袁达夫

期刊论文

Structure improvement and strength finite element analysis of VHP welded rotor of 700°C USC steam turbine

Jinyuan SHI,Zhicheng DENG,Yong WANG,Yu YANG

期刊论文

A solution to stochastic unit commitment problem for a wind-thermal system coordination

B. SARAVANAN,Shreya MISHRA,Debrupa NAG

期刊论文

Solving unit commitment problem using a novel version of harmony search algorithm

Roozbeh MORSALI,Tohid JAFARI,Amirhossein GHODS,Mohammad KARIMI

期刊论文

A solution to the unit commitment problem—a review

B. SARAVANAN, Siddharth DAS, Surbhi SIKRI, D. P. KOTHARI

期刊论文

Industrial Structure Adjustment of Shaanxi Province under the Limited Water Resources Condition

Xiao-jun Liu,Zhen-yu Guo,Chao Ding,Han-liang Fu

期刊论文

我国草原生产力

侯扶江,王春梅,娄珊宁,侯向阳,呼天明

期刊论文

Energy saving design of the machining unit of hobbing machine tool with integrated optimization

期刊论文

Association between ICU quality and in-hospital mortality of V-V ECMO-supported patients—the ECMO quality improvement action (EQIA) study: a national cohort study in China from 2017 to 2019

期刊论文

Low crosstalk switch unit for dense piezoelectric sensor networks

Lei QIU, Shenfang YUAN,

期刊论文

Ensemble unit and AI techniques for prediction of rock strain

Pradeep T; Pijush SAMUI; Navid KARDANI; Panagiotis G ASTERIS

期刊论文

Performance design of a cryogenic air separation unit for variable working conditions using the lumped

Jinghua XU, Tiantian WANG, Qianyong CHEN, Shuyou ZHANG, Jianrong TAN

期刊论文