资源类型

期刊论文 114

年份

2023 5

2022 8

2021 9

2020 6

2019 5

2018 8

2017 11

2016 6

2015 9

2014 5

2013 9

2012 4

2011 4

2010 5

2009 4

2008 4

2007 3

2005 1

2004 1

2003 1

展开 ︾

关键词

可持续发展 2

多联产 2

热电联产 2

热电联供 2

20 kt级重载组合列车 1

2型糖尿病 1

BDS/GPS双系统定轨 1

BDS码偏差 1

CO2 捕集 1

Nd-YAG 1

RE-Si3N4 1

SOFC 1

SOFC电池堆 1

一、二维数值仿真 1

三索面空间结构 1

中国铁路 1

伪码 1

低轨卫星精密定轨 1

信干比增益 1

展开 ︾

检索范围：

排序： 展示方式：

Negative weights in network time model

Zoltán A. VATTAI, Levente MÁLYUSZ

《工程管理前沿（英文）》 2022年 第9卷 第2期   页码 268-280 doi: 10.1007/s42524-020-0109-1

摘要： Time does not go backward. A negative duration, such as “time period” at first sight is difficult to interpret. Previous network techniques (CPM/PERT/PDM) did not support negative parameters and/or loops (potentially necessitating recursive calculations) in the model because of the limited computing and data storage capabilities of early computers. Monsieur Roy and John Fondahl implicitly introduced negative weights into network techniques to represent activities with fixed or estimated durations (MPM/PDM). Subsequently, the introduction of negative lead and/or lag times by software developers (IBM) apparently overcome the limitation of not allowing negative time parameters in time model. Referring to general digraph (Event on Node) representation where activities are represented by pairs of nodes and pairwise relative time restrictions are represented by weighted arrows, we can release most restraints in constructing the graph structure (incorporating the dynamic model of the inner logic of time plan), and a surprisingly flexible and handy network model can be developed that provides all the advantages of the abovementioned techniques. This paper aims to review the theoretical possibilities and technical interpretations (and use) of negative weights in network time models and discuss approximately 20 types of time-based restrictions among the activities of construction projects. We focus on pure relative time models, without considering other restrictions (such as calendar data, time-cost trade-off, resource allocation or other constraints).

关键词： graph technique     network technique     construction management     scheduling    

HTML PDF 收藏

Improved approach to quality function deployment based on Pythagorean fuzzy sets and application to assembly robot design evaluation

Huchang LIAO, Yinghan CHANG, Di WU, Xunjie GOU

《工程管理前沿（英文）》 2020年 第7卷 第2期   页码 196-203 doi: 10.1007/s42524-019-0038-z

摘要： Quality function deployment (QFD) is an effective method that helps companies analyze customer requirements (CRs). These CRs are then turned into product or service characteristics, which are translated to other attributes. With the QFD method, companies could design or improve the quality of products or services close to CRs. To increase the effectiveness of QFD, we propose an improved method based on Pythagorean fuzzy sets (PFSs). We apply an extended method to obtain the group consensus evaluation matrix. We then use a combined weight determining method to integrate former weights to objective weights derived from the evaluation matrix. To determine the exact score of each PFS in the evaluation matrix, we develop an improved score function. Lastly, we apply the proposed method to a case study on assembly robot design evaluation.

关键词： quality function deployment     Pythagorean fuzzy sets     group consensus     combined weights     assembly robot design    

HTML PDF 收藏

Balancing method without trial weights for rotor systems based on similitude scale model

Ruiduo YE, Liping WANG, Xiaojie HOU, Zhong LUO, Qingkai HAN

《机械工程前沿（英文）》 2018年 第13卷 第4期   页码 571-580 doi: 10.1007/s11465-018-0478-x

摘要：

A balancing method without trial weights based on the dynamic similitude scale model was proposed as a solution to the balancing problem of a large-scale rotor system. This method could be used to directly obtain the required coefficients for the balancing problem of the prototype system through a similarity model test without a prototype test. Thus, the weight test process of the prototype system was effectively eliminated in the proposed balancing method. First, with the rotor system as the research object, the analytical expression of the influence coefficient was derived on the basis of rotor dynamics theory. Then, through calculation and dimensional analysis methods, the similitude relationships of the rotor system and the influence coefficient were deduced on the basis of dynamic similitude theory. The correctness of the proposed similitude relationships was verified through numerical simulation and experiment. The balancing method without trial weights was proposed based on the similitude relationship of the influence coefficient. The effect of the balancing method without trial weights was compared with that of the traditional influence coefficient method through numerical simulation, and the results verified the correctness and effectiveness of the proposed balancing method. The results of this study provide theoretical supplements for the balancing method and the similitude design of the rotor system.

关键词： rotor system     dynamic similitude     balancing     without trial weights     influence coefficient    

HTML PDF 收藏

重力储能有望扩大规模

Sean O'Neill

《工程（英文）》 2022年 第14卷 第7期   页码 3-6 doi: 10.1016/j.eng.2022.05.007

HTML PDF 收藏

Development of combined transitional pavement structure for urban tram track-road grade crossings

《结构与土木工程前沿（英文）》   页码 1199-1210 doi: 10.1007/s11709-023-0949-y

摘要： The grade crossings and adjacent pavements of urban trams are generally subjected to complex load conditions and are susceptible to damage. Therefore, in this study, a novel pavement structure between tram tracks and roads constructed using polyurethane (PU) elastic concrete and ultra-high-performance concrete (UHPC), referred to as a track-road transitional pavement (TRTP), is proposed. Subsequently, its performance and feasibility are evaluated using experimental and numerical methods. First, the mechanical properties of the PU elastic concrete are evaluated. The performance of the proposed structure is investigated using a three-dimensional finite element model, where vehicle-induced dynamic and static loads are considered. The results show that PU elastic concrete and the proposed combined TRTP are applicable and functioned as intended. Additionally, the PU elastic concrete achieved sufficient performance. The recommended width of the TRTP is approximately 50 mm. Meanwhile, the application of UHPC under a PU elastic concrete layer significantly reduces vertical deformation. Results of numerical calculations confirmed the high structural performance and feasibility of the proposed TRTP. Finally, material performance standards are recommended to provide guidance for pavement design and the construction of tram-grade crossings in the future.

关键词： urban tram track     grade crossing     combined track-road transitional pavement     polyurethane elastic concrete     finite element method    

HTML PDF 收藏

emissions: a comparative study of the feasibility of the hybrid renewable energy systems incorporating combined

《能源前沿（英文）》 2022年 第16卷 第2期   页码 336-356 doi: 10.1007/s11708-021-0748-x

摘要： Fuel poverty is most prevalent in North East England with 14.4% of fuel poor households in Newcastle upon Tyne. The aim of this paper was to identify a grid connected renewable energy system coupled with natural gas reciprocating combined heat and power unit, that is cost-effective and technically feasible with a potential to generate a profit from selling energy excess to the grid to help alleviate fuel poverty. The system was also aimed at low carbon emissions. Fourteen models were designed and optimized with the aid of the HOMER Pro software. Models were compared with respect to their economic, technical, and environmental performance. A solution was proposed where restrictions were placed on the size of renewable energy components. This configuration consists of 150 kW CHP, 300 kW PV cells, and 30 kW wind turbines. The renewable fraction is 5.10% and the system yields a carbon saving of 7.9% in comparison with conventional systems. The initial capital investment is $1.24 million which enables the system to have grid sales of 582689 kWh/a. A conservative calculation determined that 40% of the sales can be used to reduce the energy cost of fuel poor households by $706 per annum. This solution has the potential to eliminate fuel poverty at the site analyzed.

关键词： greenhouse gas control     low carbon target     grid connected     renewable fraction     fuel poverty     combined heat and power     HOMER Pro    

HTML PDF 收藏

Interaction and combined toxicity of microplastics and per- and polyfluoroalkyl substances in aquatic

《环境科学与工程前沿（英文）》 2022年 第16卷 第10期 doi: 10.1007/s11783-022-1571-2

摘要：

● Adsorption of PFASs on MPs and its mechanisms are critically reviewed.

关键词： Microplastics     Per- and Polyfluoroalkyl substances     Adsorption     Transport     Transformation    

HTML PDF 收藏

Experimental study on combined buoyant-thermocapillary flow along with rising liquid film on the surface

Manuel J. GOMES, Ning MEI

《能源前沿（英文）》 2020年 第14卷 第1期   页码 114-126 doi: 10.1007/s11708-017-0483-5

摘要： Temperature distribution and variation with time has been considered in the analysis of the influences of the initial level of immersion of a horizontal metallic mesh tube in the liquid on combined buoyant and thermo-capillary flow. The combined flow occurs along with the rising liquid film flow on the surface of a horizontal metallic mesh tube. Three different levels of immersion of the metallic mesh tube in the liquid have been tested. Experiments of 60 min in duration have been performed using a heating metallic tube with a diameter of 25 mm and a length of 110 mm, sealed outside with a metallic mesh of 178 mm by 178 mm, and distilled water. These reveal two distinct flow patterns. Thermocouples and infrared thermal imager are utilized to measure the temperature. The level of the liquid free surface relative to the lower edge of the tube is measured as angle . The results show that for a smaller angle, or a low level of immersion, with a relatively low heating power, it is possible to near fully combine the upwards buoyant flow with the rising liquid film flow. In this case, the liquid is heated only in the vicinity of the tube, while the liquid away from the flow region experiences small changes in temperature and the system approaches steady conditions. For larger angles, or higher levels of immersion, a different flow pattern is noticed on the liquid free surface and identified as the thermo-capillary (Marangoni) flow. The rising liquid film is also present. The higher levels of immersion cause a high temperature gradient in the liquid free surface region and promote thermal stratification; therefore the system could not approach steady conditions.

关键词： rising liquid film     combined flow     thermo-capillary flow     buoyant flow     metallic mesh tube     horizontal tube    

HTML PDF 收藏

Simulation and experiments on a solid sorption combined cooling and power system driven by the exhaust

Peng GAO, Liwei WANG, Ruzhu WANG, Yang YU

《能源前沿（英文）》 2017年 第11卷 第4期   页码 516-526 doi: 10.1007/s11708-017-0511-5

摘要： A solid sorption combined cooling and power system driven by exhaust waste heat is proposed, which consists of a MnCl sorption bed, a CaCl sorption bed, an evaporator, a condenser, an expansion valve, and a scroll expander, and ammonia is chosen as the working fluid. First, the theoretical model of the system is established, and the partitioning calculation method is proposed for sorption beds. Next, the experimental system is established, and experimental results show that the refrigerating capacity at the refrigerating temperature of –10°C and the resorption time of 30 min is 1.95 kW, and the shaft power is 109.2 W. The system can provide approximately 60% of the power for the evaporator fan and the condenser fan. Finally, the performance of the system is compared with that of the solid sorption refrigeration system. The refrigerating capacity of two systems is almost the same at the same operational condition. Therefore, the power generation process does not influence the refrigeration process. The exergy efficiency of the two systems is 0.076 and 0.047, respectively. The feasibility of the system is determined, which proves that this system is especially suitable for the exhaust waste heat recovery.

关键词： solid sorption     exhaust waste heat     combined cooling and power system     exergy efficiency    

HTML PDF 收藏

Carbon emission impact on the operation of virtual power plant with combined heat and power system

Yu-hang XIA,Jun-yong LIU,Zheng-wen HUANG,Xu ZHANG

《信息与电子工程前沿（英文）》 2016年 第17卷 第5期   页码 479-488 doi: 10.1631/FITEE.1500467

摘要： A virtual power plant (VPP) can realize the aggregation of distributed generation in a certain region, and represent distributed generation to participate in the power market of the main grid. With the expansion of VPPs and ever-growing heat demand of consumers, managing the effect of fluctuations in the amount of available renewable resources on the operation of VPPs and maintaining an economical supply of electric power and heat energy to users have been important issues. This paper proposes the allocation of an electric boiler to realize wind power directly converted for supplying heat, which can not only overcome the limitation of heat output from a combined heat and power (CHP) unit, but also reduce carbon emissions from a VPP. After the electric boiler is considered in the VPP operation model of the combined heat and power system, a multi-objective model is built, which includes the costs of carbon emissions, total operation of the VPP and the electricity traded between the VPP and the main grid. The model is solved by the CPLEX package using the fuzzy membership function in Matlab, and a case study is presented. The power output of each unit in the case study is analyzed under four scenarios. The results show that after carbon emission is taken into account, the output of low carbon units is significantly increased, and the allocation of an electric boiler can facilitate the maximum absorption of renewable energy, which also reduces carbon emissions from the VPP.

关键词： Virtual power plant (VPP)     Carbon emissions     Electric boiler     Wind power     Combined heat and power (CHP)    

HTML PDF 收藏

Effects of combined procedure and devascularization alone on hyperdynamics of the portal venous system

HUA Rong, SUN Yongwei, WU Zhiyong

《医学前沿（英文）》 2008年 第2卷 第3期   页码 244-247 doi: 10.1007/s11684-008-0046-6

摘要： Shunts and devascularizations have totally different effects on the hemodynamics of the portal venous system. The actual results of pericardial devascularization (PCDV) alone and conventional splenorenal shunt combined with pericardial devascularization (combined procedure, CP) should be determined by more clinical observations. This study aimed to evaluate effects on hemodynamics in the portal venous system after CP and PCDV only. In 20 patients who received CP and 18 who received PCDV, hemodynamic parameters of the portal venous system were studied by magnetic resonance angiography 1 week before and 2 weeks after operation. Free portal pressure (FPP) was continuously detected by a transducer during the operations. Compared to the preoperative data, a decreased flow in the portal vein (PVF) [(563.12 ± 206.42) mL/min (1080.63 ± 352.85) mL/min, < 0.05], a decreased portal vein diameter (PVD) [(1.20 ± 0.11) cm (1.30 ± 0.16) cm, < 0.01], a decreased FPP [(21.50 ± 2.67) mmHg (29.88 ± 2.30) mmHg, < 0.01] and an increased flow in the superior mesenteric vein (SMVF) [(1105.45 ± 309.03) mL/min (569.13 ± 178.46) mL/min, < 0.05] were found in the CP group after operation; a decreased PVD [(1.27 ± 0.16) cm (1.40 ± 0.23) cm, < 0.05], a decreased PVF [(684.60 ± 165.73) mL/min (1175.64 ± 415.09) mL/min, < 0.05], a decreased FPP [(24.40 ± 3.78) mmHg (28.80 ± 3.56) mmHg, < 0.05] and an increased SMVF [(697.91 ± 121.83) mL/min (521.30 ± 115.82) mL/min, < 0.05] were observed in the PCDV group. After operation, PVF in the CP group [(563.12 ± 206.42) mL/min (684.60 ± 165.73) mL/min, > 0.05] had no significant decrease, while FPP [(21.50 ± 2.67) mmHg (24.40 ± 3.78) mmHg, < 0.01] had a significant decrease as compared with that in the PCDV group. PVF and FPP could be decreased by both surgical procedures, but the effect of decreasing FPP was much better in the combined procedure than in PCDV alone. Further, there was no significant difference in PVF between the two groups. It is suggested that the combined surgical procedure could integrate the advantages of shunting with those of devascularization, as well as maintaining the normal anatomic structure of hepatic portal system, thus it should be one of the best choices for patients with portal hypertension when surgical interventions are considered.
HTML PDF 收藏

Metabolic interventions combined with CTLA-4 and PD-1/PD-L1 blockade for the treatment of tumors: mechanisms

《医学前沿（英文）》   页码 805-822 doi: 10.1007/s11684-023-1025-7

摘要： Immunotherapies based on immune checkpoint blockade (ICB) have significantly improved patient outcomes and offered new approaches to cancer therapy over the past decade. To date, immune checkpoint inhibitors (ICIs) of CTLA-4 and PD-1/PD-L1 represent the main class of immunotherapy. Blockade of CTLA-4 and PD-1/PD-L1 has shown remarkable efficacy in several specific types of cancers, however, a large subset of refractory patients presents poor responsiveness to ICB therapy; and the underlying mechanism remains elusive. Recently, numerous studies have revealed that metabolic reprogramming of tumor cells restrains immune responses by remodeling the tumor microenvironment (TME) with various products of metabolism, and combination therapies involving metabolic inhibitors and ICIs provide new approaches to cancer therapy. Nevertheless, a systematic summary is lacking regarding the manner by which different targetable metabolic pathways regulate immune checkpoints to overcome ICI resistance. Here, we demonstrate the generalized mechanism of targeting cancer metabolism at three crucial immune checkpoints (CTLA-4, PD-1, and PD-L1) to influence ICB therapy and propose potential combined immunotherapeutic strategies co-targeting tumor metabolic pathways and immune checkpoints.

关键词： CTLA-4     PD-1     PD-L1     immune checkpoint blockade (ICB)     metabolic reprogramming     combined tumor therapeutic strategies    

HTML PDF 收藏

Enhanced formation of trihalomethane disinfection byproducts from halobenzoquinones under combined UV

《环境科学与工程前沿（英文）》 2022年 第16卷 第6期 doi: 10.1007/s11783-021-1510-7

摘要：

• 2,6-DCBQ and TCBQ generated THMs differently in chlorine and UV/chlorine processes.

关键词： Halobenzoquinone     Trihalomethane     Chlorine disinfection     UV irradiation     Disinfection byproducts     Combined UV/chlorine    

HTML PDF 收藏

Quantitative analysis of impact of green stormwater infrastructures on combined sewer overflow control

Jinsong Tao, Zijian Li, Xinlai Peng, Gaoxiang Ying

《环境科学与工程前沿（英文）》 2017年 第11卷 第4期 doi: 10.1007/s11783-017-0952-4

摘要： Stimulated by the recent USEPA’s green stormwater infrastructure (GSI) guidance and policies, GSI systems have been widely implemented in the municipal area to control the combined sewer overflows (CSOs), also known as low impact development (LID) approaches. To quantitatively evaluate the performance of GSI systems on CSO and urban flooding control, USEPA-Stormwater Management Model (SWMM) model was adopted in this study to simulate the behaviors of GSI systems in a well-developed urban drainage area, PSW45, under different circumstances. The impact of different percentages of stormwater runoff transported from impervious surfaces to the GSI systems on CSO and urban flooding control has also been investigated. Results show that with current buildup, GSI systems in PSW45 have the best performance for low intensity and short duration events on both volume and peak flow reductions, and have the worst performance for high intensity and long duration events. Since the low intensity and short duration events are dominant from a long-term perspective, utilizing GSI systems is considered as an effective measure of CSO control to meet the long-term control strategy for PSW45 watershed. However, GSI systems are not suitable for the flooding control purpose in PSW45 due to the high occurrence possibility of urban flooding during or after high intensity events where GSI systems have relatively poor performance no matter for a short or long duration event.

关键词： Green stormwater infrastructure (GSI)     Combined sewer overflows (CSOs)     Urban flooding     Low impact development (LID)     Stormwater Management Model (SWMM)    

HTML PDF 收藏

The combined effects of biomass and temperature on maximum specific ammonia oxidation rate in domestic

《环境科学与工程前沿（英文）》 2021年 第15卷 第6期 doi: 10.1007/s11783-021-1411-9

摘要：

• Actual SAORs was determined using MLVSS and temperature.

关键词： Specific ammonia oxidation rate     Sequencing batch reactor     Biomass     Temperature coefficient     Model simulation    

HTML PDF 收藏

标题 作者 时间 类型 操作

Negative weights in network time model

Zoltán A. VATTAI, Levente MÁLYUSZ

期刊论文

Improved approach to quality function deployment based on Pythagorean fuzzy sets and application to assembly robot design evaluation

Huchang LIAO, Yinghan CHANG, Di WU, Xunjie GOU

期刊论文

Balancing method without trial weights for rotor systems based on similitude scale model

Ruiduo YE, Liping WANG, Xiaojie HOU, Zhong LUO, Qingkai HAN

期刊论文

重力储能有望扩大规模

Sean O'Neill

期刊论文

Development of combined transitional pavement structure for urban tram track-road grade crossings

期刊论文

emissions: a comparative study of the feasibility of the hybrid renewable energy systems incorporating combined

期刊论文

Interaction and combined toxicity of microplastics and per- and polyfluoroalkyl substances in aquatic

期刊论文

Experimental study on combined buoyant-thermocapillary flow along with rising liquid film on the surface

Manuel J. GOMES, Ning MEI

期刊论文

Simulation and experiments on a solid sorption combined cooling and power system driven by the exhaust

Peng GAO, Liwei WANG, Ruzhu WANG, Yang YU

期刊论文

Carbon emission impact on the operation of virtual power plant with combined heat and power system

Yu-hang XIA,Jun-yong LIU,Zheng-wen HUANG,Xu ZHANG

期刊论文

Effects of combined procedure and devascularization alone on hyperdynamics of the portal venous system

HUA Rong, SUN Yongwei, WU Zhiyong

期刊论文

Metabolic interventions combined with CTLA-4 and PD-1/PD-L1 blockade for the treatment of tumors: mechanisms

期刊论文

Enhanced formation of trihalomethane disinfection byproducts from halobenzoquinones under combined UV

期刊论文

Quantitative analysis of impact of green stormwater infrastructures on combined sewer overflow control

Jinsong Tao, Zijian Li, Xinlai Peng, Gaoxiang Ying

期刊论文

The combined effects of biomass and temperature on maximum specific ammonia oxidation rate in domestic

期刊论文