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期刊论文 33

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Ribbed strip rolling by three-dimensional finite element method combining extremely thin array of elements

Zhengyi JIANG,

《机械工程前沿（英文）》 2010年 第5卷 第1期   页码 52-60 doi: 10.1007/s11465-009-0087-9

摘要： In this paper, a three-dimensional finite element modelling of the ribbed strip rolling is carried out, coupling the use of an extremely thin array of elements that is equivalent to the calculation of the additional shear deformation work rate occurred by the velocity discontinuity in the roll bite. The formulation of the finite element modelling by adding a rib inclined contact surface boundary condition is derived, and the performance of the proposed method is conducted. The simulated rib height, forward slip, and the pulling down of rib height have been compared with the measured values and are in good agreement. The equivalent strain rate of the rib was obtained in the simulation. The effect of the rib inclined angle on pulling down of rib height has also been discussed, which is helpful in optimizing the design of the rib inclined angle.

关键词： rib inclined contact boundary condition     ribbed strip     extremely thin elements     pulling down of rib height     finite element modelling    

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Yield-height correlation and QTL localization for plant height in two lowland switchgrass populations

Shiva O. MAKAJU, Yanqi WU, Michael P. ANDERSON, Vijaya G. KAKANI, Michael W. SMITH, Linglong LIU, Hongxu DONG, Dan CHANG

《农业科学与工程前沿（英文）》 2018年 第5卷 第1期   页码 118-128 doi: 10.15302/J-FASE-2018201

摘要： Switchgrass ( L.), as a model herbaceous crop species for bioenergy production, is targeted to improve biomass yield and feedstock quality. Plant height is a major component contributing to biomass yield. Accordingly, the objectives of this research were to analyze phenotypic variation for biomass and plant height and the association between them and to localize associated plant height QTLs. Two lowland switchgrass mapping populations, one selfed and another hybrid population established in the field at Perkins and Stillwater, Oklahoma, were deployed in the experiment for two years post establishment. Large genetic variation existed for plant biomass and height within the two populations. Plant height was positively correlated with biomass yield in the selfed population ( = 0.39, <0.0001) and the hybrid population ( = 0.41, <0.0001). In the selfed population, a joint analysis across all environments revealed 10 QTLs and separate analysis for each environment, collectively revealed 39 QTLs related to plant height. In the hybrid population, the joint analysis across overall environments revealed 35 QTLs and the separate analysis for each environment revealed 38 QTLs. The findings of this research contribute new information about the genetic control for plant height and will be useful for future plant breeding and genetic improvement programs in lowland switchgrass.

关键词： yield-height     QTL localization     lowland switchgrass    

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Comparison of shallow tunneling method with pile and rib method for construction of subway station in

Sina AMIRI; Ali Naghi DEHGHAN

《结构与土木工程前沿（英文）》 2022年 第16卷 第6期   页码 704-717 doi: 10.1007/s11709-021-0746-4

摘要： In the present study, a comparison between the new shallow tunneling method (STM) and the traditional pile and rib method (PRM) was conducted to excavate and construct subway stations in the geological conditions of Tehran. First, by selecting Station Z6 located in the Tehran Subway Line 6 as a case study, the construction process was analyzed by PRM. The maximum ground settlement of 29.84 mm obtained from this method was related to the station axis, and it was within the allowable settlement limit of 30 mm. The acceptable agreement between the results of numerical modeling and instrumentation data indicated the confirmation and accuracy of the excavation and construction process of Station Z6 by PRM. In the next stage, based on the numerical model validated by instrumentation data, the value of the ground surface settlement was investigated during the station excavation and construction by STM. The results obtained from STM showed a significant reduction in the ground surface settlement compared to PRM. The maximum settlement obtained from STM was 6.09 mm as related to the front of the excavation face. Also, the sensitivity analysis results denoted that in addition to controlling the surface settlement by STM, it is possible to optimize some critical geometric parameters of the support system during the station excavation and construction.

关键词： shallow tunneling method     pile and rib method     ground surface settlement     subway station construction     numerical modeling    

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Parametric equations for notch stress concentration factors of rib–deck welds under bending loading

《结构与土木工程前沿（英文）》 2021年 第15卷 第3期   页码 595-608 doi: 10.1007/s11709-021-0720-1

摘要： The effective notch stress approach for evaluating the fatigue strength of rib–deck welds requires notch stress concentration factors obtained from complex finite element analysis. To improve the efficiency of the approach, the notch stress concentration factors for three typical fatigue-cracking modes (i.e., root–toe, root–deck, and toe–deck cracking modes) were thoroughly investigated in this study. First, we developed a model for investigating the effective notch stress in rib–deck welds. Then, we performed a parametric analysis to investigate the effects of multiple geometric parameters of a rib–deck weld on the notch stress concentration factors. On this basis, the multiple linear stepwise regression analysis was performed to obtain the optimal regression functions for predicting the notch stress concentration factors. Finally, we employed the proposed formulas in a case study. The notch stress concentration factors estimated from the developed formulas show agree well with the finite element analysis results. The results of the case study demonstrate the feasibility and reliability of the proposed formulas. It also shows that the fatigue design curve of FAT225 seems to be conservative for evaluating the fatigue strength of rib–deck welds.

关键词： notch stress concentration factor     rib–deck weld     parametric analysis     regression analysis     parametric equation    

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Analysis of catchment evapotranspiration at different scales using bottom-up and top-down approaches

Xiangyu XU, Dawen YANG,

《结构与土木工程前沿（英文）》 2010年 第4卷 第1期   页码 65-77 doi: 10.1007/s11709-010-0002-9

摘要： Physically-based hydrological models are used to predict catchment water balance through detailed simulation of hydrological processes at small temporal and spatial scales. However, annual catchment water balance can also be easily and simply predicted using lumped conceptual model. Comparison between physically-based hydrological models and lumped conceptual models can help us understand the dominant factors on catchment water balance at different scales. In this paper, a distributed physically-based hydrological model (i.e., bottom-up approach) and a simple water-energy balance model (i.e., top-down approach) are used to predict actual evapotranspiration in nine sub-catchments, and the whole basin of the Luan River in northern China. Both simulations give very close values of annual evapotranspiration and show the same complementary relationship between actual and potential evapotranspiration at annual time scale. From the analysis at different time scales through comparison of the top-down and the bottom-up methods, it is shown that the annual catchment evapotranspiration is controlled mainly by annual precipitation and potential evapotranspiration, and the variability of soil water and vegetation becomes more important at a smaller time scale in the study areas. It is also known that the relationship between potential and actual evapotranspiration shows a highly nonlinear relationship at the annual and catchment scale but can be simplified to a linear relationship at hourly temporal and hillslope scales, which is commonly used in the physically-based hydrological models.

关键词： catchment evapotranspiration     distributed hydrological model     water-energy balance model     top-down and bottom-up approaches    

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Comparison of membrane fouling in ultrafiltration of down-flow and up-flow biological activated carbon

Lu Ao, Wenjun Liu, Yang Qiao, Cuiping Li, Xiaomao Wang

《环境科学与工程前沿（英文）》 2018年 第12卷 第6期 doi: 10.1007/s11783-018-1046-7

摘要：

The UF membrane fouling by down- and up-flow BAC effluents were compared.

Up-flow BAC effluent fouled the membrane faster than down-flow BAC effluent.

The combined effects dominated irreversible fouling.

The extent of fouling exacerbated by inorganic particles was higher.

关键词： Ultrafiltration     Membrane fouling     Down-flow biological activated carbon     Up-flow biological activated carbon     Particles     Polysaccharide    

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Predicting the capacity of perfobond rib shear connector using an ANN model and GSA method

Guorui SUN; Jun SHI; Yuang DENG

《结构与土木工程前沿（英文）》 2022年 第16卷 第10期   页码 1233-1248 doi: 10.1007/s11709-022-0878-1

摘要： Due to recent advances in the field of artificial neural networks (ANN) and the global sensitivity analysis (GSA) method, the application of these techniques in structural analysis has become feasible. A connector is an important part of a composite beam, and its shear strength can have a significant impact on structural design. In this paper, the shear performance of perfobond rib shear connectors (PRSCs) is predicted based on the back propagation (BP) ANN model, the Genetic Algorithm (GA) method and GSA method. A database was created using push-out test test and related references, where the input variables were based on different empirical formulas and the output variables were the corresponding shear strengths. The results predicted by the ANN models and empirical equations were compared, and the factors affecting shear strength were examined by the GSA method. The results show that the use of ANN model optimization by GA method has fewer errors compared to the empirical equations. Furthermore, penetrating reinforcement has the greatest sensitivity to shear performance, while the bonding force between steel plate and concrete has the least sensitivity to shear strength.

关键词： perfobond rib shear connector     shear strength     ANN model     global sensitivity analysis    

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Influence of nozzle height to width ratio on ignition and NO

Liutao SUN, Yonghong YAN, Rui SUN, Zhengkang PENG, Chunli XING, Jiangquan WU

《能源前沿（英文）》 2021年 第15卷 第2期   页码 431-448 doi: 10.1007/s11708-021-0726-3

摘要： To improve the ignition behavior and to reduce the high NO emissions of blended pulverized fuels (PF) of semicoke (SC), large-scale experiments were conducted in a 300 kW fired furnace at various nozzle settings, i.e., ratios (denoted by / ) of the height of the rectangular burner nozzle to its width of 1.65, 2.32, and 3.22. The combustion tests indicate that the flame stability, ignition performance, and fuel burnout ratio were significantly improved at a nozzle setting of / = 2.32. The smaller / delayed ignition and caused the flame to concentrate excessively on the axis of the furnace, while the larger / easily caused the deflection of the pulverized coal flame, and a high-temperature flame zone emerged close to the furnace wall. NO emissions at the outlet of the primary zone decreased from 447 to 354 mg/m (O = 6%), and the ignition distance decreased from 420 to 246 mm when the / varied from 1.65 to 3.22. Furthermore, the ratio (denoted by / ) of the strong reduction zone area to the combustion reaction zone area was defined experimentally by the CO concentration to evaluate the reduction zone. The / rose monotonously, but its restraining effects on NO formation decreased as / increased. The results suggested that in a test furnace, regulating the nozzle / conditions sharply reduces NO emissions and improves the combustion efficiency of SC blends possessing an appropriate jet rigidity.

关键词： rectangular jet burner     nozzle height to width ratio     ignition characteristics     pyrolyzed semicoke (SC) and bituminous blend     NOx formation    

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下降敲入续租期权定价研究

吴云,何建敏

《中国工程科学》 2004年 第6卷 第12期   页码 47-50

摘要：

阐述了现代租赁的基本内涵和实物期权的基本原理，提出了下降敲入续租期权定价模型及其定价求解，最后给出了算例分析。

关键词： 租赁     续租     租赁期权     实物期权     下降敲入期权    

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基因组测序成本将再次降低

Robert Pollie

《工程（英文）》 2023年 第23卷 第4期   页码 3-6 doi: 10.1016/j.eng.2023.02.002

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基于敲出障碍期权和博弈理论的项目投资决策分析

吴云,何建敏

《中国工程科学》 2005年 第7卷 第9期   页码 44-48

摘要：

阐述了实物期权的基本原理和敲出障碍期权的内涵及其定价求解，提出了基于敲出障碍期权的实物期权定价方法和博弈理论的项目投资决策分析，分析了双寡头市场结构下的项目投资决策，给出了算例分析。

关键词： 敲出障碍期权     实物期权     博弈理论     投资决策    

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Robust optimization of the billet for isothermal local loading transitional region of a Ti-alloy rib-web

Ke WEI, Xiaoguang FAN, Mei ZHAN, Miao MENG

《机械工程前沿（英文）》 2018年 第13卷 第3期   页码 376-384 doi: 10.1007/s11465-018-0500-3

摘要：

Billet optimization can greatly improve the forming quality of the transitional region in the isothermal local loading forming (ILLF) of large-scale Ti-alloy rib-web components. However, the final quality of the transitional region may be deteriorated by uncontrollable factors, such as the manufacturing tolerance of the preforming billet, fluctuation of the stroke length, and friction factor. Thus, a dual-response surface method (RSM)-based robust optimization of the billet was proposed to address the uncontrollable factors in transitional region of the ILLF. Given that the die underfilling and folding defect are two key factors that influence the forming quality of the transitional region, minimizing the mean and standard deviation of the die underfilling rate and avoiding folding defect were defined as the objective function and constraint condition in robust optimization. Then, the cross array design was constructed, a dual-RSM model was established for the mean and standard deviation of the die underfilling rate by considering the size parameters of the billet and uncontrollable factors. Subsequently, an optimum solution was derived to achieve the robust optimization of the billet. A case study on robust optimization was conducted. Good results were attained for improving the die filling and avoiding folding defect, suggesting that the robust optimization of the billet in the transitional region of the ILLF was efficient and reliable.

关键词： isothermal local loading forming     rib-web component     transitional region     robust optimization     dual response surface method    

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An investigation into the heat transfer characteristics of spiral wall with internal rib in a supercritical

TANG Renhu, YIN Fei, WANG Haijun, CHEN Tingkuan

《能源前沿（英文）》 2007年 第1卷 第3期   页码 300-304 doi: 10.1007/s11708-007-0043-5

摘要： Within the pressure range of 9–28 MPa, mass velocity range of 600–1 200 kg/(m · s), and heat flux range of 200–500 kW/m, experiments were performed to investigate the heat transfer to water in the inclined upward internally ribbed tube with an inclined angle of 19.5 degrees, a maximum outer diameter of 38.1 mm, and a thickness of 7.5 mm. Based on the experiments, it was found that heat transfer enhancement of the internally ribbed tube could postpone departure from nucleate boiling at the sub-critical pressure. However, the heat transfer enhancement decreased near the critical pressure. At supercritical pressure, the temperature difference between the wall and the fluid increased near the pseudo-critical temperature, but the increase of wall temperature was less than that of departure from nucleate boiling at sub-critical pressure. When pressure is closer to the critical pressure, the temperature difference between the wall and the fluid increased greatly near the pseudo-critical temperature. Heat transfer to supercritical water in the inclined upward internally ribbed tube was enhanced or deteriorated near the pseudo-critical temperature with the variety of ratio between the mass velocity and the heat flux. Because the rotational flow of the internal groove reduced the effect of natural convection, the internal wall temperature of internally ribbed tube uniformly distributed along the circumference. The maximum internal wall temperature difference of the tube along the circumference was only 10 degrees when the fluid enthalpy exceeded 2 000 J/g. Considering the effect of acute variety of the fluid property on heat transfer, the correlation of heat transfer coefficient on the top of the internally ribbed tube was provided.

关键词： m ·     diameter     critical pressure     sub-critical pressure     maximum    

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Erratum to: Folded down-conversion mixer for a 60 GHz receiver architecture in 65-nm CMOS technology

Najam Muhammad AMIN,Zhi-gong WANG,Zhi-qun LI

《信息与电子工程前沿（英文）》 2015年 第16卷 第5期 doi: 10.1631/FITEE.14e0087

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tertiary-air declination angle on combustion and steam temperature characteristics in a 350-MW supercritical down-fired

Xiaoguang LI, Lingyan ZENG, Hongye LIU, Yao LI, Yifu LI, Yunlong ZHAO, Bo JIAO, Minhang SONG, Shaofeng ZHANG, Zhichao CHEN, Zhengqi LI

《能源前沿（英文）》 2021年 第15卷 第1期   页码 132-142 doi: 10.1007/s11708-020-0803-z

摘要： Industrial-scale experiments were conducted to study the effects of tertiary air declination angle (TDA) on the coal combustion and steam temperature characteristics in the first 350-MW supercritical down-fired boiler in China with the multiple-injection and multiple-staging combustion (MIMSC) technology at medium and high loads. The experimental results indicated that as the TDA increased from 0° to 15°, the overall gas temperature in the lower furnace rose and the symmetry of temperature field was enhanced. The ignition distance of the fuel-rich coal/air flow decreased. In near-burner region, the concentration of O decreased while the concentrations of CO and NO increased. The concentration of NO decreased in near-tertiary-air region. The carbon in fly ash decreased significantly from 8.40% to 6.45% at a load of 260 MW. At a TDA of 15°, the ignition distances were the shortest (2.07 m and 1.73 m) at a load of 210 MW and 260 MW, respectively. The main and reheat steam temperatures were the highest (557.2°C and 559.4°C at a load of 210 MW, 558.4°C and 560.3°C at a load of 260 MW). The carbon in fly ash was the lowest (4.83%) at a load of 210 MW. On changing the TDA from 15° to 25°, the flame kernel was found to move downward and the main and reheat steam temperatures dropped obviously. The change of TDA has little effect on NO emissions(660–681 mg/m at 6% O ). In comprehensive consideration of the pulverized coal combustion characteristics and the unit economic performance, an optimal TDA of 15° is recommended.

关键词： supercritical down-fired boiler     industrial-scale experiment     tertiary air declination angle     coal combustion     steam temperature    

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标题 作者 时间 类型 操作

Ribbed strip rolling by three-dimensional finite element method combining extremely thin array of elements

Zhengyi JIANG,

期刊论文

Yield-height correlation and QTL localization for plant height in two lowland switchgrass populations

Shiva O. MAKAJU, Yanqi WU, Michael P. ANDERSON, Vijaya G. KAKANI, Michael W. SMITH, Linglong LIU, Hongxu DONG, Dan CHANG

期刊论文

Comparison of shallow tunneling method with pile and rib method for construction of subway station in

Sina AMIRI; Ali Naghi DEHGHAN

期刊论文

Parametric equations for notch stress concentration factors of rib–deck welds under bending loading

期刊论文

Analysis of catchment evapotranspiration at different scales using bottom-up and top-down approaches

Xiangyu XU, Dawen YANG,

期刊论文

Comparison of membrane fouling in ultrafiltration of down-flow and up-flow biological activated carbon

Lu Ao, Wenjun Liu, Yang Qiao, Cuiping Li, Xiaomao Wang

期刊论文

Predicting the capacity of perfobond rib shear connector using an ANN model and GSA method

Guorui SUN; Jun SHI; Yuang DENG

期刊论文

Influence of nozzle height to width ratio on ignition and NO

Liutao SUN, Yonghong YAN, Rui SUN, Zhengkang PENG, Chunli XING, Jiangquan WU

期刊论文

下降敲入续租期权定价研究

吴云,何建敏

期刊论文

基因组测序成本将再次降低

Robert Pollie

期刊论文

基于敲出障碍期权和博弈理论的项目投资决策分析

吴云,何建敏

期刊论文

Robust optimization of the billet for isothermal local loading transitional region of a Ti-alloy rib-web

Ke WEI, Xiaoguang FAN, Mei ZHAN, Miao MENG

期刊论文

An investigation into the heat transfer characteristics of spiral wall with internal rib in a supercritical

TANG Renhu, YIN Fei, WANG Haijun, CHEN Tingkuan

期刊论文

Erratum to: Folded down-conversion mixer for a 60 GHz receiver architecture in 65-nm CMOS technology

Najam Muhammad AMIN,Zhi-gong WANG,Zhi-qun LI

期刊论文

tertiary-air declination angle on combustion and steam temperature characteristics in a 350-MW supercritical down-fired

Xiaoguang LI, Lingyan ZENG, Hongye LIU, Yao LI, Yifu LI, Yunlong ZHAO, Bo JIAO, Minhang SONG, Shaofeng ZHANG, Zhichao CHEN, Zhengqi LI

期刊论文