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Interactive effects of high-speed rail on nodal zones in a city: exploratory study on China

Guo LIU, Kunhui YE

《工程管理前沿（英文）》 2019年 第6卷 第3期   页码 327-335 doi: 10.1007/s42524-019-0051-2

摘要： The arrival of the high-speed rail (HSR) era has accelerated the pace of urban development, but its broad socioeconomic impact remains subject to intense debates. This research aims to propose a model for measuring the impact of HSR operation on HSR stations and the surrounding areas, which this research call the HSR-based nodal zone (HNZ). The proposed model is composed of two variables (i.e., transportation situation and vitality) and three subsystems (i.e., economic, societal, and environmental). Data were collected in China through questionnaire survey. Results indicate that the effects of HSR operation on HNZ are multidimensional, transportation vitality has an intermediary role in the effects, and the effects on the physical environment are negative. This study presents an early examination of the impact of HSR operation on the HSR stations and relevant areas and contributes new evidence to academic debates on the contribution of HSR to urban development. Accordingly, urban development policies should be built on the mechanism of HSR in driving the growth of HNZ.

关键词： high-speed rail     nodal zone     interactive effects     sustainable urbanization     China    

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Nodal, zonal, or uniform electricity pricing: how to deal with network congestion

Martin WEIBELZAHL

《能源前沿（英文）》 2017年 第11卷 第2期   页码 210-232 doi: 10.1007/s11708-017-0460-z

摘要： In this paper, the main contributions to congestion management and electricity pricing, i.e., nodal, zonal, and uniform electricity pricing, are surveyed. The key electricity market concepts are structured and a formal model framework is proposed for electricity transportation, production, and consumption in the context of limited transmission networks and competitive, welfare maximizing electricity markets. In addition, the main results of existing short-run and long-run congestion management studies are explicitly summarized. In particular, the important interconnection between short-run network management approaches and optimal long-run investments in both generation facilities and network lines are highlighted.

关键词： nodal pricing     zonal pricing     uniform pricing     competitive electricity markets     welfare maximization     redispatch     optimization models    

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Achieving desired nodal lines in freely vibrating structures via material-field series-expansion topology

《机械工程前沿（英文）》 2023年 第18卷 第3期 doi: 10.1007/s11465-023-0758-y

摘要： Accurately controlling the nodal lines of vibrating structures with topology optimization is a highly challenging task. The major difficulties in this type of problem include a large number of design variables, the highly nonlinear and multi-peak characteristics of iteration, and the changeable orders of eigenmodes. In this study, an effective material-field series-expansion (MFSE)-based topology optimization design strategy for precisely controlling nodal lines is proposed. Here, two typical optimization targets are established: (1) minimizing the difference between structural nodal lines and their desired positions, and (2) keeping the position of nodal lines within the specified range while optimizing certain dynamic performance. To solve this complex optimization problem, the structural topology of structures is first represented by a few design variables on the basis of the MFSE model. Then, the problems are effectively solved using a sequence Kriging-based optimization algorithm without requiring design sensitivity analysis. The proposed design strategy inherently circumvents various numerical difficulties and can effectively obtain the desired vibration modes and nodal lines. Numerical examples are provided to validate the proposed topology optimization models and the corresponding solution strategy.

关键词： nodal line     topology optimization     structural dynamics design     material-field series-expansion    

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Applying the multi-zone model in predicting the operating range of HCCI engines

Ming JIA, Maozhao XIE, Zhijun PENG,

《能源前沿（英文）》 2010年 第4卷 第3期   页码 414-423 doi: 10.1007/s11708-010-0108-8

摘要： In this paper, a multi-zone model is developed to predict the operating range of homogeneous charge compression ignition (HCCI) engines. The boundaries of the operating range were determined by knock (presented by ringing intensity), partial burn (presented by combustion efficiency), and cycle-to-cycle variations (presented by the sensitivity of indicated mean effective pressure to initial temperature). By simulating an HCCI engine fueled with iso-octane, the knock and cycle-to-cycle variations predicted by the model showed satisfactory agreement with measurements made under different initial temperatures and equivalence ratios; the operating range was also well reproduced by the model. Furthermore, the model was applied to predict the operating range of the HCCI engine under different engine speeds by varying the intake temperatures and equivalence ratios. The potential to extend the operating range of the HCCI engine through two strategies, i.e., variable compression ratio and intake pressure boosting, was then investigated. Results indicate that the ignition point can be efficiently controlled by varying the compression ratio. A low load range can be extended by increasing the intake temperature while reducing the compression ratio. Higher intake temperatures and lower compression ratios can also extend the high load range. Boosting intake pressure is helpful in controlling the combustion of the HCCI engine, resulting in an extended high load range.

关键词： homogeneous charge compression ignition (HCCI) engine     multi-zone     operating range    

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Improved local control without elective nodal radiotherapy in patients with unresectable NSCLC treated

YANG Kunyu, LIU Li, ZHANG Tao, WU Gang, CAO Fengjun, WANG Jianhua

《医学前沿（英文）》 2007年 第1卷 第4期   页码 381-385 doi: 10.1007/s11684-007-0074-7

摘要： To investigate the influence of prophylactic elective nodal irradiation on the therapeutic results of definitive radiotherapy for patients with stage IIIA or stage IIIB unresectable non-small-cell lung cancer, 55 patients with clinically inoperable advanced non-small-cell lung cancer were studied. After four cycles of induction chemotherapy, the patients were divided into two groups at random. In one group, the elective nodal irradiation was included in clinical tumor volume (CTV) of definitive radiotherapy (ENI group); and in the other group, elective nodal irradiation was not included in CTV (non-ENI group). For the patients in the ENI group, the mean prescription dose for gross tumor volumes was 58.4 Gy, while for the patients in the non-ENI group, it was 65.8 Gy (<0.05). The responsive rates were 45.8% and 74.0% (<0.05), and the rate of the elective nodal failure (ENF) was 4.2% and 11.1%, respectively. Kaplan-Meier analysis showed that the mean local-progression-free survival time was 11.0 and 15.0 months, and one-year local-failure rates were 51.9% and 24.5% (<0.05). The median overall survival time was 13.0 and 15.0 months, respectively ( = 0.084). The one-year survival rates were 55.7% and 72.5%, and two-year survival rates were 0% and 19.9%. There was no significant difference in the occurrences of radiation-associated complications between the two groups. Our results showed that omitting elective nodal irradiation did not result in a high incidence of elective nodal failure. On the contrary, it decreased local failure by increasing prescription doses to the primary diseases and lymphadenopaphy, and thereby it may further prolong the patients survival.

关键词： significant difference     irradiation     unresectable non-small-cell     induction chemotherapy     influence    

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delamination on the stiffness of composite pipes under compressive transverse loading using cohesive zone

Sattar MALEKI, Roham RAFIEE, Abolfazl HASANNIA, Mohammad Reza HABIBAGAHI

《结构与土木工程前沿（英文）》 2019年 第13卷 第6期   页码 1316-1323 doi: 10.1007/s11709-019-0555-1

摘要： The effect of delamination on the stiffness reduction of composite pipes is studied in this research. The stiffness test of filament wound composite pipes is simulated using cohesive zone method. The modeling is accomplished to study the effect of the geometrical parameters including delamination size and its position with respect to loading direction on stiffness of the composite pipes. At first, finite element results for stiffness test of a perfect pipe without delamination are validated with the experimental results according to ASTM D2412. It is seen that the finite element results agree well with experimental results. Then the finite element model is developed for composite pips with delaminated areas with different primary shapes. Thus, the effect of the size of delaminated region on longitudinal and tangential directions and also its orientation with respect to loading direction on delamination propagation and stiffness reduction of the pipes is assessed.

关键词： delamination     composite pipes     stiffness test     cohesive zone method    

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渤海辽东带地质认识的突破与金县1-1大油田的发现

邓运华

《中国工程科学》 2011年 第13卷 第10期   页码 13-18

摘要：

辽东带系指渤海辽中凹陷的东部陡坡带及辽东凸起，被辽中及辽东凹陷所夹持。辽东带油源条件好，东营组储—盖条件优越，断鼻、断块圈闭发育。但在2002年之前的15年内，国内外公司在辽东带进行了长期研究和勘探，钻了12口探井，没有发现商业油气田。经过对辽东带油气地质条件3年的深入研究，对每口失利井原因进行了再次分析，认识到该带发育东营组及沙河街组两套主力成藏组合，控制东营组成藏的主要因素是油气运移，而沙河街组能否成藏关键是储层。在此认识指导下选择研究方向，评价有利目标，经钻探发现了金县1-1大油田，储量达1.5×108 m3，充分显示了科研在油气勘探中的作用。

关键词： 渤海辽东带     金县1-1     地质认识     大油田    

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effects of mismatch fracture properties in encapsulation-based self-healing concrete using cohesive-zone

Luthfi Muhammad MAULUDIN, Chahmi OUCIF, Timon RABCZUK

《结构与土木工程前沿（英文）》 2020年 第14卷 第3期   页码 792-801 doi: 10.1007/s11709-020-0629-0

摘要： Finite element analysis is developed to simulate the breakage of capsule in capsule-based self-healing concrete. A 2D circular capsule with different core-shell thickness ratios embedded in the mortar matrix is analyzed numerically along with their interfacial transition zone. Zero-thickness cohesive elements are pre-inserted into solid elements to represent potential cracks. This study focuses on the effects of mismatch fracture properties, namely fracture strength and energy, between capsule and mortar matrix into the breakage likelihood of the capsule. The extensive simulations of 2D specimens under uniaxial tension were carried out to investigate the key features on the fracture patterns of the capsule and produce the fracture maps as the results. The developed fracture maps of capsules present a simple but valuable tool to assist the experimentalists in designing appropriate capsule materials for self-healing concrete.

关键词： self-healing concrete     interfacial zone     capsule materials     cohesive elements     fracture maps    

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Experimental investigation and design of aluminum columns with longitudinal welds

Yun WU, Qilin ZHANG

《结构与土木工程前沿（英文）》 2011年 第5卷 第3期   页码 366-373 doi: 10.1007/s11709-011-0101-2

摘要： This paper presents an experimental investigation of longitudinally welded aluminum alloy I-section columns subjected to pure axial compression. The specimens were fabricated using 6061-T6 heat-treated aluminum alloy. The test program included 20 column tests which were separated into 2 test series of different types of welding sections. Each test series contained 10 columns. All the specimens were welded using the Tungsten Inert Gas welding method. The length of the specimens ranged from 442 to 2433 mm in order to obtain a column curve for each test series. The observed failure mode for the column tests includes mainly flexural buckling around the minor axis and the major axis by applying support except for one column (ZP1217-1) which buckled in the local zone and some columns which failed in the weld. The test strengths were compared with the design strengths predicted by the European Code and China Code for aluminum structures. The purpose of this paper is to present the tests results of two typically longitudinally welded I-section columns, and to check the accuracy of the design rules in the current specifications.

关键词： aluminum alloy     longitudinal weld     heat-affected zone (HAZ)     reduced strength zone (RSZ)     buckling     column     experimental study    

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Cohesive zone model-based analyses of localized leakage of segmentally lined tunnels

《结构与土木工程前沿（英文）》 2023年 第17卷 第4期   页码 503-521 doi: 10.1007/s11709-023-0927-4

摘要： This paper presents a novel approach for simulating the localized leakage behavior of segmentally lined tunnels based on a cohesive zone model. The proposed approach not only simulates localized leakage at the lining segment, but also captures the hydromechanically coupled seepage behavior at the segmental joints. It is first verified via a tunnel drainage experiment, which reveals its merits over the existing local hydraulic conductivity method. Subsequently, a parametric study is conducted to investigate the effects of the aperture size, stratum permeability, and spatial distribution of drainage holes on the leakage behavior, stratum seepage field, and leakage-induced mechanical response of the tunnel lining. The proposed approach yields more accurate results than the classical local hydraulic conductivity method. Moreover, it is both computationally efficient and stable. Localized leakage leads to reduced local ground pressure, which further induces outward deformation near the leakage point and slight inward deformation at its diametrically opposite side. A localized stress arch spanning across the leakage point is observed, which manifests as the rotation of the principal stresses in the adjacent area. The seepage field depends on both the number and location of the leakage zones. Pseudostatic seepage zones, in which the seepage rate is significantly lower than that of the adjacent area, appear when multiple seepage zones are considered. Finally, the importance of employing the hydromechanical coupled mechanism at the segment joints is highlighted by cases of shallowly buried tunnels subjected to surface loading and pressure tunnels while considering internal water pressure.

关键词： segmentally lined tunnel     localized leakage     cohesive element     hydraulic behavior     numerical modeling    

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Simulation of cottonseed cake melt flow in metering zone of a single screw extruder

Hong HE, Jianguo ZHOU,

《化学科学与工程前沿（英文）》 2010年 第4卷 第3期   页码 263-269 doi: 10.1007/s11705-009-0276-4

摘要： Research on the extrusion of natural polymers (food, feed, etc.) is relatively new due to the complex physicochemical transformations of raw materials, although plastics melt conveying and transport have been well studied. The structure and composition, rheological behavior as well as extrusion processing of natural polymer are much more complicated. In this study, a quasi-three-dimensional (3D) fluid flow model for non-Newtonian, non-isothermal and undeveloped temperature was developed, the model prediction being in reasonably good agreement with the experiment. Results show that the influence of moisture content, among other process variables, is the most significant, followed by screw speed. Some interaction exists between these two variables and the screw speed effect becomes marginal at high moisture contents. In addition, viscosity change in the channel was studied.

关键词： quasi-three-dimensional     rheological     viscosity     processing     influence    

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基于粉碎区控制的钻孔爆破岩石-炸药匹配方法

冷振东,卢文波,严鹏,陈明,胡英国

《中国工程科学》 2014年 第16卷 第11期   页码 28-35

摘要：

合理的炸药-岩石匹配关系对于提高炸药能量的有效利用率和改善破碎效果有着重要意义。传统上强调的波阻抗匹配理论并不合理，文章从爆破破碎机理出发，提出了一种岩石-炸药匹配的新方法，在保证相邻炮孔间岩石充分破碎的前提下，通过对粉碎区的合理控制来确定钻孔爆破最优的炸药性能参数。该方法可以直观地反映爆破破碎效果及能量有效利用率，可操作性强。考虑相邻炮孔爆炸荷载的联合作用，修正了钻孔爆破破坏分区计算模型。在此基础上，针对具体工程目标给出了混装炸药耦合装药条件下不同等级岩石的炸药性能匹配参数。

关键词： 钻孔爆破     粉碎区     岩石-炸药匹配     波阻抗匹配    

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A modified zone model for estimating equivalent room thermal capacity

Hua CHEN, Xiaolin WANG

《能源前沿（英文）》 2013年 第7卷 第3期   页码 351-357 doi: 10.1007/s11708-013-0254-x

摘要： The zone model has been widely applied in control analysis of heating, ventilation and air conditioning (HVAC) systems to achieve a high building efficiency. This paper proposed a modified zone model which is much simpler in the HVAC system simulation and has the similar accuracy to the complicated simulation model. The proposed model took into consideration the effect of envelop heat reservoir on the room indoor temperature by introducing the thermal admittance of the inner surfaces of the building enclosure. The thermal admittance for the building enclosure was developed based on the building thermal network analytical theory and transfer function method. The efficacy of the proposed model was demonstrated by comparing it with the complicated model — heat balance method (HTB2 program). The predicted results from the proposed model well agreed with those from the complicated simulation. The proposed model can then make the HVAC system dynamic simulation much faster and more acceptable for control design due to its simplicity and efficiency.

关键词： room model     thermal network analysis     transfer function     heating     ventilation and air conditioning (HVAC) system simulation    

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Long-term trends of fine particulate matter and chemical composition in the Pearl River Delta Economic Zone

Xuemei WANG,Weihua CHEN,Duohong CHEN,Zhiyong WU,Qi Fan

《环境科学与工程前沿（英文）》 2016年 第10卷 第1期   页码 53-62 doi: 10.1007/s11783-014-0728-z

摘要： Understanding the trends in PM levels is essential for formulating clean air plans. This paper analyzes PM data from various published sources for the years 2000 to 2010 in the Pearl River Delta Economic Zone (PRDEZ). The long-term variation in PM mass concentration is analyzed. Results show that PM , organic carbon (OC), elemental carbon (EC), and show a similar trend, increasing before 2005 and then decreasing slightly. The annual average PM concentration ranges from 49.1 μg·m in 2000 to 64.3 μg·m in 2010, with a peak of 84.1 μg·m in 2004. None of these 11 years meets the new National Ambient Air Quality standard (NAAQS) for PM (35 μg·m ). Overall average concentrations of OC, EC, and are 13.0, 6.5, and 11.8 μg·m , respectively. and respectively have concentrations of 1.5 μg·m and 2.9 μg·m in 2000 and 6.4 μg·m and 5.3 μg·m in 2010, with a statistically significant average annual trend of+ 0.2 μg·m ·yr and+ 0.1 μg·m ·yr . In certain geographic regions, OC and EC contribute most of the PM , while in other regions secondary water-soluble ions are more important. In general, OC and are the dominant components of PM , contributing 20.6% and 18.6%, respectively. These results provide, for the first time, a better understanding of the long-term PM characteristics and trends, on a species-by-species basis, in the PRDEZ. The results indicate that PM abatement needs to prioritize secondary species.

关键词： long-term trends     fine particulate matter     chemical components     Pearl River Delta Economic Zone (PRDEZ)    

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Isogeometric cohesive zone model for thin shell delamination analysis based on Kirchhoff-Love shell model

Tran Quoc THAI, Timon RABCZUK, Xiaoying ZHUANG

《结构与土木工程前沿（英文）》 2020年 第14卷 第2期   页码 267-279 doi: 10.1007/s11709-019-0567-x

摘要： We present a cohesive zone model for delamination in thin shells and composite structures. The isogeometric (IGA) thin shell model is based on Kirchhoff-Love theory. Non-Uniform Rational B-Splines (NURBS) are used to discretize the exact mid-surface of the shell geometry exploiting their C -continuity property which avoids rotational degrees of freedom. The fracture process zone is modeled by interface elements with a cohesive law. Two numerical examples are presented to test and validate the proposed formulation in predicting the delamination behavior of composite structures.

关键词： cohesive zone model     IGA     Kirchhoff-Love model     thin shell analysis     delamination    

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标题 作者 时间 类型 操作

Interactive effects of high-speed rail on nodal zones in a city: exploratory study on China

Guo LIU, Kunhui YE

期刊论文

Nodal, zonal, or uniform electricity pricing: how to deal with network congestion

Martin WEIBELZAHL

期刊论文

Achieving desired nodal lines in freely vibrating structures via material-field series-expansion topology

期刊论文

Applying the multi-zone model in predicting the operating range of HCCI engines

Ming JIA, Maozhao XIE, Zhijun PENG,

期刊论文

Improved local control without elective nodal radiotherapy in patients with unresectable NSCLC treated

YANG Kunyu, LIU Li, ZHANG Tao, WU Gang, CAO Fengjun, WANG Jianhua

期刊论文

delamination on the stiffness of composite pipes under compressive transverse loading using cohesive zone

Sattar MALEKI, Roham RAFIEE, Abolfazl HASANNIA, Mohammad Reza HABIBAGAHI

期刊论文

渤海辽东带地质认识的突破与金县1-1大油田的发现

邓运华

期刊论文

effects of mismatch fracture properties in encapsulation-based self-healing concrete using cohesive-zone

Luthfi Muhammad MAULUDIN, Chahmi OUCIF, Timon RABCZUK

期刊论文

Experimental investigation and design of aluminum columns with longitudinal welds

Yun WU, Qilin ZHANG

期刊论文

Cohesive zone model-based analyses of localized leakage of segmentally lined tunnels

期刊论文

Simulation of cottonseed cake melt flow in metering zone of a single screw extruder

Hong HE, Jianguo ZHOU,

期刊论文

基于粉碎区控制的钻孔爆破岩石-炸药匹配方法

冷振东,卢文波,严鹏,陈明,胡英国

期刊论文

A modified zone model for estimating equivalent room thermal capacity

Hua CHEN, Xiaolin WANG

期刊论文

Long-term trends of fine particulate matter and chemical composition in the Pearl River Delta Economic Zone

Xuemei WANG,Weihua CHEN,Duohong CHEN,Zhiyong WU,Qi Fan

期刊论文

Isogeometric cohesive zone model for thin shell delamination analysis based on Kirchhoff-Love shell model

Tran Quoc THAI, Timon RABCZUK, Xiaoying ZHUANG

期刊论文