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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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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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fluorescence spectral characterization of soil dissolved organic matters in the fluctuating water-level zone

Fang FANG, Yan YANG, Jinsong GUO, Hong ZHOU, Chuan FU, Zhe LI

《环境科学与工程前沿（英文）》 2011年第5卷第3期页码 426-434 doi: 10.1007/s11783-010-0264-4

摘要： Three-dimensional fluorescence spectroscopy was used to investigate the fluorescent properties of soil dissolved organic matter (DOM) in the water-level-fluctuation zone (WLFZ) of Kai County, Three Gorges Reservoir (TGR). Most of the soil DOM analyzed in this study was found to contain four fluorescence peaks. Peaks A and C represent humic-like fluorescence, whereas peaks B and D represent tryptophan-like fluorescence. Peaks E and F, which represent tyrosine-like fluorescence, only appeared in certain soils. Soil humus was the main source of DOM in soil, and higher concentration of soil DOM was found in the exposed soil than submerged soil. Compared to the peaks A and B, the fluorescence intensities of peaks C and D were strongly influenced by the fluctuating water level. Analysis of fluorescence intensities of different peaks in soil DOM showed that WLFZ soil was not contaminated significantly. Soil DOM contained at least two types of humic-like fluorescence groups and two types of protein-like fluorescence groups. The proportion of the content of peak A in soil organic matter was quite stable. The soil DOM in exposed soil had relatively high humification and aromaticity, and periodic submerging and exposure of soil had an impact on the humification of soil DOM.

关键词： water-level-fluctuation zone (WLFZ) soil dissolved organic matter (DOM) three-dimensional fluorescence spectra

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一种面向地面区域检测和目标跟踪的多传感器系统协同调度方法 Research Article

张昀普,付强,单甘霖

《信息与电子工程前沿（英文）》 2023年第24卷第2期页码 245-258 doi: 10.1631/FITEE.2200121

摘要：本文提出一种面向多任务协同的多传感器系统协同调度方法，并将其应用于地面区域检测和目标跟踪。调度的目的是选择最佳的传感器来完成分配的作战任务，并获得最佳作战收益。首先建立区域检测模型，并提出检测风险的计算方法以量化在调度中的检测收益。然后结合道路约束信息和多普勒盲区信息建立地面目标跟踪模型，并引入后验克拉美罗下限评估未来时刻的跟踪精度。最后，考虑检测、跟踪和能耗控制的需求建立目标函数，通过求解目标函数，得到最优的传感器调度方案。仿真结果表明，所提传感器调度方法可以选择合适的传感器完成所需作战任务，并在区域检测、目标跟踪和能耗控制方面均具有良好性能。

关键词：传感器调度；区域检测；目标跟踪；道路约束；多普勒盲区

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深部裂缝带——一种新的地震构造样式

李愿军

《中国工程科学》 2006年第8卷第4期页码 12-18

摘要：

黄河黑山峡大柳树坝址、雅砻江锦屏普斯罗坝址及其他一些水电工程区，在勘探过程相继发现了一种新的地质构造现象——深部裂缝带，并且多出现在我国强震活跃地区和强震发生断裂带上，沿断裂带历史上强震活动频繁；深部裂缝带向地下延伸超过300m，远远超出地表卸荷带的影响深度，故与强地震作用时岩体构造动力效应密切相关；讨论了根据弹性波作用下岩体的动力学响应，阐述了深部裂缝带发生的地震学原因。

关键词：深部裂缝带强震断层卸荷岩石动力学

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大尺度空间中烟气运动工程分析的多单元区域模拟方法

胡隆华,霍然,李元洲,王浩波

《中国工程科学》 2003年第5卷第8期页码 59-63

摘要：

在大尺度空间中，仍然将整个空间划分上部热烟气层和下部的冷空气层直接进行区域模拟是不合适的。提出了一种将大尺度空间划分若干常规子单元，再在各个子单元中采用上下层区域模拟的方法，并以CFAST4.02为工具，对两种典型的大尺度空间的烟气运动过程进行分析和比较。结果表明，在大尺度空间中，这种多单元区域模拟的方法相比于传统的区域模拟方法具有较好的适用性。

关键词：大尺度空间烟气运动多单元区域模拟区域模拟