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Numerical analysis of 3-D unsteady flow in a vaneless counter-rotating turbine

ZHAO Qingjun, WANG Huishe, ZHAO Xiaolu, XU Jianzhong

《能源前沿（英文）》 2007年第1卷第3期页码 352-358 doi: 10.1007/s11708-007-0053-3

摘要： To reveal the unsteady flow characteristics of a vaneless counter-rotating turbine (VCRT), a three-dimensional, viscous, unsteady computational fluid dynamics (CFD) analysis was performed. The results show that unsteady simulation is superior to steady simulation because more flow characteristics can be obtained. The unsteady effects in upstream airfoil rows are weaker than those in downstream airfoil rows in the VCRT. The static pressure distribution along the span in the pressure surface of a high pressure turbine stator is more uniform than that in the suction surface. The static pressure distributions along the span in the pressure surfaces and the suction surfaces of a high pressure turbine rotor and a low pressure turbine rotor are all uneven. The numerical results also indicate that the load of a high pressure turbine rotor will increase with the increase of the span. The deviation is very big between the direction of air flow at the outlet of a high pressure turbine rotor and the axial direction. A similar result can also be obtained in the outlet of a low pressure turbine rotor. This means that the specific work of a high pressure turbine rotor and a low pressure turbine rotor is big enough to reach the design objectives.

关键词： unsteady flow three-dimensional pressure distribution similar result unsteady simulation

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Development of a constitutive model for rockfills and similar granular materials based on the disturbed

Mehdi VEISKARAMI, Ali GHORBANI, Mohammadreza ALAVIPOUR

《结构与土木工程前沿（英文）》 2012年第6卷第4期页码 365-378 doi: 10.1007/s11709-012-0178-2

摘要： Behavior of rockfills was investigated experimentally and theoretically. A series of standard triaxial compression tests were carried out on a quarried rockfill material at different stress levels. It was found that both the stress level and the shear stress ratio, like most of granular materials, controls the behavior of rockfill materials. At lower shear stress ratios the behavior is much more similar to a nonlinear elastic solid. When the shear stress goes further, the stress-strain curve shows an elasto-plastic behavior which suggests using the disturbed state concept to develop a constitutive model to predict the stress-strain behavior. The presented constitutive model complies reasonably with the experimental data.

关键词： constitutive model granular material rockfill plasticity disturbed state concept stress level

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Pluripotent stem cells exhibiting similar characteristics can be isolated from human fetal bone marrow

FANG Baijun, SONG Yongping, LIN Quande, ZHAO Chunhua, SHI Mingxia

《医学前沿（英文）》 2007年第1卷第2期页码 185-191 doi: 10.1007/s11684-007-0035-1

摘要： Previously, we reported that a cell population derived from human fetal bone marrow (BM), termed here Flk1CD34 postembryonic pluripotent stem cells (PPSCs) that have the characteristics of mesenchymal stem cells (MSCs), could differentiate into ectodermal, endodermal and mesodermal cell types at the single cell level , and that these cells could also differentiate into the epithelium of liver, lung, gut, as well as the hematopoietic and endothelial lineages after transplantion into irradiated non-obese diabetic/severe combined immunodeficient (NOD/SCID) mice. In this study, we further isolated pluripotent stem cells from human fetal heart, liver, muscle, lung, derma, kidney, and fat and then analyzed the characteristics and function of these stem cells. It was found that the phenotype of the culture-expanded pluripotent stem cells from different fetal tissues was similar to BM-derived Flk1CD34 PPSCs, i.e. Flk1 and CD44 positive, GlyA, CD34, CD45, class I-HLA and HLA-DR negative. Morphologically, these cells were fibroblast-like and the doubling time was about 30 h. More importantly, culture-expanded pluripotent stem cells from all these fetal tissues were able to differentiate into cells with morphologic and phenotypic characteristics of adipocytes, osteocytes, neurons, glial cells and hepatocytes. These pluripotent stem cells with characteristics similar to fetal BM-derived Flk1CD34 PPSCs can be selected and cultured from tissues other than the BM. This phenomenon may help explain the stem cell plasticity found in multiple human tissues. In addition, as fetal BM-derived Flk1CD34 PPSCs, these pluripotent stem cells from different fetal tissues had the capacity for self-renewal and multi-lineage differentiation even after being expanded for more than 40 population doublings . Thus, they may be an ideal source of stem cells for treatment of inherited or degenerative diseases.

关键词： endothelial phenomenon ectodermal Flk1CD34 postembryonic irradiated non-obese

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value of the 21-gene recurrence score in ER-positive, HER2-negative, node-positive breast cancer was similar

Jiayi Wu, Weiqi Gao, Xiaosong Chen, Chunxiao Fei, Lin Lin, Weiguo Chen, Ou Huang, Siji Zhu, Jianrong He, Yafen Li, Li Zhu, Kunwei Shen

《医学前沿（英文）》 2021年第15卷第4期页码 621-628 doi: 10.1007/s11684-020-0738-0

摘要： Multi-gene assays have emerged as crucial tools for risk stratification in early-stage breast cancer. This study aimed to evaluate the prognostic significance of the 21-gene recurrence score (RS) in Chinese patients with pN0-1, estrogen receptor-positive (ER ), human epidermal growth factor receptor 2-negative (HER2 ) breast cancer. Among 800 patients recruited between 2009 and 2016, the median RS was 24 (0–69), with 27.4%, 46.8%, and 25.9% patients classified into low-, intermediate-, and high-risk groups. Cox regression analysis demonstrated that the high-risk category was associated with significantly higher odds of invasive disease-free survival (IDFS) and distant disease-free survival (DDFS) events compared with the low-risk category (IDFS: HR= 2.450, 95% CI 1.017–5.902, = 0.046; DDFS: HR= 2.829, 95% CI 1.013–7.901, = 0.047). No significant association between RS category and overall survival (OS) was found (intermediate vs. low: HR= 1.244, 95% CI 0.292–5.297, = 0.768; high vs. low: HR= 2.933, 95% CI 0.759–11.327, = 0.119). RS, as a continuous variable, was a highly significant predictor for IDFS (HR= 1.028, 95% CI 1.010–1.047, = 0.002), DDFS (HR= 1.030, 95% CI 1.010–1.051, = 0.003), and OS (HR= 1.034, 95% CI 1.007–1.063, = 0.014). Our findings suggested that RS may predict IDFS in Chinese patients with ER /HER2 breast cancer with N0 or N1 disease.

关键词： early breast cancer 21-gene assay recurrence score prognosis

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高速铁路是运输市场竞争和科学技术进步的产物

臧其吉,吴玉树,曾树谷,杨悌惠

《中国工程科学》 2000年第2卷第5期页码 1-7

摘要：

介绍了高速铁路的产生过程、定义、主要类型、主要技术经济优势、世界高速铁路的现状和发展趋势；论述了高速铁路是高新技术的综合集成，包括高速铁路线路是高速行车的基础，高速列车是高速行车的核心，行车指挥系统是高速行车的中枢，安全监控系统是高速行车的保障。

关键词：高速铁路科技进步发展

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乌鲁木齐市部分地区农牧民和流动人口孕前优生结果分析

于江,单湘婷,王军,谢金荣

《中国工程科学》 2014年第16卷第5期页码 52-55

摘要：

为了解计划怀孕夫妇双方一般情况及健康状况，开展孕前健康教育及优生咨询指导工作，降低出生缺陷发生风险，本文对606 对符合生育政策、计划怀孕的农牧民和流动人口夫妇的孕前优生健康检查资料进行分析。实验结果表明：606 对夫妇男方吸烟人数为381 人，占男方受检总人数的62.87 %，女方被动吸烟的人数为324 人，占女方受检总人数的53.46 %；存在不良饮食习惯人数男女共计152 人；接触农药及新装修、油漆等人数男女共计228 人；女方检出疾病中以生殖系统炎症发病率最高。参检人员由于文化程度低，语言沟通障碍等因素，造成孕前优生知识缺乏，优生意识淡漠。因此，应根据孕前优生健康检查结果，为计划怀孕夫妇提供综合性指导，从而有效减少出生缺陷发生，提高人口素质。

关键词：优生健康检查风险因素出生缺陷

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大直径盾构侧穿地铁站的变形预测与实测结果分析

张继清,索晓明

《中国工程科学》 2010年第12卷第12期页码 18-22

摘要：

通过数值计算方法对北京地下直径线侧穿地铁2号线某车站的结构变形进行预测，并将预测值与实测值进行对比和差异性原因分析，以期对类似工程预测变形、指定控制指标有一定指导作用。

关键词：大直径盾构地铁车站变形预测监测数值分析

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Space-time evolution rules study on acoustic emission location in rock under cyclic loading

Jiang XU, Shuchun LI, Yunqi TAO, Yongdong JIANG, Xiaojun TANG,

《结构与土木工程前沿（英文）》 2009年第3卷第4期页码 422-427 doi: 10.1007/s11709-009-0056-8

摘要： An acoustic emission (AE) location experiment was performed on sandstone using an advanced AE test system. The space-time evolution rule regarding damage was analyzed under cyclic loading as well as AE. The results show that AE on static loading process is consistent with the damage evolution rule of compression and the elastic-plastic deformation phase; at the beginning of cyclic loading with low duration time and energy, AE events came from a small crack. The location result showed that most events occurred in the core zone forming at the static loading process, and the location points changed slowly. AE energy changed little during the metaphase of cyclic process. There was a modest increase of location points in every cycle. The tendency of steady development could be predicted from the AE location events. At the end of each cyclic loading, the quantity of AE events and energy increased quite rapidly, reaching a maximum at the last cycle. AE events had high energy and duration time. Location events changed quite rapidly and assembled and linked continuously in the core zone. At the same time, they expanded to the top of specimen. A macroscopic crack finally formed. In the postfailure process, some AE events still existed due to fracturing of gliding friction. Owing to the inner stress balance of rock even after loading stopped, minor AE events still occurred.

关键词： location result AE location consistent friction elastic-plastic deformation

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电动汽车锂电池模块设计中相似性能电池聚类的综合方法 Article

李伟, 陈思琦, 彭雄斌, 肖蜜, 高亮, Akhil Garg, 包能胜

《工程（英文）》 2019年第5卷第4期页码 795-802 doi: 10.1016/j.eng.2019.07.005

摘要：

新能源汽车的核心组成部分为能量存储系统，该系统由多个锂电池模块组成，为车辆传动系统提供主要动力。然而模块中的单体电池由于生产制造的缺陷，在性能上往往表现出差异。这些差异的存在会导致电池模块的不完全充放电以及温度分布的不均匀，进而导致循环寿命和电池容量随着时间的推移而降低。为解决这一问题，本工作采用实验和数值方法对性能相似的电池进行了全面的聚类研究，从而得到了电化学性能更好的电池模块。首先通过模块拆解实验来测量电池性能参数，并基于k-均值聚类与支持向量聚类算法设计电池模块，每个模块均由12块电池组成。然后在风冷条件下测量一定时间内电池模块的实际温升，验证聚类设计的效果。研究发现第三类（支持向量聚类）电池模块的性能最佳，充放电最高观测温度为32 ℃。相比之下，其他电池模块的最高温度值要更高：第一类（厂家原装）电池模块为40 ℃，第二类（厂家原装）电池模块为36 ℃，以及第四类（k-均值聚类）电池模块为35 ℃。

关键词：聚类算法电池模块均衡电动汽车

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开采煤层顶板环形裂隙圈内走向长钻孔法抽放瓦斯研究

刘泽功,袁亮,戴广龙,石必明,卢平,涂敏

《中国工程科学》 2004年第6卷第5期页码 32-38

摘要：

开采煤层工作面的瓦斯主要来源于该煤层、采空区和邻近层的卸压解吸瓦斯。由于煤层松软，顺层钻孔施工难，不便钻孔抽放瓦斯。若对采空区实施大面积抽放，工程难度大，而且抽不出高浓度瓦斯。因此，寻找瓦斯运移的裂隙通道和瓦斯富集区，实施有效的瓦斯抽放工程是实现高效瓦斯抽放的技术关键。采用实验室相似材料试验、数值模拟计算和工业性试验研究方法，研究寻找采场上覆岩层中环形裂隙圈形成机理和位置，把抽放钻孔布置在环形裂隙圈内，进行“环形裂隙圈内走向长钻孔法”瓦斯抽放。这种瓦斯抽放技术使低透气性高瓦斯煤层的开采和瓦斯抽放分层区进行，在开采层工作面采煤，在顶板层裂隙区抽放卸压瓦斯，对流向工作面上隅角的瓦斯起到了截流作用，解决了松软低透气性高瓦斯煤层群开采瓦斯抽放困难的关键技术难题。该瓦斯抽放技术在淮南矿区高瓦斯工作面的应用结果表明，采煤工作面瓦斯抽放率达到60%以上，实现煤层群首采煤层安全、高效、集约化开采。

关键词：煤层顶板相似材料试验数值计算环形裂隙圈瓦斯抽放