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Availability growth models and verification of power equipment

Jinyuan SHI, Jiamin XU

《能源前沿（英文）》 2021年 第15卷 第2期   页码 529-538 doi: 10.1007/s11708-019-0624-0

摘要： The general availability growth models for large scale complicated repairable system such as electric generating units, power station auxiliaries, and transmission and distribution installations are presented. The calculation formulas for the maintenance coefficient, mathematical expressions for general availability growth models, ways for estimating, and fitting on checking the parameters of the model are introduced. Availability growth models for electric generating units, power station auxiliaries, and transmission and distribution installations are given together with verification examples for availability growth models of 320–1000 MW nuclear power units and 1000 MW thermal power units, 200–1000 MW power station auxiliaries, and 220–500 kV transmission and distribution installations. The verification results for operation availability data show that the maintenance coefficients for electric generating units, power station auxiliaries, transmission and distribution installations conform to the power function, and general availability growth models conform to rules of availability growth tendency of power equipment.

关键词： repairable system     power equipment     electric generating unit     power station auxiliary     transmission and distribution installation     reliability     availability     availability growth model    

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A reliability growth model for 300?MW pumped-storage power units

Jinyuan SHI , Yu YANG , Zhicheng DENG ,

《能源前沿（英文）》 2009年 第3卷 第3期   页码 337-340 doi: 10.1007/s11708-009-0032-y

摘要： A reliability growth model for pumped-storage power units is presented. Ways for estimating and fitting on checking the model’s parameters are given together with analysis results concerning the reliability growth of 300MW pumped-storage power units. On site operation, reliability data show that the reliability growth model conforms to rules of reliability growth tendency. Analysis results of reliability growth indicate that measures taken for improving maintenance and operation by the pumped-storage power companies are effective and that the reliability of the 300MW pumped-storage power units exhibits a rising tendency.

关键词： pump-storage power unit     availability     reliability growth     reliability prediction    

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Economic Growth Model Based on Six Basic Factors of Production—Xu Growth Rate Equation

Shou-bo Xu,Zong-yuan Huang

《工程管理前沿（英文）》 2014年 第1卷 第2期   页码 160-175 doi: 10.15302/J-FEM-2014024

摘要： This paper proposes an economic growth model based on the Six Basic Factors of Production and Xu Growth Rate Equation for the first time, which fills-in the deficits of the New Classical Economic Growth Model based on the Solow Model. The empirical analysis indicates that over the past three decades, the consumption of six basic factors of production had complicated relations with economic growth. In some years, the consumption rate of the basic factors of production was meager, but the economy witnessed relatively rocketing growth rate; in some years, the factors of production consumption rate was very high, but the economy growth rate slowed down. In general, economy grows at the expenses of huge consumption of four factors. There is an obvious characteristic of huge input and low efficiency. The average contribution rate of technological advance peaks in the middle, while it drops down at two ends. Noticeably, since 2004, the technology contribution rate generally shows a downward trend, reasons of which should be explored systematically in aspects like economic policy and industry structure with a view to boost further transformation of the macro-economy scientific growth model.

关键词： six basic factors of production     economic growth model     Xu Growth Rate Equation    

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Concurrent fatigue crack growth simulation using extended finite element method

Zizi LU, Yongming LIU,

《结构与土木工程前沿（英文）》 2010年 第4卷 第3期   页码 339-347 doi: 10.1007/s11709-010-0078-2

摘要： In this paper, a concurrent simulation framework for fatigue crack growth analysis is proposed using a novel small time scale model for fatigue mechanism analysis and the extended finite element method (X-FEM) for fatigue crack growth simulation. The proposed small time scale fatigue model does not require the cycle counting as those using the classical fatigue analysis methods and can be performed concurrently with structural/mechanical analysis. The X-FEM greatly facilitates crack growth simulation without remeshing requirements ahead of the crack tip as in the classical finite element method. The basic concept and theory of X-FEM was briefly introduced and numerical predictions of stress intensity factors are verified with reference solutions under both uniaxial and multiaxial loadings. The small time scale fatigue model is integrated into the numerical simulation algorithm for concurrent fatigue crack growth analysis. Model predictions are compared with available experimental observations for model validation.

关键词： small time scale model     extended finite element method (X-FEM)     crack growth     multiaxial    

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Bridging reliability and operations management for superior system availability: Challenges and opportunities

《工程管理前沿（英文）》   页码 391-405 doi: 10.1007/s42524-022-0206-4

摘要： Recently, firms have begun to handle the design, manufacturing, and maintenance of capital goods through a consolidated mechanism called the integrated product-service system. This new paradigm enables firms to deliver high-reliability products while lowering the ownership cost. Hence, holistic optimization models must be proposed for jointly allocating reliability, maintenance, and spare parts inventory across the entire value chain. In the existing literature, these decisions are often made fragmentally, thus resulting in local optimality. This study reviews the extant works pertaining to reliability-redundancy allocation, preventative maintenance, and spare parts logistics models. We discuss the challenges and opportunities of consolidating these decisions under an integrated reliability-maintenance-inventory framework for attaining superior system availability. Specific interest is focused on the new product introduction phase in which firms face a variety of uncertainties, including installed base, usage, reliability, and trade policy. The goal is to call for tackling the integrated reliability-maintenance-inventory allocation model under a nonstationary operating condition. Finally, we place the integrated allocation model in the semiconductor equipment industry and show how the firm deploys reliability initiatives and after-sale support logistics to ensure the fleet uptime for its global customers.

关键词： system availability     product-service integration     installed base     new product introduction     service supply chain     reliability-maintenance-inventory optimization    

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Bacteria-mediated tumor-targeted delivery of tumstatin (54-132) significantly suppresses tumor growthin mouse model by inhibiting angiogenesis and promoting apoptosis

《医学前沿（英文）》 2022年 第16卷 第6期   页码 873-882 doi: 10.1007/s11684-022-0925-2

摘要： Tumor growth is an angiogenesis-dependent process and accompanied by the formation of hypoxic areas. Tumstatin is a tumor-specific angiogenesis inhibitor that suppresses the proliferation and induces the apoptosis of tumorous vascular endothelial cells. VNP20009, an attenuated Salmonella typhimurium strain, preferentially accumulates in the hypoxic areas of solid tumors. In this study, a novel Salmonella-mediated targeted expression system of tumstatin (VNP-Tum5) was developed under the control of the hypoxia-induced J23100 promoter to obtain anti-tumor efficacy in mice. Treatment with VNP-Tum5 effectively suppressed tumor growth and prolonged survival in the mouse model of B16F10 melanoma. VNP-Tum5 exhibited a higher efficacy in inhibiting the proliferation and inducing the necrosis and apoptosis of B16F10 cells in vitro and in vivo compared with VNP (control). VNP-Tum5 significantly inhibited the proliferation and migration of mouse umbilical vascular endothelial cells to impede angiogenesis. VNP-Tum5 downregulated the expression of anti-vascular endothelial growth factor A, platelet endothelial cell adhesion molecule-1, phosphorylated phosphoinositide 3 kinase, and phosphorylated protein kinase B and upregulated the expression of cleaved-caspase 3 in tumor tissues. This study is the first to use tumstatin-transformed VNP20009 as a tumor-targeted system for treatment of melanoma by combining anti-tumor and anti-angiogenic effects.

关键词： Salmonella VNP20009     tumstatin     B16F10     melanoma     apoptosis     angiogenesis    

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Analyzing the service availability of mobile cloud computing systems by fluid-flow approximation

Hong-wu LV,Jun-yu LIN,Hui-qiang WANG,Guang-sheng FENG,Mo ZHOU

《信息与电子工程前沿（英文）》 2015年 第16卷 第7期   页码 553-567 doi: 10.1631/FITEE.1400410

摘要： Mobile cloud computing (MCC) has become a promising technique to deal with computation- or data-intensive tasks. It overcomes the limited processing power, poor storage capacity, and short battery life of mobile devices. Providing continuous and on-demand services, MCC argues that the service must be available for users at anytime and anywhere. However, at present, the service availability of MCC is usually measured by some certain metrics of a real-world system, and the results do not have broad representation since different systems have different load levels, different deployments, and many other random factors. Meanwhile, for large-scale and complex types of services in MCC systems, simulation-based methods (such as Monte-Carlo simulation) may be costly and the traditional state-based methods always suffer from the problem of state-space explosion. In this paper, to overcome these shortcomings, fluid-flow approximation, a breakthrough to avoid state-space explosion, is adopted to analyze the service availability of MCC. Four critical metrics, including response time of service, minimum sensing time of devices, minimum number of nodes chosen, and action throughput, are defined to estimate the availability by solving a group of ordinary differential equations even before the MCC system is fully deployed. Experimental results show that our method costs less time in analyzing the service availability of MCC than the Markov- or simulation-based methods.

关键词： Service availability     Mobile cloud computing     Fluid-flow approximation     Ordinary differential equations    

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Effect of atorvastatin on tumor growth and metastasis in a breast cancer cell xenograft model and its

Liu LIU MD, PhD, Yaogui NING MM, Chen CHEN MD, Daowen WANG MD, PhD,

《医学前沿（英文）》 2009年 第3卷 第4期   页码 443-446 doi: 10.1007/s11684-009-0079-5

摘要： This paper aims to evaluate the effects and the possible mechanisms of atorvastatin on tumor growth and metastasis in a xenograft tumor model. Twenty-four female athymic BALB/C mice with MDA-MB-435 xenograft tumors were randomly assigned to three groups: a control group, a low-dose atorvastatin treatment group, and a high-dose atorvastatin treatment group. The mice in the treatment groups began to be administered with atorvastatin (10 or 20 mg/kg per day) when the xenograft tumors reached 1 cm in diameter. At the end of the experiment, the tumor volume and weight and the lung metastasis colonies of each mouse were measured. Western blotting was applied to detect phosphorylation of protein kinase B (PKB, Akt), extracellular signal regulated kinase (ERK), c-Jun N-terminal Kinase (JNK), and the expression of cytochrome P450 (CYP) subtype CYP2J2. Atorvastatin suppressed xenograft tumor growth and metastasis both in the low-dose and the high-dose treatment groups ( < 0.05). Atorvastatin also decreased the phosphorylated Akt (p-Akt) and p-ERK but increased p-JNK expression. However, atorvastatin did not alter the expression of CYP2J2 in tumor tissue. This suggests that atorvastatin has the efficacy of suppressing tumor growth and metastasis . These effects were not dependent on down-regulation of CYP2J2 expression.

关键词： atorvastatin     xenograft tumor     metastasis     CYP2J2    

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Influence of welding residual stresses on the ductile crack growth resistance of circumferentially cracked

Xiaobo REN, Odd M. AKSELSEN, B?rd NYHUS, Zhiliang ZHANG

《结构与土木工程前沿（英文）》 2012年 第6卷 第3期   页码 217-223 doi: 10.1007/s11709-012-0169-3

摘要： Welding residual stress is one of the main concerns for fabrication and operation of steel structures due to its potential effect on structural integrity. This paper focuses on the effect of welding residual stress on the ductile crack growth resistance of circumferentially cracked steel pipes. Two-dimensional axi-symmetry model has been used to simulate the pipe. Residual stresses were introduced into the model by using so-called eigenstrain method. The complete Gurson model has been employed to calculate the ductile crack growth resistance. Results show that residual stresses reduce the ductile crack growth resistance. However, the effect of residual stresses on ductile crack growth resistance decreases with the increase of crack growth. The effect of residual stress has also been investigated for cases with different initial void volume fraction, material hardening and crack sizes.

关键词： residual stress     ductile crack growth resistance     complete Gurson model     eigenstrain method    

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大空间内着火位置对火灾增长的影响

石龙,张瑞芳, 谢启源,付丽华

《中国工程科学》 2008年 第10卷 第11期   页码 37-42

摘要：

以大空间展厅为例，利用火源辐射模型和烟气辐射模型并结合CFAST6.0区域模拟软件的计算结果，对比分析了大空间内不同着火位置下火灾增长的情况。研究结果表明仅考虑火源热辐射的情况下，展厅内着火位置越处于左右中间对称处，其火灾增长越快，热释放速率峰值也越大，达到热释放速率峰值的时间和火灾的持续时间越短，处于展厅中心位置时所有值达峰值。对火源热辐射和烟气辐射综合考虑时，到达热释放速率峰值时间与火灾持续时间的规律同仅考虑火源辐射模型时一致，但热释放速率峰值均有不同程度的提高。

关键词： 火灾增长     大空间着火位置     火灾场景设置     火源辐射模型     烟气辐射模型    

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Simulation of cohesive crack growth by a variable-node XFEM

Weihua FANG, Jiangfei WU, Tiantang YU, Thanh-Tung NGUYEN, Tinh Quoc BUI

《结构与土木工程前沿（英文）》 2020年 第14卷 第1期   页码 215-228 doi: 10.1007/s11709-019-0595-6

摘要： A new computational approach that combines the extended finite element method associated with variable-node elements and cohesive zone model is developed. By using a new enriched technique based on sign function, the proposed model using 4-node quadrilateral elements can eliminate the blending element problem. It also allows modeling the equal stresses at both sides of the crack in the crack-tip as assumed in the cohesive model, and is able to simulate the arbitrary crack-tip location. The multiscale mesh technique associated with variable-node elements and the arc-length method further improve the efficiency of the developed approach. The performance and accuracy of the present approach are illustrated through numerical experiments considering both mode-I and mixed-mode fracture in concrete.

关键词： extended finite element method     cohesive zone model     sign function     crack propagation    

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Aerobic granular sludge formation based on substrate availability: Effects of flow pattern and fermentation

Quan Yuan, Hui Gong, Hao Xi, Kaijun Wang

《环境科学与工程前沿（英文）》 2020年 第14卷 第3期 doi: 10.1007/s11783-020-1226-0

摘要： Penetration depth and substrate characters affect AGS formation and performance. The relationship between substrate gradient and particle size affects AGS stability. The fermentation process is proposed as a pretreatment to improve AGS stability. The influences of flow patterns (mixed-flow and plug-flow) and fermentation pretreatment on aerobic granular sludge (AGS) formation with various substrate availability levels were investigated by running four identical laboratory-scale sequencing batch reactors (R1–R4), comparing two anaerobic feeding strategies and three kinds of substrates. R1 achieved faster granulation with a fast influent fill step followed by a modified anaerobic mixed-flow phase, but the AGS showed poorer stability with a cracked structure and a high suspended solids concentration in the effluent. The anaerobic plug-flow feeding mode (with influent fed slowly from the bottom) in R2 provided deeper penetration depth for the substance to reach the core of AGS and accordingly strengthen AGS stability. An acidogenic up-flow sludge bed reactor was introduced as a pretreatment to improve the AGS performance by enhancing glucose pre-fermentation (R4). AGS fed with mixed volatile fatty acids (VFA) after glucose fermentation showed similar performance compared with the reactor fed with acetate in the aspects of stability, structure, size distribution and nitrogen removal efficiency, and 74% similarity in the microbial community. For actual wastewater with low VFA concentrations, fermentation treatment was suggested as a promising pretreatment for stable AGS granulation and operation.

关键词： Anaerobic plug-flow feeding mode     Anaerobic mixed-flow mode     Fermentation pretreatment     Substrate gradient     Penetration depth    

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Modeling and simulation of landfill gas production from pretreated MSW landfill simulator

Rasool Bux MAHAR,Abdul Razaque SAHITO,Dongbei YUE,Kamranullah KHAN

《环境科学与工程前沿（英文）》 2016年 第10卷 第1期   页码 159-167 doi: 10.1007/s11783-014-0685-6

摘要： The cumulative landfill gas (LFG) production and its rate were simulated for pretreated municipal solid waste (MSW) landfill using four models namely first order exponential model, modified Gompertz model, single component combined growth and decay model and Gaussian function. Considering the behavior of the pretreated MSW landfill, a new multi component model was based on biochemical processes that occurring in landfilled pretreated MSW. The model was developed on the basis of single component combined growth and decay model using an anaerobic landfill simulator reactor which treats the pretreated MSW. It includes three components of the degradation i.e. quickly degradable, moderately degradable and slowly degradable. Moreover, the developed model was statistically analyzed for its goodness of fit. The results show that the multi components LFG production model is more suitable in comparison to the simulated models and can efficiently be used as a modeling tool for pretreated MSW landfills. The proposed model is likely to give assistance in sizing of LFG collection system, generates speedy results at lower cost, improves cost-benefit analysis and decreases LFG project risk. It also indicates the stabilization of the landfill and helps the managers in the reuse of the landfill space. The proposed model is limited to aerobically pretreated MSW landfill and also requires the values of delay times in LFG productions from moderately and slowly degradable fractions of pretreated MSW.

关键词： combine growth and decay model     pretreated municipal solid waste (MSW)     multi component landfill gas (LFG) model    

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Clinical evaluation of recombinant human growth hormone injection in children with growth hormone deficiency

Ling HOU, Xiaoping LUO, Minlian DU, Huamei MA, Chunxiu GONG, Yuchuan LI, Shuixian SHEN, Zhuhui ZHAO, Li LIANG, Guanping DONG, Chaoying YAN, Hongwei DU

《医学前沿（英文）》 2009年 第3卷 第2期   页码 171-176 doi: 10.1007/s11684-009-0027-4

摘要： Recombinant human growth hormone (rhGH) has been widely used in the clinical treatment of growth hormone deficiency. To simplify the injection process and increase drug compliance, application of the GH injection has become a new treatment plan in recent years. The purpose of the current study was to evaluate the efficacy and safety of rhGH injection for the treatment of growth hormone deficiency (GHD) in children in China. In a nationwide, noncomparative, prospective, randomized, open trial, 31 children with confirmed complete GHD received subcutaneous injection of rhGH at 0.25 mg/kg·wk (0.107 IU/kg·d). The injection was given daily and the total weekly amount was separated into 6-7 injections. The patients were followed up at 3-month intervals and the treatment duration was 12 months. The height (HT), annual growth velocity (GV), mean height standard deviation score (HT SDS), blood serum insulin-like growth factor I (IGF-I), insulin-like growth factor binding protein 3 (IGFBP-3), and bone maturity before and after treatment were compared, and the safety of the treatment was analyzed. The mean HT, GV, and HT SDS were increased from 109.0±14 cm, 2.7±0.9 cm/yr, and -4.62±1.46 at baseline to 121.8±13.4 cm, 12.9±3.3 cm/yr, and -2.47±1.86 after 12 months of treatment, respectively ( <0.001). At the same time, blood IGF-I and IGFBP-3 were increased significantly [41.27±64.43 μg/L 159.21±167.92 μg/L and 1540.00±1325.11 mg/L 3533.93±1413.82 mg/L, respectively ( <0.001)]. The bone age assessments performed 6 and 12 months after the treatment showed that no advanced bone maturation was noted. No serious adverse events occurred during the treatment, and the drug-related adverse events were mainly decreased thyroid function. We conclude that rhGH injection is a safe and effective drug for treatment of growth hormone deficiency in children.

关键词： recombinant human growth hormone     injection     growth hormone deficiency    

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SARS流行预测分析

王建锋

《中国工程科学》 2003年 第5卷 第8期   页码 23-29

摘要：

表面上突如其来的SARS本质上却有极规律的内在发展演化机制，遵从初始缓慢增长、加速、减速和稳定终止四个阶段总体道路，自然和社会生活领域众多事件演化都符合这一规律，因而可以运用广义的Logistic生长模型进行描述。基于先期流行的广东SARS感染病例数据，以及尚未结束的北京、全国2003年SARS流行统计数据，借助于最优化分析技术，运用广义的Logistic生长模型对该事件演化特征参量进行了辨识；在此基础上，又借助于广义生长模型的特例——Gompertz函数进行了演化过程的预测，并与其他生长模型结果进行了比较。研究表明，生长模型模拟结果均与实际数据有很好的一致性，可以用来预测事件的发生演化过程，此次SARS事件堪称生长模型的经典实例。

关键词： SARS     广义的Logistic生长模型     Gompertz分布     预测     最优化    

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标题 作者 时间 类型 操作

Availability growth models and verification of power equipment

Jinyuan SHI, Jiamin XU

期刊论文

A reliability growth model for 300?MW pumped-storage power units

Jinyuan SHI , Yu YANG , Zhicheng DENG ,

期刊论文

Economic Growth Model Based on Six Basic Factors of Production—Xu Growth Rate Equation

Shou-bo Xu,Zong-yuan Huang

期刊论文

Concurrent fatigue crack growth simulation using extended finite element method

Zizi LU, Yongming LIU,

期刊论文

Bridging reliability and operations management for superior system availability: Challenges and opportunities

期刊论文

Bacteria-mediated tumor-targeted delivery of tumstatin (54-132) significantly suppresses tumor growthin mouse model by inhibiting angiogenesis and promoting apoptosis

期刊论文

Analyzing the service availability of mobile cloud computing systems by fluid-flow approximation

Hong-wu LV,Jun-yu LIN,Hui-qiang WANG,Guang-sheng FENG,Mo ZHOU

期刊论文

Effect of atorvastatin on tumor growth and metastasis in a breast cancer cell xenograft model and its

Liu LIU MD, PhD, Yaogui NING MM, Chen CHEN MD, Daowen WANG MD, PhD,

期刊论文

Influence of welding residual stresses on the ductile crack growth resistance of circumferentially cracked

Xiaobo REN, Odd M. AKSELSEN, B?rd NYHUS, Zhiliang ZHANG

期刊论文

大空间内着火位置对火灾增长的影响

石龙,张瑞芳, 谢启源,付丽华

期刊论文

Simulation of cohesive crack growth by a variable-node XFEM

Weihua FANG, Jiangfei WU, Tiantang YU, Thanh-Tung NGUYEN, Tinh Quoc BUI

期刊论文

Aerobic granular sludge formation based on substrate availability: Effects of flow pattern and fermentation

Quan Yuan, Hui Gong, Hao Xi, Kaijun Wang

期刊论文

Modeling and simulation of landfill gas production from pretreated MSW landfill simulator

Rasool Bux MAHAR,Abdul Razaque SAHITO,Dongbei YUE,Kamranullah KHAN

期刊论文

Clinical evaluation of recombinant human growth hormone injection in children with growth hormone deficiency

Ling HOU, Xiaoping LUO, Minlian DU, Huamei MA, Chunxiu GONG, Yuchuan LI, Shuixian SHEN, Zhuhui ZHAO, Li LIANG, Guanping DONG, Chaoying YAN, Hongwei DU

期刊论文

SARS流行预测分析

王建锋

期刊论文