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故障诊断 2

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Novel methods by using non-vacuum insulated tubing to extend the lifetime of the tubing

Chenglong ZHOU,Guojin ZHU,Yongxiang XU,Jifei YU,Xiaoliang ZHANG,Hongzhi SHENG

《能源前沿（英文）》 2015年 第9卷 第2期   页码 142-147 doi: 10.1007/s11708-015-0357-7

摘要： The analysis of the failure mechanics, namely hydrogen permeation of vacuum insulated tubing (VIT), indicated that the failure of VIT could be decreased but could not be avoided. To solve this problem, some measures by using non-vacuum materials were proposed and analyzed in this paper. The results show that to fill the tubing with foam-glass beads or high pressure argon may lead to a good performance.

关键词： vacuum insulated tubing     cyclic steam stimulation     insulation material     thermal conductivity     foam-glass     hydrogen permeation    

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电刺激小脑顶核与中枢神经源性神经保护

董为伟

《中国工程科学》 2001年 第3卷 第11期   页码 32-38

摘要：

电刺激小脑顶核为一种重要的条件性中枢神经源性神经保护途径，文章介绍了中枢神经源性神经保护及其机制，神经保护特点及所涉及的解剖部位；重点讨论电刺激小脑顶核对缺血性脑损伤的神经保护机理，并展望其临床应用及研究前景。

关键词： 神经保护     条件性     小脑顶核     电刺激     脑缺血    

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EEG-controlled functional electrical stimulation rehabilitation for chronic stroke: system design and

《医学前沿（英文）》 2021年 第15卷 第5期   页码 740-749 doi: 10.1007/s11684-020-0794-5

摘要： Stroke is one of the most serious diseases that threaten human life and health. It is a major cause of death and disability in the clinic. New strategies for motor rehabilitation after stroke are undergoing exploration. We aimed to develop a novel artificial neural rehabilitation system, which integrates brain--computer interface (BCI) and functional electrical stimulation (FES) technologies, for limb motor function recovery after stroke. We conducted clinical trials (including controlled trials) in 32 patients with chronic stroke. Patients were randomly divided into the BCI-FES group and the neuromuscular electrical stimulation (NMES) group. The changes in outcome measures during intervention were compared between groups, and the trends of ERD values based on EEG were analyzed for BCI-FES group. Results showed that the increase in Fugl Meyer Assessment of the Upper Extremity (FMA-UE) and Kendall Manual Muscle Testing (Kendall MMT) scores of the BCI-FES group was significantly higher than that in the sham group, which indicated the practicality and superiority of the BCI-FES system in clinical practice. The change in the laterality coefficient (LC) values based on μ-ERD (ΔLCm-ERD) had high significant positive correlation with the change in FMA-UE(r= 0.6093, P=0.012), which provides theoretical basis for exploring novel objective evaluation methods.

关键词： brain–computer interface     functional electrical stimulation     electroencephalogram     laterality coefficient     chronic stroke    

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EEG controlled neuromuscular electrical stimulation of the upper limb for stroke patients

Hock Guan TAN, Cheng Yap SHEE, Keng He KONG, Cuntai GUAN, Wei Tech ANG

《机械工程前沿（英文）》 2011年 第6卷 第1期   页码 71-81 doi: 10.1007/s11465-011-0207-1

摘要：

This paper describes the Brain Computer Interface (BCI) system and the experiments to allow post-acute (<3 months) stroke patients to use electroencephalogram (EEG) to trigger neuromuscular electrical stimulation (NMES)-assisted extension of the wrist/fingers, which are essential pre-requisites for useful hand function. EEG was recorded while subjects performed motor imagery of their paretic limb, and then analyzed to determine the optimal frequency range within the -rhythm, with the greatest attenuation. Aided by visual feedback, subjects then trained to regulate their -rhythm EEG to operate the BCI to trigger NMES of the wrist/finger. 6 post-acute stroke patients successfully completed the training, with 4 able to learn to control and use the BCI to initiate NMES. This result is consistent with the reported BCI literacy rate of healthy subjects. Thereafter, without the loss of generality, the controller of the NMES is developed and is based on a model of the upper limb muscle (biceps/triceps) groups to determine the intensity of NMES required to flex or extend the forearm by a specific angle. The muscle model is based on a phenomenological approach, with parameters that are easily measured and conveniently implemented.

关键词： brain computer interface     neuromuscular electrical stimulation     stroke     musculoskeletal modeling    

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Repetitive transcranial magnetic stimulation causes significant changes of chemical substances in the

GUO Tiecheng, CAO Xuebing, XIA Limin

《医学前沿（英文）》 2008年 第2卷 第4期   页码 406-409 doi: 10.1007/s11684-008-0078-y

摘要： More and more studies have reported the usefulness of repetitive transcranial magnetic stimulation (rTMS) in the treatment of stroke patients. This article is to explore if rTMS can cause changes of such chemical substances as N-acetylaspartate (NAA), choline (Cho) and creatine (Cr) in the surrounding area of experimental intracerebral hematoma of rabbits. A total of 36 rabbits were randomly divided into 3 groups: a control group (group A), a sham rTMS group (group B) and an rTMS group (group C). The experimental intracerebral hemorrhage (ICH) was induced by intracerebral injection of self-body blood of the animals in groups B and C, while those of the group A serving as controls were injected with normal saline. The rabbits of groups B and C were treated with sham and real rTMS, respectively, but those of group A were not. The contents of chemical substances including NAA, Cho and Cr in the perihematomal brain tissues were measured by using H-magnetic resonance spectroscopy (H-MRS) 12 hours, 72 hours, 1 week and 2 weeks after the experimental ICH was induced. The results show that the contents of NAA, Cr and NAA/Cr ratio were decreased significantly, but Cho, Cho/Cr increased significantly in groups B and C ( < 0.01) as compared against those in group A. A comparison between the groups B and C revealed that the contents of NAA, Cr, NAA/Cr were higher, but Cho and Cho/Cr were significantly lower in group C than those in group B ( < 0.01). It is concluded that rTMS could result in changes of the chemical substance contents in perihematomal brain tissues, which leads to neuroprotective effects in the brain.
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Modeling analysis on solar steam generator employed in multi-effect distillation (MED) system

Zhaorui ZHAO, Bao YANG, Ziwen XING

《能源前沿（英文）》 2019年 第13卷 第1期   页码 193-203 doi: 10.1007/s11708-019-0608-0

摘要： Recently the porous bilayer wood solar collectors have drawn increasing attention because of their potential application in solar desalination. In this paper, a thermodynamic model has been developed to analyze the performance of the wood solar collector. A modeling analysis has also been conducted to assess the performance and operating conditions of the multiple effect desalination (MED) system integrated with the porous wood solar collector. Specifically, the effects of operating parameters, such as the motive steam temperature, seawater flow rate, input solar energy and number of effects on the energy consumption for each ton of distilled water produced have been investigated in the MED desalination system combined with the bilayer wood solar steam generator. It is found that, under a given operating condition, there exists an optimum steam generation temperature of around 145°C in the wood solar collector, so that the specific power consumption in the MED system reaches a minimum value of 24.88 kWh/t. The average temperature difference is significantly affected by the solar heating capacity. With the solar capacity increasing from 50 kW to 230 kW, the average temperature difference increases from 1.88°C to 6.27°C. This parametric simulation study will help the design of efficient bilayer wood solar steam generator as well as the MED desalination system.

关键词： solar energy     steam generating     multi-effect desalination    

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Intrinsic kinetics and external diffusion of catalytic steam gasification of fine coal char particles

Xuantao Wu, Jie Wang

《化学科学与工程前沿（英文）》 2019年 第13卷 第2期   页码 415-426 doi: 10.1007/s11705-018-1725-8

摘要： Catalytic steam gasification of fine coal char particles was carried out using a self-made laboratory reactor to determine the intrinsic kinetics and external diffusion under varying pressures (0.1–0.5 MPa) and superficial gas flow velocities (GFVs) of 13.8–68.8 cm?s . In order to estimate the gas release rate at a low GFV, the transported effect of effluent gas on the temporal gasification rate pattern was simulated by the Fluent computation and verified experimentally. The external mass transfer coefficients ( ) and the effectiveness factors were determined at lower GFVs, based on the intrinsic gasification rate obtained at a high GFV of 55.0 cm?s . The was found to be almost invariable in a wider carbon conversion of 0.2–0.7. The variations of at a median carbon conversion with GFV, temperature and pressure were found to follow a modified Chilton-Colburn correlation: (0.04< <0.19), where is total pressure and is atmospheric pressure. An intrinsic kinetics/external diffusion integrating model could well describe the gasification rate as a function of GFV, temperature and pressure over a whole gasification process.

关键词： coal char     catalytic steam gasification     pressure     kinetics     diffusion    

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An enhanced damage plasticity model for predicting the cyclic behavior of plain concrete under multiaxial

Mohammad Reza AZADI KAKAVAND, Ertugrul TACIROGLU

《结构与土木工程前沿（英文）》 2020年 第14卷 第6期   页码 1531-1544 doi: 10.1007/s11709-020-0675-7

摘要： Some of the current concrete damage plasticity models in the literature employ a single damage variable for both the tension and compression regimes, while a few more advanced models employ two damage variables. Models with a single variable have an inherent difficulty in accounting for the damage accrued due to tensile and compressive actions in appropriately different manners, and their mutual dependencies. In the current models that adopt two damage variables, the independence of these damage variables during cyclic loading results in the failure to capture the effects of tensile damage on the compressive behavior of concrete and vice-versa. This study presents a cyclic model established by extending an existing monotonic constitutive model. The model describes the cyclic behavior of concrete under multiaxial loading conditions and considers the influence of tensile/compressive damage on the compressive/tensile response. The proposed model, dubbed the enhanced concrete damage plasticity model (ECDPM), is an extension of an existing model that combines the theories of classical plasticity and continuum damage mechanics. Unlike most prior studies on models in the same category, the performance of the proposed ECDPM is evaluated using experimental data on concrete specimens at the material level obtained under cyclic multiaxial loading conditions including uniaxial tension and confined compression. The performance of the model is observed to be satisfactory. Furthermore, the superiority of ECDPM over three previously proposed constitutive models is demonstrated through comparisons with the results of a uniaxial tension-compression test and a virtual test.

关键词： damage plasticity model     plain concrete     cyclic loading     multiaxial loading conditions    

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Effect of repeated gonadotropin stimulation on ovarian reserves and proliferation of ovarian surface

Linlin LIANG, Bei XU, Guijin ZHU

《医学前沿（英文）》 2009年 第3卷 第2期   页码 220-226 doi: 10.1007/s11684-009-0037-2

摘要： This study aimed to evaluate the effect of repeated ovarian stimulation (OS) on the ovarian follicular population and morphology in female mice and its influence on the embryo’s developmental ability, and the profile of the ovarian surface epithelium (OSE). A total of 75 mice were enrolled in this experiment and randomly assigned into three groups: repeated ovarian stimulated group [ =25; receiving 5 IU pregnant mare serum gonadotrophin (PMSG) and human chorionic gonadotropin (hCG) at 6 day intervals for 5 cycles]; single ovarian stimulated group ( =25; receiving 5 IU PMSG and hCG for 1 cycle), and control group ( =25; without additional treatment). The follicle number at various stages and the morphologies were recorded respectively in the three groups. The harvested oocytes or embryos, cleavage rate, good quality embryo rate, and blastocyst production rate were counted and calculated, and the proliferations of ovarian surface epithelium were evaluated respectively. In the three groups, the single ovarian stimulation treatment significantly increased the mean number of ovarian oocytes or embryos (39.25±10.77 one-cell embryos/female); on the other hand, repeated gonadotropin stimulation obtained the lowest mean number (5.15± 2.81 eggs/female, <0.01). Repeated ovarian stimulation also tended to decrease normal follicles of primary follicles (66.67%) and secondary follicles (72.86%), and got the lowest cleavage rate (67.47%), lowest good quality embryo rate (2.41%), and lowest blastocyst production rate (0). The OSE cells adjacent to the antral follicles and corpus luteum (CL) in the repeated ovarian stimulated group (81.8%) had a significantly higher proliferation rate than the other groups. The proliferation rate of the OSE in the single ovarian stimulated group (56.4%) was significantly higher than that in the control group (37.5%) ( <0.01). In conclusion, single ovarian stimulation may produce more oocytes/embryos. However, repeated gonadotropin stimulation may have a negative effect on the ovarian follicular quality, the number of mature retrieved oocytes, and the embryo quality, even increasing the chance of ovarian cancer.

关键词： gonadotropin-releasing hormone     ovarian reserve     embryo developmental ability     ovarian surface epithelium    

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Isogeometric analysis of coupled thermo-elastodynamic problems under cyclic thermal shock

Asghar AMANI DASHLEJEH

《结构与土木工程前沿（英文）》 2019年 第13卷 第2期   页码 397-405 doi: 10.1007/s11709-018-0473-7

摘要： The isogeometric analysis (IGA) method was extended for the solution of the coupled thermo-elastodynamic equations. The dimensionless formulation was accepted in discretization of the uncoupled and coupled thermoelasticity equations and the Generalized Newmark method was used in the time integration procedure. First, the performance of the proposed method was verified against a two-dimensional benchmark example subjected to constant thermal shock with available exact analytical solutions. Then a two-dimensional half-space benchmark example under thermal shock was solved. Finally, cyclic thermal shock (CTS) loading was applied on the half-space problem. The results dedicated that IGA can be used as a suitable approach in the analysis of the general thermomechanical problems.

关键词： isogeometric analysis     coupled thermo-elastodynamic     dynamic analysis     generalized newmark     cyclic thermal shock    

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Performance evaluation of an improved biomass-fired cogeneration system simultaneously using extraction steam

《能源前沿（英文）》 2022年 第16卷 第2期   页码 321-335 doi: 10.1007/s11708-021-0741-4

摘要： An advanced cogeneration system based on biomass direct combustion was developed and its feasibility was demonstrated. In place of the traditional single heat source (extraction steam), the extraction steam from the turbine, the cooling water from the plant condenser, and the low-pressure feedwater from the feedwater preheating system were collectively used for producing district heat in the new scheme. Hence, a remarkable energy-saving effect could be achieved, improving the overall efficiency of the cogeneration system. The thermodynamic and economic performance of the novel system was examined when taking a 35 MW biomass-fired cogeneration unit for case study. Once the biomass feed rate and net thermal production remain constant, an increment of 1.36 MW can be expected in the net electric production, because of the recommended upgrading. Consequently, the total system efficiency and effective electrical efficiency augmented by 1.23 and 1.50 percentage points. The inherent mechanism of performance enhancement was investigated from the energy and exergy aspects. The economic study indicates that the dynamic payback period of the retrofitting project is merely 1.20 years, with a net present value of 5796.0 k$. In conclusion, the proposed concept is validated to be advantageous and profitable.

关键词： biomass-fired cogeneration     district heat production system     absorption heat pump     extraction steam     cooling water     low-pressure feedwater    

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High-efficiency inspecting method for mobile robots based on task planning for heat transfer tubes in a steam

《机械工程前沿（英文）》 2023年 第18卷 第2期 doi: 10.1007/s11465-022-0741-z

摘要： Many heat transfer tubes are distributed on the tube plates of a steam generator that requires periodic inspection by robots. Existing inspection robots are usually involved in issues: Robots with manipulators need complicated installation due to their fixed base; tube mobile robots suffer from low running efficiency because of their structural restricts. Since there are thousands of tubes to be checked, task planning is essential to guarantee the precise, orderly, and efficient inspection process. Most in-service robots check the task tubes using row-by-row and column-by-column planning. This leads to unnecessary inspections, resulting in a long shutdown and affecting the regular operation of a nuclear power plant. Therefore, this paper introduces the structure and control system of a dexterous robot and proposes a task planning method. This method proceeds into three steps: task allocation, base position search, and sequence planning. To allocate the task regions, this method calculates the tool work matrix and proposes a criterion to evaluate a sub-region. And then all tasks contained in the sub-region are considered globally to search the base positions. Lastly, we apply an improved ant colony algorithm for base sequence planning and determine the inspection orders according to the planned path. We validated the optimized algorithm by conducting task planning experiments using our robot on a tube sheet. The results show that the proposed method can accomplish full task coverage with few repetitive or redundant inspections and it increases the efficiency by 33.31% compared to the traditional planning algorithms.

关键词： steam generator transfer tubes     mobile robot     dexterous structure     task planning     efficient inspection    

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Prediction of cyclic large plasticity for prestrained structural steel using only tensile coupon tests

Liang-Jiu JIA, Tsuyoshi KOYAMA, Hitoshi KUWAMURA

《结构与土木工程前沿（英文）》 2013年 第7卷 第4期   页码 466-476 doi: 10.1007/s11709-013-0219-5

摘要： Cold-formed steel members, which experience complicated prestrain histories, are frequently applied in structural engineering. This paper aims to predict cyclic plasticity of structural steels with tensile and compressive prestrain. Monotonic and cyclic tests on hourglass specimens with tensile and compressive prestrain are conducted, and compared with numerical simulations using the Chaboche model. Two approaches are taken in the simulation. The first requires only the monotonic tensile test data from the prestrained steels, and the second requires both the monotonic tensile test data from the virgin steel and the prestrain histories. The first approach slightly overestimates the compressive stress for specimens with tensile prestrain, while the second approach is able to accurately predict the cyclic plasticity in specimens with tensile and compressive prestrain.

关键词： cyclic plasticity     prestrain     Chaboche model     mild steel    

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循环双谱及在周期平稳类故障中的应用

苏中元,贾民平,许飞云,胡建中

《中国工程科学》 2006年 第8卷 第9期   页码 57-60

摘要：

论述了未知循环频率的周期平稳信号循环双谱的估计方法；研究了在循环双谱的循环累积量计算中涉及变量的简化存储方法，提出了该变量矩阵是对称阵，通过算法可以三角阵的元素来表述，克服了循环双谱传统估计方法计算量较大的缺陷，提高了运算效率；提出了循环双谱对调相故障信号的分析能力，以及对加性噪声的处理能力，仿真并验证了该方法的有效性，并将其应用于旋转机械状态分析。

关键词： 周期平稳     循环双谱     滞后积    

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A steam dried municipal solid waste gasification and melting process

Gang XIAO, Baosheng JIN, Mingjiang NI, Kefa CEN, Yong CHI, Zhongxin TAN

《环境科学与工程前沿（英文）》 2011年 第5卷 第2期   页码 193-204 doi: 10.1007/s11783-010-0268-0

摘要： Considering high-moisture municipal solid waste (MSW) of China, a steam dried MSW gasification and melting process was proposed, the feasibility was tested, and the mass and energy balance was analyzed. Preliminary experiments were conducted using a fixed-bed drying apparatus, a 200 kg per day fluidized-bed gasifier, and a swirl melting furnace. Moisture percentage was reduced from 50% to 20% roughly when MSW was dried by slightly superheated steam of 150°C–350°C within 40 min. When the temperature was less than 250°C, no incondensable gas was produced during the drying process. The gasifier ran at 550°C–700°Cwith an air equivalence ratio (ER) of 0.2–0.4. The temperature of the swirl melting furnace reached about 1240°C when the gasification ER was 0.3 and the total ER was 1.1. At these conditions, the fly ash concentration in the flue gas was 1.7 g·(Nm ) , which meant over 95% fly ash was trapped in the furnace and discharged as slag. 85% of Ni and Cr were bound in the slag, as well as 60% of Cu. The mass and energy balance analysis indicates that the boiler heat efficiency of an industrial MSW incineration plant reaches 86.97% when MSW is dried by steam of 200°C. The boiler heat efficiency is sensitive to three important parameters, including the temperature of preheated MSW, the moisture percentage of dried MSW and the fly ash percentage in the total ash.

关键词： municipal solid waste (MSW)     steam drying     gasification and melting    

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标题 作者 时间 类型 操作

Novel methods by using non-vacuum insulated tubing to extend the lifetime of the tubing

Chenglong ZHOU,Guojin ZHU,Yongxiang XU,Jifei YU,Xiaoliang ZHANG,Hongzhi SHENG

期刊论文

电刺激小脑顶核与中枢神经源性神经保护

董为伟

期刊论文

EEG-controlled functional electrical stimulation rehabilitation for chronic stroke: system design and

期刊论文

EEG controlled neuromuscular electrical stimulation of the upper limb for stroke patients

Hock Guan TAN, Cheng Yap SHEE, Keng He KONG, Cuntai GUAN, Wei Tech ANG

期刊论文

Repetitive transcranial magnetic stimulation causes significant changes of chemical substances in the

GUO Tiecheng, CAO Xuebing, XIA Limin

期刊论文

Modeling analysis on solar steam generator employed in multi-effect distillation (MED) system

Zhaorui ZHAO, Bao YANG, Ziwen XING

期刊论文

Intrinsic kinetics and external diffusion of catalytic steam gasification of fine coal char particles

Xuantao Wu, Jie Wang

期刊论文

An enhanced damage plasticity model for predicting the cyclic behavior of plain concrete under multiaxial

Mohammad Reza AZADI KAKAVAND, Ertugrul TACIROGLU

期刊论文

Effect of repeated gonadotropin stimulation on ovarian reserves and proliferation of ovarian surface

Linlin LIANG, Bei XU, Guijin ZHU

期刊论文

Isogeometric analysis of coupled thermo-elastodynamic problems under cyclic thermal shock

Asghar AMANI DASHLEJEH

期刊论文

Performance evaluation of an improved biomass-fired cogeneration system simultaneously using extraction steam

期刊论文

High-efficiency inspecting method for mobile robots based on task planning for heat transfer tubes in a steam

期刊论文

Prediction of cyclic large plasticity for prestrained structural steel using only tensile coupon tests

Liang-Jiu JIA, Tsuyoshi KOYAMA, Hitoshi KUWAMURA

期刊论文

循环双谱及在周期平稳类故障中的应用

苏中元,贾民平,许飞云,胡建中

期刊论文

A steam dried municipal solid waste gasification and melting process

Gang XIAO, Baosheng JIN, Mingjiang NI, Kefa CEN, Yong CHI, Zhongxin TAN

期刊论文