Search | Engineering

订阅投稿

首页工程期刊工程焦点工程成就工程前沿关于我们 English

资源类型

期刊论文 313

会议视频 3

年份

2023 11

2022 22

2021 15

2020 18

2019 11

2018 12

2017 14

2016 7

2015 8

2014 12

2013 26

2012 12

2011 33

2010 23

2009 14

2008 16

2007 16

2006 5

2005 6

2004 6

展开︾

关键词

三峡工程 38

升船机 11

三峡升船机 10

三塔悬索桥 4

混凝土 4

三峡库区 3

施工技术 3

横梁 3

设计 3

2021全球十大工程成就 2

三塔两跨悬索桥 2

三点弯曲梁 2

三相界面 2

三维 2

创新 2

动力特性 2

升船机塔柱 2

南京长江第四大桥 2

工程管理 2

展开︾

检索范围：

排序：展示方式：

A space solar cell bonding robot

FU Zhuang, ZHAO Yan-zheng, LIU Ren-qiang, DONG Zhi

《机械工程前沿（英文）》 2006年第1卷第3期页码 360-363 doi: 10.1007/s11465-006-0027-x

摘要： A space solar cell bonding robot system which consists of a three-axis Cartesian coordinate s robot, coating device, bonding device, orientation plate, and control subsystem was studied. A method, which can control the thickness o

关键词： Cartesian coordinate thickness three-axis Cartesian orientation control subsystem

HTML PDF 收藏

多孔质气体静压轴承在三轴转台设计中的应用

杜金名

《中国工程科学》 2005年第7卷第1期页码 65-68

摘要：

气体静压轴承广泛应用于航空、航天、精密电子工业中。三轴转台是高精度的测试设备，用来对惯性系统和惯性元件进行检定、标定以及建立相应的误差模型，它的测试精度直接影响航空、航天等飞行器的控制和导航。转台的检测精度与回转轴的回转精度有密切关系。多孔质气体静压轴承同其他节流形式的轴承相比具有很高的承载能力、静态刚度以及很好的阻尼效应。文章对多孔质气体静压轴承进行了理论分析，并同气体静压小孔节流轴承的静态性能进行了比较，结果表明，此类轴承的承载能力明显优于小孔节流轴承。

关键词：气体静压轴承多孔质小孔节流三轴转台

HTML PDF 收藏

Five-axis rough machining for impellers

Ruolong QI, Weijun LIU, Hongyou BIAN, Lun LI

《机械工程前沿（英文）》 2009年第4卷第1期页码 71-76 doi: 10.1007/s11465-009-0010-4

摘要： The most important components used in aerospace, ships, and automobiles are designed with free form surfaces. An impeller is one of the most important components that is difficult to machine because of its twisted blades. Rough machining is recognized as the most crucial procedure influencing machining efficiency and is critical for the finishing process. An integrated rough machining course with detailed algorithms is presented in this paper. An algorithm for determining the minimum distance between two surfaces is applied to estimate the tool size. The space between two blades that will be cleared from the roughcast is divided to generate CC points. The tool axis vector is confirmed based on flank milling using a simple method that could eliminate global interference between the tool and the blades. The result proves that the machining methodology presented in this paper is useful and successful.

关键词： five-axis impeller tool-path planning flank milling ruled surface

HTML PDF 收藏

Kinematic error separation on five-axis NC machine tool based on telescoping double ball bar

Min WANG, Jianzhong HU, Tao ZAN

《机械工程前沿（英文）》 2010年第5卷第4期页码 431-437 doi: 10.1007/s11465-010-0110-1

摘要： The theory and algorithm of the homogeneous transformation matrix (HTM) method are applied in establishing the kinematic error model of five-axis machining tool with two-axis turntable. Based on this model, a new method for the kinematic error separation in five-axis numerical control (NC) machining tool is proposed. In this study, three types of simultaneous three-axis control motions are designed for each rotary axis to identify the deviations. In the measurement, two translational axes and one rotary axis are simultaneously controlled to keep a constant distance between the tool and the worktable. Telescoping double ball bar is used to measure the relative distance between the spindle and the worktable in the motion of NC machining tool. Finally, the value measured by telescoping double ball bar is substituted into the model to obtain kinematic error of NC machining tool. Comparison has confirmed that the proposed method is high precision and can be applied to effectively and conveniently measure the five-axis machining tool.

关键词： error modeling error separation telescoping double ball bar five-axis numerical control (NC) machining tool

HTML PDF 收藏

Optimization model for rotor blades of horizontal axis wind turbines

LIU Xiong, CHEN Yan, YE Zhiquan

《机械工程前沿（英文）》 2007年第2卷第4期页码 483-488 doi: 10.1007/s11465-007-0084-9

摘要： This paper presents an optimization model for rotor blades of horizontal axis wind turbines. The model refers to the wind speed distribution function on the specific wind site, with an objective to satisfy the maximum annual energy output. To speed up the search process and guarantee a global optimal result, the extended compact genetic algorithm (ECGA) is used to carry out the search process. Compared with the simple genetic algorithm, ECGA runs much faster and can get more accurate results with a much smaller population size and fewer function evaluations. Using the developed optimization program, blades of a 1.3 MW stall-regulated wind turbine are designed. Compared with the existing blades, the designed blades have obviously better aerodynamic performance.

关键词： population extended algorithm developed optimization accurate

HTML PDF 收藏

Performance of vertical axis water turbine with eye-shaped baffle for pico hydropower

Zhuohuan HU, Dongcheng WANG, Wei LU, Jian CHEN, Yuwen ZHANG

《能源前沿（英文）》 2022年第16卷第4期页码 683-696 doi: 10.1007/s11708-020-0689-9

摘要： A series of inline pico hydropower systems, which could be used in confined space, especially for water distribution networks (WDNs), was designed and investigated. The turbine with an eye-shaped vertical water baffle was developed to evaluate the hydraulic performance. A three-dimensional dynamic mesh was employed and the inlet velocity was considered as the inlet boundary condition, whereas the outlet boundary was set as the outflow. Then, numerical simulations were conducted and the standard turbulence model was found to be the best capable of predicting flow features through the comparison with the experimental results. The effects of the opening diameter of the water baffle and installation angle of the rotor on the flow field in the turbine were investigated. The results suggested that the water baffle opening at = 30 mm and the rotor at a 52° angle could achieve the highest efficiency of 5.93%. The proper eye-shaped baffle not only accelerates the fluid flow and generates positive hydrodynamic torque, but also eliminates the flow separation. The scheme proposed in this paper can be exploited for practical applications in the water pipelines at various conditions and power requirements.

关键词： vertical axis water turbine eye-shaped vertical water baffle pico hydropower

HTML PDF 收藏

Determination of the feasible setup parameters of a workpiece to maximize the utilization of a five-axis

Aqeel AHMED, Muhammad WASIF, Anis FATIMA, Liming WANG, Syed Amir IQBAL

《机械工程前沿（英文）》 2021年第16卷第2期页码 298-314 doi: 10.1007/s11465-020-0621-3

摘要： The machining industry must maximize the machine tool utilization for its efficient and effective usage. Determining a feasible workpiece location is one of the significant tasks performed in an iterative way via machining simulations. The maximum utilization of five-axis machine tools depends upon the cutting system’s geometry, the configuration of the machine tool, and the workpiece’s location. In this research, a mathematical model has been developed to determine the workpiece’s feasible location in the five-axis machine tool for avoiding the number of iterations, which are usually performed to eliminate the global collision and axis limit errors. In this research, a generic arrangement of the five-axis machine tool has been selected. The mathematical model of post-processor has been developed by using kinematic modeling methods. The machine tool envelopes have been determined using the post-processor and axial limit. The tooltip reachable workspace is determined by incorporating the post-processor, optimal cutting system length, and machining envelope, thereby further developing an algorithm to determine the feasible workpiece setup parameters accurately. The algorithm’s application has been demonstrated using an example. Finally, the algorithm is validated for feasible workpiece setup parameters in a virtual environment. This research is highly applicable in the industry to eliminate the number of iterations performed for the suitable workpiece setup parameters.

关键词： workpiece setup parameter five-axis space utilization setup parameters machine tool

HTML PDF 收藏

Role of the forkhead transcription factor FOXO-FOXM1 axis in cancer and drug resistance

null

《医学前沿（英文）》 2012年第6卷第4期页码 376-380 doi: 10.1007/s11684-012-0228-0

摘要：

The forkhead transcription factors FOXO and FOXM1 have pivotal roles in tumorigenesis and in mediating chemotherapy sensitivity and resistance. Recent research shows that the forkhead transcription factor FOXM1 is a direct transcriptional target repressed by the forkhead protein FOXO3a, a vital downstream effector of the PI3K-AKT-FOXO signaling pathway. Intriguingly, FOXM1 and FOXO3a also compete for binding to the same gene targets, which have a role in chemotherapeutic drug action and sensitivity. An understanding of the role and regulation of the FOXO-FOXM1 axis will impact directly on our knowledge of chemotherapeutic drug action and resistance in patients, and provide new insights into the design of novel therapeutic strategy and reliable biomarkers for prediction of drug sensitivity.

关键词： FOXO3a FOXM1 transcription factor cancer drug resistance tumorigenesis

HTML PDF 收藏

Estimation of power in low velocity vertical axis wind turbine

Sampath S. S.,Sawan SHETTY,Chithirai Pon Selvan M.

《机械工程前沿（英文）》 2015年第10卷第2期页码 211-218 doi: 10.1007/s11465-015-0338-x

摘要：

The present work involves in the construction of a vertical axis wind turbine and the determination of power. Various different types of turbine blades are considered and the optimum blade is selected. Mechanical components of the entire setup are built to obtain maximum rotation per minute. The mechanical energy is converted into the electrical energy by coupling coaxially between the shaft and the generator. This setup produces sufficient power for consumption of household purposes which is economic and easily available.

关键词： wind turbine shaft design power generation generator

HTML PDF 收藏

FMO3--TMAO axis modulates the clinical outcome in chronic heart-failure patients with reduced ejection

《医学前沿（英文）》 2022年第16卷第2期页码 295-305 doi: 10.1007/s11684-021-0857-2

摘要： The association among plasma trimethylamine-N-oxide (TMAO), FMO3 polymorphisms, and chronic heart failure (CHF) remains to be elucidated. TMAO is a microbiota-dependent metabolite from dietary choline and carnitine. A prospective study was performed including 955 consecutively diagnosed CHF patients with reduced ejection fraction, with the longest follow-up of 7 years. The concentrations of plasma TMAO and its precursors, namely, choline and carnitine, were determined by liquid chromatography-mass spectrometry, and the FMO3 E158K polymorphisms (rs2266782) were genotyped. The top tertile of plasma TMAO was associated with a significant increment in hazard ratio (HR) for the composite outcome of cardiovascular death or heart transplantation (HR=1.47, 95% CI=1.13–1.91, P=0.004) compared with the lowest tertile. After adjustments of the potential confounders, higher TMAO could still be used to predict the risk of the primary endpoint (adjusted HR=1.33, 95% CI=1.01–1.74, P=0.039). This result was also obtained after further adjustment for carnitine (adjusted HR=1.33, 95% CI=1.01–1.74, P=0.039). The FMO3 rs2266782 polymorphism was associated with the plasma TMAO concentrations in our cohort, and lower TMAO levels were found in the AA-genotype. Thus, higher plasma TMAO levels indicated increased risk of the composite outcome of cardiovascular death or heart transplantation independent of potential confounders, and the FMO3 AA-genotype in rs2266782 was related to lower plasma TMAO levels.

关键词： chronic heart failure trimethylamine-N-oxide flavin monooxygenase 3 single nucleotide polymorphism

HTML PDF 收藏

Chidamide inhibits the NOTCH1-MYC signaling axis in T-cell acute lymphoblastic leukemia

《医学前沿（英文）》 2022年第16卷第3期页码 442-458 doi: 10.1007/s11684-021-0877-y

摘要： T-cell acute lymphoblastic leukemia (T-ALL) is one of the most dangerous hematological malignancies, with high tumor heterogeneity and poor prognosis. More than 60% of T-ALL patients carry NOTCH1 gene mutations, leading to abnormal expression of downstream target genes and aberrant activation of various signaling pathways. We found that chidamide, an HDAC inhibitor, exerts an antitumor effect on T-ALL cell lines and primary cells including an anti-NOTCH1 activity. In particular, chidamide inhibits the NOTCH1-MYC signaling axis by down-regulating the level of the intracellular form of NOTCH1 (NICD1) as well as MYC, partly through their ubiquitination and degradation by the proteasome pathway. We also report here the preliminary results of our clinical trial supporting that a treatment by chidamide reduces minimal residual disease (MRD) in patients and is well tolerated. Our results highlight the effectiveness and safety of chidamide in the treatment of T-ALL patients, including those with NOTCH1 mutations and open the way to a new therapeutic strategy for these patients.

关键词： T-cell acute lymphoblastic leukemia HDAC inhibitor chidamide NOTCH1 MYC ubiquitination

HTML PDF 收藏

Effects of parenteral nutrition with and without GH on the GH/IGF-1 axis after hepatectomy in hepatocellular

CAO Jie, LUO Shimin, LIANG Lijian, LAI Jiaming, CHEN Shanming

《医学前沿（英文）》 2007年第1卷第3期页码 287-293 doi: 10.1007/s11684-007-0055-x

摘要： Postoperative hepatic insulin-like growth factor-1 (IGF-1) production may be severely disturbed in patients with liver cirrhosis. Complex alterations in the GH/IGF-1 axis are thought to play an important role in the protein catabolism that complicates major surgical procedures. The aim of this study was to explore the effects of parenteral nutrition (PN) with and without growth hormone (GH) on the GH/IGF-1 axis after hepatectomy for hepatocellular carcinoma (HCC) with cirrhosis and evaluate the potential roles of recombinant human GH (rhGH) therapy. Twenty-four patients with HCC with cirrhosis who underwent hepatectomy were randomly divided into two groups: a PN group ( = 12) and an rhGH+PN group ( = 12). Liver function, serum GH, IGF-1 and IGFBP-3 were measured before the operation and at postoperative days (POD) 1 and 6. Insulin-like growth factor-1 and IGFBP-3 mRNA in the liver tissue was detected by RT-PCR. The liver Ki67 immunohistochemistry staining was studied. At the same time, 12 patients with cholelithiasis or liver hemangioma who underwent operation served as normal control group. On POD 6, serum prealbumin, GH, IGF-1, IGFBP-3, hepatic IGF-1 mRNA, IGFBP-3 mRNA and liver Ki67 LI were higher in the rhGH+PN group than in the PN group. There was no significant difference in the 6- and 12-month tumor-free survival rate and the median tumor-free survival time between the PN group and the rhGH+PN group (〉0.05). These data indicate that rhGH+PN could ameliorate the changes in the GH/IGF-1 axis after hepatectomy for HCC in the setting of cirrhosis.

关键词： control function production surgical Complex

HTML PDF 收藏

硅微z轴谐振陀螺仪负电刚度效应分析及实验验证

夏敦柱,周百令,王寿荣

《中国工程科学》 2007年第9卷第8期页码 66-68

摘要：

介绍了在开环工作状态下硅微z轴谐振陀螺仪由于加工工艺缺陷所导致的误差机理。为减小陀螺仪初始电容差和抑制正交耦合误差，提出了一种闭环控制检测策略。重点分析了其力矩反馈器的电刚度效应并给出其线性数学模型表示式。通过对硅微z轴陀螺仪敏感模态的反馈力与谐振频率的关系分析，间接得出了在敏感方向上电负刚度与力矩器所施电压的内在联系，并在实验上进一步验证电刚度效应。这将为下一步闭环控制方案的设计奠定重要基础。

关键词：硅微z轴陀螺仪负电刚度力矩反馈器微机电系统

HTML PDF 收藏

Atypical pituitary hormone–target tissue axis

《医学前沿（英文）》 2023年第17卷第1期页码 1-17 doi: 10.1007/s11684-022-0973-7

摘要： A long-held belief is that pituitary hormones bind to their cognate receptors in classical target glands to actuate their manifold functions. However, a number of studies have shown that multiple types of pituitary hormone receptors are widely expressed in non-classical target organs. Each pituitary gland-derived hormone exhibits a wide range of nonconventional biological effects in these non-classical target organs. Herein, the extra biological functions of pituitary hormones, thyroid-stimulating hormone, follicle-stimulating hormone, luteinizing hormone, adrenocorticotrophic hormone, and prolactin when they act on non-classical organs were summarized, defined by the novel concept of an “atypical pituitary hormone–target tissue axis.” This novel proposal explains the pathomechanisms of abnormal glucose and lipid metabolism, obesity, hypertension, fatty liver, and atherosclerosis while offering a more comprehensive and systematic insights into the coordinated regulation of environmental factors, genetic factors, and neuroendocrine hormones on human biological functions. The continued exploration of the physiology of the “atypical pituitary hormone–target tissue axis” could enable the identification of novel therapeutic targets for metabolic diseases.

关键词： thyroid-stimulating hormone follicle-stimulating hormone luteinizing hormone adrenocorticotrophic hormone prolactin

HTML PDF 收藏

Analysis and characterization of wind-solar-constant torque spring hybridized model

Shantanu ACHARYA,Subhadeep BHATTACHARJEE

《能源前沿（英文）》 2014年第8卷第3期页码 279-289 doi: 10.1007/s11708-014-0312-z

摘要： Solar and wind are the most promising renewable energy resources. But their unpredictable and varying nature prevents them from being used as the sole resource for power generation. This paper presents a model of wind and solar thermal hybrid power plant with a spring storage system which is expected to play an efficient role in combating with the drawbacks related to renewable power generation. In the proposed scheme, wind energy is harnessed by a hybrid vertical axis wind turbine, solar energy is utilized by a Stirling engine, and the surplus energy is stored in a winding spring. The paper discusses the working methodologies and analyses the performance of such 2.6 kW hybrid power plant model. It has been observed that the plant is capable of consistently generating 50% of its rated capacity irrespective of limitations in solar and wind resources.

关键词： hybrid vertical axis wind turbine Stirling engine solar-thermal energy wind energy constant torque spring