检索结果-南通市图书馆

Active-passive radial-additive friction stir repairing of mechanical hole out of dimension tolerance of AZ31 magnesium alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2023年第9期11卷 3186-3199页

作者： Hua liu zhenlei liu Shude Ji Yumei Yue Zhibo Dong Changlong Chen College of Aerospace Engineering Shenyang Aerospace UniversityShenyang 110136China State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China

In order to avoid the depth increasing of repaired hole and eliminate the super-fine grain band in stir zone by radial-additive friction stir repairing(R-AFSR), a solid-state repairing technique of active-passive radial-additive friction stir repairing(AP-RAFSR) assisted by the truncated cone-shaped filling material was proposed in this study. The mechanical hole out of dimension tolerance of AZ31 magnesium alloy was chosen as the repaired object. The results indicated that the AP-RAFSR process rather than the R-AFSR process avoided the kissing bond in the bottom of the repairing interface under the condition of the tool pin length equal to the height of the standard mechanical *** continuously-distributed and large-length super-fine grain bands were eliminated in the stir zone by AP-RAFSR. The maximum tensile and compressive-shear strengths of repaired hole by AP-RAFSR reached 190.6 MPa and 138.9 MPa at 1200 rpm respectively, which were equivalent to 97.7% and 89.6% of those of the standard mechanical hole. This AP-RAFSR process assisted by the truncated cone-shaped filling material provides a new technique to obtain a no-depth-increasing, defect-free and high-strength repaired mechanical hole.

关键词： Active-passive radial-additive friction stir repairing Mechanical hole out of dimension tolerance Numerical simulation Microstructure Mechanical properties

Development of a procedure for estimating the parameters of mechanistic VOC emission source models from chamber testing data

在线全文

学校读者我要写书评

暂无评论

Building Simulation 2021年第2期14卷 269-282页

作者： zhenlei liu Andreas Nicolai Marc Abadie Menghao Qin John Grunewald Jianshun Zhang Department of Mechanical and Aerospace Engineering Syracuse UniversitySyracuseUSA Dresden University of Technology DresdenGermany University of La Rochelle La RochelleFrance Technical University of Denmark Kongens LyngbyDenmark School of Architecture and Urban Planning Nanjing UniversityNanjingChina

In order to evaluate the impacts of volatile organic compounds(VOCs)emissions from building materials on the indoor air quality beyond the standard chamber test conditions and test period,mechanistic emission source models have been developed in the ***,very limited data are available for the required model parameters including the initial concentration(C_(m0)),in-material diffusion coefficient(D_(m)),partition coefficient(Kma),and convective mass transfer coefficient(k_(m)).In this study,a procedure was developed for estimating the model parameters by using VOC emission data from standard small chamber *** the procedure,initial values of the model parameters were refined by multivariate regression analysis of the measured emission *** verify the procedure and estimate its uncertainty,simulated chamber test data were generated by adding 10% experimental uncertainties on the theoretical curve from the analytical solution to a mechanistic emission *** the procedure was applied to the generated data to estimate the model *** indicated that estimates converged to the original parameter values used for the data generation and the error of estimated parameters D_(m1)C_(m0) and K_(ma) were within±10%,±23%,and±25%of the true values,*** procedure was further demonstrated by applying it to estimate the model parameters from real chamber test *** application of the procedure would result in a database of mechanistic source model parameters for assessing the impact of VOC emissions on indoor pollution load,which are essential input data for evaluating the effectiveness of various indoor air quality(IAQ)design and control strategies as well as the energy required for meeting given IAQ requirements.

关键词： building materials volatile organic compounds(VOCs) emission source model indoor air quality building energy efficiency

Influences of Synthesis Conditions on the Formation of Methotrexate Intercalated Layered Double Hydroxides by Exfoliation-reassembly Route

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2019年第5期35卷 901-907页

作者： liu zhenlei JIA Qingyang ZHAO Xiufen LI Shuping SHEN Jian LI Xiaodong Jiangsu Key Laboratory of Biofunctional Material College of Chemistry and Material ScienceNanjing Normal UniversityNanjing 210023P.R.China

The intercalation of methotrexate(MTX) into layered double hydroxides(LDHs) via an exfoliation-reassembly process was performed and the resulting hybrids were then characterized by X-ray difEractiometry( XRD), Fourier transform infrared(FTIR) spectroscopy, thermogravimetry(TG) and differential scanning calorimetry(DSC), etc. In the synthesis procedure, LDHs particles were firstly delaminated, and the reassembly process was performed to get MTX intercalated LDH(MTX/LDHs) hybrids. Tlie reassembly conditions, such as reassembly time and diflerent reassembly solvent, were studied emphatically. It was fbimd that 20 min is the optimum time and formamide is the most suitable solvent in the reassembly process. At last, the controlled release property and the drug-loading capacity were examined emphatically to reveal that MTX/LDHs hybrids reassembled in fomiamide exhibit the highest drug-loading capacity. The cytotoxicity of the hybrids was estimated by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-/7-tetrazolium bromide, thiazolyl blue tetrazolium bromide(MTT) assays on the human lung cancer cells(A549), with the results showing that MTX/LDHs hybrids have effective suppress role on the proliferation of cancer cells, and tlie hybrids obtained from the formamide solution present much better anticancer efleet than the other samples.

关键词： Methotrexatum Layered double hydroxide Exfoliation-reassembly process

Effect of pin rotating speed on lap shear strength of stationary shoulder friction stir lap welded 6005A-T6 aluminum alloy

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Welding 2016年第2期25卷 58-63页

作者： liu zhenlei Cui Hutao Ji Shude Xu Minqiang Li Zhengwei Deep Space Exploration Research Center Harbin Institute of Technology Harbin 150080 Faculty of Aerospace Engineering Shenyang Aerospace University Shenyang 110136

Stationary shoulder friction stir lap welding （SSFSLW） was successfully used to weld 6005A-T6 aluminum alloy in this paper. Effect of pin rotating speed on cross section morphologies and lap shear strength of the SSFSLW joints were mainly discussed. Results show that joints without flash and shoulder marks can be obtained by the stationary shoulder. Cross section of the SSFSLW joint presents a basin-like morphology and little material loss. By increasing the rotating speed from 1 000 rpm to 1 600 rpm, both effective sheet thickness and lap width increase, while lap shear failure load firstly decreases and then increases. The maximum failure load of 14. 05 kN /s attained when 1 000 rpm is used. All SSFSLW joints present shear fracture mode.

关键词： friction stir lap welding stationary shoulder rotating speed lap shear failure load

How to locate the dural defect in a spinal extradural meningeal cyst: a literature review

在线全文

学校读者我要写书评

暂无评论

Chinese Neurosurgical Journal 2022年第3期8卷 195-205页

作者： Qiang Jian zhenlei liu Wanru Duan Fengzeng Jian Zan Chen Department of Neurosurgery Xuanwu HospitalCapital Medical UniversityBeijing 100053China

Spinal extradural meningeal cysts(SEMCs)are rare lesions of the spinal *** closure of the dural defect can achieve satisfactory therapeutic effects,locating the fistula is *** review summarizes the methods for locating the fistula of SEMCs and the distribution and features of fistula *** was a non-systematic literature review of studies on *** searched PubMed for English-language articles to summarize the methods of locating the *** search words were“epidural arachnoid cyst,”“dural cyst,”“epidural cyst,”and“epidural meningeal cyst.”For the defect location component of the study,case reports,studies with a sample size less than four,controversial ventral dural dissection(s),and undocumented fistula location reports were *** review showed that radiography and computed tomography(CT)may show changes in the bony structure of the spine,with the largest segment of change indicating the fistula ***,magnetic resonance imaging(MRI)can show a cerebrospinal fluid(CSF)flow void at the fistula *** middle segment of the cyst on sagittal MRI,the largest cyst area,and cyst laterality in the axial view indicate the fistula *** can show the fistula location in the area of the enhanced cyst and subarachnoid *** subtraction or delayed CT can be used to observe the location of the initial cyst *** MRI and time-spatial labeling inversion pulse techniques can be used to observe CSF ***-state image construction interference sequence MRI has a high spatial ***,MRI myelography,and ultrasound fistula detection can be performed ***,the fistula was located most often in the T12–L1 *** the fistula location is difficult and requires a combination of multiple examinations and experience for comprehensive judgment.

关键词： Spinal extradural meningeal cyst Dural cyst Dural defect Communication Fistula

Reconsideration of the transoral odontoidectomy in complex craniovertebral junction patients with irreducible anterior compression

在线全文

学校读者我要写书评

暂无评论

中华神经外科杂志(英文) 2021年第1期6卷 28-35页

作者： Wang Xingwen Ma Longbing liu zhenlei Chen Zan Wu Hao Jian Fengzeng Department of Neurological Surgery Xuanwu Hospital Capital Medical University Beijing 100053 China

Background: Although the single-stage posterior realignment craniovertebral junction (CVJ) surgery could treat most of the basilar invagination (BI) and atlantoaxial dislocation (AAD), there are still some cases with incomplete decompression of the spinal cord, which remains a technique challenging ***: Eleven patients were included with remained myelopathic symptoms after posterior correction due to incomplete decompression of the spinal cord. Transoral odontoidectomy assisted by image-guided navigation and intraoperative CT was performed. Clinical assessment and image measurements were performed preoperatively and at the most recent ***: Eleven patients were followed up for an average of 47 months. Symptoms were alleviated in 10 of 11 patients (90.9%). One patient died of an unknown reason 1 week after the transoral approach. The clinical and radiological parameters pre- and postoperatively were ***: Transoral odontoidectomy as a salvage surgery is safe and effective for properly selected BI and AAD patients after inadequate indirect decompression from posterior distraction and fixation. Image-guided navigation and intraoperative CT can provide precise information and accurate localization during operation, thus enabling complete resection of the odontoid process and decompression of the spinal cord.

关键词： Transoral approach Odontoidectomy Basilar invagination Atlantoaxial dislocation Image-guided navigation

焊接工艺参数对FGH96合金惯性摩擦焊过程材料塑性流动行为的影响

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

机械工程学报 2012年第12期48卷 69-74页

作者：姬书得刘建光张利国陶军刘震磊沈阳航空航天大学航空航天工程学部沈阳110136 哈尔滨工业大学金属精密热加工国家级重点实验室哈尔滨150001 北京航空制造工程研究所北京100024

采用数值模拟方法对FGH96合金惯性摩擦焊过程进行分析,获得温度、轴向缩短量、材料流动与飞边四者之间的关系,着重研究初始转速与轴向压力等焊接工艺参数对材料塑性流动行为的影响规律。研究结果表明:在惯性摩擦焊初始阶段,材料温度与... 详细信息

采用数值模拟方法对FGH96合金惯性摩擦焊过程进行分析,获得温度、轴向缩短量、材料流动与飞边四者之间的关系,着重研究初始转速与轴向压力等焊接工艺参数对材料塑性流动行为的影响规律。研究结果表明:在惯性摩擦焊初始阶段,材料温度与流动速度较低,无飞边产生;随着焊接过程的进行,材料的温度与流动速度呈现先升高后降低的规律;在焊接过程进入稳态后,摩擦面中心区域的材料主要沿试件的旋转方向流动,而摩擦面上两边界附近的材料向面外流动并形成飞边,飞边尺寸与弯曲程度随焊接时间的增加而增加。同时,随到摩擦面距离的增加,材料的流动速度逐渐降低且材料沿轴向流动的速度分量增大。结合FGH96合金惯性摩擦焊轴向缩短量的数值模拟结果,解释了从提高材料流动速度的幅度上看增加轴向压力优于初始转速的原因。

关键词： FGH96合金惯性摩擦焊流动行为焊接工艺参数

考虑源荷频率特性的含风电交直流系统概率连续潮流方法

在线全文

学校读者我要写书评

暂无评论

电力系统自动化 2020年第6期44卷 27-36页

作者：马瑞刘振磊贺平平禹海峰长沙理工大学电气与信息工程学院湖南省长沙市410114 国网湖南省电力有限公司经济技术研究院湖南省长沙市410004

针对传统连续潮流方法难以适应大规模风电接入交直流互联系统的实际情况,提出了一种含风电交直流系统概率连续潮流计算方法。该方法在兼顾常规机组调频特性和负荷电压/频率静特性基础上,进一步考虑风电出力随机性、直流控制方式和频率... 详细信息

针对传统连续潮流方法难以适应大规模风电接入交直流互联系统的实际情况,提出了一种含风电交直流系统概率连续潮流计算方法。该方法在兼顾常规机组调频特性和负荷电压/频率静特性基础上,进一步考虑风电出力随机性、直流控制方式和频率波动偏差约束,建立考虑电源调频和负荷电压/频率静特性的含风电交直流系统概率连续潮流方程;通过其修正方程的雅可比矩阵,推导能反映频率波动、风电出力和控制方式等因素的负荷裕度灵敏度指标;基于统一迭代法,结合蒙特卡洛方法和预估-校正方法获取系统N和N-1状态时多场景潮流解和负荷裕度。最后,修改的IEEE 39节点系统算例仿真结果验证了所提方法的正确性和有效性。

关键词：交直流系统风力发电概率连续潮流调频特性负荷电压/频率静特性

论利益分化的制度统合——基于新制度主义的思考

在线全文

学校读者我要写书评

暂无评论

社科纵横 2020年第2期35卷 70-76页

作者：刘振磊青岛市社会科学院山东青岛266071

与中国现代化进程相伴,利益分化与统合之争始终是社会的主流议题。在改革开放40年后,社会面临着越来越强烈的利益统合需求。利益统合面临着利益自身不确定性及价值变迁的困扰,却也有全能型国家范式、主流价值认同及先行国家经验的支持... 详细信息

与中国现代化进程相伴,利益分化与统合之争始终是社会的主流议题。在改革开放40年后,社会面临着越来越强烈的利益统合需求。利益统合面临着利益自身不确定性及价值变迁的困扰,却也有全能型国家范式、主流价值认同及先行国家经验的支持。新时期的利益统合应当走出“冲突、压制”的路径依赖,将价值基准构建于人的自由而全面发展之上,进而选择符合发展阶段的利益衡量原则,构建民主、制衡的制度统合体系。

关键词：利益分化利益统合价值序列新制度主义

同方期刊数据库