检索结果-南通市图书馆

Analysis and Inverse Substructuring Computation on Dynamic Quality of Mechanical Assembly

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2016年第3期29卷 539-548页

作者： Lü Guangqing YI Chuijie FANG Ke key Lab of Disasters Forecast and Control in Engineering of Ministry of Education Jinan University Research Center of Equipment Energy & Environment Qingdao Technological University

Mechanical assembly has its own dynamic quality directly affecting the dynamic quality of whole product and should be considered in quality inspection and estimation of mechanical assembly. Based on functional relations between dynamic characteristics involved in mechanical assembly, the effects of assembling process on dynamic characteristics of substructural components of an assembly system are investigated by substructuring analysis. Assembly-coupling dynamic stiffness is clarified as the dominant factor of the effects and can be used as a quantitative measure of assembly dynamic quality. Two computational schemes using frequency response functions（FRFs） to determine the stiffness are provided and discussed by inverse substructuring analysis, including their applicable conditions and implementation procedure in application. Eigenvalue analysis on matrix-ratios of FRFs before and after assembling is employed and well validates the analytical outcomes and the schemes via both a lumped-parameter model and its analogic experimental counterpart. Applying the two schemes to inspect the dynamic quality provides the message of dynamic performance of the assembly system, and therefore improves conventional quality inspection and estimation of mechanical assembly in completeness.

关键词： mechanical assembly dynamic quality substructuring analysis inverse substructuring assembly-coupling dynamic stiffness

The Transformation of Rural Household Reproduction Model and Its Impact on Family Relations

在线全文

学校读者我要写书评

暂无评论

学术界 2019年第6期 193-203页

作者： ke fang School of Marxism Southwest Jiaotong University School of Marxism Chongqing University of Technology

Under the pressure of marketization and urbanization,rural family reproduction mode has transformed from simple reproduction to expanded family reproduction,thus changing the family structure and family relationship.Under the mode of expanded family reproduction,family relationship is a highly rational and deeply mobilized interaction pattern.And the family element configuration profoundly reflects the practical form of family relationship.Under the mode of expanded family reproduction,the changes in rural family relations are mainly reflected in three aspects:the decline of the paternal authority and the increasing family status of the offspring;the increasing status of women along with a decisive role in family decision-making;the more independent,equal,competitive and rational relationship among brothers.These changes bring forward new requirements on rural governance system,which requires improvements on social security and public culture.

关键词： simple family reproduction expanded family reproduction family relationship rural governance

Development and Validation of a Prediction Model on Adult Emergency Department Patients for Early Identification of Fulminant Myocarditis

在线全文

学校读者我要写书评

暂无评论

Current Medical Science 2023年第5期43卷 961-969页

作者： Min JIANG Jian ke Ming-hao fang Su-fang HUANG Yuan-yuan LI Department of Emergency Medicine Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030China

Objective It is difficult to predict fulminant myocarditis at an early stage in the emergency department.The objective of this study was to construct and validate a simple prediction model for the early identification of fulminant myocarditis.Methods A total of 61 patients with fulminant myocarditis and 160 patients with acute myocarditis were enrolled in the training and internal validation cohorts.LASSO regression and multivariate logistic regression were selected to develop the prediction model.The selection of the model was based on overall performance and simplicity.A nomogram based on the optimal model was built,and its clinical usefulness was evaluated by decision curve analysis.The predictive model was further validated in an external validation group.Results The resulting prediction model was based on 4 factors:systolic blood pressure,troponin I,left ventricular ejection fraction,and ventricular wall motion abnormality.The Brier scores of the final model were 0.078 in the training data set and 0.061 in the internal testing data set,respectively.The C-indexes of the training data set and the testing data set were 0.952 and 0.968,respectively.Decision curve analysis showed that the nomogram model developed based on the 4 predictors above had a positive net benefit for predicting probability thresholds.In the external validation cohort,the model also showed good performance(Brier score=0.007,and C-index=0.989).Conclusion We developed and validated an early prediction model consisting of 4 clinical factors(systolic blood pressure,troponin I,left ventricular ejection fraction,and ventricular wall motion abnormality)to identify potential fulminant myocarditis patients in the emergency department.

关键词： fulminant myocarditis emergency risk prediction nomogram

Hierarchical auditory perception for species discrimination and individual recognition in the music frog

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

Current Zoology 2022年第5期68卷 581-591页

作者： Yanzhu Fan ke fang Ruolei Sun Di Shen Jing Yang Yezhong Tang Guangzhan fang Chengdu Institute of Biology Chinese Academy of SciencesChengdu 610041China College of Life Sciences University of Chinese Academy of SciencesBeijing 100049China School of Life Science Anhui UniversityHefei 230601China

The ability to discriminate species and recognize individuals is crucial for reproductive success and/or survival in most animals.However,the temporal order and neural localization of these decision-making processes has remained unclear.In this study,event-related potentials(ERPs)were measured in the telencephalon,diencephalon,and mesencephalon of the music frog Nidirana daunchina.These ERPs were elicited by calls from 1 group of heterospecifics(recorded from a sympatric anuran species)and 2 groups of conspecifics that differed in their fundamental frequencies.In terms of the polarity and position within the ERP waveform,auditory ERPs generally consist of 4 main components that link to selective attention(N1),stimulus evaluation(P2),identification(N2),and classification(P3).These occur around 100,200,250,and 300 ms after stimulus onset,respectively.Our results show that the N1 amplitudes differed significantly between the heterospecific and conspecific calls,but not between the 2 groups of conspecific calls that differed in fundamental frequency.On the other hand,the N2 amplitudes were significantly different between the 2 groups of conspecific calls,suggesting that the music frogs discriminated the species first,followed by individual identification,since N1 and N2 relate to selective attention and stimuli identification,respectively.Moreover,the P2 amplitudes evoked in females were significantly greater than those in males,indicating the existence of sexual dimorphism in auditory discrimination.In addition,both the N1 amplitudes in the left diencephalon and the P2 amplitudes in the left telencephalon were greater than in other brain areas,suggesting left hemispheric dominance in auditory perception.Taken together,our results support the hypothesis that species discrimination and identification of individual characteristics are accomplished sequentially,and that auditory perception exhibits differences between sexes and in spatial dominance.

关键词： event-related potentials(ERPs) individual identification music frog species discrimination temporal hierarchy

An adaptive sequential experiment design method for model validation

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

Chinese Journal of Aeronautics 2020年第6期33卷 1661-1672页

作者： ke fang Yuchen ZHOU Ping MA Control and Simulation Center Harbin Institute of TechnologyHarbin 150080China

Efficient experiment design is of great significance for the validation of simulation model with high nonlinearity and large input space.Excessive validation experiment raises the cost while insufficient test increases the risks of accepting an invalid model.In this paper,an adaptive sequential experiment design method combining global exploration criterion and local exploitation criterion is proposed.The exploration criterion utilizes discrepancy metric to improve the space-filling property of the design points while the exploitation criterion employs the leave one out error to discover informative points.To avoid the clustering of samples in the local region,an adaptive weight updating approach is provided to maintain the balance between exploration and exploitation.Besides,the credibility distribution function characterizing the relationship between the input and result credibility is introduced to support the model validation experiment design.Finally,six benchmark problems and an engineering case are applied to examine the performance of the proposed method.The experiments indicate that the proposed method achieves satisfactory performance for function approximation in accuracy and convergence.

关键词： Adaptive sequential experiment design Credibility distribution function Gaussian process model Metamodeling Model validation

Wire and arc additive manufacturing of dissimilar 2319 and 5B06 aluminum alloys

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2022年第29期124卷 65-75页

作者： Tianxing Chang Xuewei fang Gang Liu Hongkai Zhang ke Huang State key Laboratory for Manufacturing Systems Engineering School of Mechanical EngineeringXi’an Jiaotong UniversityXi’an 710049China State key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049China

Aluminum alloy is the most widely used light alloy at present.By combining different types of aluminum alloys,their functional properties can be expanded.In the present research,two components composed of 2319(Al-6.5Cu)and 5B06(Al-6.4Mg)dissimilar alloys were fabricated by wire and arc additive manufacturing(WAAM).The deposited component with the bottom half of 2319 and the top half of 5B06 exhibits better mechanical properties than its counterpart deposited vice versa.Its ultimate tensile strength,yield strength,and elongation are 258.5 MPa,139.3 MPa,and 5.6%,respectively,which are only slightly inferior to the mechanical properties of 2319 base metal.The results show that for both components,fracture occurred at a layer thickness above the interface layer during the tensile test,regardless of the deposition order.It appears that the thermal stress due to the long dwell time and the remelting of the S-AlCu Mg phase are the main factors promoting crack initiation.Depending on the deposition order,cracks propagate either along the aggregated pores or stripθ-AlCu phase distributed along the grain boundary.By analyzing the heat input and selecting the appropriate depositing order,the strength of WAAM dissimilar aluminum alloys can be effectively improved through the proper control of microstructure and internal defects.

关键词： Wire and arc additive manufacturing Dissimilar materials Defects Microstructure Mechanical Properties Aluminum alloy

Unveiling the key factor affecting the illumination deterioration and response measures for lead halide perovskite solar cells

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2022年第10期31卷 429-435,I0011页

作者： Feihong Ye Haibing Wang Weijun ke Chen Tao Guojia fang School of Physics and Technology Wuhan UniversityWuhan 430000HubeiChina

So far,it's been widely acknowledged that the Pb I2decomposition under illumination mainly accounts for the degradation of perovskite solar cells(PSCs)under maximum power point(MPP)tracking condition.However,PSCs without excess Pb I2were also reported to deteriorate rapidly under the same condition.Here,we demonstrate that the key to enhance PSCs stability under MPP tracking condition is not to have fascinating surface morphology with effective suppression of nonradiative recombination traps but to prevent the migration of iodine ion(I-)under light illumination.By partially substituting methylammonium chloride(MACl)with methylammonium iodide(MAI)and simutaneouly introducing I2during the sequential deposition,the iodine vacancies in perovskite films are substantially suppressed,thereby limiting the pathways for I^(-)migration.As a consequence,PSCs with efficiency of 24.28%are fabricated with remarkably enhanced working stability.

关键词： Perovskite solar cell Degradation mechanism Light-induced halide ion migration MPP stability

The Chinese national guidelines on diagnosis and management of cough （December 2010）

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2011年第20期124卷 3207-3219页

作者： LAI ke-fang State key Laboratory of Respiratory Disease First Affiliated Hospital of Guangzhou Medical College Guangzhou Guangdong 510120 China

Cough is a defensive physiological reflex of the human body that enables vital clearance of secretionsand harmful elements from the respiratory tract; however, frequent and intense coughing may adversely impact on a patient＇s work, daily life and social activities. Cough is one of the most commonly observed symptoms in clinical practice arising from a wide range of aetiologies. A chronic cough may be overlooked by clinicians, particularly if reassured by the normal appearance on a chest radiograph. Furthermore, 70%-80% of these patients are readily mislabelled or diagnosed with ＂chronic bronchitis＂ or ＂bronchitis＂ in China, then typically treated with substantial but ineffective courses of antibiotics, or subjected to repeated investigations as a result of a diagnosis that is unclear, and may thus suffer more discomfort and financial burden from their disease.

关键词：反射呼吸系统抗菌药咳嗽血气分析亚洲大陆世系人群胰岛素元素

Efficient extraction of U(VI)ions from solutions

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2023年第1期34卷 13-22页

作者： Ya‑Wen Cai Ming fang Bao‑Wei Hu Xiang‑ke Wang School of Life Science Shaoxing UniversityShaoxing 312000China College of Environmental Science and Engineering North China Electric Power UniversityBeijing 102206China

The rapid development of advanced techniques for selective and efficient U(Ⅵ) extraction from aqueous solutions is essential for addressing U(Ⅵ) environmental pollution and energy issues. Here, we share recent progress in U(Ⅵ) extraction from aqueous solutions, especially the most frequently applied techniques such as adsorption, catalysis(photocatalysis, piezocatalysis, and electrocatalysis), chemical deposition, and reduction by zero-valent metal particles. We attempt to elucidate the strategies and various mechanisms that contribute to the enhancement of selective U(Ⅵ) extraction. At the end of our review, we highlight the outlook, challenges, and prospects for the development of this field.

关键词： Uranium extraction Adsorption Catalysis Reduction Chemical deposition