检索结果-南通市图书馆

A study on the form contemporary developments of Tabriz leather and shoe Bazaar(marketplace)from the late Qajar to current period

在线全文

学校读者我要写书评

暂无评论

Frontiers of Architectural Research 2024年第4期13卷 741-763页

作者： Rana Najjari Nabi Nahideh Rezaei Rahmat Mohammad Zadeh Farzin Haghparast Department of Architectural Engineering&Urban design Shahid Rajaee Teacher Training UniversityTehranIran Faculty of Architecture and Urbanism Tabriz Islamic Art UniversityTabrizIran Department of Civil Architecture GroupUniversity of TabrizTabrizIran

Bazaars are considered essential components of a society’s economy and significant features in the urban context of cities,which have emerged based on exchanging goods and meeting people’s *** the late Qajar period,amidst the rapid changes resulting from interaction with modernization,the form of Tabriz Grand Bazaar has undergone significant *** research aims to explain the contemporary transformations of marketplace form in the leather and shoe *** objectives aim to elucidate the contemporary physical,functional,and sementic changes and propose *** research method is qualitative,with a phenomenological *** results indicate that the Bazaar has lost some physical and sementic *** providing goods,it has failed to meet the public’s demands because of eliminating production workshops by changing the productive function to service-oriented and the size and shape of *** decline of religious activities is also one reason for the diminished sementic *** functional and physical aspects,some proposed solutions include preserving the authenticity of the spaces and utilizing suitable Functions with the dominant architectural *** sementic characteristics,suggestions include enhancing the sense of identity.

关键词： contemporary developments Form Functional_Physical_Semantic factors Marketplace Bazaar

Reversing design methodology of investment casting die profile based on ProCAST

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 Foundry 2010年第2期7卷 132-137页

作者： Dou Yangqing Bu Kun Dou Yangliu Dong Yiwei The Key Laboratory of contemporary design and Integrated Manufacturing Technology Northwestern Polytechnical University Xi＇an710072 China

Turbine blade is one of the critical components of aircraft *** performance of the engine depends on the shape and dimensions of components,but superalloy blade material cannot be easily *** investment casting is an ideal process for such net-shape components,it requires an accurate determination of the casting-die *** this paper,a reversing design methodology for investment casting die using ProCAST is *** combining the methods of simplifying grid files and quick sorting,the efficiency of sorting and matching can be largely ***,the mould/die cavity anti-deformation system can be easily *** ProCAST,the optimized die profile for investment casting can be established.

关键词： investment casting reversing design methodology node matching numerical simulation ProCAST

Cutting force prediction for circular end milling process

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2013年第4期26卷 1057-1063页

作者： Wu Baohai Yan Xue Luo Ming Gao Ge Key Laboratory of contemporary design and Integrated Manufacturing Technology Ministry of Education Northwestern Polytechnical University AVIC Commercial Aircraft Engine Co. Ltd.

A deduced cutting force prediction model for circular end milling process is presented in this paper. Traditional researches on cutting force model usually focus on linear milling process which does not meet other cutting conditions, especially for circular milling process. This paper presents an improved cutting force model for circular end milling process based on the typical linear milling force model. The curvature effects of tool path on chip thickness as well as entry and exit angles are analyzed, and the cutting force model of linear milling process is then corrected to fit circular end milling processes. Instantaneous cutting forces during circular end milling process are predicted according to the proposed model. The deduced cutting force model can be used for both linear and circular end milling processes. Finally, circular end milling experiments with constant and variable radial depth were carried out to verify the availability of the proposed method. Experiment results show that measured results and simulated results corresponds well with each other.

关键词： Chip thickness Circular end milling Cutting force Machining Radial depth Tool path curvature

Time-domain modeling of a cutter exiting a workpiece in the slot milling process

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2016年第6期29卷 1852-1858页

作者： Luo Ming Mei Jiawei Zhang Dinghua Key Laboratory of contemporary design and Integrated Manufacturing Technology Ministry of EducationNorthwestern Polytechnical University Machining and Condition Monitoring Group Faculty of Engineering University of Nottingham

In a milling operation, there must be processes of a cutter entering and exiting the workpiece boundary. The cutter exit is usually in the feed direction and the dynamic response is different from that in the normal cutting process. This paper presents a new time-domain modeling of mechanics and dynamics of the cutter exit process for the slot milling process. The cutter is assumed to exit the workpiece for the first time with one tooth right in the feed direction. The dynamic chip thickness is summed up along the feed direction and compared with the remaining workpiece length in the feed direction to judge whether the cutter is ready to exit the workpiece or not. The developed model is then used for analyzing the cutting force and machining vibration in the cutter exit *** developed mathematical model is experimentally validated by comparing the simulated forces and vibrations against the measured data collected from real slotting milling tests. The study shows that stable cutting parameters cannot guarantee stable cutting in a cutter exit process and further study can be performed to control the vibration amplitude in this specific process.

关键词： Cutting force Chip thickness Dynamic stability Machining Milling Vibration

Size effects of effective Young's modulus for periodic cellular materials

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2009年第8期52卷 1262-1270页

作者： DAI GaoMing ZHANG WeiHong Engineering Simulation and Aerospace Computing Key Laboratory of Contemporary Design&Integrated Manufacturing TechnologyNorthwestern Polytechnical UniversityXi’an 710072China

With the wide demands of cellular materials applications in aerospace and civil engineering,research effort sacrificed for this type of materials attains nowadays a higher level than ever *** paper is focused on the prediction methods of effective Young's modulus for periodical cellular *** on comprehensive studies of the existing homogenization method(HM),the G-A meso-mechanics method(G-A MMM) and the stretching energy method(SEM) that are unable to reflect the size effect,we propose the bending energy method(BEM) for the first time,and a comparative study of these four methods is further made to show the generality and the capability of capturing the size effect of the BEM ***,the underlying characteristics of each method and their relations are *** do this,the detailed finite element computing and existing experimental results of hexagonal honeycombs from the literature are adopted as the standard of comparison for the above four *** and bending models of periodical cellular materials are taken into account,respectively for the comparison of stretch and flexural displacements resulting from the above *** conclude that the BEM has the strong ability of both predicting the effective Young's modulus and revealing the size *** a method is also able to predict well the variations of structural displacements in terms of the cell size under stretching and bending loads including the non-monotonous variations for the hexagonal *** the contrary,other three methods can only predict the limited results whenever the cell size tends to be infinitely small.

关键词： periodic cellular materials effective Young’s modulus size effect bending energy method homogenization method G-A mesomechanics method stretching energy method

An integration system for investment casting mould design of aeroengine turbine blade

在线全文

学校读者我要写书评

暂无评论

China Foundry 2008年第2期5卷 114-118页

作者： Jiang Ruisong Zhang Dinghua Wang Wenhu Shi Huajie Key Laboratory of contemporary design and Integrated Manufacturing Ministry of Education Northwestern Polytechnical University Xi＇an 710072 China

An integration system was developed to satisfy the need of information integration in the process of designing, investment casting and monitoring aero-engine's turbo blade. The general architecture is detailed presented in this paper. The system mainly comprises of product master model, design information management, anti-deformation design of mould cavity, intelligence mould design and blade testing. The developed system can manage mould design and blade test data flow, optimize mould design process and achieve the goal of integration design.

关键词： turbo blade investment casting mould design integration design product master model (PMM)

Point spread function modeling and image restoration for cone-beam CT

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2015年第3期39卷 101-106页

作者：张华黄魁东史仪凯徐哲 School of Mechanical Engineering Northwestern Polytechnical University Key Lab of contemporary design and Integrated Manufacturing Technology (Northwestern Polytechnical University) Ministry of Education

X-ray cone-beam computed tomography （CT） has such notable features as high efficiency and precision, and is widely used in the fields of medical imaging and industrial non-destructive testing, but the inherent imaging degradation reduces the quality of CT images. Aimed at the problems of projection image degradation and restoration in cone-beam CT, a point spread function （PSF） modeling method is proposed first. The general PSF model of cone- beam CT is established, and based on it, the PSF under arbitrary scanning conditions can be calculated directly for projection image restoration without the additional measurement, which greatly improved the application convenience of cone-beam CT. Secondly, a projection image restoration algorithm based on pre-filtering and pre-segmentation is proposed, which can make the edge contours in projection images and slice images clearer after restoration, and control the noise in the equivalent level to the original images. Finally, the experiments verified the feasibility and effectiveness of the proposed methods.

关键词： cone-beam CT point spread function image restoration noise control

Robust scatter correction method for cone-beam CT using an interlacing-slit plate

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2016年第6期40卷 95-102页

作者：黄魁东徐哲张定华张华时稳龙 Key Lab of contemporary design and Integrated Manufacturing Technology of the Ministry of Education Northwestern Polytechnical University School of Mechanical Engineering Northwestern Polytechnical University

Cone-beam computed tomography （CBCT） has been widely used in medical imaging and industrial nondestructive testing, but the presence of scattered radiation will cause significant reduction of image quality. In this article, a robust scatter correction method for CBCT using an interlacing-slit plate （ISP） is carried out for convenient practice. Firstly, a Gaussian filtering method is proposed to compensate the missing data of the inner scatter image, and simultaneously avoid too-large values of calculated inner scatter and smooth the inner scatter field. Secondly, an interlacing-slit scan without detector gain correction is carried out to enhance the practicality and convenience of the scatter correction method. Finally, a denoising step for scatter-corrected projection images is added in the process flow to control the noise amplification The experimental results show that the improved method can not only make the scatter correction more robust and convenient, but also achieve a good quality of scatter-corrected slice images.

关键词： CBCT scatter correction image fusion interlacing-slit noise control

Shape optimization of 3D curved slots and its application to the squirrel-cage elastic support design

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2010年第10期53卷 1895-1900页

作者： WANG Dan ZHANG WeiHong WANG ZhenPei ZHU JiHong Engineering Simulation and Aerospace Computing The Key Laboratory of Contemporary Design&Integrated Manufacturing TechnologyNorthwestern Polytechnical UniversityXi’an 710072China

The squirrel-cage elastic support is one of the most important components of an aero-engine rotor system.A proper structural design will favor the static and dynamic performances of the *** view of the deficiency of the current shape optimization techniques,a new mapping approach is proposed to define shape design variables based on the parametric equations of 3D curves and *** is then applied for the slot shape optimization of a squirrel-cage elastic *** this end,an automatic design procedure that integrates the Genetic Algorithm (GA) is developed to solve the *** typical examples with different shape constraints are *** results provide reasonable optimum designs for the improvement of stiffness and strength of the squirrel-cage elastic support.

关键词： shape optimization mapping design approach stress concentration spindly slot squirrel-cage elastic support