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High Shock-Resistant Design of Piezoresistive High-g Accelerometer

  • Yongle Lu;Zhen Qu;Jie Yang;Wenxin Wang;Wenbo Wang;Yu Liu
    • Journal of Information Processing Systems
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    • v.19 no.2
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    • pp.173-188
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    • 2023
  • To improve the shock-resistance of piezoresistive high-g accelerometer, we propose a design of piezoresistive high-g accelerometer. The accelerometer employs special-shaped proof masses system with a cross gap. Four tiny sensing beams are bonded above the cross gap. The expression of the deformation, natural frequency and damping is deduced, and the structural parameters are optimized. The accelerometer structure is simulated and verified by finite element method (FEM) simulation. The results show that the range of the accelerometer can reach 200,000 g, the natural frequency is 453.6 kHz, and the cross-axis sensitivity of X-axis and Y-axis is 0.25% and 0.11%, respectively, which can apply to the measurement of high shock. Contrastively, the cross-axis sensitivity of X-axis and Y-axis is respectively, reduced by 93.2% and 96.9%. The sensitivity of our accelerometer is 0.88 μV/g. It is of great value for the application of piezoresistive high-g accelerometer with high shock-resistance.

Optimal Design of Two-Span Steel Box Girder Bridges by LRFD (LRFD에 의한 2경간 강박스형교 최적화 설계)

  • 국중식;신영석
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2001.04a
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    • pp.173-180
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    • 2001
  • In this study steel box girders used as main members of a two span continuous steel bridge, are optimally designed by a Load and Resistance Factor Design method(LRFD) using an numerical optimization method. The width, height, web thickness and flange thickness of the main girder are set as design variables, and light weight design is attempted by choosing the cross-sectional area as an object function. We studied the results of steel box girders and compared with those of 1-type girders. The main program is coded with C++ and connected with optimization modul ADS. which is coded with FORTRAN.

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A Model Specification for the Household Demand for Credit (가계의 신용 수요 모형 설정에 관한 연구)

  • 최현자
    • Korean Journal of Rural Living Science
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    • v.6 no.2
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    • pp.173-183
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    • 1995
  • On the basis of intertemporal utility maximization theory and stock-adjustment hypothesis, a multivariate stock-adjustment credit demand model, which included on- and cross-adjustment effects of credit and cross-adjustment effects of assets was developed. With weighted four-year panel data from 1983 and 1986 Surveys of Consumer Finances, the theoretical model was tested using two-stage estimation method for tobit model. The results supported the hypothesis that, in general, the household demand for a certain type of credit was related to the demand for other types of credit and asset components in the portfolio. The household demand for mortgage credit, installment credit and revolving credit card debt depended not only on the disequilibrium of itself but on the disequilibrium of the other types of credit and asset components in the portfolio. The household demand for non-installment credit was related not to the disequilibrium of itself and other types of credit but to the disequilibria of asset components in the portfolio.

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Shear deformation effect in flexural-torsional buckling analysis of beams of arbitrary cross section by BEM

  • Sapountzakis, E.J.;Dourakopoulos, J.A.
    • Structural Engineering and Mechanics
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    • v.35 no.2
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    • pp.141-173
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    • 2010
  • In this paper a boundary element method is developed for the general flexural-torsional buckling analysis of Timoshenko beams of arbitrarily shaped cross section. The beam is subjected to a compressive centrally applied concentrated axial load together with arbitrarily axial, transverse and torsional distributed loading, while its edges are restrained by the most general linear boundary conditions. The resulting boundary value problem, described by three coupled ordinary differential equations, is solved employing a boundary integral equation approach. All basic equations are formulated with respect to the principal shear axes coordinate system, which does not coincide with the principal bending one in a nonsymmetric cross section. To account for shear deformations, the concept of shear deformation coefficients is used. Six coupled boundary value problems are formulated with respect to the transverse displacements, to the angle of twist, to the primary warping function and to two stress functions and solved using the Analog Equation Method, a BEM based method. Several beams are analysed to illustrate the method and demonstrate its efficiency and wherever possible its accuracy. The range of applicability of the thin-walled theory and the significant influence of the boundary conditions and the shear deformation effect on the buckling load are investigated through examples with great practical interest.

A Study on the Construction of Weights for KYPS (한국청소년패널조사(KYPS) 가중치 부여 방법 연구: 중학교 2학년 패널의 경우)

  • Park, Min-Gue;Lee, Kyeong-Sang;Park, Hyun-Soo;Kang, Hyun-Cheol
    • Survey Research
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    • v.12 no.3
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    • pp.173-186
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    • 2011
  • We introduced the methodologies used to construct the longitudinal weights and cross-sectional weight that are required for the analysis of Korea Youth Panel Survey. To analyze the longitudinal dynamic change of the population, we derived the longitudinal weight through nonresponse adjustment based on logistic regression and post-stratification. Cross-sectional weights that are necessary to produce an asymptotically unbiased estimator of the population parameter were constructed through simple nonresponse adjustment based on overall response rate and post-stratification.

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Validation of Job Analysis for Hospital HIV/AIDS Nurse Counselor (의료기관 에이즈 상담간호사 직무의 타당성)

  • Baek, Hee Chong;Cho, Hee;Han, Jong Sook
    • Journal of Home Health Care Nursing
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    • v.19 no.2
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    • pp.173-182
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    • 2012
  • The purpose of this study is to identify the appropriateness and validity of the HIV/AIDS nurse counselor's job, and to propose the job description. Mixed method was used: nominal group interview was used as a qualitative research and a survey was used as a quantitative research. Three of the nominal group members evaluated the appropriateness of the duties and tasks. To identify the validity of the evaluated duties and tasks, importance, difficulty and frequency were surveyed by 14 nurses who were working at the hospital as a HIV/AIDS nurse counselors. For the HIV/AIDS nurse counselor, 7 duties and 35 tasks - infection control of the HIV/AIDS, counseling, client advocacy, development of the educational material, referral to the resources, referral services at the hospital, and self-improvement - were identified. Proposed job description will be used as a reference for the role position and the training curriculum of the HIV/AIDS nurse counselors who are working at the hospital.

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Food Security in Households of People Living With Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome: A Cross-sectional Study in a Subdivision of Darjeeling District, West Bengal

  • Dasgupta, Pallabi;Bhattacherjee, Sharmistha;Das, Dilip Kumar
    • Journal of Preventive Medicine and Public Health
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    • v.49 no.4
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    • pp.240-248
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    • 2016
  • Objectives: Human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) adversely impacts food security in households of people living with HIV/AIDS (PLWHA). Little research has focused on food insecurity among PLWHA in India. The purpose of this study was to identify the prevalence of and factors relating to food security in households of PLWHA in the Siliguri subdivision of Darjeeling, West Bengal, India. Methods: A cross-sectional community-based study was carried out among 173 PLWHA residing in Siliguri and registered at the Anti-retroviral Therapy Centre of North Bengal Medical College & Hospital. Data was collected at the household level with interviews of PLWHA using a food security survey instrument. We analyzed the associations using logistic regression. Results: The prevalence of household food security among the participants was 50.9% (88/173). Five years or more of schooling, higher socioeconomic class and males were found to be significantly associated with a higher likelihood of food security. A later stage of the disease and the presence of other family members with HIV/AIDS were significantly associated with a lower likelihood of food security. The major coping strategies to deal with food insecurity in the acute phase HIV infection included borrowing money (56.1%), followed by spousal support, loans from microfinance institutions, banks, or money lenders, borrowing food, or selling agricultural products. Conclusions: The present study revealed that only about half of households with PLWHA were food secure. Prior interventions relating to periods of food and economic crisis as well as strategies for sustaining food security and economic status are needed in this area.

Preparation and Characterization of Self-assembled Glycol Chitosan Hydrogels Containing Palmityl-acylated Exendin-4 for Extended Hypoglycemic Action

  • Lee, Ju-Ho;Lee, Chang-Kyu;Bae, Sung-Ho;Yoon, Jeong-Hyun;Choi, Eun-Joo;Oh, Kyung-Taek;Lee, Eun-Seong;Lee, Kang-Choon;Youn, Yu-Seok
    • Journal of Pharmaceutical Investigation
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    • v.41 no.3
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    • pp.173-178
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    • 2011
  • Injectable chitosan hydrogels have attracted great potential due to sustained-release property and safety. Here, palmityl-acylated glycol chitosan (Pal-GC) was used to generate physically cross-linked hydrogels by virtue of hydrophobic attraction of linear fatty carbons. Glycol chitosan was chemically modified with N-hydroxysuccinimide-activated palmitic acid in dimethylsulfoxide (DMSO) containing dimethylaminopyridine. Through a series of preparation steps of (i) dialysis with DMSO, (ii) addition of palmityl-acylated exendin-4 (Ex4-C16), and (iii) dialysis with water, Pal-GC was self-assembled to form physically cross-linked hydrogels entrapped with Ex4-C16. The Pal-GC derivative was analyzed by using 1H NMR, and the surface morphology of Pal-GC hydrogels formed was examined by scanning electron microscopy. Also, the hypoglycemic effect induced by Pal-GC hydrogels containing Ex4-C16 (250 nmol/kg) was evaluated in non-fasted type 2 diabetic db/db mice and compared with GC hydrogels containing native Ex4 at the same dose. Results showed that palmityl group was successfully conjugated with the amines of glycol chitosan, and that Pal-GC efficiently generated the hydrogels formation. Moreover, Pal-GC hydrogels containing Ex4-C16 was found to greatly prolong the hypoglycemia duration (~ 4 days). This was due to the dual-functions of the palmityl groups present in both GC and exendin-4 such as hydrophobic attraction and plasma albumin-binding. We consider this new type of self-assembled GC hydrogels loaded with Ex4-C16 would be a promising long-acting sustained-release system with anti-diabetic property.

Design and construction of shaft for rock caverns in Singapore

  • Zhang, Xiao-Ping;Lu, Ming;Mao, Dawei;Zhao, Zhiye;Hao, Liu
    • Geomechanics and Engineering
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    • v.13 no.1
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    • pp.173-194
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    • 2017
  • Access shaft is of critical importance to the construction and operation of underground rock caverns. It usually has a relatively large cross-section and penetrates through fill materials, soil layers, and weathered rocks before reaching the caverns excavated in solid bedrock. In this paper, the design and construction of vertical shafts are reviewed in terms of diameter, depth, geological conditions, and support structure. Three shaft alternatives, namely alternative I: vertical shaft with spiral roads, alternative II: upper shaft with spiral roads & lower tunnels, alternative III: plain shaft, are proposed based on a simplified geological profile of the Jurong formation, Singapore. The advantages and limitations of the three types of shafts are discussed. The key issues relating to shaft design and construction, such as the shaft sinking, water control, support structure, are also discussed with a series of solutions provided, such as the sequential excavation, pre-grouting and diaphragm walls.

Factors Associated with Mental Health-related Quality of Life in Workers (사업장 근로자의 정신건강 관련 삶의 질 영향요인)

  • Lee, Young Joo;Noh, Gyeongmin
    • Korean Journal of Occupational Health Nursing
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    • v.29 no.3
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    • pp.173-183
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    • 2020
  • Purpose: The purpose of this study was to identify factors associated with the mental health-related quality of life (MHQoL) of Korean workers. Methods: This was a cross-sectional study of 192 Korean pay workers who worked in the Daegu and Gyeongbuk Province, Korea. Data were collected from May 15 to July 2, 2019, through selfreported questionnaires. The survey had a total of 87 questions including individual, organizational, and psychosocial factors. MHQoL was measured using short form-36 version 1. Data were divided into four domains of MHQoL and analyzed using a hierarchical linear regression model. Results: From the hierarchical linear regression analysis, when the psychosocial factors were included in the regression model, the R2 change in the four domains of MHQoL increased significantly by 19~47%. A common predicting factor associated with the four domains of MHQoL was identified as perceived stress symptoms. Other factors affecting MHQoL showed slight differences in each domain. Conclusion: Based on the study results, it is necessary to monitor the psychosocial symptoms to improve MHQoL of Korean workers. Considering each factor affecting the four areas of MHQoL, workplace-based interventions to improve MHQoL should be provided to workers.