• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.11
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• pp.1773-1778
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• 2010

To evaluate the structural integrity of the main cooling-water pump of a nuclear power plant under different seismic conditions, the seismic analysis was performed in accordance with IEEE-STD-344 code. The finite element computer program, ANSYS, was used to perform both mode frequency analysis and response spectrum analysis for the pump assembly. The natural frequencies, the mode shapes, and the mode participation factors were obtained from the results of the mode frequency analysis. The stresses resulting from various loadings and their combinations were within the allowable limits specified in the above-mentioned IEEE code. The results of the seismic evaluation fully satisfied the structural acceptance criteria of the IEEE code. Thus, it was proved that the structural integrity of the pump assembly was satisfactory.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.3
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• pp.1755-1760
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• 2013

Objective: To investigate the prevalence of genital high-risk human papillomavirus (HR-HPV) in male sexual partners of HR-HPV infected women and the concordance of viral types in couples in China, and comprehend the role of men play in HPV transmission to women. Methods/Materials: 94 asymptomatic women and their husbands from rural Chaozhou participated in epidemiologic screening for HPV infection. Cervical cells from females were collected for high risk HPV screening by real time-PCR, and they were positive for at least 1 of 13 HR-HPV subtypes, then these samples were genotyped. Approximately one mouth later, penile epithelial cells from 94 asymptomatic husbands were collected for HPV genotyping. At the same time, a cross-sectional study was conducted in 366 male patients from sexually transmitted disease (STD) outpatient clinic in China for the prevalence of genital HR-HPV infection in men having frequent sex behavior. Penial epithelial cells were collected for HPV 6/11 and HPV 16/18 detection by fluorescent real-time quantified PCR. Results: Among 94 couples, the prevalence of genital HR-HPV infection in men whose wife was positive for cervical HR-HPV was 5.32% (5/94). Only 2.63% (2/76) had the same high risk viral type presented by their wife. HPV 16 proved to be the most prevalent viral type in men and in couples. Of 366 male patients from STD outpatient clinic, the prevalence of HPV 16/18 infection in men with or without HPV 6/11 was 6.85% and 8.16%, respectively. The incidence of HPV 16/18 was higher in men aged more than 35 years than the young men (18-35 years). Conclusion: The prevalence of genital HR-HPV infection in male sexual partners of HPV-positive women in China was lower than that expected, and the concordance of high risk viral type between couples was extremely low. These data suggested that infected men consitute an important viral reservoir, contributing to transmission of HR-HPV to women and maintenance of infection, but HR-HPV infection may be less likely to persist in men than in women.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.3
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• pp.237-244
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• 2020

Currently, sexually transmitted diseases (STD) are referred to as "sexually transmitted infections" (STIs) in the sense of including asymptomatic infections. STIs have a range of interrelationships. This study used the STI defined by the Minister of Health and Welfare of the Republic of Korea, and targeted syphilis, gonorrhea, chlamydia infection, chancroid, genital herpes simplex, condyloma, human papillomavirus, and non-gonococcal urethritis. The factors were characterized by identifying multiple and simultaneous STIs. This study used the data from the laboratory information system of a consigned inspection institution located in Seoul from 2014 to 2019. In this study, multiple STIs were identified as overlapping STIs of a double infectious source (10 types) and multiple STIs of a third infectious source (6 types). Among the 16 types of multiple STIs, U. urealyticum (9 types), HSV-2 (8 types), C. trachomatis (7 types), HPV 6, 11 (7 types), N. gonorrhoeae (6 types), and T. pallidum (1 type) were included. Therefore, additional research on interrelationship studies, such as STIs, which has the highest proportion of multiple STIs, will be necessary.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.1
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• pp.11-20
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• 2007

A fast Montgomery multiplication occupies important to the design of RSA cryptosystem. Montgomery multiplication consists of two addition, which calculates using CSA or RBA. In terms of CSA, the multiplier is implemented using 4-2 CSA o. 5-2 CSA. In terms of RBA, the multiplier is designed based on redundant binary system. In [1], A new redundant binary adder that performs the addition between two binary signed-digit numbers and apply to Montgomery multiplier was proposed. In this paper, we reconstruct the logic structure of the RBA in [1] for reducing time and space complexity. Especially, the proposed RB multiplier has no coupler like the RBA in [1]. And the proposed RB multiplier is suited to binary exponentiation as modified input and output forms. We simulate to the proposed NRBA using gates provided from SAMSUNG STD130 $0.18{\mu}m$ 1.8V CMOS Standard Cell Library. The result is smaller by 18.5%, 6.3% and faster by 25.24%, 14% than 4-2 CSA, existing RBA, respectively. And Especially, the result is smaller by 44.3% and faster by 2.8% than the RBA in [1].

• Journal of Preventive Medicine and Public Health
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• v.29 no.2 s.53
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• pp.331-346
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• 1996

Exploring the epidemiological trend of HIV/AIDS is required for making the national AIDS policy. In this study, the trend of HIV/AIDS incidence, rout of transmission and some characteristics of AIDS for the past 11 years in Korea using the reported cases from the national STD screening scheme were reviewed. Based on the results, the trend of main route of transmission according to the year was established by stage and the HIV/AIDS cases in this year was estimated and that to the year 2000 was projected by 'Epimodel' programme. The results were as follows : 1. Of the total infected persons, 76% were in their twenties and thirties, socioeconomically and sexually active age groups. While the transmission by sexual contact overseas was decreasing, the infection through domestic heterosexual and homosexual contact was increasing. 2. In the middle of the 1980's, the infected persons were mainly prostitutes infected through heterosexual contact with the HIV positive foreigner in this county(stage 1). And in the late of the 1980's the main source of infection was the sexual contact overseas and the domestic heterosexual contact(stage 2). Since the early of the 1990's, the infection through the heterosexual contact with non-regular sexual partner in this country has increased rapidly(stage 3), which was the evidence of the possibility of HIV epidemics. After that, it was expected that the infection through the homosexual contacts, the heterosexual contacts with commercial sex workers outside and the non-regular sexual contact inside of this country would increase continuously. In the result, the occurrence of neonatal infection by vertical transmission was expected(stage4). 3. The number of HIV/AIDS was estimated at 572 to 2,313 and the projected number of HIV/AIDS to the you 2000 was around 5,800 including 627 AIDS patients. For the further study on the estimation and projection of HIV/AIDS, it was suggested that the sampling survey on the HIV infection rate in the high risk groups and the sentinel hospital surveillance system should be conducted.

• Journal of Powder Materials
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• v.15 no.5
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• pp.359-364
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• 2008

To satisfy the demand of higher cutting performance, mechanical properties with tungsten carbide (WC-Co) tool materials were investigated. Hardness and transverse rupture strength with WC grain size, Co content and density were measured. Compared to H, K, and S manufacture maker as tungsten carbide (WC-Co) tool materials were used for high-speed machining of end-milling operation. The three tungsten carbide (WC-Co) tool materials were evaluated by cutting of STD 11 cold-worked die steel (HRC25) under high-speed cutting condition. Also, tool life was obtained from measuring flank wear by CCD wear measuring system. Tool dynamometer was used to measure cutting force. The cutting force and tool wear are discussed along with tool material characteristics. Consequently, the end-mill of K, H manufacture maker showed higher wear-resistance due to its higher hardness, while the S maker endmill tool showed better performance for high metal removal.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.1
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• pp.31-37
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• 2011

Recently, the technology of surface treatment is being more important which affects the material cost reduction and substitution to the expensive material. The material used for the mechanical processing should have not only high intensity, but also strength toughness, wear resistance and corrosion resistance. In order to increase the durability and have better quality of the parts using such kind of tooling material, various kinds of research of the surface hardening through many kinds of heat resources is being done and practically applied. In this study, the characteristics of hardening surface zone for high strength of the press die material through laser beam irradiation are researched. In this study, it is experimentally observed by the status of the surface morphology, tensile strength, the hardness distribution of the base metal and wear condition by the surface hardness pattern by the laser beam based on the process parameters of $CO_2$ laser by using SM45C and STD11 used for press tool. Through this research, the characteristics of surface hardened zone for high strength of the thin metal by laser beam irradiation is done.

• Design & Manufacturing
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• v.6 no.2
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• pp.90-95
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• 2012

The sheet metal forming proceccing is very important and indispensable in the automotive industry because the accuracy of prsee worked parts is directly related to the automotive quality. But when making mold it is difficult and expensive to modify mold. mold design technology is a critical technology in press plastic working. When design the mold there are lots of variables in press plastic working according to worked material, mold materials, conditions of heat treatment, clearance and so on. Abrasion of mold depends on these kind of conditions and sheared surface which is crucial for quality of product also depends on them. In this study, we conduct research on abrasion loss of mold according to 8, 10 and 12% of clearance for thickness of 1.0mm of worked material out of mold design variables of the products whose worked materials are high carbon steel and carbon tool steel by a practical experiment and perform a comparative evaluation of difference of abrasion loss mold with the alloy tool steel (STD11) and Tungsten Carbide (WC).

• Journal of the Korean Society for Precision Engineering
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• v.14 no.4
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• pp.30-37
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• 1997

This thesis is concerned with the study on the characteristics of the tool failure occuring at the beginning of cutting in finish machining of hardened steels such as carbon tool steel and alloy tool steel by a ceramic tool (Al$_{2}$O$_{3}$+TiC) with nose radius. In the machining of hardened carbon steel STC3, the wear mechanism on the flank face of the ceramic tool is abrasion wear. The mode of tool failure is developed into catastropic fracture with flaking. It is thought that the fracture caused by FeO and TiO$_{2}$ results from the oxidation of Fe in the workpice and TiC in the ceramic tool and the deposit of Fe formed on the surface of the ceramic tool. In the machining of hardened alloy steel STD11, the wear mechanism on the flank face of the ceramic tool is that abrasion and adhesion wear exist simultaneously. The mode of tool failure at the beginning of cutting features is DOC notch wear. It is thought that the DOC notch wear caused by FeO and TiO$_{2}$results from the oxidation of Fe and TiC in the workpiece and ceramic tool, respectively.

• Transactions of Materials Processing
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• v.24 no.4
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• pp.264-271
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• 2015

In the current study, a method was proposed to quantitatively predict the wear and fatigue life of a shearing die in order to determine an effective replacement period for the die. The shearing die model of a retainer manufacturing process was used for the proposed method of quantitative life prediction. The retainer is produced through shearing steps, such as piercing and notching. The shearing die of the retainer is carefully controlled because the dimensional accuracy of the retainer is critical. The fatigue life for the shearing die was predicted using ANSYS considering S-N curves of STD11 and Gerber’s equation. The wear life for the shearing die was predicted using DEFORM-3D considering the Archard’s wear model. Experimental shearing of the retainer was conducted to verify the effectiveness of the proposed method for predicting die life. The fatigue failure of the shearing die was macroscopically measured. The wear depth was measured using a 3D coordinate measuring machine. The results showed that the wear and fatigue life in the FE analysis agree well with the experimental results.