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선반 기어박스의 기어열 - 축계 진동 해석 및 저감에 관한 연구
최영휴,박선균,배병태,정택수,김청수 한국공작기계학회 2001 한국공작기계학회 춘계학술대회논문집 Vol.2001 No.-
In this study, torsional and lateral vibrations of a gear box transmission system were analyzed theoretically using some mathematical models and examined to determine the causes of its excessive vibrations. As the results, it was found there exist possibility of resonance between gear mesh frequencies and lateral vibration mode of the transmission shaft during the third shifting mode operation. In order to avoid this resonance, we proposed changing the arrangement of gears on the transmission shaft. The measured vibration levels of the improved gear box were dramatically reduced. These results may be helpful to design a machine tool gear box with low noise and vibration.
NC선반 기어박스의 기어열 : 축계 진동해석 Spindle System for an NC Lathe Gear Box
최영휴,박선균,배병태,정택수,김청수 한국공작기계학회 2000 한국공작기계학회 추계학술대회논문집 Vol.2000 No.-
In this study, two mathematical models are first constructed to analyze vibration characteristics of a gear train - spindle system of an NC lathe gear box. One is a lumped parameter model which is used for calculating natural frequencies of the torsional vibration, the other is a finite element model for analyzing lateral vibration and critical speeds of the spindle system. In addition, this study examines some possible resonance conditions such as gear mesh frequencies, IX shaft rpm frequencies over whole operating speed range, and so on. The results may be helpful to design a machine tool gear box with low noise and vibration.
천연항균성 물질을 이용한 Vibrio vulnificus의 살균 및 독소생성 억제효과
조성환,서일원,최종덕,전상수,라택균,정수근,강동훈 國立統營水産專門大學 附設 水産科學硏究所 1993 수산과학연구소보고 Vol.4 No.-
생선회용 해산물에 오염되어, 생식한 경우 발생되는 패혈병의 원인균주인 Vibrio vulnificus의 생육 및 독성생성을 억제할 목적으로 천연 항균제인 Grapefruit종자추출물(GPSE)을 이용하여 그 항균효과를 검토하였다. In vitro 시험결과, Vibrio vulnificus에 대한 GFSE의 생육최소저해농도는 50~100 ppm 정도이었으며, Vibrio vulnificus 균체세포틀 100 ppm 농도의 GFSE 용액으로 처리하고 전자현미경 촬영시료로 조제하여 촬영한 후, 미생물형태을 무처리대조구와 비교, 검토한 결과, GFSE 처리로 세포막 기능이 파괴되어 세포내용물이 균체외부로 유출되어 균체의 생육이 억제되고 균체내부가 빈 ghost 형태의 균체수가 증대되어 GFSE의 항균효과를 확인할 수 있었다. 한편, 생선회용 해산물에 GFSE를 근육주사하고 Vibrio vulnificus를 접종한 수조내에서 사육하여 채취한 어육부를 마쇄하여 일정량씩을 표준사료에 첨가해서 통닭용 병아리를 실험동물로 하여 사양실험을 실시한 결과. 체중증가율, 단백질이용효율, 혈청내 효소활성, 혈청의 주요성분함량 등에 있어서, GFSE 처리수조내에서 사육한 해산물을 첨가한 시료시험구의 경우, 무첨가사료처리구와 비교할 때 뚜렷한 차이를 목격할 수 없었으며, GFSE 첨가에 따른 실험동물의 성장저해 또는 독성현상을 유발하지 않음을 알 수 있었다. 아울러, 각 처리구에서 사양한 해산물의 어육부에 오염된 Vibrio vulnificus의 균수를 측정한 결과, 250ppm 이상의 GFSE 처리구에서는 Vibrio vulnificus를 전혀 검출할 수 없었다. To prevent food-poisoning outbreaks by Vibrio vulnificus the antimicrobial efficacy of grapefruit seed extract (GFSE) was examined. Minimal inhibitory concentration (in vitro) for the microorganism was found to be 50~100 ppm. Transmission electron micrographs of Vibrio vulnificus showed the biocidal action of this natural antimicrobial agent would be related to specific respiratory effect coupled with the destruction of permeable function of microbial cell membrane. After Anguilla japonia GFSE-injected to the body was incubated in the seawater contaminated by Vibrio vulnficus the fish meats were taken up, mixed with control diet and used as a diet in the feeding experiment. In this experiment the effect of GFSE treated with fish muscle on body weight protein efficiency ratio, serum enzymes and serum blood component of broiler chicks was investigated. It is proved from this study that there is neither Vibriosis nor toxicity associated with GFSE itself and fish meats treated with it when it is injected to the fish body at a level of 250 ppm or less.
Microstructure and properties of cross-roll rolled and heat treated metastable TiNbSn alloy.
Jung, Taek-Kyun,Choi, Ho-Joon,Kim, Kyung-Taek,Shin, Young-Chul,Lee, Hyo-Soo,Lim, Sung-Chul,Kwon, Hyouk-Chon,Hanada, Shuji American Scientific Publishers 2014 Journal of Nanoscience and Nanotechnology Vol.14 No.10
<P>A (Ti-35mass%Nb)-4mass%Sn alloy was cross-roll rolled with a reduction ratio of 70% in which the roll axes are tilted by 5 degrees away from the transverse direction of the rolled sample and then aged at 250 degrees C for 2 h. Cross-roll rolling was found to increase yield strength and Young's modulus, simultaneously. Yield strength was higher in cross-roll rolled than in conventionally rolled at same reduction ratio. Yield and tensile strength further increased by a low temperature ageing by ψ precipitation hardening and microstructure refinement. Yield and tensile strength of the aged 70% cross-roll rolled sample were higher than those of the aged 70% conventionally rolled one.</P>
Cheong, Taek-Chin,Shin, Eon Pil,Kwon, Eun-Kyung,Choi, Ji-Hye,Wang, Kang-Kyun,Sharma, Prashant,Choi, Kyong Hoon,Lim, Jin-Muk,Kim, Hong-Gee,Oh, Keunhee,Jeon, Ju-Hong,So, Insuk,Kim, In-Gyu,Choi, Myung-Si American Chemical Society 2015 ACS CHEMICAL BIOLOGY Vol.10 No.3
<P>Reactive oxygen species (ROS) play an important role in cellular signaling as second messengers. However, studying the role of ROS in physiological redox signaling has been hampered by technical difficulties in controlling their generation within cells. Here, we utilize two inert components, a photosensitizer and light, to finely manipulate the generation of intracellular ROS and examine their specific role in activating dendritic cells (DCs). Photoswitchable generation of intracellular ROS rapidly induced cytosolic mobilization of Ca<SUP>2+</SUP>, differential activation of mitogen-activated protein kinases, and nuclear translocation of NF-κB. Moreover, a transient intracellular ROS surge could activate immature DCs to mature and potently enhance migration <I>in vitro</I> and <I>in vivo</I>. Finally, we observed that intracellular ROS-stimulated DCs enhanced antigen specific T-cell responses <I>in vitro</I> and <I>in vivo</I>, which led to delayed tumor growth and prolonged survival of tumor-bearing mice when immunized with a specific tumor antigen. Therefore, a transient intracellular ROS surge alone, if properly manipulated, can cause immature DCs to differentiate into a motile state and mature forms that are sufficient to initiate adaptive T cell responses <I>in vivo</I>.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/acbcct/2015/acbcct.2015.10.issue-3/cb5009124/production/images/medium/cb-2014-009124_0004.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cb5009124'>ACS Electronic Supporting Info</A></P>
Study on the biodegradation of perfluorooctanesulfonate (PFOS) and PFOS alternatives
Choi, Bongin,Na, Suk-Hyun,Son, Jun-Hyo,Shin, Dong-Soo,Ryu, Byung-Taek,Byeon, Kyun-Suk,Chung, Seon-Yong The Korean Society of Environmental Toxicology 2016 환경독성보건학회지 Vol.31 No.-
Objectives In this study, we investigated the biodegradation features of 4 perfluorooctanesulfonate (PFOS) alternatives developed at Changwon National University compared to those of PFOS. Methods Biodegradation testing was performed with microorganisms cultured in the good laboratory practice laboratory of the Korea Environment Corporation for 28 days following the Organization for Economic Cooperation and Development guidelines for the testing of chemicals (Test No. 301 C). Results While $C_8F_{17}SO_3Na$, PFOS sodium salt was not degraded after 28 days, the 4 alternatives were biodegraded at the rates of 20.9% for $C_{15}F_9H_{21}S_2O_8Na_2$, 8.4% for $C_{17}F_9H_{25}S_2O_8Na_2$, 22.6% for $C_{23}F_{18}H_{28}S_2O_8Na_2$, and 23.6% for $C_{25}F_{17}H_{32}O_{13}S_3Na_3$. Conclusions $C_{25}F_{17}H_{32}S_3O_{13}Na_3$, $C_{23}F_{18}H_{28}S_2O_8Na_2$, and $C_{15}F_9H_{21}S_2O_8Na_2$ were superior to PFOS in terms of biodegradation rates and surface tension, and thus they were considered highly applicable as PFOS alternatives. Environmental toxicity, human toxicity, and economic feasibility of these compounds should be investigated prior to their commercialization.
Case report : SIADH Associated with Prostate Cancer
( Kyun Sang Lee ),( Taek Won Kang ),( Seong Kwon Ma ),( Soo Wan Kim ),( Nam Ho Kim ),( Ki Chul Choi ) 대한전해질,혈압학회 2007 Electrolytes & Blood Pressure Vol.5 No.1
Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is the most common disease leading to hyponatremia, and it is characterized by an inappropriately elevated serum ADH level relative to serum osmolality. This syndrome may occur in a variety of clinical settings including malignancies. However, it is rarely observed in association with prostate cancer. Moreover, its pathogenesis and clinical characteristics have not been completely understood. We report a case of SIADH associated with prostate cancer in a 64-year-old male patient with a literature review.