• Title/Summary/Keyword: 피로특성

Search Result 1,368, Processing Time 0.033 seconds

Factors Affecting Physicians who will be Vaccinated Every Year after Receiving the COVID-19 Vaccine in Healthcare Workers (의료종사자의 COVID-19 예방 백신 접종받은 후 향후 매년 예방접종 의향에 미치는 요인)

  • Hyeun-Woo Choi;Sung-Hwa Park;Eun-Kyung Cho;Chang-hyun Han;Jong-Min Lee
    • Journal of the Korean Society of Radiology
    • /
    • v.17 no.2
    • /
    • pp.257-265
    • /
    • 2023
  • The purpose of this study was to vaccinate every year according to the general characteristics of COVID-19, whether to vaccinate every year according to the vaccination experience, whether to vaccinate every year according to knowledge/attitude about vaccination, and negative responses to the vaccinate every year In order to understand the factors affecting the vaccination physician every year by identifying the factors of Statistical analysis is based on general characteristics, variables based on vaccination experience, and knowledge/attitudes related to vaccination. The doctor calculates the frequency and percentage, A square test (-test) was performed, and if the chi-square test was significant but the expected frequency was less than 5 for 25% or more, a ratio difference test was performed with Fisher's exact test. Through multiple logistic regression analysis using variables that were significant in simple analysis, a predictive model for future vaccination and the effect size of each independent variable were estimated. As statistical analysis software, SAS 9.4 (SAS Institute Inc., Cary, NC, USA) was used, and because the sample size was not large, the significance level was set at 10%, and when the p-value was less than 0.10, it was interpreted as statistically significant. In the simple logistic regression analysis, the reason why they answered that they would not be vaccinated every year was that they answered 'to prevent infection of family and hospital guests' rather than 'to prevent my infection' as the reason for the vaccination. It was 11.0 times higher and 3.67 times higher in the case of 'for the formation of collective immunity of the local community and the country'. The adverse reactions experienced after the 1st and 2nd vaccination were 8.42 times higher in those who did not experience pain at the injection site than those who did not, 4.00 times higher in those who experienced swelling or redness, and 5.69 times higher in those who experienced joint pain. There was a 5.57 times higher rate of absenteeism annually than those who did not. In addition, the more anxious they felt about vaccination, the more likely they were to not get the vaccine every year by 2.94 times.

Evaluation of nutritive value of chestnut hull for ruminant animals using in vitro rumen fermentation (밤 가공 부산물의 반추가축용 사료 가치 평가: in vitro 반추위 배양)

  • Jeong, Sin-Yong;Jo, Hyeon-Seon;Park, Gi-Su;Kang, Gil-Nam;Jo, Nam-Chul;Seo, Seongwon
    • Korean Journal of Agricultural Science
    • /
    • v.39 no.3
    • /
    • pp.335-340
    • /
    • 2012
  • During the manufacturing process of chestnut, 50% of biomass is produced as chestnut shell (CS) or chestnut hull (CH), a forestry by-product. Due to its high fiber content and economic benefit, there is a possibility of using chestnut hull as a supplement for a ruminant diet. Few studies, however, have been conducted on evaluating nutritive value of chestnut hull for ruminant animals. The objective of this study were thus to analyze chemical composition of CS, a by-product after the first processing of chestnut, and CH, a by-product after the second processing, and access in vitro rumen fermentation characteristics of them. For the in vitro fermentation using strained rumen fluid obtained from a fistulated Hanwoo steer, commercial total mixed ration (TMR) for dairy goat was used as a basal diet and was replaced with different proportions of chestnut shell and hull. A total number of 13 treatments were carried out in this study: 100% TMR, 100% CS, 100% CH, a mix with 50% CS and 50% of CH (MIX), TMR replaced with 5%, 10%, or 15% of CS, CH, or MIX, respectively. For each treatment, in vitro dry matter digestibility (IVDMD) and pH after 48 hours of rumen fermentation were measured. Gas production at 6, 12, 24, 48 hours of incubation was also analyzed. Compared to CH, CS contains higher level of fiber (NDF, ADF, lignin) and consequently has a lower amount of non-fiber carbohydrate, but no difference was observed in the other nutrients (i.e. crude protein, crude fat, and ash). IVDMD was significantly (p<0.05) the highest in 100% CH (71.97%) and the lowest in 100% CS (42.80%). Addition of CH by replacing TMR did not affect IVDMD, while an increase in the proportion of CS tended to decrease IVDMD. The total gas production after 48 hours of incubation and the rate of gas production were also the highest in 100% CH and the lowest in 100% CS (P<0.05). Likewise, the pH after 48 hours of fermentation was significantly (p<0.05) the lowest in 100% CH (6.33) and the highest in 100% CS (6.50), and no significant difference in gas production was observed when TMR was replaced with CS or CH up to 15% (P>0.05). In conclusion, CH may successfully be used for a supplement in a ruminant diet. The nutritive value of CS is relative low, but can replace, if not 100%, low quality forage. This study provides valuable information about the nutritive value of CS and CH. An in vivo trials, however, is needed for conclusively accessing the nutritive value of CS and CH.

Clinical Characteristics, Histology and Prognosis of Autoimmune Hepatitis in Korean Children (소아 자가면역성 간염: 임상적 특성, 조직 소견 및 예후)

  • Chung, Dae-Lim;Seo, Jeong Kee;Yang, Hye Ran;Ko, Jae Sung;Park, Sung Hye
    • Pediatric Gastroenterology, Hepatology & Nutrition
    • /
    • v.7 no.2
    • /
    • pp.186-196
    • /
    • 2004
  • Purpose: Autoimmune hepatitis is a chronic inflammatory liver disease with unknown cause that is characterized by liver histology, circulating autoantibodies and increased levels of immunoglobulin G. Only sporadic reports are available on autoimmune hepatitis in children. The aim of this study was to evaluate the clinical, biochemical, and histological features, and the long-term outcome of autoimmune hepatitis in Korean children. Methods: We reviewed the medical records of 14 children diagnosed as having autoimmune hepatitis at Seoul National University Children's Hospital from 1990 to 2004, and analyzed clinical, biochemical, and histological features, and clinical outcomes. Results: Mean age at diagnosis was 9 years and 11 of the 14 children were female. Six children presented with acute hepatitis-like manifestations. Jaundice and fatigue were the most common symptoms. Other autoimmune diseases accompanied in 6 children. Anti-nuclear antibody was detected in 13 patients and anti-smooth muscle antibody was positive in 8. All 14 patients were type 1 autoimmune hepatitis. The main histologic findings were interface hepatitis, rosette formation, and cirrhosis. Clinical and biochemical features were improved in six patients treated with ursodeoxycholic acid. Eight patients were treated with corticosteroid alone or in combination with azathioprine and five of them are in biochemical remission. Conclusion: Autoimmune hepatitis is an inflammatory liver disease, which has a favorable long-term outcome if it is diagnosed and treated promptly. Therefore, autoimmune hepatitis should be suspected in children with chronic hepatitis of unknown etiology, especially in female patients who show hypergammaglobulinemia or some clinical features of autoimmune disease.

  • PDF

Effect of Planting and Harvesting Time of Vegetative Nodes and Rhizomes on Yield of Ligusticum chuanxiong Hort (토천궁(土川芎) 노두(蘆頭)와 근경(根莖)의 재식시기(栽植時期) 및 수확연차(收穫年次)가 수량(收量)에 미치는 영향(影響))

  • Kim, Chung-Guk;Lee, Seoung-Tack;Im, Dae-Joon
    • Korean Journal of Medicinal Crop Science
    • /
    • v.2 no.3
    • /
    • pp.181-186
    • /
    • 1994
  • Vegetative node and rhizome of Ligusticum chuanxiong Hort. were planted in spring and autumn and harvested after one and two years to determine the appropriate harvesting time which produced a high yield. Plant height, leaf number and branch number per plant were increased in order of rhizome planted in spring and harvested after two year(RST), rhizome planted in autumn and harvested after one year(RAO), vegetative node planted in autumn and harvested after one year(VNAO), and vegetative node planted in spring and harvested after one year(VNSO). Leaf area index and dry leaf weight in VNSO were highest on August 16, but dry weights of stem and rhizome was increased until harvesting time. The appropriate harvesting time was October 17, in RST, November 9 in RAO and VNAO, and November 13 in VNSO. Yield in autumn planting was more increased than that in spring planting and also that in RST was 443kg per 10a and increased by 2.8 times compared to RAO. However the yield in the rhizome planting was more increased by 17 percent than the vegetative node planting, the latter planting was inexpensive and economic for purchasing seed materials.

  • PDF

Bottom electrode optimization for the applications of ferroelectric memory device (강유전체 기억소자 응용을 위한 하부전극 최적화 연구)

  • Jung, S.M.;Choi, Y.S.;Lim, D.G.;Park, Y.;Song, J.T.;Yi, J.
    • Journal of the Korean Crystal Growth and Crystal Technology
    • /
    • v.8 no.4
    • /
    • pp.599-604
    • /
    • 1998
  • We have investigated Pt and $RuO_2$ as a bottom electrode for ferroelectric capacitor applications. The bottom electrodes were prepared by using an RF magnetron sputtering method. Some of the investigated parameters were a substrate temperature, gas flow rate, RF power for the film growth, and post annealing effect. The substrate temperature strongly influenced the surface morphology and resistivity of the bottom electrodes as well as the film crystallographic structure. XRD results on Pt films showed a mixed phase of (111) and (200) peak for the substrate temperature ranged from RT to $200^{\circ}C$, and a preferred (111) orientation for $300^{\circ}C$. From the XRD and AFM results, we recommend the substrate temperature of $300^{\circ}C$ and RF power 80W for the Pt bottom electrode growth. With the variation of an oxygen partial pressure from 0 to 50%, we learned that only Ru metal was grown with 0~5% of $O_2$ gas, mixed phase of Ru and $RuO_2$ for $O_ 2$ partial pressure between 10~40%, and a pure $RuO_2$ phase with $O_2$ partial pressure of 50%. This result indicates that a double layer of $RuO_2/Ru$ can be grown in a process with the modulation of gas flow rate. Double layer structure is expected to reduce the fatigue problem while keeping a low electrical resistivity. As post anneal temperature was increased from RT to $700^{\circ}C$, the resistivity of Pt and $RuO_2$ was decreased linearly. This paper presents the optimized process conditions of the bottom electrodes for memory device applications.

  • PDF

Actual Status of and Measure for False Alarm of Electronic Security in Korea (한국 기계경비업무의 오경보 대응책)

  • Park, Dong-Kyun;Kim, Tae-Min
    • Korean Security Journal
    • /
    • no.30
    • /
    • pp.33-60
    • /
    • 2012
  • False alarm of Electronic security causes various serious side effects such as decrease of electronic security guard's morale caused by unnecessary mobilization, increase of fatigue caused by workload increase, increase of electronic security company owner's management burden and decrease of electronic security service utilization rate caused by customer's distrust. Therefore, the study considered the Korean regulation related with false alarm of electronic security and proposed actual status of false alarm and measure for it. The study proposed systematic resolution assignments and political assignments in relation with the measure for false alarm. Systematic resolution assignments are as follows. First, electronic security company should construct electronic security system accurately from the initial step of security consulting and security planning related with target facility. Second, it is necessary to encourage installation and operation of video monitoring system. Third, sensor wiring should be separated. Fourth, the measures for false alarm depending on main system causes should be prepared. It is necessary to encourage the installation of 'arming disarming alarm sound' generator. In addition, the measures for false arm depending on the characteristics of sensor should be prepared and standardized. Fifth, system maintenance should be reinforced. Political assignments related with the measures for false alarm are as follows. First, it is necessary to reinforce education & training. Individual nurturing & education process should be run by electronic security company or the education focusing on the measure for false alarm should be performed in job training defined in "Security Industry Act". Second, it is necessary to establish and reinforce legal regulation and establish device. If police authority standardizes the documents related with false alarm, provides their forms and requires them for periodical reports or documents, it is expected that good measures for false alarm will be prepared on the basis of actual data in the future. Third, cooperation organization to discuss the measures for false alarm like 'Conference for False Alarm of Electronic Security' should be organized and operated. Fourth, interest and role of electronic security company and electronic security supervisor should be enlarged.

  • PDF

A Study on the Optimum Design of Multiple Screw Type Dryer for Treatment of Sewage Sludge (하수슬러지 처리를 위한 다축 스크류 난류 접촉식 건조기의 최적 설계 연구)

  • Na, En-Soo;Shin, Sung-Soo;Shin, Mi-Soo;Jang, Dong-Soon
    • Journal of Korean Society of Environmental Engineers
    • /
    • v.34 no.4
    • /
    • pp.223-231
    • /
    • 2012
  • The purpose of this study is to investigate basically the mechanism of heat transfer by the resolution of complex fluid flow inside a sophisticated designed screw dryer for the treatment of sewage sludge by using numerical analysis and experimental study. By doing this, the result was quite helpful to obtain the design criteria for enhancing drying efficiency, thereby achieving the optimal design of a multiple screw type dryer for treating inorganic and organic sludge wastes. One notable design feature of the dryer was to bypass a certain of fraction of the hot combustion gases into the bottom of the screw cylinder, by the fluid flow induction, across the delicately designed holes on the screw surface to agitate internally the sticky sludges. This offers many benefits not only in the enhancement of thermal efficiency even for the high viscosity material but also greater flexibility in the application of system design and operation. However, one careful precaution was made in operation in that when distributing the hot flue gas over the lump of sludge for internal agitation not to make any pore blocking and to avoid too much pressure drop caused by inertial resistance across the lump of sludge. The optimal retention time for rotating the screw at 1 rpm in order to treat 200 kg/hr of sewage sludge was determined empirically about 100 minutes. The corresponding optimal heat source was found to be 150,000 kcal/hr. A series of numerical calculation is performed to resolve flow characteristics in order to assist in the system design as function of important system and operational variables. The numerical calculation is successfully evaluated against experimental temperature profile and flow field characteristics. In general, the calculation results are physically reasonable and consistent in parametric study. In further studies, more quantitative data analyses such as pressure drop across the type and loading of drying sludge will be made for the system evaluation in experiment and calculation.

The Clinical Study on the Constitutional symptomatic pattern of Soyangin and Taeumin inpatients in stroke (중풍입원환자(中風入院患者)의 소양인(少陽人)·태음인(太陰人) 체질병증유형(體質病證類型)에 관한 임상적(臨床的) 고찰(考察))

  • Lee, Jun-hee;Koh, Byung-hee;Song, Il-byung
    • Journal of Sasang Constitutional Medicine
    • /
    • v.12 no.1
    • /
    • pp.120-135
    • /
    • 2000
  • Objective ; The purpose of this study is to find out the constitutional symptomatic pattern of Soyangin and Taeumin through investigation of difference between two groups in stroke. Method ; 70 inpatients(Soyangin 31, Taeumin 39) in stroke, admitted into Kyung-Hee Oriental Hospital from 1. July. 1999 to 20. Sept. 1999, were investigated through questionnare which consists of 16 parts 155 questions, and the problems which have significant difference between Soyangin and Taeumin group were analyzed statistically. Result 1. The analysis of general characteristic difference between Soyangin and Taeumin group (1) The number of Soyangin patients is 31, Taeumin 39 and the number of Male patients 43, Female 27. (2) The mean weight of Taeumin group is heavier than that of Soyangin group and the degree of obesity of Taeumin group higher. (3) The number of patients who have smoking history is more at Soyangin group. (4) In neurological problem, dizziness is more complained of in Soyangin group. 2. The analysis about the result of Questionnare (1) In problems related with 'Sleeping', the time of going to bed and getting up and the duration of sleeping are more irregular in Taeumin group. (2) In problems related with 'Defecation', the shape of stool is more variable in Taeumin group. (3) In problems related with 'Urination', Soyangin group have more complaint. (4) In problems related with 'The condition of digestion', Taeumin group have a good appetite and more compalint in lower abdominal region, but on the contrary Soyangin group lose appetite and have more complaint in upper abdominal region. (5) In problems related with 'Head and Face', Soyangin group have more complaint. (6) In problems related with 'Eye, Ear and Nose', Soyangin group have more complaint at eye and ear. (7) In promlems related with 'Chest region', Soyangin group easily feel choked up and Taeumin group heart throbs. (8) In problems related with 'Skin', Taeumin group easily feel change of color tone at skin and Soyangin group dry.

  • PDF

The effect of thickness and deflection of orthodontic thermoplastic materials on its mechanical properties (교정용 열가소성 재료의 두께와 변형량이 재료의 물리적 특성에 미치는 영향)

  • Min, Sam;Hwang, Chung-Ju;Yu, Hyung-Seog;Lee, Sang-Bae;Cha, Jung-Yul
    • The korean journal of orthodontics
    • /
    • v.40 no.1
    • /
    • pp.16-26
    • /
    • 2010
  • Objective: The purposes of this study were to evaluate the force and stress depending on the type, deflection and thickness of the materials and to evaluate the mechanical properties of thermoplastic materials after repeated loading. Methods: Four types of thermoplastic products were tested. Force until the deflections of 2.0 mm and the stress when the materials were restoring to its resting position were evaluated. The mechanical properties of thermoplastic materials evaluated after 5 repeated loading cycles. Results: The interaction was observed between the thickness and the deflection (p < 0.05) from the regression equation. Thickness and amount of deflection rather than products and materials showed the largest effect on force and stress. In all products, at least 159 gf of force was required for more than 1.0 mm deflection or when materials with 1.0 mm thickness were deflected. The stress recorded was more than 19 gf/$mm^2$. During repeated loading, each group showed significant difference on the force and the stress (p < 0.01), 10 - 17% reduction of force and 4 - 7% reduction of stress in average. Conclusions: Proper thickness of thermoplastic materials and deflection level of tooth movement should be decided for the physiologic tooth movement. Force decay after repeated loading should be considered for the efficient tooth movement.

핵융합로용 플라즈마 대향부품 개발을 위해 제작된 텅스텐/FM강 HIP 접합 목업의 수명 평가 해석

  • Lee, Dong-Won;Sin, Gyu-In;Kim, Seok-Gwon;Jin, Hyeong-Gon;Lee, Eo-Hwak;Yun, Jae-Seong;Mun, Se-Yeon;Hong, Bong-Geun
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2014.02a
    • /
    • pp.452-452
    • /
    • 2014
  • 블랑켓 일차벽이나 디버터와 같은 핵융합로 플라즈마 대향부품은 플라즈마로부터 입사되는 중성자 및 입자들을 차폐하여 구조물을 보호하고, 발생열을 에너지로 변환하기 위해 냉각재를 활용한 열제거 기능을 담당한다. 특히, 고속중성자와 입사 열부하 및 여러 입자들로부터 블랑켓 및 내부 구조물을 보호하기 위해 차폐체와 구조물로 구성된다. 세계적으로 차폐체로서는 텅스텐 혹은 텅스텐 합금, 구조물용 재료로는 저방사화 Ferritic Martensitic (FM) 강이 유력한 후보재료로 개발, 연구 중에 있다. 국내에서는 국제핵융합로(ITER) 사업을 통해 고온등방가압(HIP, Hot Isostatic Pressing)을 이용한 이종금속간 접합기술과 한국형 저방사화 고온구조재료인 ARAA (Advanced Reduced Activation Alloy)가 개발되고 있으며, 이를 활용한 설계, 접합법 개발, 제작목업의 건전성 평가 등이 수행되고 있다. 한국원자력연구원에서는 핵융합 기초사업의 일환으로 전북대와 공동으로 수행 중인 건전성 평가체계 개발을 위해, 기 개발된 접합법을 활용한 $45mm(H){\times}45mm(W){\times}2mm(T)$의 W/FM강 목업을 제작한 바 있으며, 이를 국내 구축된 고열부하 시험 장비인 KoHLT-EB (Electron Beam)를 활용한 고열부하 인가 건전성 평가시험을 준비 중에 있다. 이종금속간 접합 특성은 기계적 평가를 위한 파괴시험을 통해 검증, 이를 활용한 목업이 제작되었으며, 제작된 목업에 대한 초음파를 이용한 접합면의 비파괴 검사를 통해 결함이 없음을 확인하였다. 최종적으로 실제 사용되는 핵융합 운전조건과 유사 혹은 가혹한 조건에서 고열부하를 인가하여, 그 건전성을 평가가 이루어질 것이다. 고열부하 시험을 위해서는 냉각조건, 인가 열부하, 수명평가를 통한 반복 고열부하 인가 횟수 등이 사전에 결정되어야 한다. 이를 위해 상업용 열수력, 구조해석 코드인 ANSYS-CFX와 -mechanical을 이용한 시험조건 모의 및 수명 평가가 수행되었다. 구축 장비의 냉각계통을 고려하여 냉각수의 온도 및 속도는 $25^{\circ}C$, 0.15 kg/sec로, 열부하는 0.5 및 $1.0MW/m^2$에 대해 모의를 수행하였다. 정상상태 시 텅스텐의 최대 온도는 각 열부하 조건에 따라 $285.3^{\circ}C$$546.8^{\circ}C$였으며, 이에 도달하는 시간을 구하기 위해 천이해석을 수행하였고, 이를 통해 30초에 최대온도 95 %이상의 정상상태 온도에 도달함을 확인하였다. 또한, 목업의 초기 온도에 도달하는 냉각시간도 동일한 천이해석을 통해 30초로 가능함을 확인하였고, 최종 시험 조건을 30초 가열, 30초 냉각으로 결정하였다. 결정된 반복 열부하 인가 조건에서 이종금속 접합체가 받는 다른 열팽창 정도에 따른 응력을 계산하여 목업의 수명을 도출하였고, 이를 시험해야 할 반복 횟수로 결정하였다. 각 열부하 조건에 따른 온도조건을 ANSYS-mechanical 코드를 활용하여 열팽창과 이에 따른 접합면의 응력분포로 계산하였다. 0.5 및 $1.0MW/m^2$에 대해, 목업이 받는 최대 응력은 334.3 MPa와 588.0 MPa 였으며, 이 때 텅스텐과 FM강이 받는 strain을 도출하여 물성치로 알려진 cycle to failure 값을 도출하였다. 열부하에서 예상되는 수명은 0.5 및 $1.0MW/m^2$에 대해, 100,000 사이클 이상과 2,655 사이클로 계산되었으며, 시간적 제약을 고려 최종 평가는 $1.0MW/m^2$에 대해, 3,000사이클 정도의 실험을 통해 그 수명까지 접합건전성이 유지되는 지 실험을 통해 평가할 예정이다.

  • PDF