• 제목/요약/키워드: Active failure

검색결과 399건 처리시간 0.022초

대극동러시아 농산물 수출사례 분석 (Analysis of the cases of Agricultural Export to Russian Far East)

  • 김경필;한혜성;김진석
    • 농업생명과학연구
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    • 제44권6호
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    • pp.213-222
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    • 2010
  • 본 연구는 농산물 수출잠재력이 높은 러시아국가 중에서 한국과 거리가 가깝고 수출교두보로 활용하기에 유리한 극동러시아 지역으로의 수출사례를 분석하여 수출시장 진출의 성공가능성을 높일 수 있는 시사점을 도출하기 위해 수행하였다. 수출사례 조사업체 수는 5개, 수출사례는 8개이며, 분석대상 품목은 김치, 딸기, 장미, 멜론, 배, 사과 등 7개 수출품목이다. 수출 성공사례는 사전 시장조사 및 수요파악, 포장방법 개선, 유통채널 진입 및 정착, 홍보 및 판촉활동 요인으로, 실패사례는 소비자 인지도 및 선호도 파악 미흡, 저품위 수출 요인으로 구분하여 분석하였다.

Minimally Invasive Percutaneous Plate Osteosynthesis via a Deltoid-splitting Approach with Strut Allograft for the Treatment of Displaced 3- or 4-part Proximal Humeral Fractures

  • Noh, Young-Min;Kim, Dong Ryul;Kim, Chul-Hong;Lee, Seung Yup
    • Clinics in Shoulder and Elbow
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    • 제21권4호
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    • pp.220-226
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    • 2018
  • Background: This study introduces a surgical technique with good clinical outcome useful in the treatment of osteoporotic displaced 3- or 4-part proximal humeral fractures. Methods: From May 2014 to February 2016, 16 patients with displaced 3- or 4-part proximal humeral fractures were treated by application of a locking plate with an endosteal strut allograft via a deltoid splitting approach with a minimum follow-up of 12 months. The allograft was inserted through a fractured gap of the greater tuberosity to support the humeral head and then fixed by a locking plate with meticulous soft tissue dissection to protect the axillary nerve. Surgical outcomes were evaluated by the American Shoulder and Elbow Surgeons (ASES) and visual analogue scale (VAS) scores, radiological imaging, and clinical examination. Fixation failure on radiographs was defined as a >$5^{\circ}$ loss of neck shaft angle (NSA) compared to that on an immediate postoperative radiograph. Avascular necrosis (AVN) of the humeral head was also evaluated. Results: In all cases, complete union was achieved. The ASES and VAS scores were improved to $85.4{\pm}2.1$ and $3.2{\pm}1.3$, respectively. Twelve patients (75.0%) had greater than a $5^{\circ}$ change in NSA; the average NSA change was $3.8^{\circ}$. Five patients (31.3%) had unsatisfactory ranges of motion exhibiting a <$100^{\circ}$ active forward flexion. No axillary nerve injuries or AVN were observed at the last follow-up. One patient was converted to reverse total arthroplasty due to severe pain and functional deficit. Conclusions: Minimally invasive fixation via a locking compression plate and an endosteal fibula strut allograft in Neer classification 3-or 4-part fractures with severe osteoporosis in elderly patients can achieve good clinical results.

Recent Update of Advanced Imaging for Diagnosis of Cardiac Sarcoidosis: Based on the Findings of Cardiac Magnetic Resonance Imaging and Positron Emission Tomography

  • Chang, Suyon;Lee, Won Woo;Chun, Eun Ju
    • Investigative Magnetic Resonance Imaging
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    • 제23권2호
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    • pp.100-113
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    • 2019
  • Sarcoidosis is a multisystem disease characterized by noncaseating granulomas. Cardiac involvement is known to have poor prognosis because it can manifest as a serious condition such as the conduction abnormality, heart failure, ventricular arrhythmia, or sudden cardiac death. Although early diagnosis and early treatment is critical to improve patient prognosis, the diagnosis of CS is challenging in most cases. Diagnosis usually relies on endomyocardial biopsy (EMB), but its diagnostic yield is low due to the incidence of patchy myocardial involvement. Guidelines for the diagnosis of CS recommend a combination of clinical, electrocardiographic, and imaging findings from various modalities, if EMB cannot confirm the diagnosis. Especially, the role of advanced imaging such as cardiac magnetic resonance (CMR) imaging and positron emission tomography (PET), has shown to be important not only for the diagnosis, but also for monitoring treatment response and prognostication. CMR can evaluate cardiac function and fibrotic scar with good specificity. Late gadolinium enhancement (LGE) in CMR shows a distinctive enhancement pattern for each disease, which may be useful for differential diagnosis of CS from other similar diseases. Effectively, T1 or T2 mapping techniques can be also used for early recognition of CS. In the meantime, PET can detect and quantify metabolic activity and can be used to monitor treatment response. Recently, the use of a hybrid CMR-PET has introduced to allow identify patients with active CS with excellent co-localization and better diagnostic accuracy than CMR or PET alone. However, CS may show various findings with a wide spectrum, therefore, radiologists should consider the possible differential diagnosis of CS including myocarditis, dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy, amyloidosis, and arrhythmogenic right ventricular cardiomyopathy. Radiologists should recognize the differences in various diseases that show the characteristics of mimicking CS, and try to get an accurate diagnosis of CS.

A Facile Process for Surface Modification with Lithium Ion Conducting Material of Li2TiF6 for LiMn2O4 in Lithium Ion Batteries

  • Kim, Min-Kun;Kim, Jin;Yu, Seung-Ho;Mun, Junyoung;Sung, Yung-Eun
    • Journal of Electrochemical Science and Technology
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    • 제10권2호
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    • pp.223-230
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    • 2019
  • A facile method for surface coating with $Li_2TiF_6$ which has a high lithium-ion conductivity, on $LiMn_2O_4$ spinel cathode material for high performance lithium ion batteries. The surface coating is performed by using a co-precipitation method with $Li_2CO_3$ powder and $H_2TiF_6$ solution under room temperature and atmospheric pressure without special equipment. Total coating amount of $Li_2TiF_6$ is carefully controlled from 0 to 10 wt.% based on the active material of $LiMn_2O_4$. They are evaluated by a systematic combination of analyses comprising with XRD, SEM, TEM and ICP. It is found that the surface modification of $Li_2TiF_6$ is very beneficial to high cycle life and excellent rate capability by reducing surface failure and supporting lithium ions transportation on the surface. The best coating condition is found to have a high cycle life of $103mAh\;g^{-1}$ at the 100th cycle and a rate capability of $102.9mAh\;g^{-1}$ under 20 C. The detail electrochemical behaviors are investigated by AC impedance and galvanostatic charge and discharge test.

Vanadium계 촉매의 NH3-SCR 저온 활성 영향 연구 (A Study on the Effect of Low-Temperature Activity on Vanadium Catalysts)

  • 여종현;홍성창
    • 청정기술
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    • 제26권4호
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    • pp.321-328
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    • 2020
  • 본 실험은 상용 촉매인 V/W/TiO2와 V/Mo/TiO2 촉매를 비교하여 SCR 반응에서 저온 활성에 미치는 영향 연구를 진행하였다. NH3-SCR 반응에서의 중요한 영향을 미치는 NH3 산점과 산소의 영향을 확인하기 위해 NH3-TPD, DRIFT, H2-TPR 분석과 O2-on/off 실험을 진행하였다. 반응 활성이 높은 온도인 250 ℃와 활성 저하가 크게 나타나는 180 ℃에서 반응 활성에 미치는 영향을 분석하였다. 250 ℃에서는 SCR 반응에 참여하는 NH3 중, B산점과 L산점이 반응에 참여하는 것을 확인할 수 있었으며, 기상의 산소가 반응에 참여하여 재산화 영향에 크게 나타내는 것을 확인할 수 있었다. 하지만 180 ℃에서는 B산점의 영향이 저하되고, 기상의 산소에 의한 재산화의 영향이 적어 활성이 저하되는 것으로 판단된다.

Preliminary design and assessment of a heat pipe residual heat removal system for the reactor driven subcritical facility

  • Zhang, Wenwen;Sun, Kaichao;Wang, Chenglong;Zhang, Dalin;Tian, Wenxi;Qiu, Suizheng;Su, G.H.
    • Nuclear Engineering and Technology
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    • 제53권12호
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    • pp.3879-3891
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    • 2021
  • A heat pipe residual heat removal system is proposed to be incorporated into the reactor driven subcritical (RDS) facility, which has been proposed by MIT Nuclear Reactor Laboratory for testing and demonstrating the Fluoride-salt-cooled High-temperature Reactor (FHR). It aims to reduce the risk of the system operation after the shutdown of the facility. One of the main components of the system is an air-cooled heat pipe heat exchanger. The alkali-metal high-temperature heat pipe was designed to meet the operation temperature and residual heat removal requirement of the facility. The heat pipe model developed in the previous work was adopted to simulate the designed heat pipe and assess the heat transport capability. 3D numerical simulation of the subcritical facility active zone was performed by the commercial CFD software STAR CCM + to investigate the operation characteristics of this proposed system. The thermal resistance network of the heat pipe was built and incorporated into the CFD model. The nominal condition, partial loss of air flow accident and partial heat pipe failure accident were simulated and analyzed. The results show that the residual heat removal system can provide sufficient cooling of the subcritical facility with a remarkable safety margin. The heat pipe can work under the recommended operation temperature range and the heat flux is below all thermal limits. The facility peak temperature is also lower than the safety limits.

고혈압 복합제 복용환자에서 동일계열약물 중복 현황 (Class duplication prescriptions in patients taking fixed-dose combination antihypertensives)

  • 구현지;이지원;최하은;제남경;정경혜
    • 한국임상약학회지
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    • 제32권2호
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    • pp.125-132
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    • 2022
  • Background: Fixed-dose combinations have the advantage of improving patient compliance, but may increase the risk of duplicate prescriptions. As the use of fixed-dose combination antihypertensives increases, it is necessary to investigate the current status of class duplication prescriptions (CDP) in patients taking fixed-dose combination antihypertensives in Korea and to identify factors associated with CDP. Methods: We conducted a retrospective observational study using nationally representative claim data. Hypertensive patients aged 20 years or older taking fixed-dose combination antihypertensives were extracted. Among these patients, patients with CDP were identified. A chi-square test was applied to determine the differences between patients with CDP and non-CDP. The associated factors of CDP were identified through multiple logistic regression. Results: Of the 74,165 patients who were prescribed fixed-dose combination antihypertensives, 426 patients (0.6%) with CDP were identified. The most common antihypertensive class associated with CDP was calcium channel blockers (194 patients, 45.5%), followed by angiotensin II receptor blockers (136 patients, 31.9%). Patients aged 75 years or older (odds ratio [OR] 1.83, 95% confidence interval [CI] 1.02-3.52), chronic kidney disease (OR 4.45, 95% CI 2.15-8.25), chronic heart failure (OR 2.71, 95% CI 1.93-3.72), coronary artery disease (OR 2.22, 95% CI 1.60-3.03) and Medical Aid/Patriots and Veterans Insurance (OR 1.49, 95% CI 1.04-2.07) were significantly associated with increased CDP. Conclusions: The factors associated with CDP were the elderly, comorbidities, and low socioeconomic status. Since CDP can result in negative clinical outcomes, active intervention by the pharmacist is warranted.

시나리오별 충방전에 따른 리튬이온(Li-ion) 배터리 특성 (Characteristics of Lithium-ion(Li-ion) Batteries according to Charging and Discharging by Scenario)

  • 윤용호
    • 한국인터넷방송통신학회논문지
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    • 제23권4호
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    • pp.171-176
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    • 2023
  • 21세기 현대사회에 있어서 이차전지 배터리(Battery)를 이용한 휴대용 전자제품은 계속해서 경량, 소형화되어가는 추세 속에서 있다. 그리고 이러한 추세와 더불어 우리는 몸에 착용할 수 있는 전자 장비를 이용하여 하루 일상생활에서 정보를 수집, 공유하는 4차 산업혁명 시대에 활동하고 있다. 따라서 소형 가전제품 및 디지털 기기를 사용하면서 재충전할 수 있는 이차전지 배터리의 역할은 점점 더 중요하게 증가하고 있다. 이러한 증가와 더불어 이차전지 배터리 성능시험은 특성, 수명, 고장진단, 재활용 등의 다양한 시험방법을 요구하고 있으며 있다. 또한 배터리의 안전과 적절한 기능을 보장하기 위한 배터리 테스트 시스템 구축과 이에 따른 지침 및 올바른 기본지식이 고려되고 있다. 따라서 본 논문에서는 배터리의 성능과 직접으로 연결된 시나리오별 충방전에 따른 이차전지 리튬이온(Li-ion) 배터리의 특성에 대해 살펴보고자 한다.

Transient heat transfer and crust evolution during debris bed melting process in the hypothetical severe accident of HPR1000

  • Chao Lv;Gen Li;Jinchen Gao;Jinshi Wang;Junjie Yan
    • Nuclear Engineering and Technology
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    • 제55권8호
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    • pp.3017-3029
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    • 2023
  • In the late in-vessel phase of a nuclear reactor severe accident, the internal heat transfer and crust evolution during the debris bed melting process have important effects on the thermal load distribution along the vessel wall, and further affect the reactor pressure vessel (RPV) failure mode and the state of melt during leakage. This study coupled the phase change model and large eddy simulation to investigate the variations of the temperature, melt liquid fraction, crust and heat flux distributions during the debris bed melting process in the hypothetical severe accident of HPR1000. The results indicated that the heat flow towards the vessel wall and upper surface were similar at the beginning stage of debris melting, but the upward heat flow increased significantly as the development of the molten pool. The maximum heat flux towards the vessel wall reached 0.4 MW/m2. The thickness of lower crust decreased as the debris melting. It was much thicker at the bottom region with the azimuthal angle below 20° and decreased rapidly at the azimuthal angle around 20-50°. The maximum and minimum thicknesses were 2 and 90 mm, respectively. By contrast, the distribution of upper crust was uniform and reached stable state much earlier than the lower crust, with the thickness of about 10 mm. Moreover, the sensitivity analysis of initial condition indicated that as the decrease of time interval from reactor scram to debris bed dried-out, the maximum debris temperature and melt fraction became larger, the lower crust thickness became thinner, but the upper crust had no significant change. The sensitivity analysis of in-vessel retention (IVR) strategies indicated that the passive and active external reactor vessel cooling (ERVC) had little effect on the internal heat transfer and crust evolution. In the case not considering the internal reactor vessel cooling (IRVC), the upper crust was not obvious.

Problems and suggested improvement plans for occupational health service in Korea

  • Dongmug Kang
    • Annals of Occupational and Environmental Medicine
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    • 제35권
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    • pp.10.1-10.10
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    • 2023
  • The purpose of this paper was to review the problems relating to Korea's occupational health services and suggest ways to improve them. Korea can be classified as a welfare state type of conservative corporatism partially interwoven with liberalism. While experiencing compressed economic growth, the economic sectors of developed (excess areas) and developing (deficient areas) countries are interwoven. Therefore, it is necessary to perfect conservative corporatism along with a complementary reinforcement of liberal contents and to apply a multilayered approach focusing on complementing the deficient areas. It is essential to form a national representative indicator related to occupational health, and a strategy for selection and concentration is needed. The proposed central indicator is the occupational health coverage rate (OHCR), which is the number of workers who have applied for mandatory occupational health services under the Occupational Safety and Health Act in the numerator with the total working population in the denominator. This paper proposes ways to raise the OHCR, which is currently at the level of 25%-40%, to 70%-80%, which is the level of Japan, Germany, and France. To achieve this target, it is necessary to focus on small businesses and vulnerable workers. This is an area of market failure and requires the active input of community-oriented public resources. For access to larger workplaces, the marketability of services should be strengthened and personal intervention using digital health resources should be actively attempted. Taking a national perspective, work environment improvement committees with tripartite (labor, management, and government) participation for improvement of the working environment need to be established at the center and in the regions. Through this, prevention funds linked to industrial accident compensation and prevention could be used efficiently. A national chemical substance management system must be established to monitor the health of workers and the general public.