• 제목/요약/키워드: GER

검색결과 186건 처리시간 0.024초

Coordinated supporting method of gob-side entry retaining in coal mines and a case study with hard roof

  • Liu, X.S.;Ning, J.G.;Tan, Y.L.;Xu, Q.;Fan, D.Y.
    • Geomechanics and Engineering
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    • 제15권6호
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    • pp.1173-1182
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    • 2018
  • The coal wall, gob-side backfill, and gangues in goaf, constitute the support system for Gob-side entry retaining (GER) in coal mines. Reasonably allocating and utilizing their bearing capacities are key scientific and technical issues for the safety and economic benefits of the GER technology. At first, a mechanical model of GER was established and a governing equation for coordinated bearing of the coal-backfill-gangue support system was derived to reveal the coordinated bearing mechanism. Then, considering the bearing characteristics of the coal wall, gob-side backfill and gangues in goaf, their quantitative design methods were proposed, respectively. Next, taking the No. 2201 haulage roadway serving the No. 7 coal seam in Jiangjiawan Mine, China, as an example, the design calculations showed that the strains of both the coal wall and gob-side backfill were larger than their allowable strains and the rotational angle of the lateral main roof was larger than its allowable rotational angle. Finally, flexible-rigid composite supporting technology and roof cutting technology were designed and used. In situ investigations showed that the deformation and failure of surrounding rocks were well controlled and both the coal wall and gob-side backfill remained stable. Taking the coal wall, gob-side backfill and gangues in goaf as a whole system, this research takes full consideration of their bearing properties and provides a quantitative basis for design of the support system.

Cloning, Expression, and Biochemical Characterization of dTDP-Glucose 4,6-Dehydratase Gene (gerE) from Streptomyces sp. GERI-155

  • Lee, Hei-Chan;Sohng, Jae-Kyung;Kim, Hyung-Jun;Nam, Doo-Hyun;Seong, Chi-Nam;Han, Ji-Man;Yoo, Jin-Cheol
    • Journal of Microbiology and Biotechnology
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    • 제14권3호
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    • pp.576-583
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    • 2004
  • GERI-155 is a macrolide antibiotic containing two deoxyhexose molecules and shows antimicrobial activities against Gram-positive bacteria. Deoxysugar biosynthetic gene cluster of GERI-155 from Streptomyces sp. GERI-l55 genome was cloned. Four orfs were identified and a putative orf presumed to be the dTDP g]ucose-4,6-dehydratase gene was designated as gerE. GerE was expressed in E. coli by using a recombinant expression vector pHJ1. The expressed protein was purified from E. coli cell lysate by using ammonium sulfate fractionation, and DEAE-sepharose CL-6B and hydroxylapatite column chromatography. The molecular mass of the expressed protein correlated with the predicted mass that was deduced from the cloned gene sequence data. The recombinant protein was a homodimer with a subunit relative molecular weight of 39,000 Dalton. It was found to have dTDP-glucose 4,6-dehydratase activity and also found to be highly specific for dTDP-glucose as a substrate. The values of $K_{m} and V_{max}$ for dTDP-g]ucose were $32\mu$M and 335 nmol $min^{-1}$ (mg protein)^{-1}$, respectively. dTTP and dTDP were strong inhibitors of the protein. $NAD^+$, the coenzyme for dTDP-glucose 4,6-dehydratase, was tightly bound to the expressed protein.

생성율 개념에 기초한 화재모델의 신뢰성에 대한 연구 (On the Reliability of the Computational Fire Model Based on the Yield Rate Concept of Combustion Gases)

  • 김성찬;고권현;이성혁
    • 한국화재소방학회논문지
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    • 제23권4호
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    • pp.130-136
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    • 2009
  • 본 연구는 생성율 개념에 기초하여 화재유동장의 연소가스를 해석하는 필드모델의 신뢰성을 평가하기 위해 수행되었다. 환기조건에 따른 화재실 내부의 일산화탄소와 연기밀도를 해석하기 위하여 총괄당량비(GER) 개념이 도입되었으며 FDS 모델에 의해 예측된 일산화탄소와 연기밀도는 ISO-9705 표준화재실의 축소실험결과와 직접 비교하였다. 환기부족화재에 대해 수치해석결과는 일산화탄소와 연기밀도를 하향 예측하는 경향을 보였으며 총괄당량비가 증가함에 따라 수치해석결과와 실험결과의 오차는 증가하였다. 생성율 모델을 이용하여 화재발생으로 인한 연소생성물의 농도장을 해석하고자 하는 경우 공간내부의 환기 조건에 따라 해석결과의 신뢰성 검증에 주의를 기울여야 하며 지속적인 연구를 통해 타당한 물리적 모델개발과 함께 다양한 화재조건에 대한 모델의 검증이 요구된다.

Computed tomographic features of gastric and esophageal content in dogs undergoing CT myelography and factors influencing the presence of esophageal fluid

  • Benzimra, Caroline;Cerasoli, Ilaria;Rault, Delphine;Chalvet-Monfray, Karine;Cauvin, Eddy;Couturier, Laurent;Gatel, Laure
    • Journal of Veterinary Science
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    • 제21권6호
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    • pp.84.1-84.11
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    • 2020
  • Background: Gastroesophageal reflux (GER) has been reported to be a common finding in dogs under general anesthesia. Objectives: The aim of this retrospective study was to assess the esophageal and gastric contents in a population of dogs undergoing computed tomographic myelography (myeloCT) examination and to evaluate the factors influencing the presence of esophageal fluid (gastric content, duration of anesthesia, body position, and intrinsic factors). Methods: Esophageal and gastric contents of 83 non-brachycephalic dogs were retrospectively assessed based on plain and myelo-CT scans. Age, weight, breed, sex, and the time between the 2 computed tomography [CT] scans were included. Results: Esophageal fluid was present in 19% (16/83) of the animals, and 14% (12/83) and 46% (37/83), respectively, had fluid or food material in their stomachs. The frequency of observing esophageal fluid on myelo-CT scans was significantly increased compared with plain CT scans (p = 0.006). The presence of gastric fluid was significantly associated with an increased frequency of observing esophageal fluid compared to other gastric contents (p = 0.049; odds ratio, 3.1). The presence of esophageal fluid was not correlated with alimentary gastric contents (p = 0.17). Increased body weight and duration of anesthesia were significantly associated with an increased frequency of observing esophageal fluid (p = 0.022, p = 0.021). Conclusions: Unlike alimentary gastric contents, fluid gastric contents were correlated with the presence of esophageal fluid upon myelo-CT. The observation of fluid in the esophagus may be consistent with GER. This study provides data additional to pH monitoring studies of GER and may support previous studies recommending shorter pre-anesthetic fasting periods in dogs.

Stability analysis of roof-filling body system in gob-side entry retained

  • Jinlin Xin;Zizheng Zhang;Weijian Yu;Min Deng
    • Geomechanics and Engineering
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    • 제36권1호
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    • pp.27-37
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    • 2024
  • The roof-filling body system stability plays a key role in gob-side entry retained (GER). Taking the GER of the 1103 belt transportation roadway in Heilong Coal Mine as engineering background, stability analysis of roof-filling body system was conducted based on the cusp catastrophe theory. Theoretical results showed that the current design parameters of 1103 belt transportation roadway could ensure the roof-filling body system stable during the resistance-increasing support stage of the filling body and the stable support stage of the filling body. Moreover, a verified global numerical model in FLAC3D was established to analyze the failure characteristics including surrounding rock deformation, stress distribution, and plastic zone. Numerical simulation indicated that the width-height ratio of the filling body had a great influence on the stability of the roof-filling body system. When the width-height ratio was greater than 0.62, with the decrease of the width-height ratio, the peak stress of the filling body gradually decreased; when the width-height ratio was greater than 0.92, as the distance to the roadway increased, the roof stress increased and then decreased. The theoretical analysis and numerical simulation findings in this study provide a new research method to analyze the stability of the roof-filling body system in GER.

독일의 해상유류오염 예방 및 방제체계 고찰 (Study on the Prevention and Combat System of Oil Pollution in Germany)

  • 신옥주
    • 환경정책연구
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    • 제8권1호
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    • pp.97-127
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    • 2009
  • 독일에 있어서 북해와 동해는 여러 측면에서 매우 중요한 의미를 가지고 있다. 북해의 연안국에게 북해변의 경제적 의미가 매우 크다. 이곳에는 수많은 항만들 외에 많은 공업시설이 있으며, 이곳은 또한 농업 발달지역이기도 하다. 바닷물과 강물이 섞인 곳(Brackwassermeer)인 동해의 특징은 북해와는 협수로 연결이 되어서 북해와의 물의 순환이 원활하지 못한 지정학적 위치 때문에 북해처럼 빠른 속도로 유해물질이 처리될 수 없다는 점이다. 크고 작은 선박사고 및 각종 오염 원으로부터 보호하기 위해 동해는 특히 HELKOM협약을 통하여, 그리고 북해는 OSPAR협약을 통하여 노력을 기울이고 있다. 또한 선박사고 시 예인선에 관하여 NethGer-Plan과 DenGer-Plan을 통하여 네덜란드와 독일, 덴마크와 독일간에 협조가 이루어지고 있다. 1995년에 브레멘 부근에서 발생한 팔라스(Pallas)호 사건 이후 독일에서는 미래의 해양안전을 위해서 사용가능한 자원에 대한 연안 각 주간의 협조가 개선되어야 할 필요성이 증대되었다. 그 결과 2003년 1월 1일에 연방과 연안 주정부들은 공동으로 하바리 코만도(Havarie-Kommanando 선박사고 대책부대)를 조직하였다. 하바리 코만도는 중대한 선박 사고 발생 시 대국민작업 및 선박 사고 관련 조직의 동원을 통합적으로 지휘하는 업무를 담당하는 것을 골자로 각 업무별 담당기관의 조정을 위한 연방-주 공동 기관이다. 또한 해상에서의 비상사태 시 연방과 주의 참여기관, 각 해운회사, 헬리콥터 회사인 Hiking-Helicopters-Service 등과의 협동이 잘 이루어지고 있으며, 동해 최대 여객선사인 독일-덴마크 선박회사인 Scandlines, ARGE Kuestenschutz와도 공조가 잘 되고 있다.

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Streptozotocin 유발 당뇨 쥐의 거대배아미 식이에 의한 혈액 및 간조직의 지질조성 (Supplementary Effect of the Giant Embryonic Rice on Serum and Heaptic Lipid Levels of Streptozotocin-induced Diabetic Rats)

  • 이연리;김채은;남석현;강미영
    • 한국식품과학회지
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    • 제38권4호
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    • pp.562-566
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    • 2006
  • 본 연구는 거대배아미 급여가 당뇨모델의 지질대사에 미치는 영향을 검토하고자 수행되었다. 실험모델은 스트렙토조토신으로 유발된 인슐린 의존형 당뇨 흰쥐를 이용하여, 실험식이를 6주간 급여한 후의 체내 지질함량 및 대변으로의 배설량을 각각 조사 하였다 거대배아미를 급여한 경우에는 당뇨가 유발되었음에도 불구하고 체중 증가의 현상이 나타났고, 장기 비대 현상은 억제 되고 있었다. 혈청 중성지방 몇 간의 총 콜레스테롤 함량도 현미 및 거대배아미 급여군에서 억제효과가 있었다. 그리고 대변으로 배설되는 총지질 및 콜레스테롤의 양도 거대배아미 급여군에서 대조군보다 유의하게 많은 것으로 나타났다. 이상의 결과들로부터 거대배아미 식이는 인슐린 의존형 당뇨쥐에서 대변중의 총 지질 및 총 콜레스테롤 배설량의 증가와 연관지어 당뇨병 모델의 체내 지질대사에 개선효과가 있음을 알 수 있다.