• 제목/요약/키워드: Pressure recovery factor

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Surgical Treatment of Subdural Hygromas in Infants and Children

  • Cho, Jun-Beom;Cho, Ki-Hong;Kim, Se-Hyuk;Shin, Yong-Sam;Lee, Won-Chung;Yoon, Soo-Han
    • Journal of Korean Neurosurgical Society
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    • 제38권4호
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    • pp.273-280
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    • 2005
  • Objective : There is no acceptable indication and treatment of choice for infantile and child subdural hygroma and there are only a few reports about that in Korea. So the authors studied the clinical findings of infantile and child patients with subdural hygroma to improve the understanding and to suggest a standard treatment method. Methods : The authors retrospectively evaluated the causes, preoperative symptoms, radiological thicknesses, and postoperative results of 25patients with subdural hygroma who received surgical therapy. Results : There were 16boys and 9girls whose median age was 6months[range $2{\sim}120months$]. The main clinical manifestations were seizures, increased intracranial pressure, macrocrania and alteration of consciousness. Radiological thicknesses of the subdural hygroma varied from 7mm to 42mm and postoperative changes of thickness[y] could be expressed with the factor of month[x]: $y\;=\;-1.32\;{\times}\;+11.8$ in subdural drainage, and $y\;=\;-1.52\;{\times}\;+14.9$ in subduroperitoneal shunts. Of the 25patients, 2 [50%] were successfully treated by aspiration, 13 [59%] by subdural drainage, and 9 [69%] by subduroperitoneal shunt. Conclusion : It is suggested that the diagnosis and treatment of subdural hygroma in infants and children should be carefully addressed because of its high prevalence in children, and especially in infants. It is also suggested that the subdural drainage could be primary initial treatment method because it is simpler than a shunt, and since our data show that there is no statistical difference in postoperative recovery duration between the two operative methods.

PID 제어기를 이용한 초음속 엔진 흡입구의 버즈마진 제어에 관한 연구 (A Study on Buzz Margin Control in Supersonic Engine Intake using PID Controller)

  • 공창덕;기자영;고성희;강명철
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2009년도 춘계학술대회 논문집
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    • pp.88-92
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    • 2009
  • 초음속 추진기관은 기계적인 압축기를 통해 흡입공기를 압축하는 방식이 아니라 램 압축 현상을 이용하여 흡입공기를 압축하기 때문에 흡입구에서의 전압력 회복율이 초음속 추진기관 전체의 작동특성에 결정적인 영향을 주게 된다. 제어기 설계에 앞서 엔진의 동특성 해석을 수행한 결과 비행체의 받음각이 커질수록 버즈마진 값이 작아져 일부영역에서는 충격파가 흡입구 외부에서 발생하게 됨을 확인할 수 있었다. 따라서 흡입구 내의 충격파 특성이 성능요구조건을 만족할 수 있도록 버즈마진을 제어하기 위한 PID 제어알고리즘을 설계하였다. 제어변수는 연료유량과 노즐 목면적이며 버즈마진 값이 양의 값을 갖도록 PID 제어기를 설계하였다.

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장기혈액투석환자의 투석중 혈압하강과 Coil내 혈액손실 방지를 위한 기초조사 (A Study on the long-term Hemodialysis patient중s hypotension and preventation from Blood loss in coil during the Hemodialysis)

  • 박순옥
    • 대한간호학회지
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    • 제11권2호
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    • pp.83-104
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    • 1981
  • Hemodialysis is essential treatment for the chronic renal failure patient's long-term cure and for the patient management before and after kidney transplantation. It sustains the endstage renal failure patient's life which didn't get well despite strict regimen and furthermore it becomes an essential treatment to maintain civil life. Bursing implementation in hemodialysis may affect the significant effect on patient's life. The purpose of this study was to obtain the basic data to solve the hypotension problem encountable to patient and the blood loss problem affecting hemodialysis patient'a anemic states by incomplete rinsing of blood in coil through all process of hemodialysis. The subjects for this study were 44 patients treated hemodialysis 691 times in the hemodialysis unit, The .data was collected at Gang Nam 51. Mary's Hospital from January 1, 1981 to April 30, 1981 by using the direct observation method and the clinical laboratory test for laboratory data and body weight and was analysed by the use of analysis of Chi-square, t-test and anlysis of varience. The results obtained an follows; A. On clinical laboratory data and other data by dialysis Procedure. The average initial body weight was 2.37 ± 0.97kg, and average body weight after every dialysis was 2.33 ± 0.9kg. The subject's average hemoglobin was 7.05±1.93gm/dl and average hematocrit was 20.84± 3.82%. Average initial blood pressure was 174.03±23,75mmHg and after dialysis was 158.45±25.08mmHg. The subject's average blood ion due to blood sample for laboratory data was 32.78±13.49cc/ month. The subject's average blood replacement for blood complementation was 1.31 ±0.88 pint/ month for every patient. B. On the hypotensive state and the coping approaches occurrence rate of hypotension was 28.08%. It was 194 cases among 691 times. 1. In degrees of initial blood pressure, the most 36.6% was in the group of 150-179mmHg, and in degrees of hypotension during dialysis, the most 28.9% in the group of 40-50mmHg, especially if the initial blood pressure was under 180mmHg, 59.8% clinical symptoms appeared in the group of“above 20mmHg of hypotension”. If initial blood pressure was above 180mmHg, 34.2% of clinical symptoms were appeared in the group of“above 40mmHg of hypotension”. These tendencies showed the higher initial blood pressure and the stronger degree of hypotension, these results showed statistically singificant differences. (P=0.0000) 2. Of the occuring times of hypotension,“after 3 hrs”were 29.4%, the longer the dialyzing procedure, the stronger degree of hypotension ann these showed statistically significant differences. (P=0.0142). 3. Of the dispersion of symptoms observed, sweat and flush were 43.3%, and Yawning, and dizziness 37.6%. These were the important symptoms implying hypotension during hemodialysis accordingly. Strages of procedures in coping with hypotension were as follows ; 45.9% were recovered by reducing the blood flow rate from 200cc/min to 1 00cc/min, and by reducing venous pressure to 0-30mmHg. 33.51% were recovered by controling (adjusting) blood flow rate and by infusion of 300cc of 0,9% Normal saline. 4.1% were recovered by infusion of over 300cc of 0.9% normal saline. 3.6% by substituting Nor-epinephiine, 5.7% by substituting blood transfusion, and 7,2% by substituting Albumin were recovered. And the stronger the degree of symptoms observed in hypotention, the more the treatments required for recovery and these showed statistically significant differences (P=0.0000). C. On the effects of the changes of blood pressure and osmolality by albumin and hemofiltration. 1. Changes of blood pressure in the group which didn't required treatment in hypotension and the group required treatment, were averaged 21.5mmHg and 44.82mmHg. So the difference in the latter was bigger than the former and these showed statistically significant difference (P=0.002). On the changes of osmolality, average mean were 12.65mOsm, and 17.57mOsm. So the difference was bigger in the latter than in the former but these not showed statistically significance (P=0.323). 2. Changes of blood pressure in the group infused albumin and in the group didn't required treatment in hypotension, were averaged 30mmHg and 21.5mmHg. So there was no significant differences and it showed no statistical significance (P=0.503). Changes of osmolality were averaged 5.63mOsm and 12.65mOsm. So the difference was smaller in the former but these was no stitistical significance (P=0.287). Changes of blood pressure in the group infused Albumin and in the group required treatment in hypotension were averaged 30mmHg and 44.82mmHg. So the difference was smaller in the former but there is no significant difference (P=0.061). Changes of osmolality were averaged 8.63mOsm, and 17.59mOsm. So the difference were smaller in the former but these not showed statistically significance (P=0.093). 3. Changes of blood pressure in the group iutplemented hemofiltration and in the Uoup didn't required treatment in hypotension were averaged 22mmHg and 21.5mmHg. So there was no significant differences and also these showed no statistical significance (P=0.320). Changes of osmolality were averaged 0.4mOsm and 12.65mOsm. So the difference was smaller in the former but these not showed statistical significance(P=0.199). Changes of blood pressure in the group implemented hemofiltration and in the group required treatment in hypotension were averaged 22mmHg and 44.82mmHg. So the difference was smatter in the former and these showed statistically significant differences (P=0.035). Changes of osmolality were averaged 0.4mOsm and 17.59mOsm. So the difference was smaller in the former but these not showed statistical significance (P=0.086). D. On the changes of body weight, and blood pressure, between the group of hemofiltration and hemodialysis. 1, Changes of body weight in the group implemented hemofiltration and hemodialysis were averaged 3.340 and 3.320. So there was no significant differences and these showed no statistically significant difference, (P=0.185) but standard deviation of body weight averaged in comparison with standard difference of body weight was statistically significant difference (P=0.0000). Change of blood Pressure in the group implemented hemofiltration and hemodialysis were averaged 17.81mmHg and 19.47mmHg. So there was no significant differences and these showed no statistically significant difference (P=0.119), But in comparison with standard deviation about difference of blood pressure was statistically significant difference. (P=0.0000). E. On the blood infusion method in coil after hemodialysis and residual blood losing method in coil. 1, On comparing and analysing Hct of residual blood in coil by factors influencing blood infusion method. Infusion method of saline 200cc reduced residual blood in coil after the quantitative comparison of Saline Occ, 50cc, 100cc, 200cc and the differences showed statistical significance (p < 0.001). Shaking Coil method reduced residual blood in Coil in comparison of Shaking Coil method and Non-Shaking Coil method this showed statistically significant difference (P < 0.05). Adjusting pressure in Coil at OmmHg method reduced residual blood in Coil in comparison of adjusting pressure in Coil at OmmHg and 200mmHg, and this showed statistically significant difference (P < 0.001). 2. Comparing blood infusion method divided into 10 methods in Coil with every factor respectively, there was seldom difference in group of choosing Saline 100cc infusion between Coil at OmmHg. The measured quantity of blood loss was averaged 13.49cc. Shaking Coil method in case of choosing saline 50cc infusion while adjusting pressure in coil at OmmHg was the most effective to reduce residual blood. The measured quantity of blood loss was averaged 15.18cc.

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살포량 감소에 의한 살충제 Acetamipride의 작물 부착량과 나방류 방제효과 (Adhesion Amount of Acetamipride on Plant and the Pest Control Effect According to the Reduced Application Amount)

  • 김영신;장지웅;진나영;유용만;윤영남;임치환
    • 농약과학회지
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    • 제19권3호
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    • pp.317-322
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    • 2015
  • 본 연구는 농약 살포량과 유효성분의 부착량 그리고 해충방제 효과와의 상관관계를 조사하여 효율적 해충방제를 위한 적정 농약 살포량을 도출하는 기초 자료를 얻고자 실시되었다. 시험약제의 유효성분인 acetamiprid의 표준검량선의 직선성 $R^2=0.9994$, 회수율 71~93%, 변이계수 6% 이하로 농약 잔류분석기준에 적합하였다. 2015년도 실험에서는 살포량을 전년도보다 70 L 감량한 302 L/10a로하고 살포압을 낮추어 살포한 후 유효성분의 부착량을 비교 분석한 결과, 부착량의 상관계수가 82%에서 69%로 낮게 조사되어 전년도에 비해 고르게 살포되었음 알 수 있었다. 약제 살포량을 줄였음에도 해충에 대한 방제가가 95%이상 우수한 것으로 나타나, 유효성분 부착량의 상관계수와 밀접한 관계가 있는 것으로 보여 진다. 또한 사과원 토양 표면의 유효성분 부착량을 분석한 결과 과수에 부착되는 양과 비교해 2.2배까지 높게 부착되는 것으로 분석되었다.

Rubbery 고분가 막을 이용한 휘발성 유기화학물의 제거 및 회수 (Removal/Recovery of VOCs Using a Rubbery Polymeric Membrane)

  • Cha, Jun-Seok
    • 멤브레인
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    • 제6권3호
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    • pp.173-181
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    • 1996
  • 실리콘 코팅한 복합막을 이용하여 톨로엔이나 메탄올 같은 휘발성 유기화합물의 제거 및 회수에 관한 연구를 수행하였다. 사용된 막은 코팅층의 두께가 얇고($~1\mu$m), 지지층의 기고율이 커서 투과저항은 적었으며 코팅층과 지지층은 플라즈마 중합에 의해 결합되어 있어서 높은 압력에도 견딜 수 있었다. Feed의 유속은 60cc/min. 이하일 때 사용된 모듈에 위해 휘발성 유기화합물의 제거율은 96~99%이었으며, feed의 농도가 높을수록 제거율은 더 증가하였다. 이 공정은 휘발성 유기화합물의 농도가 높고 유속이 낮은 흐름을 처리하는데 아주 적합함을 알 수 있었다. 사용된 막을 통한 휘발성 유기 화합물들의 투과도는 $4~30 \times 10^{-9}gmol/sec \cdot cm^{2}\cdot cmHg$이었고, 질소의 투과도는 $3~9 \times 10^{-10}gmol/sec \cdot cm^{2} \cdot cmHg$의 범위에 있었다. 휘발성 유기화합물과 질소의 선택도는 유속과 휘발성 유기화합물의 농도에 따라 톨루엔/질소의 경우 10~55, 메탄올/질소의 경우 15~125의 값을 얻었다.

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폐스팀을 이용한 가역 고체산화물 연료전지의 기술적 경제적 해석 (Techno-Economic Analysis of Reversible Solid Oxide Fuel Cell System Couple with Waste Steam)

  • 잡반티엔;이영덕;김영상;안국영
    • 한국수소및신에너지학회논문집
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    • 제30권1호
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    • pp.21-28
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    • 2019
  • Reversible solid oxide fuel cell (ReSOC) system was integrated with waste steam for electrical energy storage in distributed energy storage application. Waste steam was utilized as external heat in SOEC mode for higher hydrogen production efficiency. Three system configurations were analyzed to evaluate techno-economic performance. The first system is a simple configuration to minimize the cost of balance of plant. The second system is the more complicated configuration with heat recovery steam generator (HRSG). The third system is featured with HRSG and fuel recirculation by blower. Lumped models were used for system performance analyses. The ReSOC stack was characterized by applying area specific resistance value at fixed operating pressure and temperature. In economical assessment, the levelized costs of energy storage (LCOS) were calculated for three system configurations based on capital investment. The system lifetime was assumed 20 years with ReSOC stack replaced every 5 years, inflation rate of 2%, and capacity factor of 80%. The results showed that the exergy round-trip efficiency of system 1, 2, 3 were 47.9%, 48.8%, and 52.8% respectively. The high round-trip efficiency of third system compared to others is attributed to the remarkable reduction in steam requirement and hydrogen compression power owning to fuel recirculation. The result from economic calculation showed that the LCOS values of system 1, 2, 3 were 3.46 ¢/kWh, 3.43 ¢/kWh, and 3.14 ¢/kWh, respectively. Even though the systems 2 and 3 have expensive HRSG, they showed higher round-trip efficiencies and significant reduction in boiler and hydrogen compressor cost.