• Archives of design research
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• v.19 no.2 s.64
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• pp.261-272
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• 2006

As we cannot think of our lives without a nation, it is closely related to almost every part of our daily lives. The role of government is becoming more important in the complex modern society as an essential element of national authority even though the government has indirect and secondary characteristics in its functional performance. Therefore, the government has to be efficient in planning and executing its policies, and it needs to be representative and fair as part of a national authoritative community. In the 21st century when symbolic and cultural importance of images are becoming more important, it is crucial for the government organizations to have an integrated identity design system that can satisfy both of these requirements of the government. However, the C.I.(Corporate Identity) of each Korean administrative branch has been developed separately and sporadically, which resulted in lack of consistency as part of the government. Shape and material of their C.I.s that follow short term design trend and popularity also lack uniqueness which can be distinguished from those of any private corporation. This may show that our government lacks systematic administrative capability, since image of a feature represents its characteristics and reality, and their recognition and evaluation from others become identity of the feature. In this perspective, the purpose of this thesis is to suggest an identity design system that has certain rules and regularity with wide variety of possible alterations for the central administration in Korea. In order to represent this visually, identity design system with both integrity and variety of possible alteration is created based on traditional Korean culture, especially the concept of Umyang-ohaeng and Samjae.

• Pediatric Infection and Vaccine
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• v.4 no.2
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• pp.265-270
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• 1997

Purpose: Rapid diagnosis and prompt treatment remain the cornerstone of management of patients with meningitis. Examination of cerebrospinal fluid(CSF) for glucose, protein, cells, and organisms is necessary for accurate diagnosis, but in many parts of the world facilities do not exist to do so. We tested CSF samples from 69 children with suspected meningitis with urinary reagent strips and analyzed the results to know the usability of urinary reagent strips in diagnosis of meningitis. Methods: 69 CSF samples obtained from children with suspected meningitis were analysed. Each sample was divided into two; one was sent to the laboratory for routine diagnostic evaluation, and the other was tested with the reagent strip(Combur10 Test M). Laboratory values of CSF glucose, protein, and leucocytes for each CSF sample were plotted against the corresponding reagent-strip category. Results: There was good agreement between the dipstick and laboratory values for CSF protein and cell count but not for glucose. Conclusion: Rapid diagnosis of meningitis could be made with three component of the Combur10 test strip. It is easy to do and would be of particular value to those working in parts of the world where no laboratory facilities exist.

• Journal of Life Science
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• v.28 no.11
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• pp.1354-1360
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• 2018

The aim of this study was to develop a simple, environmentally friendly synthesis of silver nanoparticles (SNPs) without the use of chemical reducing agents by exploiting the extracellular synthesis of SNPs in a culture supernatant of Bacillus thuringiensis CH3. Addition of 5 mM $AgNO_3$ to the culture supernatant at a ratio of 1:1 caused a change in the maximum absorbance at 418 nm corresponding to the surface plasmon resonance of the SNPs. Synthesis of SNPs occurred within 8 hr and reached a maximum at 40-48 hr. The structural characteristics of the synthesized SNPs were investigated by various instrumental analysis. FESEM observations showed the formation of well-dispersed spherical SNPs, and the presence of silver was confirmed by EDS analysis. The X-ray diffraction spectrum indicated that the SNPs had a face-centered cubic crystal lattice. The average SNP size, calculated using DLS, was about 51.3 nm and ranged from 19 to 110 nm. The synthesized SNPs exhibited a broad spectrum of antimicrobial activity against a variety of pathogenic Gram-positive and Gram-negative bacteria and yeasts. The highest antimicrobial activity was observed against C. albicans, a human pathogenic yeast. The FESEM observations determined that the antimicrobial activity of the SNPs was due to destruction of the cell surface, cytoplasmic leakage, and finally cell lysis. This study suggests that B. thuringiensis CH3 is a potential candidate for efficient synthesis of SNPs, and that these SNPs have potential uses in a variety of pharmaceutical applications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.425-433
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• 2019

In this study, a simple method of calculating the passive earth pressure coefficient, which is based on the limit equilibrium method, was proposed and the calculated earth pressure coefficients were compared with those of several researchers. The angle of the linear failure surface, which is combined with the logarithmic spiral arc, to the failure surfaces of the passive zone was derived and the whole passive thrust acting on the Rankine passive zone was considered in the proposed method instead of considering the horizontal component of passive thrust. The variations of the passive earth pressure coefficients of the proposed method showed the same tendency as that of the Coulomb's passive earth pressure coefficients with an inclined angle of backfill and internal friction angle. The magnitude of passive earth pressure coefficients of the proposed method were smaller than those of the Coulomb in almost all cases. A comparison of the passive earth pressure coefficients with the wall friction angle revealed the passive earth pressure coefficients of the proposed method to be smaller than those of the Coulomb and the differences between the two values increased with increasing internal friction angle and wall friction angle. A comparison of the passive earth pressure coefficients of the proposed method with those of the existing researchers for the considered internal friction angles of $25^{\circ}$, $30^{\circ}$, $35^{\circ}$, and $40^{\circ}$ and three wall friction angles revealed the maximum percentage differences for the Kerisel and Absi method, Soubra method, Lancellotta method, $Ant\tilde{a}o$ et al. method, Kame method, and Reddy et al. method to be 4.8%, 3.8%, 31.1%, 4.0%, 20.6%, and 12.8% respectively. The passive earth pressure coefficient and existing pressures were similar in all cases.

• Journal of the Daesoon Academy of Sciences
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• v.21
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• pp.157-195
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• 2013

대순진리회는 '구천응원뇌성보화천존강성상제(이하 '구천상제')'를 주신(主神)으로 신앙하는 종교단체이다. 그렇다면 대순진리회의 '구천상제'와 중국 도교에서 모셔지는 '구천응원뇌성보화천존'(이하 '보화천존')은 어떤 연관성이 있는 것인가? 이런 질문을 토대로 본 글에서는 이 신들의 기원과 칭호, 도세법문(度世法門 : 세상을 제도하고자 펼친 법도) 등의 관점에서 그 차이점과 공통점을 하나씩 비교해 보았다. 먼저 기원이라는 측면에서 '구천상제'와 '보화천존'을 비교해보면, '구천상제'는 천지인 삼계의 최고신으로서 강씨 가문을 선택하여 인간의 육신으로 태어났다. 강씨 성은 상고 신농씨에서 시작되었는데, 고대 문헌에 근거하면 신농씨는 태양신, 남쪽, 불(火) 등으로 상징화된다. 이런 상징들은 '구천상제'가 인간으로 태어날 때 나타난 "하늘이 남북으로 갈라지다", "큰 불덩이가 몸을 덮치다", "천지가 밝아지는도다" 등의 현상들에서 찾아볼 수 있다. 도교의 '보화천존'은 뇌신의 특징을 가지면서 일신(日神), 월신(月神)과 관계를 맺고 있는데, 이런 면들은 신농씨로부터 분석한 '구천상제'의 신적 기원과 일치하고 있다. 또한 도교에서는 신농씨가 다스리던 세상을 중국 상고시대의 가장 이상적인 사회형태로 보고 있는데, 이것을 '구천상제'가 건설하려는 후천선경과 연관 지어 생각해보면 '구천상제'가 신농씨의 후손인 강씨 종가에서 태어난 배경을 이해할 수 있다. 도교의 '보화천존' 역시 중생의 이익을 도모하고, 조화로운 인간세상을 만드는 것을 목표로 삼고 있으며, 이것은 대순진리회 '구천상제'가 행한 대순의 목적과 거의 비슷하다고 볼 수 있다. 다음으로 '구천상제'와 '보화천존'은 칭호에서도 공통점과 차이점을 살펴볼 수 있다. 단적으로 말하자면, '구천상제'에는 '보화천존'에 비해 '강성상제'라는 칭호가 추가되어 있다는 것이다. 또한 도교에서는 '보화천존'을 최고신으로 모시지 않으며, '구천상제' 신앙에서는 '보화천존' 신앙에서와 달리 뇌신과의 관계에 대한 설명을 찾아볼 수 없다. 마지막으로 '구천상제'와 '보화천존'의 도세법문을 비교해보면 첫째, 구천상제는 세상이 혼란, 불공평, 죄악에 빠졌기에 육신으로 인간 세상에 강림한 후 대순진리를 선포하였다. 이와 유사하게 보화천존도 천하와 인간세상을 순시하여 죄악과 겁액을 없앤다는 '순시천하(巡視天下)' 사상이 있다. 물론 여기에는 차이점이 존재하는데, 그 중 하나는 '보화천존'은 순시할 때 인간의 육신으로 화하지 않았다는 점이다. 또 다른 하나는 '보화천존'이 인간 세상에 창교의 방법을 통하여 선경을 건설하고자 하는 목표를 전해주지 않았다는 점이다. '보화천존'은 교리를 가르치거나 신통을 발휘하는 데에만 중점을 두고 있다. 둘째, '구천상제'가 내린 가르침인 해원상생은 후천선경을 건설하기 위한 수단과 과정이다. 도교의 '보화천존'도 인간이 지은 많은 죄악과 겁액은 세상 사람들이 맺은 원한과 관계가 있으므로, 이런 겁액과 죄를 해소하려면 해원부터 해야 한다는 것을 수차례에 걸쳐 언급하고 있다. 도교에서 말하는 '해원'의 구체적인 내용은 주로 인간의 시비, 질병, 겁액에 관한 것이며, 그 해결 방법으로는 주로 마음속으로 『옥추보경』을 읽는 것이다. 이를 '구천상제'의 '해원상생' 가르침과 비교하면 그 사상의 폭이나 깊이, 중요성, 이론적 측면 등에서 비교적 간단한 형태로서 체계적인 면모로까지 나아가지는 못하였다. 셋째, '구천상제' 는 곤경에 처한 사람이 신명의 호칭을 부르면 그에 상응하는 신명이 달려와서 구원해준다는 '소리감응' 방법을 사용하고 있는데, 이 방법은 도교의 '보화천존' 역시 사용하고 있는 것이다. 넷째, '구천상제'는 과오를 범한 사람이 자신의 과오를 뉘우치면, 그 다음에 상제의 용서를 받음으로써 그 원한이 풀리게 된다는 참법(懺法 : 懺悔法)을 세인(世人) 교화에 자주 사용하였다. 물론 이것은 해원상생의 구체적인 적용이라 할 수 있다. 기능면에서 보면 이 방법은 『구천응원뇌성보화천존옥추보참(九天應元雷聲普化天尊玉樞寶懺)』의 참의(懺儀)와 공통되는 점이 있다. 참의는 수도자 스스로 자신의 잘못을 뉘우치고, 수도에 정진하며, 사회의 안정을 도모하고, 포덕에 힘쓰고, 악을 물리치고 선을 널리 펼친다는 것인데, 이런 의미에서 양자는 일치한다고 생각된다. 필자가 생각하건대, 대순진리회의 '구천응원뇌성보화천존강성상제'와 도교의 '구천응원뇌성보화천존' 사이에는 공통점이 아주 많지만 동시에 차이점 또한 적지 않다. 만약 더욱 다양한 자료들을 수집하여 더욱 깊고 광범위한 연구를 진행한다면 한국 대순진리회와 중국 도교, 특히 도교의 뇌법종파(雷法宗派)와의 상관관계를 해석하는 데 큰 도움이 될 것이라 생각한다.

• Tuberculosis and Respiratory Diseases
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• v.53 no.5
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• pp.497-509
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• 2002

Background : The mechanisms through which cellular activation results in intracellular mycobacterial killing is only partially understood. However, in vitro studies of human immunity to Mycobacterium tuberculosis have been largely modeled on the work reported by Crowle, which is complicated by several factors. The whole blood culture is simple and allows the simultaneous analysis of the relationship between bacterial killing and the effect of effector cells and humoral factors. In this study, we attempted to determine the extent to which M. tuberculosis is killed in a human whole blood culture and to explore the role of the host and microbial factor in this process. Methods : The PPD positive subject were compared to the umbilical cord blood and patients with tuberculosis, diabetes and lung cancer. The culture is performed using heparinized whole blood diluted with a culture medium and infected with a low number of M. avium or M. tuberculosis $H_{37}Ra$ for 4 days by rotating the culture in a $37^{\circ}C$, 5% $CO_2$ incubator. In some experiments, methlprednisolone- or pentoxifyline were used to inhibit the immune response. To assess the role of the T-cell subsets, CD4+, CD8+ T-cells or both were removed from the blood using magnetic beads. The ${\Delta}$ log killing ratio was defined using a CFU assay as the difference in the log number of viable organisms in the completed culture compared to the inoculum. Results : 1. A trend was noted toward the improved killing of mycobacteria in PPD+ subjects comparing to the umbilical cord blood but there was no specific difference in the patients with tuberculosis, diabetes and lung cancer. 2. Methylprednisolone and pentoxifyline adversely affected the killing in the PPD+ subjects umbilical cord blood and patients with tuberculosis. 3. The deletion of CD4+ or CD8+ T-lymphocytes adversely affected the killing of M. avium and M. tuberculosis $H_{37}Ra$ by PPD+ subjects. Deletion of both cell types had an additive effect, particularly in M. tuberculosis $H_{37}Ra$. 4. A significantly improved mycobacterial killing was noted after chemotherapy in patients with tuberculosis and the ${\Delta}$ logKR continuously decreased in a 3 and 4 days of whole blood culture. Conclusion : The in vitro bactericidal assay by human whole blood culture model was settled using a CFU assay. However, the host immunity to M. tuberculosis was not apparent in the human whole blood culture bactericidal assay, and patients with tuberculosis showed markedly improved bacterial killing after anti-tuberculous chemotherapy compared to before. The simplicity of a whole blood culture facilitates its inclusion in a clinical trial and it may have a potential role as a surrogate marker in a TB vaccine trial.

• Tuberculosis and Respiratory Diseases
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• v.50 no.3
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• pp.320-333
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• 2001

Background : Peak expiratory flow (PEF) provides a simple, quantitative, and reproducible measure of the existence and severity of airflow obstructions. Peak flow meters are designed to monitor the condition asthma patients. There are many reports showing the normal predicted value of PEF in other countries. Studies on healthy Korean adults have been performed in a relatively small sample number and a lower limit for the normal value was not reported. Therefore, an attempt to provide normal predictive PEF value with a lower limit was made. Method : The PEF(Mini-Wright Peak Flow Meter) measurements and spirometry were done in 233 men and 631 women without history of respiratory disease. All subjects were non-smokers with no respiratory symptoms. The normal predictive value and its lower limit were developed by multiple regression analysis. The result was compared with regression equations in other reports. Results : The regression equation for the normal PEF predictive value(L/min) is $25.117+4.587{\times}$Age(year)-$0.064{\times}Age^2+2.931{\times}$Height(cm) in men($R^2=025$), and 146.942-$0.011{\times}Age^2+1.795{\times}$Height(cm)+$0.836{\times}$Weight(kg) in women($R^2=0.21$). The regression equation for the lower limit of this value (L/min) is $25.117+4.587{\times}$Age(year)-$0.064{\times}Age^2+1.936{\times}$Height(cm) in men, and $146.942-0.011{\times}Age^2+1.232{\times}$Height(cm)+$0.481{\times}$Weight(kg) in women. The residuals were normally distributed. The PEF in Korean males was sililar to those reported in British and Japanese subjects. The PEF in Korean females was similar to that in British subjects, but higher than the PEF in Japanese subjects. The lower limit of normal value was 71% of normal predictive PEF value in men and 76% in women. Conclusion : The normal predictive PEF value and its lower limit was measured from 233 male and 631 female asymptomatic, lifelong non-smoking participants. The normal predictive value was different from those of other studies on Korean subjects. Therefore, further studies are required.

• The Korean Journal of Petroleum Geology
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• v.14 no.1
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• pp.1-11
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• 2008

As conventional oil and gas reservoirs become depleted, interests for oil sands has rapidly increased in the last decade. Oil sands are mixture of bitumen, water, and host sediments of sand and clay. Most oil sand is unconsolidated sand that is held together by bitumen. Bitumen has hydrocarbon in situ viscosity of >10,000 centipoises (cP) at reservoir condition and has API gravity between $8-14^{\circ}$. The largest oil sand deposits are in Alberta and Saskatchewan, Canada. The reverves are approximated at 1.7 trillion barrels of initial oil-in-place and 173 billion barrels of remaining established reserves. Alberta has a number of oil sands deposits which are grouped into three oil sand development areas - the Athabasca, Cold Lake, and Peace River, with the largest current bitumen production from Athabasca. Principal oil sands deposits consist of the McMurray Fm and Wabiskaw Mbr in Athabasca area, the Gething and Bluesky formations in Peace River area, and relatively thin multi-reservoir deposits of McMurray, Clearwater, and Grand Rapid formations in Cold Lake area. The reservoir sediments were deposited in the foreland basin (Western Canada Sedimentary Basin) formed by collision between the Pacific and North America plates and the subsequent thrusting movements in the Mesozoic. The deposits are underlain by basement rocks of Paleozoic carbonates with highly variable topography. The oil sands deposits were formed during the Early Cretaceous transgression which occurred along the Cretaceous Interior Seaway in North America. The oil-sands-hosting McMurray and Wabiskaw deposits in the Athabasca area consist of the lower fluvial and the upper estuarine-offshore sediments, reflecting the broad and overall transgression. The deposits are characterized by facies heterogeneity of channelized reservoir sands and non-reservoir muds. Main reservoir bodies of the McMurray Formation are fluvial and estuarine channel-point bar complexes which are interbedded with fine-grained deposits formed in floodplain, tidal flat, and estuarine bay. The Wabiskaw deposits (basal member of the Clearwater Formation) commonly comprise sheet-shaped offshore muds and sands, but occasionally show deep-incision into the McMurray deposits, forming channelized reservoir sand bodies of oil sands. In Canada, bitumen of oil sands deposits is produced by surface mining or in-situ thermal recovery processes. Bitumen sands recovered by surface mining are changed into synthetic crude oil through extraction and upgrading processes. On the other hand, bitumen produced by in-situ thermal recovery is transported to refinery only through bitumen blending process. The in-situ thermal recovery technology is represented by Steam-Assisted Gravity Drainage and Cyclic Steam Stimulation. These technologies are based on steam injection into bitumen sand reservoirs for increase in reservoir in-situ temperature and in bitumen mobility. In oil sands reservoirs, efficiency for steam propagation is controlled mainly by reservoir geology. Accordingly, understanding of geological factors and characteristics of oil sands reservoir deposits is prerequisite for well-designed development planning and effective bitumen production. As significant geological factors and characteristics in oil sands reservoir deposits, this study suggests (1) pay of bitumen sands and connectivity, (2) bitumen content and saturation, (3) geologic structure, (4) distribution of mud baffles and plugs, (5) thickness and lateral continuity of mud interbeds, (6) distribution of water-saturated sands, (7) distribution of gas-saturated sands, (8) direction of lateral accretion of point bar, (9) distribution of diagenetic layers and nodules, and (10) texture and fabric change within reservoir sand body.

• Korean Journal of Heritage: History & Science
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• v.46 no.3
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• pp.230-250
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• 2013

possessed by Dong-A University Museum is designated as Treasure No. 595, and has been known for a more exquisite, delicate and realistic expression and a colorful three-dimensional structure compared to the 'grass and insect painting' work and its value in art history. However, it has not been analyzed and studied in fabric craft despite it being an embroidered work. This study used scientific devices to examine and analyze the Screen's fabric, thread colors, and embroidery techniques to clarify its patterns and fabric craft characteristics for its value in the history of fabric craft. As a result, consists of eight sides and its subject matters and composition are similar to those of the general paintings of grass and insects. The patterns on each side of the 'grass and insect painting' include cucumber, cockscomb, day lily, balsam pear, gillyflower, watermelon, eggplant, and chrysanthemums from the first side. Among these flowers, the balsam pear is a special material not found in the existing paintings of grass and insect. The eighth side only has the chrysanthemums with no insects and reptiles, making it different from the typical forms of the paintings of grass and insect. The fabric of the Screen uses black that is not seen in other decorative embroideries to emphasize and maximize various colors of threads. The fabric used the weave structure of 5-end satin called Gong Dan [non-patterned satin]. The threads used extremely slightly twisted threads that are incidentally twisted. Some threads use one color, while other threads use two or mixed colors in combination for three-dimensional expressions. Because the threads are severely deterioration and faded, it is impossible to know the original colors, but the most frequently used colors are yellow to green and other colors remaining relatively prominently are blue, grown, and violet. The colors of day lily, gillyflower, and strawberries are currently remaining as reddish yellow, but it is anticipated that they were originally orange and red considering the existing paintings of grass and insects. The embroidery technique was mostly surface satin stitch to fill the surfaces. This shows the traditional women's wisdom to reduce the waste of color threads. Satin stitch is a relatively simple embroidery technique for decorating a surface, but it uses various color threads and divides the surfaces for combined vertical, horizontal, and diagonal stitches or for the combination of long and short stitches for various textures and the sense of volume. The bodies of insects use the combination of buttonhole stitch, outline stitch, and satin stitch for three-dimensional expressions, but the use of buttonhole stitch is particularly noticeable. In addition to that, decorative stitches were used to give volume to the leaves and surface pine needle stitches were done on the scouring rush to add more realistic texture. Decorative stitches were added on top of gillyflower, strawberries, and cucumbers for a more delicate touch. is valuable in the history of paintings and art and bears great importance in the history of Korean embroidery as it uses outstanding technique and colors of Korea to express the Shin Sa-im-dang's 'Grass and Insect Painting'.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.9 no.1
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• pp.1-18
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• 1973

For regulating the depth of midwater trawl nets towed at the optimum constant speed, the changes in the shape of warps caused by adding a weight on an arbitrary point of the warp of catenary shape is studied. The shape of a warp may be approximated by a catenary. The resultant inferences under this assumption were experimented. Accordingly feasibilities for the application of the result of this study to the midwater trawl nets were also discussed. A series of experiments for basic midwater trawl gear models in water tank and a couple of experiments of a commercial scale gears at sea which involve the properly designed depth control devices having a variable attitude horizontal wing were carried out. The results are summarized as follows: 1. According to the dimension analysis the depth y of a midwater trawl net is introduced by $$y=kLf(\frac{W_r}{R_r},\;\frac{W_o}{R_o},\;\frac{W_n}{R_n})$$) where k is a constant, L the warp length, f the function, and $W_r,\;W_o$ and $W_n$ the apparent weights of warp, otter board and the net, respectively, 2. When a boat is towing a body of apparent weight $W_n$ and its drag $D_n$ by means of a warp whose length L and apparent weight $W_r$ per unit length, the depth y of the body is given by the following equation, provided that the shape of a warp is a catenary and drag of the warp is neglected in comparison with the drag of the body: $$y=\frac{1}{W_r}\{\sqrt{{D_n^2}+{(W_n+W_rL)^2}}-\sqrt{{D_n^2+W_n}^2\}$$ 3. The changes ${\Delta}y$ of the depth of the midwater trawl net caused by changing the warp length or adding a weight ${\Delta}W_n$_n to the net, are given by the following equations: $${\Delta}y{\approx}\frac{W_n+W_{r}L}{\sqrt{D_n^2+(W_n+W_{r}L)^2}}{\Delta}L$$ $${\Delta}y{\approx}\frac{1}{W_r}\{\frac{W_n+W_rL}{\sqrt{D_n^2+(W_n+W_{r}L)^2}}-{\frac{W_n}{\sqrt{D_n^2+W_n^2}}\}{\Delta}W_n$$ 4. A change ${\Delta}y$ of the depth of the midwater trawl net by adding a weight $W_s$ to an arbitrary point of the warp takes an equation of the form $${\Delta}y=\frac{1}{W_r}\{(T_{ur}'-T_{ur})-T_u'-T_u)\}$$ Where $$T_{ur}^l=\sqrt{T_u^2+(W_s+W_{r}L)^2+2T_u(W_s+W_{r}L)sin{\theta}_u$$ $$T_{ur}=\sqrt{T_u^2+(W_{r}L)^2+2T_uW_{r}L\;sin{\theta}_u$$ $$T_{u}^l=\sqrt{T_u^2+W_s^2+2T_uW_{s}\;sin{\theta}_u$$ and $T_u$ represents the tension at the point on the warp, ${\theta}_u$ the angle between the direction of $T_u$ and horizontal axis, $T_u^2$ the tension at that point when a weights $W_s$ adds to the point where $T_u$ is acted on. 5. If otter boards were constructed lighter and adequate weights were added at their bottom to stabilize them, even they were the same shapes as those of bottom trawls, they were definitely applicable to the midwater trawl gears as the result of the experiments. 6. As the results of water tank tests the relationship between net height of H cm velocity of v m/sec, and that between hydrodynamic resistance of R kg and the velocity of a model net as shown in figure 6 are respectively given by $$H=8+\frac{10}{0.4+v}$$ $$R=3+9v^2$$ 7. It was found that the cross-wing type depth control devices were more stable in operation than that of the H-wing type as the results of the experiments at sea. 8. The hydrodynamic resistance of the net gear in midwater trawling is so large, and regarded as nearly the drag, that sweeping depth of the gear was very stable in spite of types of the depth control devices. 9. An area of the horizontal wing of the H-wing type depth control device was $1.2{\times}2.4m^2$. A midwater trawl net of 2 ton hydrodynamic resistance was connected to the devices and towed with the velocity of 2.3 kts. Under these conditions the depth change of about 20m of the trawl net was obtained by controlling an angle or attack of $30^{\circ}$.