• Journal of Ocean Engineering and Technology
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• v.15 no.4
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• pp.1-7
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• 2001

Mainly, Floating Breakwaters (FBs) have been constructed in many coastal regions due to the advantages of the coastal environment and construction cost. In general, the FB becomes fixed or its width broadened because the movement of the FB comes to be large and its the wave control function lower for the long period incident waves. This study discusses the wave control function of two-rowed Fixed Floating Breakwater (FFBs) that have narrower width than that of the one-rowed FFB by using numerical approach. Boundary Element Method (BEM) based on the Green formula and Eigenfunction Expansion Method (EEM) are applied to evaluate the three-dimensional wave transformation near the wave fields of two-rowed FFBs. The validity of the present study is confirmed by comparing it with the results of Ijima et al. (1974) and Yoshida et al. (1992) for the one-rowed Fixed Floating Structure. It is revealed that the wave control function of two-rowed FFBs is more effective than that of the one-rowed FFB.

• KOREAN POULTRY JOURNAL
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• v.7 no.7 s.69
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• pp.48-51
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• 1975

이제부터 본격적인 더위가 시작될 것 같다. 뭇 사람들은 시원한 해변이나 소름이 오싹 끼치는 심심계곡의 폭포수 밑을 연상하겠지만 우리 양계인에게는 수난의 계절이 아닐 수 없다. 혹서로 인하여 방열을 억제당하므로 체온이 상승되고 축적되는 열을 발산하기 위하여 호흡량이 증가된다. 또 식욕부진, 음수량의 증가와 난중의 저하는 피할 수 없는 난관이다. 그러나 세심한 관찰과 합리적인 사양관리로 어느정도 극복 할 수 있으리라 생각된다. 계사내의 온도 및 습도조절로 식욕증진, 양질의 단백질사료 급여, 지속적인 항생제 투여, 청채급여 등의 대책을 강구하여 혹서로 인한 피해를 최대한 방지하여야 할 것이다. 이 모든 문제가 극복될 때 악취풍기는 답답한 계사내이지만 이열치열의 피서지로 최적지라고 말한다면 너무 잔인하다고 할까?

• Clinics in Shoulder and Elbow
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• v.11 no.2
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• pp.77-81
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• 2008

The goal of rotator cuff repairs is to achieve high initial fixation strength, minimize gap formation, maintain mechanical stability under cyclic loading and optimize the biology of the tendon-bone interface until the cuff heals biologically to the bone. Single row repairs are least successful in restoring the footprint of the rotator cuff and are most susceptible to gap formation. Double row repairs have an improved load to failure and minimal gap formation. Transosseous equivalent repairs (suture bridge technique) have the highest ultimate load and resistance to shear and rotational forces and the lowest gap formation. Even though the superior advantages of double row and transosseous equivalent repairs, those techniques take longer surgical time and are more expensive than single row repairs. Therefore single row repairs can be useful in bursal side partial thickness or small size full thickess rotator cuff tear.

• Journal of Korean Orthopaedic Sports Medicine
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• v.10 no.2
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• pp.61-68
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• 2011

Purpose: We evaluated the clinical outcome after arthroscopic repair in full thickness rotator cuff tears with and without delamination. Materials and Methods: From March 2006 to October 2008, we included 48 consecutive shoulders (31 males, 17 females; mean age 57.6 years; 45~68) who had arthroscopic double row repair for fullthickness tears of the rotator cuff. Mean rotator cuff tear size was 2.8 cm (range: 1.2~3.6) and the techniques of tendon-to-bone fixation varied according to the presence of delamination; separate row fixations of bursal and articular layer were used in delaminated tear. The mean follow-up was 26 months (range: 18~33) and functional and structural results were evaluated by American Shoulder and Elbow Surgeons (ASES), University of California at Los Angeles (UCLA) scale, isokinetic strength testing and magnetic resonance imaging (MRI) obtained mean 8 months (range:6~13) postoperatively. The patterns of delamination, age, sex, symptom duration, size of tear, satisfaction rate, retear rate ware compared and significance was set at p values < 0.05. Results: Postoperative functional shoulder score improved significantly in 44 shoulders (91.7%). Delamination was observed in 15 shoulders (31%) and it extended proximally and posteriorly in the majority of shoulders, and the articular layer was thicker (8/15, 53%) and more retracted (9/15, 60%) compared with the superficial bursal layer. Final follow up functional shoulder scores showed no differences between non-delaminated and delaminated tears and the presence of delamination had no correlations with sex, symptom duration, tear size and satisfaction rate, however, older age had more delaminated tears (p=0.041). Follow up MRI in 29 shoulders revealed that fourteen (48%) shoulders had complete healing; nine (31%), partial healing; six (21%), complete retear but the half of the retear group showed favorable clinical results. 79% (15/19) in non-delaminated tear and 80% (8/10) in delaminated tear were judged as healed tendon on MRI and double-layer double row repairs in delaminated tears resulted in nearly same rate of structural integrity of single-layer double row repairs (p=0.165). Conclusion: The incidence of delamination in our series was 31% and older age had more delaminated tears. Sex, symptom duration, preoperative size of the tear, functional results and satisfaction rate had no significant correlations with the presence of delamination. Nearly the same postoperative structural integrity was noted in both delaminated and non-delaminated tears.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.1
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• pp.60-67
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• 2000

An experimental investigation on transient heat transfer phenomena of impinging diesel-spray on a flat plate in a pressurized chamber is carried out. A diesel spray is injected from a single-hole nozzle and impinges to a heated flat plate in the chamber. A fast-response thermocouple installed in the top surface of the plate measures the transient variation of surface temperature of the plate under various conditions of the chamber pressures. Utilizing the semi-infinite model, the temporal variation of the heat flux on the plate is determined. Effects of various parameters, such as vertical distances between the nozzle and the plate, radial distances from the injection-axis, and the chamber pressures, on the heat flux characteristics of impinging diesel-spray are studied.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.2
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• pp.8-14
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• 2018

In the present work, a numerical study is carried out to observe the characteristics of the flow and particle behaviors in a supersonic double Venturi abrasive blasting nozzle. Schlieren flow visualization and Pitot pressure at the nozzle downstream are also carried out, and those measurement results are compared to the numerical ones for code validation. Open and closed secondary holes on the double Venturi nozzle surface are tested for various nozzle pressures, and the results are compared with the ones observed for other similar supersonic Laval nozzles.

• Journal of the Korean Wood Science and Technology
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• v.19 no.3
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• pp.77-85
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• 1991

은행나무 지재(枝材)에 발달(發達)하여 있는 압축이상재(壓縮異常材)와 대응재(對應材)의 해부학적(解剖學的) 특성(特性) 차이(差異)를 조직(組織) 및 그 구성요소(構成要素)의 크기 면에서 서로 검토(檢討) 비교(比較)하였다. 조직적(組織的)인 특성(特性)으로는 압축이상재(壓縮異常材)가 연륜폭(年輪幅), 횡단면상(橫斷面上) 가도관(假導官) 형상(形狀) 및 방사조직(放射組織) 비례상태(比例狀態), 세포간극(細胞間隙), 가도관(假導官) 선단(先端)의 굴곡(屈曲), 나선열(螺旋裂) 및 접선단면상(接線斷面上)의 방사조직(放射組織) 형상(形狀) 면에서 대응재(對應材)와 차이(差異)를 나타냈으며 구성요소(構成要素)의 크기에 있어서는 가도관(假導官)의 벽후(壁厚) 및 접선직경(接線直徑), 단열(單列) 방사조직(放射組織)의 높이, 이열방사조직(二列放射組織)의 수(數) 및 방사조직(放射組織) 밀도(密度) 면에서 압축이상재(壓縮異常材)가 대응재(對應材)와 차이(差異)를 나타내는 것으로 여겨졌다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.1
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• pp.33-38
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• 2012

An experimental study was carried out to observe the characteristics of impingement of assist gas from a rectangular supersonic nozzle on kerf surface in laser machining. A micro-scale supersonic (Mach number 2.0) rectangular nozzle system was designed and fabricated for the purposes, and hot tests of the performance of the nozzle system was proceeded in the ITI corporation laboratory. For various related parameters such as laser powers, nozzle pressures and cutting speeds, the quality of the frontal view of cut edge surfaces was observed by a microscope. In the study, it was shown that the application of the present micro-rectangular supersonic nozzle in an off-axis configuration made it possible to cut a mild steel, by combinations of relatively low laser - powers, large standoff distances, and assist gas with no oxygen, which was not achieved by conventional laser cutting processes.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.159-160
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• 2002

New S-shaped aeroelastic mesoflaps are utilized to control normal shock/boundary-layer interactions. New generation of the mesoflaps is designed f3r a better rigidness and a good flow uniformity across the ulteractions. ,Major advantages of the mesoflap system can be a better total pressure recovery downstream of the interactions due to the lambda shock structure over the flap system, and a rehabilitation of the thickened boundary layer due to bleeding through a cavity underneath the flap system. Skin friction has been measured downstream of the interactions, using the laser interferometer skin friction (LISF) meter, which optically detects the rate of thinning of an oil film applied to the test surface. Various flap-thicknesses of the S-shaped mesoflap arrays are tested, and the results are compared to the solid-wall reference case. Overall, not much difference in the level of skin friction is noticed for the S-shaped flap arrays of various thicknesses, and its level is lower than the skin friction downstream of the solid-wall interaction

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.525-530
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• 2000

The effects of vortex generators, in the form of small tabs projecting into the flow at the axisymmetric supersonic nozzle exit and triangular thin tapes attached on the inner surface at the nozzle exit, on the characterixtics of supersonic mixing enhancements are experimentally investigated. Delta-shaped tabs as small as 1% of the nozzle exit area produce strong counter-rotating vortices, and is found to produce significant effects on the jet flowfield downstream of the nozzle. The effects is larger on the under-expanded cases than over- and perfect-expanded cases. Nozzle inner surface roughness also can do a role of centerline pressure decay for highly under-expanded jet cases. The effects of the angle of tabs with respect to flow direction are also investigated.