태권도의 전자호구 충격값과 포스플랫폼 충격력과의 관련성

배영상 ( Young Sang Bae ) 한국운동역학회 2013 한국운동역학회지 Vol.23 No.2

1. 엘리트 태권도선수와 태권도학 전공학생의 충격력 태권도 발차기에 대해 충격력을 측정한 연구는 Bae, Shibukawa와 Ishijima (1989), Pieter, F.와 Pieter, W. (1995), Bae와 Lee (2006), Pedzich, Mastalertz와 Urbanik (2006), O`Sullivan 등 (2009)의 보고가 있으며, 발차기기술에 대한 연구보다 발차기 충격력 연구는 상대적으로 거의 발표가 이루어지고 있지 않는 실정이다. 그러나 매년 국기원에서 실시하는 태권도한마당대회의 격파왕 선발대회에는 많은 참가자들이 격파왕 타이틀을 차지하기 위해 도전하는 등 태권도의 위력이라고 말한다면 격파의 위력을 지칭할 정도로 태권도인 뿐만 아니라 일반인까지도 많은 관심을 가지고 있다. 그러나 상대적으로 충격력에 관련된 연구가 적은 이유는 다음과 같이 두 가지로 생각할 수 있다. 즉 첫째는 충격력 측정에 참가하는 피험자가 부상을 우려하여 참가를 기피한다는 점이며, 둘째는 포스플랫폼 등의 신뢰성과 정밀성을 갖춘 장비라고 하더라도 표면이 철판이기 때문에 직접 충격력을 측정하는 것은 불가능하기 때문에 표적면에 완충재료를 사용할 수밖에 없고, 그때의 충격력 값은 측정조건에 따라 상대값으로 사용할 수 밖에 없다는 점이다. 본 연구에서는 연구방법의 실험방법에서 제시한 충격력의 산출과정을 거쳐 데이터를 확보하였기에 연구의 목적을 달성하는데 문제가 없을 것이라 생각한다. 또한 본 연구에서는 데이터의 안정성을 확보할 의도로 많은 피험자를 동원하고자 엘리트태권도선수군 21명과 태권도학 전공학생군 20명을 피험자로 사용하였다. 그러나 두 집단 모두 숙달된 태권도 수련군이지만 수련군별 특성에 차이가 있다고 생각되기 때문에, 동질집단으로 간주해도 좋을지를 판단하는 과정을 거치고자 엘리트태권도선수군과 태권도학 전공학생을 비교 검토하는 과정이 필요하다고 생각되었다. <Table 1>에서 보면 앞차기와 뒤차기의 최대충격력에서 두 그룹 사이에 통계적으로 유의한 차이를 나타냈는바, 발차기 기술에 따라 엘리트 태권도선수군이 우수한 능력을 발휘한 기술(뒤차기)과 태권도학전공 학생군이 우수한 능력을 발휘한 기술(앞차기)이 다르게 나타났다는 점이 주목 된다. 즉 돌려차기에서는 두 그룹 간에 비슷한 충격력(약 4,000 N)의 크기를 나타냈으나, 앞차기는 태권도학전공 학생들이 큰 충격력(약 4,700 N)을, 뒤차기는 엘리트 태권도 선수군이 큰 충격력(약 5,300 N)을 발휘하였다. 이를 좀더 세밀히 분석하고자 세 가지 발차기 기술의 최대충격력에 대한 일원배치분산분석과 다중비교검정을 실시하였다. 그 결과 최대충격력의 크기는 엘리트 태권도선수군에서 통계적으로 유의(p<.01)한 차이를 나타내면서, 다중비교검정에서 뒤차기, 돌려차기, 앞차기 순으로 유의한 최대충격력의 크기(약 4,000 N)를 나타났다. 그러나 태권도학 전공 학생군에서는 통계적으로 유의한 차이를 나타내지 않았다. 이상의 것을 미루어 볼 때 태권도에서 발차기 빈도가 가장 많은 돌려차기 기술(Bae, 1992)은 두 그룹 모두 평소의 수련에서 많은 반복연습을 실시하는 관계로 거의 동일한 수준의 위력을 발휘하는 것으로 생각된다. 그러나 앞차기 기술의 경우는 태권도경기의 특성상 앞차기 기술로 발차기를 한다는 것은 차기가 아닌 밀어내기가 되기 때문에 득점으로 인정받기 어렵다는 인식 때문에 거의 사용하지 않고 있어(Bae, 1992) 대부분의 선수들은 앞차기 기술에 대한 수련을 하지 않는다는 점을 생각 할 수 있다. 또한 뒤차기 기술은 앞차기나 돌려차기에 비해 상대적으로 어려운 기술이기 때문에 정확하게 뒤차기 기술을 구사하기 위해서는 숙달을 위한 훈련시간이 필요하다. 따라서 발차기 수련시간이 상대적으로 짧은 일반 태권도학전공학생이 엘리트 태권도선수군 수준의 뒤차기 위력을 발휘하는데 한계가 있으리라 생각된다. 2. 전자호구 충격값과 포스플랫폼 충격력데이터와의 관련성 태권도경기에 전자호구가 도입되면서 판정의 객관성을 보장받았다는 점에서는 큰 호응을 얻고 있지만, 전통적으로 인정되지 않았던 밀어차기 공격이 득점으로 인정된다는 점에 대해 문제점을 제기하는 태권도 현장지도자가 많다(Kim, 2012; Seo, 2012). 태권도 경기에서 사용되는 발차기 기술은 다양하지만 가장 기본적인 발차기는 앞차기와 돌려차기 그리고 뒤차기이다. 태권도의 다양한 발차기 기술은 대부분 이들 세 가지 기본발차기 기술을 바탕으로 한 응용발차기 기술인 것이다. 이 세 가지 발차기 기술을 발차기 유형으로 보면 앞차기와 뒤차기는 지르기형의 발차기이며, 돌려차기는 치기형 발차기 기술이다. 또한 앞차기와 뒤차기는 동일한 지르기형의 발차기로 분류할 수 있지만, 엄밀히 보면 앞차기는 밀어차기형의 발차기 기술이다. 즉 앞차기는 밀어차기형, 돌려차기는 치기형, 뒤차기는 지르기로 분류할 수 있다(Kaneko & Fukunaga, 2006). 이상과 같은 발차기 기술의 특성을 바탕으로 전자호구의 충격값과 포스플랫폼의 충격력데이터와의 관련성을 논의하고자 한다. 돌려차기의 전자호구 충격값과 포스플랫폼의 충격력데이터의 관련성은 <Figure 3>에 나타난 바와 같이, 충격력의 모든 요소에서 양자 간에는 통계적인 유의성을 나타내지 않았다. 그러나 앞차기<Figure 2>에서는 최대충격력(p<.01), 체중당 최대충격력(p<.01), 그리고 평균충격력(p<.05)에서 통계적인 유의성을 나타내었다. 또한 뒤차기<Figure 4>에서는 최대충격력(p<.001), 체중당 최대충격력(p<.001), 체중당 평균충격력(p<.01), 그리고 평균충격력(p<.05) 등 모든 충격력데이터에서 통계적으로 유의한 관련성을 나타내었다. 이상의 것을 종합해 본다면 지르기형인 뒤차기, 밀어차기형인 앞차기에서는 전자호구 충격값과 포스플랫폼의 충격력데이터가 높은 상관을 나타낸 반면, 치기형인 돌려차기에서는 양자 간에 통계적으로 관련성이 없는 것으로 나타났다는 것이다. 여기서 세 가지 발차기 기술이 표적에 임팩트 되는 순간을 본다면 돌려차기는 보다 비스듬하게(사선) 진입하는데 비해(Bae et al., 1989) 앞차기와 뒤차기는 보다 수직으로 표적에 진입하는 것을 연상할 수 있다. 즉 표적면에 대해 보다 수직으로 임팩트하는 뒤차기와 앞차기는 전자호구 충격값과 포스플랫폼 충격력값이 통계적으로 관련성이 높은 반면, 표적면에 대해 비스듬히 진입하는 돌려차기는 양자 간에 통계적 관련성이 없다는 것이다. 이것은 태권도경기현장에 태권도지도자들이 전자호구 도입에 따라 제기하고 있는 문제점(Kim, 2012; Seo, 2012)과도 일치하는 사항이다. 여기서 고려할 수 있는 사항은 전자호구의 충격력인식 센서가 표적면에 대해 수직방향만 인식하는 것이 아닌가 하는 의구심이 제기된다. 즉 충격력은 벡터량이기 때문에 표적에 대해 좌우방향, 상하방향, 그리고 수직방향을 측정할 수 있는 시스템을 갖추어야 되기 때문이다. 따라서 태권도경기 현장지도자들이 제기하고 있는 문제점을 해결하고 보다 객관적인 경기진행을 위해서는 현재 사용하고 있는 각종 전자호구의 충격력인식 시스템을 재 점검할 필요가 있다고 생각한다. Although the electronic body protector has been officially adopted by the World Taekwondo Federation(WTF) in 2006, no scientific information is available about the reliability of its performance. The purpose of this study, therefore, was to investigate the relationship between the impact value of electronic body protector and the impact force of force platform. Male collegiate Taekwondo athletes([MCTA], n=21) and male collegiate Taekwondo students([MCTS], n=20) volunteered to participate in the study. Each subject performed the apchagi, dollyeochagi and dwichagi on the force platform and the electronic body protector. At the apchagi, it showed that MCTS(about 4,700 N) generated more maximum kick force than MCTA(about 3,900 N), but it expressed that MCTA(about 5,300 N) generated more maximum kicking force than MCTS(about 4,400 N) at the dwichagi. At the apchagi and the dwichagi, it indicated the high coefficient of correlation(over r=.8) which supports higher explanation force the relationship between the impact value of electronic body protector and the impact force of force platform, but there was no statistically significant difference at the dollyeochagi.

A simple approach to estimate the mechanical properties of collagen-like microfibrils surrounded by water

Young-june Yoon,Cheol-soo Bae,Ho-sik Park 한국멀티미디어학회 2010 한국멀티미디어학회 국제학술대회 Vol.2010 No.-

The effective Young's modulus of a microfibril surrounded by water may be simply calculated by using the upper (Voigt) and lower (Reuss) bounds. The result is compared to the Young's modulus estimated by using the Steered Molecular Dynamics (SMD) (Zhang et al. 2007). Our result shows 9.2% difference from the result estimated by SMD, but the steps using these bounds are much simpler than SMD..

Assessment of Alcohol Level in Inebriated Victims of Sexual Assault using Ethyl Glucuronide

Young?Hoon Jo,Mia Kwon,Joon-Bae Lee,Jeong A Ko 한국분석과학회 2022 학술대회논문집 Vol.2022 No.5

급성 골수성 백혈병 환자에서 발생한 침습성 아스페르길루스중에 대한 수술적치료 1 예

배영환;어원식;어상민;김승만 김태영;박수영;서영경;정은주;안효정 인제대학교 2011 仁濟醫學 Vol.32 No.-

Invasive pulmonary aspergillosis is known to have a poor prognosis and major cause of morbidity and motality in patients with hematologic disease. Without adequate therapy, invasive pulmonary aspergillosis will almost always progress to fatal pneumonia. Early administration of antifungal agents in patient with invasive pulmonary aspergillosis is most important. And surgical resection of aspergillous-infected tissue may be useful in patients with lesions that are contiguous with great vessel and lesions causing hemoptysis. We reported a rare case of surgical resection as curative treatment for invasive pulmonary aspergillosis patient in 58-year-old man who had the history of acute myeloid leukemia.

현대시에 나타난 불교의식 연구 : 한용운·서정주·조지훈 시를 중심으로

배영애 숙명여자대학교 1999 숙명語文論集 Vol.- No.2

This thesis aims to review modern poetry considering a poetic feature of Han Young-con, Suh Jung-joo, and Cho Ji-hoon in the epistemological aspect of Buddhist consciousness. The Buddhist consciousness means general aspects of individual response on Buddhism such as Buddhist ideas and experiences appeared in three poets' poems. In this thesis, an intention to study three poets' works begins with an assumption which Buddhist consciousness affects their poetry directly or indirectly, because they are deeply connected with Buddhism. As all poems ought to be made from a poet's own ideas, inner orders and experiences, an immanent consciousness in poetry reflects the poet's world view. Therefore this thesis analyzes three poets' works in the two aspects of a discordant structure against reality and a concord one for ideal world. The second chapter in this thesis cites as follows: how the discordant situation against the reality is embodied by each poet who accepts the Buddhist consciousness in his poems, defining its characteristic as an affirmative response for the reality: how this expression is related with the Buddhist consciousness. The third chapter focuses how the ideal world sought by each poet is expressed in his poems, concentrating the Buddhist consciousness on a solution against the discord and a pursuit for the ideal world. First, Han Young-oon endures his anguish by denying a parting with "Nim" (lover) and giving more affirmative meanings over death. On the basis of this consciousness is karma' and an idea which oneself and others are not separate. The parting cited by Han does not mean gloomy feeling or grief, rather than it is made to be linked to process of fervent love and waiting, and it is possible that restraint means freedom. Leaving lover is replaced by re-rneeting, which gets together with all things and realized the ideal world. Therefore a poetic narrator keeps on pursuing self-realization in order to arrive at the ideal world and to unite into one. These aspects, in Han's works, appear as poetic literature of Buddhist emancipation, not as that of traditional "Han" (恨 : hatred and grief). So the process of meeting with "Nim" is that of self-realization, and come to change into various figures. So it is represented that "Nim" gets over-layered meanings such as a symbol of hope and a way of individual existence. In such a process of embodiment is transcendence of Buddhist consciousness applied. As the Buddhist transcendence is characterized by making sense with "indirection", such as 'negative of negative' or an oxymoron. Han shows the affirmative idea for the world and the transcendence for comprehensive attitude through the oxymoron(which is mainly used). Then in Suh Jung-joo's poetry. the physical and sensual desire and the discord are transfigured in Suh Jung-joo's poetry, the Buddhist consciousness is accepted. Such a poetic acceptance is a real alternative to work out the real discord and desire. As a poetic narrator transfigures the world of 'flower', where was the object of desire, into Seo-Youk, or Jung-To(the Buddhist Elysium), he moves up to the place of transmigration from the early burning life-recognition. To be short, Suh's Buddhist consciousness is concentrated on "eternalism" of the Shilla Dynasty. There is Buddhist consciousnes in his poems as a confrontation between physical sense and spirit, death and life keep on being focused on his poetic world, and human's life comes to be the center of the poetic change and extension. Therefore human's death means not an abandonment or a despair, but a change up to the holy place, and it is possible for the departed to appear as main characters of the poetic world. In the result, the world of death reconstructed in Suh's poems means the eternal transmigratory life in Buddhism, and a semantic integration is accomplished as a sign implied by a poet in a poem. Accordingly, as human's birth and death turn into qualities of myth composing a' set of Buddhist consciousness, they are embodied as implied meanings, that is, universal cycle of time, and life and death. For Suh, the Buddhist consciousness as a storage representing the world experienced by him is motivated into a meaning of the real discord and integration, and it forms a inner meaning, The Buddhist consciousness on the bottom of changing poetic world makes Suh overcome his instinctive desire and discord, and gives spirit tranquillity to realize the ideal which is searching hometown and life-archetype. According to this fact, forSuh, the poetic acceptance of Buddhist consciousness means one of ways inquiring profoundly for his own existence. Expressed into Heaven like Seo- Youk, or Jung- To, the Buddhist consciousness shows a range of transmigratory lifes in Suh's poems. This means the trial to search his own self, life-archetype, and the desire to imitate universal order. He tries to explain the principle of the universal order, that is, cycle of nature and that of human's life and death in the same structural dimension. So his poetry is characterized by correspondence and repeat, and an aspect of transition toward the opposite world appears. Such a characteristic of poetic expression gets an order changing into a ring of Buddhist transmigration. Last, Cho Ji-hoon, also, embodies a discord of those days and negative consciousness which an intellectual could have under the rule of Japanese imperialism through the process of "appearing and disappearing", and responds to the reality. Although all these aspects do not begin from the Buddhist consciousness, it is Buddhist. at least, for poetic narrator to overcome the discord and to embody this. Cho's poetic expression does not aim for only nature, but an union between the nature and the self arrives at a stage of the "meditation"(禪) through the aspect of Buddhist emancipation, not through an usual aim for nature. The nature in Cho's poems is the object to symbolize simplicity rather than the nature of Do-Ka(道家) to be free and easy, and is the object of the secondary spirit world, too. Therefore his poetic world is more 'complicated aspect, the stage of the "meditation" rather than a structural ornament. This "meditation" means the phase which the border of everything disappears, and it is represented simply and shortly into the ideal world where is no pain, and no thought or no idea. The world represented with this way, however, overcomes the actual limit with 'minus-device' which has a simple structure but can respond to each different reality, and keeps a lot of implied meanings. First of all, Cho's Buddhist consciousness, however, stems out of an affirmative recognition. The principle of poetic structure pursued by Cho is the world of the "meditation", where a leap and an imagination are enabled. For Cho, this "meditation" is the process of the indirection and the center of the poetic structure. He realizes the "meditation" in his poems through the nature, but he does not just duplicate the nature, but arrives at the stage of "the meditation" showing a Buddhist emancipatory process. Accordingly, it is explained that his poetry is not understood as only the nature of Do-Ka, rather it is affected from the Buddhist consciousness accepting reality and being affirmative about it. Now the Buddhist consciousness, for three poets, has influence, directly or indirectly, upon representing the poetic theme and the poetic form as a catalyst and a mechanism of expression laid on a basis of verse. It is a mechanism which responds to an era, and plays a role as a prospect and a vision for the future, too. Han converts a parting into a meeting, Suh gives life to physics and sensuality, and Cho converts loneliness and anguish into tranquillity and stability. It is clear that three poets uses the Buddhist consciousness as the catalyst in order to sublime the risk and the discord of those days and to aim for a new ideal world. Therefore the Buddhist consciousness represented by these poets is not accepted as a technique for a time, but· appears as depth of poetic immanence, an awe for life, a generous attitude and an affirmative recognition about the life. To be short, Han's poetry can be summarized to. "united poetry", Suh's to "transmigratory poetry", and Cho's to "Buddhist emancipatory poetry". Although this Buddhist consciousness is different from the time and the way of poetic acceptance, it is embodied as a way overcoming tragic reality, an alternative principle and a way searching self-realization and life-archetype.

1~2기 본태성 고혈압 환자들에서 Imidapril 대 Enalapril의 항고혈압 효과를 평가하기 위한 무작위, 이중맹검 임상시험

최영진,손대원,김용진,이홍자,채인호,김효수,김철호,오병희,이명묵,박영배,채윤식,이영우 대한순환기학회 1999 Korean Circulation Journal Vol.29 No.11

유산균들의 콜레스테를 저하성, 내산성, 내담즙성, 항생제 내성 비교

박소영,고영태,정후길,양진오,정현서,김영배,지근억 한국미생물생명공학회 ( 구 한국산업미생물학회 ) 1996 한국미생물·생명공학회지 Vol.24 No.3

기능성 요구르트의 제조에 사용되는 유산균은 인체에 유익한 생리활성과 우수한 생존능력을 보유하고 있는 것이 바람직하다. 본 연구에서는 다양한 유산균주의 산과 담즙 및 항생제에 대한 내성을 조사하였으며 in vitro에서 콜레스테롤 저하능을 조사하였다. In vitro에서 콜레스테롤 저하능이 우수한 13균주를 선발하여 이들의 동결건조 분말을 고 콜레스테롤 식이의 실험쥐에 투여하였다. 그 결과 8균주는 비 투여구보다 유의적으로 18.3~27.3%의 콜레스테롤 저하능을 나타냈다(P≤0.05). 이들 중에서 Bifidobacterium infantis AM-220, Lactobacillus AM-245, Streptococcus MA-1의 3균주를 이용하여 요구르트를 제조한 후 동결건조 분말을 이용하여 급여실험을 수행한 결과, 총 콜레스테롤과 LDL 함량이 유의적으로 감소하는 것으로 나타났다. For a probiotic yoghurt it is desirable to utilize lactic acid bacteria with a high survival rate and beneficial function to human beings. We have examined a variety of lactic acid bacteria to assess the acid and bile tolerance and antibiotic resistance. In addition, an in vitro culture experiment was performed to evaluate their ability to reduce cholesterol levels in the growth medium. Thirteen strains were selected from in vitro cholesterol assays and fed to Sprague-Dawley rats with a high-cholesterol diet. Among the 13 strains tested, 8 strains were shown to reduce serum cholesterol levels significantly after 24 days of administration in vivo. Rats were fed lyophilized yoghurt powder fermented with a combination of 3 selected strains: Bifidobacterium infantis AM-220, Lactobacillus AM-245, and Streptococcus MA-1. The levels of total cholesterol and low density lipoprotein were significantly lower (p≤0.05) in rats fed the yoghurt powder compared with control group. These studies suggest that yoghurt fermented with appropriately selected lactic acid bacteria may have a anticholesterolemic effect.

김치에서 분리한 Lactobacillus sp. JC-7과 Lactobacillus acidophilus 88간의 Electrofusion 최적조건 설정

조영배,최현정,백형석,전홍기 부산대학교 유전공학연구소 1997 분자생물학 연구보 Vol.13 No.-

김치 발효 숙성기간을 연장하고 신선도를 오랫동안 유지 할 수 있는 김치발효 starter의 개발을 목적으로 최적숙성기에 있는 김치로부터 bacteriocin생성능이 없는 유산균을 분리하여 동정하였으며, bacteriocin생성능이 우수한 L.acidophilus 88을 융합시키기 위해 electrofusion에 대한 최적 조건을 검토하였다. 분리균주는 Lactobacillus속으로 동정되어 Lactobacillus sp. JC-7이라 명명하였다. Electrofusion에 의해 생성된 융합주를 식별하기 위해 streptomycin(2.5㎎/ml)에 내성을 나타내는 Lactobacillus sp. JC-7변이주와 kanamycin(600㎍/ml)에 내성을 나타내는 L.acidophilus 88변이주를 분리하였다. Electrofusion을 100V/㎝, 120msec(72ohms,1670 capacitance) 에서 수행했을 때 융합효율이 가장 양호하였으며 전기장의 세기와 시간이 중가할수록 융합 효율이 현저히 감소하였다. 2가 양이온은 농도가 중가할수록 대체적으로 융합효율을 감소시키는 경향을 나타내었으나 1mM MGCl_2에서는 대조군에 비해 융합효율이 약간 증가하였다. PEG매개에 의한 융합법의 융합효율을 비교한 결과, 융합효율은 chemical fusion<electrofusion<electrofusion+20% PEG순을 나타내었다. Evaluation of Optimum Conditions for the Electrofusion between Lactobacillus sp. JC-7 Isolated from Kimchi and Lactobacillus acidophilus 88. Young-Bae Jo, Hyun-Jung Choi, Hyung-Suk Baik and Hong-Ki Jun*. Department of Microbiology, Pusan National University, Pusan 609-735,Korea-A lactic acid bacterium was isolated from kimchi. The isolated strain was identified as the genus Lactobacillus thrugh its morphological characteristics and named as Lactobacillus sp. JC-7. The optimum conditions for the electrofusion between streptomycin(2.5㎎/ml)resistant mutant of Lactobacillus acidophilus 88 and kanamycin(600㎍/ml) resistant mutant Lactobacillus sp. JC-7 were evaluated. The highest number of fusants were obtained at a capacitance value of 120msec(1670㎌), a field strength of 100V/㎝,and a pulse controller setting of 72Ω. The potimum pH of elecroporation buffer was 7.5 and the concentration of divalent cation was 1mM MG^2+. Electrofusants were efficiently obtained by addition 20% polyethylene glycol to electroporation buffer. The yield of fusion was better than that of using polyethylene glycol mediated chemical induction.

서울 시내 일부 대학생의 성지식과 성태도에 관한 연구

김보배,노은경,박서영,박영,오승희,전영란,차현진,윤희상,김수지,이자형 이화여자대학교 간호과학대학 2004 이화간호학회지 Vol.- No.38

This study surveyed and analyzed comparatively college students-knowledge' attitude, was to cultivate the right knowledge and attitude on sex, and serve the foundational data for the suitable sex education. The purpose of the study was to identify and examine: 1) students; sexual knowledge and sexual attitude; 2) the differences between variables of gender, age, and self-perceived sexual knowledge in relation to sexual knowledge and sexual attitude; and 3) the relationship between sexual knowledge and sexual attitude. For this study the questionaires were given to 300 students from five different universities located seoul areas. the questionaires were collected Jenuary 8th to 15th in 2004. Two hundred and nigty one samples were analyzed for the study. The adapted SKAT(saxual knowledge & attitude test; Lief & Reed, 1986) was used to determine sexual knowledge and the students' sexual attitude. Collected data were analyzed statistically by means of percentage, t-test, ANOVA test, and pearson correlation analysis with SPSS 12.0 package program. The main results of this analysis are as follows: Participants consisted of male(48.1%) and female(51.9%) which were mainly between the ages of 21.25(71.8%) with an age range of 19 to 30. Knowledge of sexual disease was scored highest of 92.4%, and konwledge of the knowledge of the male and female's anatomy was the lowest at 60.9%. The respondents' level of sexual attitude was tolerant as on average 3.66(on the basis of 5) Relating to the items, the respondents' score of the sexual curiosity was 4.16, sexual behavior 3.85, self-consolation 3.81, aborthon 3.23, virgine 3.19, extramarital experiences 3.17. There were no significant differences in sexual knowledge between male and females, between younger and older students, residence, sexual experience, and how students mainly obtained their sexual knowledge. But a significant difference was also found religion in their sexual attitude(p<.005). In addition, results showed the relationship between sexual knowledge and sexual attitude(P=0.332).

Effect of Ultrasonic Melt Treatment on Solidification Microstructure of Al–5Ti–1B Alloy Containing Numerous Inoculant Particles

Soo‑Bae Kim,Jae‑Gil Jung,Young‑Hee Cho,Su‑Hyeon Kim,Kwangjun Euh,Jung‑Moo Lee 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7

The effect of ultrasonic melt treatment (UST) on the solidification microstructure of an Al–5Ti–1B alloy containing highvolumefractions of Al3Tiand TiB2particles is investigated for various UST times with different melt holding times. Theas-cast Al–5Ti–1B alloy is composed of TiB2and polygonal Al3Tiparticles (present prior to UST), plate-like Al3Tiparticles,and Al grains (formed during UST and/or solidification). The UST causes a size reduction and homogeneous distributionof the TiB2-agglomerated region containing many submicron-sized TiB2particles pushed to the grain boundaries. The USTslightly decreases the size and improves the distribution of polygonal Al3Tiparticles enriched in the TiB2-agglomeratedregion. Unlike the TiB2and polygonal Al3Tiparticles, which exhibit a minor refining effect, the plate-like Al3Tiparticlesshow a significant refinement with UST application. The UST has a significant effect on the size distribution of Al grains byinducing the formation of medium-sized grains at the expense of small and large grains; however, it only has a slight effecton grain refinement. The degree of microstructure modification increases with increasing UST time but decreases with meltholding time after UST. The mechanisms for the refinement and dispersion of the TiB2and Al3Tiparticles and Al grains arediscussed considering fragmentation, nucleation, and growth behaviors induced by the UST and subsequent solidification.