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이태호 대한기계학회 1991 大韓機械學會誌 Vol.31 No.7
일반적으로 로켓 추진기관이라고 하면 외부로부터의 산소 공급없이, 추진제라고 불리는 물질이 연소할 때 발생하는 고온 고압의 연소가스를 고속으로 노즐로 통과시켜 추력을 얻는기관을 말 한다. 연소는 산소와의 화합반응이 급격히 일어날 때 일어나는 현상이므로 외부로부터 산소공 급이 없다는 것은, 추진제 자체에서 산소공급이 가능하다는 것을 의미한다. 즉, 추진제는 그 자 체가 흔히 말하는 연료성분과 산소를 공급할 수 있는 산소화합물을 같이 묶어둔 물질이어야 한다. 그러나 지구를 둘러싸고 있는 대기에는 산소가 20%나 포함되어 있으며, 이 무궁무진한 산소를 이용하지 않는다는 것은 여러 면에서 손실임을 쉽게 알 수 있을 것이다. 그럼에도 불구 하고 이를 이용하지 못하고 있었음은 그 나름대로의 어려움이 있었기 때문일 것이다. 그러나 인간의 노력과 연구로 불가능했던 많은 사실도 가능하게 된 것이 헤아릴 수 없이 많아지고 있음 또한 주지의 사실이다. 로켓 추진기관 분야에서도 순수 연료 성분만을 로켓에 탑재하고 산소는 흡입되는 대기중의 것을 이용하자는 것이 새로운 연구분야로 각광을 얻고 있으며, 실제로 이러한 방법이 실용화되고 있다. 이와 같이 흡입공기를 산소원으로 하는 추진기관을 총칭 램제트 추진 기관이라고 한다.
이태호,전성재,한용운,문두경 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0
The conjugated polymers have gained much attention because of their unique semiconducting properties in fabricating large area, flexible, and low cost electronic devices. Research into bulk heterojunction OPVs has attracted in both academia and industry because of their potential application in solar cells via cost-effective solution processes. The versatility and processability of the polymers offer tunable electronic, optical, and crystalline properties for optimizing the device performance. In designing materials for polymer solar cells it is well established that apart from the chemical structure, which determines the optical energy levels, the morphology of extended side π-conjugation blend plays a crucial role. Benzo[1,2-b,3,4-b``]dithiophene (BDT) is another well used donor unit in high performance polymers at present. Because it have many advantages which are long π conjugation length, low HOMO level and high charge carrier mobility. In this study, we synthesized extended side conjugation length based copolymer and investigated their PSCs property.
Effect of male age on reproductive function: A comparison of young and middle-aged men
이태호,김동석,김대근,신동혁,오미희,이원희,송승훈 대한비뇨의학회 2023 Investigative and Clinical Urology Vol.64 No.1
Purpose: There have been concerns regarding potential effects of older paternal age on male reproductive function. However, currently available data on this topic are insufficient and controversy exists. We analyzed semen characteristics and reproductive hormones in young men and middle-aged men to investigate the effect of age on male reproductive function. Materials and Methods: This study examined healthy males of reproductive age who visited a single infertility center from January 2016 to July 2021. The young group consisted of men who were less than 35 years-old, and the middle-age group consisted of men who were more than 45 years-old. Results: The two groups had no significant differences in sperm concentration ([89.9±59.4]×106/mL vs. [104.4±82.1]×106/mL, p=0.108) or sperm morphology (normal forms: 3.6%±1.5% vs. 3.4%±1.6%, p=0.131). However, the middle-age group had a smaller semen volume (3.2±1.5 mL vs. 2.5±1.4 mL, p<0.001), lower sperm motility (42.3%±9.8% vs. 31.2%±12.4%, p<0.001), lower progressive sperm motility (39.2%±10.3% vs. 28.4%±12.6%, p<0.001), and a higher serum follicle-stimulating hormone level. Conclusions: Our results suggest that advanced male age might have a negative effect on fertility potential, as in women. This finding has important clinical implications because more couples are choosing to have children when they are older. Further studies on this issue, especially those that examine reproductive outcome, are warranted.
이태호,이지근 한국기계기술학회 2020 한국기계기술학회지 Vol.22 No.5
In this study, four types of water-heavy fuel oil hybrid emulsion oil were manufactured depending on the moisture content ratio in order to reduce exhaust emissions of heavy fuel oil(Bunder-C), which is necessarily used in vessels, power plants and boilers. The components of the manufactured emulsion oil were analyzed using the ISO standard testing method. The analysis result showed that in the EM25 fuel with a maximum moisture content ratio of 25.0%, the moisture content was 25.0%, the sulphur content was 0.20%, the kinematic viscosity was 144.8mm2/s, the specific gravity was 0.9382, and the flash point was 100 Celsius degrees or above.
Myocardial atrophy in children with mitochondrial disease and Duchenne muscular dystrophy
이태호,은영민,최재영,권혜은,이영목,김흥동,강성웅 대한소아청소년과학회 2014 Clinical and Experimental Pediatrics (CEP) Vol.57 No.5
Purpose: Mitochondrial disease (MD) and Duchenne muscular dystrophy (DMD) are often associatedwith cardiomyopathy, but the myocardial variability has not been isolated to a specific characteristic. We evaluated the left ventricular (LV) mass by echocardiography to identify the general distribution andfunctional changes of the myocardium in patients with MD or DMD. Methods: We retrospectively evaluated the echocardiographic data of 90 children with MD and 42with DMD. Using two-dimensional echocardiography, including time-motion (M) mode and Dopplermeasurements, we estimated the LV mass, ratio of early to late mitral filling velocities (E/A), ratio ofearly mitral filling velocity to early diastolic mitral annular velocity (E/Ea), stroke volume, and cardiacoutput. A “z score” was generated using the lambda-mu-sigma method to standardize the LV masswith respect to body size. Results: The LV mass-for-height z scores were significantly below normal in children with MD(–1.02±1.52, P<0.001) or DMD (–0.82±1.61, P =0.002), as were the LV mass-for-lean body-mass zscores. The body mass index (BMI)-for-age z scores were far below normal and were directly proportionalto the LV mass-for-height z scores in both patients with MD (R=0.377, P<0.001) and those with DMD(R =0.330, P=0.033). The LV mass-for-height z score correlated positively with the stroke volume index(R =0.462, P<0.001) and cardiac index (R =0.358, P<0.001). Conclusion: LV myocardial atrophy is present in patients with MD and those with DMD and may beclosely associated with low BMI. The insufficient LV mass for body size might indicate deterioration ofsystolic function in these patients.