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공군사관생도의 기초체력, 심폐기능, 등속성 근기능 비교분석
김근수(Kim, Keun-Su),최진(Choi, Jean),김정운(Kim, Jung-Woon),유도상(Ryu, Do-Sang),김병주(Kim, Byoung-Joo),류현승(Rhyu, Hyun-Seung) 한국체육과학회 2016 한국체육과학회지 Vol.25 No.4
The purpose of the study was to analyze the grade-related differences of physical fitness, cardiopulmonary function, isokinetic muscular function in Air Force academy cadets and to provide useful data on the direction and design of the physical education program. Participants were 80 male cadets(1st grade 40, 4th grade 40). The events in measurement of physical fitness were ‘grip strength’, ‘balance test’, ‘long-jump’, ‘trunk forward flexion’, ‘side-step’, "3km run", "sit-up" and "push-up". Cardiopulmonary function was measured by the respiratory gas metabolic analyzer using the treadmill and knee isokinetic muscle strength was measured using the Humac NORM. Means and standard deviations were calculated. Independent t-test was applied to evaluate the difference of variables between two groups. The significance level was accepted at p<0.05. The results were as follows. First, ‘grip strength’, ‘balance test’, ‘side-step’, "3km run", "sit-up" and "push-up" in 4th grade group were significantly higher than 1st grade group(p<.05). Second, in cardiopulmonary function, the maximal oxygen uptake and arteriovenous oxygen difference of 4th grade group were significantly higher than those of 1st grade group(p<.05). Third, knee extension and flexion test showed that 4th grade group were significantly high. In contrast, muscle fatigue index and extension fatigue index showed that 1st grade group was much higher than 4th grade group. but there was no difference in the ratio of extension and flexion on right and left. Therefore, especially more emphasis should be focused on programs of flexibility, aerobic capacity and lower body strength in order to prevent injury, overcome hypoxia and enhance G tolerance. In this direction, there is a need to complement and strengthen the systematic physical fitness program.
RF Sputtering의 증착 조건에 따른 HfO₂ 박막의 Nanocrystal에 의한 Nano-Mechanics 특성 연구
김주영(Joo Young Kim),김수인(Soo In Kim),이규영(Kyu Young Lee),권구은(Ku Eun Kwon),김민석(Min Suk Kim),엄승현(Seoung Hyun Eum),정현진(Hyun Jean Jung),조용석(Yong Seok Jo),박승호(Seung Ho Park),이창우(Chang Woo Lee) 한국진공학회(ASCT) 2012 Applied Science and Convergence Technology Vol.21 No.5
재 Hf (Hafnium)을 기반으로한 게이트 유전체의 연구는 여러 분야에서 다양하게 진행되어져 왔다. 이는 기존의 SiO₂보다 유전상수 값이 크고, 또한 계속되는 scaling-down 공정에서도 양자역학적인 터널링을 차단하는 특성이 뛰어나기 때문이다. MOSFET 구조에서 유전체 박막의 두께 감소로 인한 전기적 특성 저하를 보완하기 위해서 high-K 재료가 대두되었고 현재 주를 이루고 있다. 그러나 현재까지 HfO₂에 대한 nano-mechanical 특성 연구는 부족한 상태이므로 본 연구에서는 게이트 절연층으로 최적화하기 위하여 HfO₂ 박막의 nano-mechanical properties를 자세히 조사하였다. 시료는 rf magnetron sputter를 이용하여 Si (silicon) 기판 위에 Hafnium target으로 산소유량(4, 8 sccm)을 달리하여 증착하였고, 이후 furnace에서 400에서 800℃까지 질소분위기에서 20분간 열처리를 실시하였다. 실험결과 산소 유량을 8 sccm으로 증착한 시료가 열처리 온도가 증가할수록 누설전류 특성 성능이 우수 해졌다. Nano-indenter로 측정하고 Weibull distribution으로 정량적 계산을 한 결과, HfO₂ 박막의 stress는 as-deposited 시료를 기준으로 400℃에서는 tensile stress로 변화되었다. 그러나 온도가 증가(600, 800℃)할수록 compressive stress로 변화 되었다. 특히, 400℃ 열처리한 시료에서 hardness 값이 (산소유량 4 sccm : 5.35 GPa, 8 sccm : 5.54 GPa) 가장 감소되었다. 반면에 800℃ 열처리한 시료에서는(산소유량 4 sccm : 8.09 GPa, 8sccm : 8.17 GPa) 크게 증가된 것을 확인하였다. 이를 통해 온도에 따른 HfO₂ 박막의 stress 변화를 해석하였다. Over the last decade, the hafnium-based gate dielectric materials have been studied for many application fields. Because these materials had excellent behaviors for suppressing the quantum-mechanical tunneling through the thinner dielectric layer with higher dielectric constant (high-K) than SiO₂ gate oxides. Although high-K materials compensated the deterioration of electrical properties for decreasing the thickness of dielectric layer in MOSFET structure, their nano-mechanical properties of HfO₂ thin film features were hardly known. Thus, we examined nano-mechanical properties of the Hafnium oxide (HfO2) thin film in order to optimize the gate dielectric layer. The HfO₂ thin films were deposited by rf magnetron sputter using hafnium (99.99%) target according to various oxygen gas flows. After deposition, the HfO₂ thin films were annealed after annealing at 400℃, 600℃ and 800℃ for 20 min in nitrogen ambient. From the results, the current density of HfO₂ thin film for 8 sccm oxygen gas flow became better performance with increasing annealing temperature. The nano-indenter and Weibull distribution were measured by a quantitative calculation of the thin film stress. The HfO₂ thin film after annealing at 400℃ had tensile stress. However, the HfO₂ thin film with increasing the annealing temperature up to 800℃ had changed compressive stress. This could be due to the nanocrystal of the HfO₂ thin film. In particular, the HfO₂ thin film after annealing at 400℃ had lower tensile stress, such as 5.35 GPa for the oxygen gas flow of 4 sccm and 5.54 GPa for the oxygen gas flow of 8 sccm. While the HfO₂ thin film after annealing at 800℃ had increased the stress value, such as 9.09 GPa for the oxygen gas flow of 4 sccm and 8.17 GPa for the oxygen gas flow of 8 sccm. From these results, the temperature dependence of stress state of HfO₂ thin films were understood.
Vision Inspection Methods for Uniformity Enhancement in Long-Length 2G HTS Wire Production
Jae-Hun Lee,Byoung-Jean Mean,Tae-Jin Kim,Young-Soon Kim,Kyekun Cheon,Taehoon Kim,Dae-Gwan Park,Dae-Won Song,Ho-Kyum Kim,Woosuk Chung,Hunju Lee,Seung-Hyun Moon Institute of Electrical and Electronics Engineers 2014 IEEE transactions on applied superconductivity Vol.24 No.5
<P>With much effort devoted by many research groups, the performance of 2nd generation (2G) superconducting wires, also called coated conductors (CC), was drastically improved, leading to many meaningful and impressive demonstrations of electric power devices. Now that the performances such as critical current, in-field characteristics, and mechanical strengths became sufficient to the application, the attention has moved to how we can produce long 2G wires with high uniformity. Many in-line inspection tools are tested and introduced to address these challenges. In this paper, we describe two methods that we adopted for in-line monitoring and feedback control of layer deposition. One is for texture control of ion beam assisted deposition (IBAD) of an MgO layer through reflection high-energy electron diffraction (RHEED) pattern monitoring and analysis. The other is for composition control of a superconducting layer through surface color observation and control of metal source evaporation rates. By applying the above two methods, we achieved in-plane texture of about 4.8 ° in the MgO layer, as measured by FWHM of phi-scan of (220) peak, and the critical current of 750 A/12 mm width in the GdBCO layer along the length of more than 650 m, with excellent uniformity.</P>
Bae Eun-Jin,Choi Minsun,Kim Jeong Tae,Kim Dong-Kyu,Jung Min Kyo,Kim Changyoun,Kim Tae-Kyung,Lee Jun Sung,Jung Byung Chul,Shin Soo Jean,Rhee Ka Hyun,Lee Seung-Jae 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-
Cell-to-cell propagation of α-synuclein is thought to be the underlying mechanism of Parkinson’s disease progression. Recent evidence suggests that inflammation plays an important role in the propagation of protein aggregates. However, the mechanism by which inflammation regulates the propagation of aggregates remains unknown. Here, using in vitro cultures, we found that soluble factors secreted from activated microglia promote cell-to-cell propagation of α-synuclein and further showed that among these soluble factors, TNF-α had the most robust stimulatory activity. Treatment of neurons with TNF-α triggered cellular senescence, as shown by transcriptomic analyses demonstrating induction of senescence-associated genes and immunoanalysis of senescence phenotype marker proteins. Interestingly, secretion of α-synuclein was increased in senescent neurons, reflecting acquisition of a senescence-associated secretory phenotype (SASP). Using vacuolin-1, an inhibitor of lysosomal exocytosis, and RNAi against rab27a, we demonstrated that the SASP was mediated by lysosomal exocytosis. Correlative light and electron microscopy and immunoelectron microscopy confirmed that propagating α-synuclein aggregates were present in electron-dense lysosome-like compartments. TNF-α promoted the SASP through stimulation of lysosomal exocytosis, thereby increasing the secretion of α-synuclein. Collectively, these results suggest that TNF-α is the major inflammatory factor that drives cell-to-cell propagation of α-synuclein by promoting the SASP and subsequent secretion of α-synuclein.
Koo, Gi-Bang,Morgan, Michael J,Lee, Da-Gyum,Kim, Woo-Jung,Yoon, Jung-Ho,Koo, Ja Seung,Kim, Seung Il,Kim, Soo Jung,Son, Mi Kwon,Hong, Soon Sun,Levy, Jean M Mulcahy,Pollyea, Daniel A,Jordan, Craig T,Yan Springer Science and Business Media LLC 2015 Cell research Vol.25 No.6
<P>Receptor-interacting protein kinase-3 (RIP3 or RIPK3) is an essential part of the cellular machinery that executes 'programmed' or 'regulated' necrosis. Here we show that programmed necrosis is activated in response to many chemotherapeutic agents and contributes to chemotherapy-induced cell death. However, we show that RIP3 expression is often silenced in cancer cells due to genomic methylation near its transcriptional start site, thus RIP3-dependent activation of MLKL and downstream programmed necrosis during chemotherapeutic death is largely repressed. Nevertheless, treatment with hypomethylating agents restores RIP3 expression, and thereby promotes sensitivity to chemotherapeutics in a RIP3-dependent manner. RIP3 expression is reduced in tumors compared to normal tissue in 85% of breast cancer patients, suggesting that RIP3 deficiency is positively selected during tumor growth/development. Since hypomethylating agents are reasonably well-tolerated in patients, we propose that RIP3-deficient cancer patients may benefit from receiving hypomethylating agents to induce RIP3 expression prior to treatment with conventional chemotherapeutics.</P>