Kr Atoms and Their Chlustering in Zeolite A

임우택,장장환,정기진,허남호,Im, U Taek,Jang, Jang Hwan,Jeong, Gi Jin,Heo, Nam Ho Korean Chemical Society 2001 Bulletin of the Korean Chemical Society Vol.22 No.9

The positions of Kr atoms encapsulated in the molecular-dimensioned cavities of fully dehydrated zeolite A of unit-cell composition Cs3Na8HSi12Al12O48 (Cs3-A) have been determined. Cs3-A was exposed to 1025 atm of krypton gas at 400 $^{\circ}C$ for four days, followed by cooling at pressure to encapsulate Kr atoms. The resulting crystal structure of Cs3-A(6Kr) (a = $12.247(2)\AA$, R1 = 0.078, and R2 = 0.085) has been determined by single-crystal X-ray diffraction techniques in the cubic space group Pm3m at $21(1)^{\circ}C$ and 1 atm. In the crystal structure of Cs3-A(6Kr), six Kr atoms per unit cell are distributed over three crystallographically distinct positions: each unit cell contains one Kr atom at Kr(1) on a threefold axis in the sodalite unit, three at Kr(2) opposite four-rings in the large cavity, and two at Kr(3) on threefold axes in the large cavity. Relatively strong interactions of Kr atoms at Kr(1) and Kr(3) with Na+ ions of six-rings are observed: Na-Kr(1) = 3.6(1) $\AA$ and Na-Kr(3) = $3.08(5)\AA.$ In each sodalite unit, one Kr atom at Kr(1) was displaced $0.74\AA$ from the center of the sodalite unit toward a Na+ ion, where it can be polarized by the electrostatic field of the zeolite, avoiding the center of the sodalite unit which by symmetry has no electrostatic field. In each large cavity, five Kr atoms were found, forming a trigonal-bipyramid arrangement with three Kr(2) atoms at equatorial positions and two Kr(3) atoms at axial positions. With various reasonable distances and angles, the existence of Kr5 cluster was proposed (Kr(2)-Kr(3) = $4.78(6)\AA$ and Kr(2)-Kr(2) = $5.94(7)\AA$, Kr(2)-Kr(3)-Kr(2) = 76.9(3), Kr(3)-Kr(2)-Kr(3) = 88(1), and Kr(2)-Kr(2)-Kr(2) = $60^{\circ}).$ These arrangements of the encapsulated Kr atoms in the large cavity are stabilized by alternating dipoles induced on Kr(2) by four-ring oxygens and Kr(3) by six-ring Na+ ions, respectively.

암환자의 우울증과 카켁시아 간 시토카인 매개 연결

임우택 대한물리치료과학회 2019 대한물리치료과학회지 Vol.26 No.3

Despite the advances in medical technology, there are limited therapeutic interventions for cancer. Currently, the main goal of treatment is to remove a tumor completely. However, recent studies have shown that mortality is highly influenced by symptoms such as depression and cachexia, not solely by cancer itself. Depression is caused by psychological stress, and cachexia involves extreme weight loss with skeletal muscle atrophy, which are widely observed in patients with cancer. Although those two appear completely different from each other, they have a common etiology: cytokines. The production of cytokines can lead to depression and cachexia, and it contributes greatly to the increase in mortality rate. A better understanding of depression and cachexia in patients with cancer will help establish efficient treatment strategies.

최대 수의적 수축 동안 뒤넙다리근 근력 반복성의 남녀 차이

임우택 대한물리치료과학회 2020 대한물리치료과학회지 Vol.27 No.1

Background: This study aimed to examine the repeatability of hamstring strength during maximal voluntary contractions (MVCs) and to examine the sex difference. Design: Quasi-experiment design. Methods: The study recruited 23 healthy young individuals as participants. Hamstring flexibility was measured before and after MVCs by active knee extension test. Five trials of MVCs were performed, and hip extension forces were measured using a strain gauge during MVCs. Repeatability was confirmed by intraclass correlation coefficient (ICC) and coefficient of variation, and the difference between male and female participants was confirmed by independent samples t-test. Results: The forces measured during MVCs were significantly different between men and women over five trials. We observed the minimum and maximum force production at the first and fifth trial of MVCs in both men and women. Excellent to moderate reliability of the hamstring strength during MVCs was found in men (ICC range, 0.70–0.98) and women (ICC range, 0.66–0.90). There was no significant difference in hamstring flexibility between men and women. Conclusion: In clinical settings, we recommend excluding the first trial of MVCs in both men and women. Additionally, performing at least three trials of MVCs would be useful to improve the reliability of the baseline measures in women.

양벽온이 다른 장방형용기 내에서 얼음의 융해과정에 관한 실험적 연구

임우택,김병철,Lim, W.T.,Kim, B.C. 대한설비공학회 1995 설비공학 논문집 Vol.7 No.4

Melting process of ice in a rectangular cavity with different temperature walls has been studied experimentally. Front shape of ice and melting rate were affected by initial temperature of ice and variation of temperature distribution and density gradient. When the hot wall temperature was below $8^{\circ}C$, the melting rates were higher at the bottom than those of at the top due to the density inversion, but with increasing the hot wall temperature the melting rates at the top were affected by hot wall and were higher than those of at the bottom. When the initial temperature of ice was low, melting rates were low, but with increasing the time melting rates were almost the same with those of each initial temperature of ice.

Synthesis and Crystal Structure of Ag4Br4 Nanoclusters in the Sodalite Cavities of Fully K+-Exchanged Zeolite A (LTA)

임우택,최식영,김복조,김창민,In Su Lee,김석한,허남호 대한화학회 2005 Bulletin of the Korean Chemical Society Vol.26 No.7

Ag4Br4 nanoclusters have been synthesized in about 75% of the sodalite cavities of fully K+-exchanged zeolite A (LTA). An additional KBr molecule is retained in each large cavity as part of a near square-planar K4Br3+ cation. A single crystal of Ag12-A, prepared by the dynamic ion-exchange of Na12-A with aqueous 0.05 M AgNO3 and washed with CH3OH, was placed in a stream of flowing 0.05 M KBr in CH3OH for two days. The crystal structure of the product (K9(K4Br)Si12Al12O48•0.75Ag4Br4, a = 12.186(1) Å) was determined at 294 K by single-crystal X-ray diffraction in the space group Pm m. It was refined with all measured reflections to the final error index R1 = 0.080 for the 99 reflections for which Fo > 4(Fo). The thirteen K+ ions per unit cell are found at three crystallographically distinct positions: eight K+ ions in the large cavity fill the six-ring site, three K+ ions fill the eight-rings, and two K+ ions are opposite four-rings in the large cavity. One bromide ion per unit cell lies opposite a four-ring in the large cavity, held there by two eight-ring and two six-ring K+ ions (K4Br3+). Three Ag+ and three Br ions per unit cell are found on 3-fold axes in the sodalite unit, indicating the formation of nano-sized Ag4Br4 clusters (interpenetrating tetrahedra; symmetry Td; diameter ca. 7.9 Å) in 75% of the sodalite units. Each cluster (Ag-Br = 2.93(3) Å) is held in place by the coordination of its four Ag+ ions to the zeolite framework (each Ag+ cation is 2.52(3) A from three six-ring oxygens) and by the coordination of its four Br ions to K+ ions through six-rings (Br-K = 3.00(4) A).

넓적다리뒤근육의 유연성 측정을 위한 무릎폄 검사

임우택 대한물리치료과학회 2023 대한물리치료과학회지 Vol.30 No.1

Hamstring flexibility is an important factor that affects muscle performance of the lower extremities and is closely associated with sports injuries. Therefore, evaluation of flexibility is important in clinical practice. Results of evaluation are determined by types of tests and cut-off values used; therefore, accurate and detailed understanding of these is necessary before examination. Although the straight leg raise and sit and reach tests are used to evaluate hamstring extensibility, structures including the nerves, fascia, and other muscles can significantly confound the re- sults of these tests. The knee extension test is performed at 90° of hip flexion to minimize the posterior pelvic tilt that occurs during the straight leg test. The knee extension test is most recommended for selective evaluation of hamstring flexibility. The knee extension test is classified into active and passive tests. The cut-off value is usually set at 20° for the active and at 10° for the passive knee extension test. Although a strong association is observed between the two tests, the active knee extension test is preferred in clinical practice because it can be performed by a single ex- aminer, which serves as an advantage. Age, sex, and warm-up exercise tend to affect flexibility; therefore, results should be interpreted with caution. Detailed understanding of each flexibility test is important for reliable evaluation.

연속적 능동무릎폄 검사가 뒤넙다리근의 유연성에 미치는 영향

임우택,Lim, Woo Taek 대한물리치료과학회 2021 대한물리치료과학회지 Vol.28 No.1

Background: In clinical practice, active knee extension (AKE) test has been widely used to measure hamstring flexibility. During the AKE test, the knee extension is repeated six times. The first five repetitions are considered as warm-up, and the sixth is used as baseline. In order to accurately measure the subject's inherent flexibility, warm-up trials have been proposed as mentioned above; but currently, the evidence is insufficient. Design: Cross-sectional study. Methods: Forty-three healthy adults participated in this study. The AKE was performed slowly after flexing the hip and knee joints by 90° in a supine position. The knee was extended as far as could be done without causing discomfort or pain. When reaching the end range, knee flexion was performed without stopping. As per standard protocol, the subjects performed the knee extension six times. Results: There was no significant difference between the AKE value in the first trial with those in the other five trials. During the repetitions, the average value in the group with higher flexibility tended to decrease and the Intraclass correlation coefficient gradually decreased. Conclusion: Successive repetitions of the AKE test can misrepresent an individual's inherent hamstring flexibility. In order to avoid a decrease in hamstring flexibility, it is strongly recommended that individuals with high initial hamstring flexibility avoid unnecessary repetitions of the AKE test.

농구경기 관람자의 스포츠 소비 행동에 관한 연구

林雨澤 중앙대학교 스포츠과학연구소 1992 體育硏究 Vol.- No.5

The purpose of this investigation was to study the behaviors of sport consumtion among basketball. More specifically, the study examine types and characteristics of sport consumtiom which basketball spectators represent in the context of sport events. Data collected from a questionnaire designed for this study consisted of forced-choice response to item constructed to represent the operational definitions for each variable. The inventory was administered to six hundred and twenty-six visited basketball competitions. To data analysis, statistics employed this study was Chi-square test. Based upon the result of this study, the following conclustion appear warranted. Behaviors of sport consumtion among basketball spectators is influenced with such demographic and economic factors as sex, age, educational level, and marital status, and also represented in different patterns according to characteristics of each factor.

3PL Strategy & H사 사례

임우택 한국물류협회 2001 물류혁신 컨퍼런스 Vol.9 No.1

The Relationship between Hip Extension Force Measured by Using a Hand-held Dynamometer and the Effect of Proprioceptive Neuromuscular Facilitation Stretching on Hamstring Flexibility

임우택 대한스트레스학회 2016 스트레스硏究 Vol.24 No.4

The purpose of this study was to investigate the relationship between hip extension force measured by using a hand-held dynamometer (HHD) and the effect of proprioceptive neuromuscular facilitation (PNF) stretching on hamstring flexibility. Many athletes try to avoid strains by excessive stress while maintaining or improving performance. It has been widely demonstrated that PNF stretching increases hamstring flexibility by decreasing active resistance. Thirty-four young men and women participated in the study. Active knee extension (AKE) was measured with a goniometer before and after hold-relax PNF stretching. Additionally, AKE data were collected at 2, 6, 10, 20, and 30 min. The maximal isometric contraction force of the hamstring was measured by using a HHD during a single set of PNF stretches (6 trials×5 s/trial). The mean forces measured by using the hand-held dynamometer were not significantly different between the trials; however, the averages of the maximum and minimum values obtained for each trial were significantly different. Hamstring flexibility at pre-stretch differed between men and women, but the immediate and sustained effects of stretching did not differ between the sexes. The isometric contraction force of the hip extensor during hold-relax PNF stretching was successfully measured and quantified with the use of a HHD. The inconsistencies in the isometric contraction force between trials might diminish the effect of stretching. The use of a HHD to monitor the effort applied by a subject and provide real-time feedback might enhance the effectiveness of stretching in the clinical field or in sports physiotherapy.