• Bulletin of the Korean Chemical Society
• /
• 제18권9호
• /
• pp.961-965
• /
• 1997

1H NMR spectra of 3,3-dimethylpiperidine (1) at -70 to 30 ℃ exhibit gradual change from slow to rapid exchange between two alternate chair forms. The exchange rate constant was determined as a function of temperature by simulating the line shape of the signal from the two methyl groups using the modified Bloch equations. The resulting free energy of activation is ΔG* = 44.4±1.9 kJ mol-1 at 298 K. The 1H NMR spectrum of a D2O or dimethylsulfoxide-d6 (DMSO-d6) solution containing 1 and [SiW11CoⅡO39]6- exhibits separate signals for the free ligand and the complex, indicating that the ligand exchange is slow on the NMR time scale. In D2O the piperidine ring is frozen as a chair form even at room temperature with the cobalt ion bonded to the axial position of the nitrogen atom. When DMSO-d6 is added to the D2O solution, the NMR spectral change suggests that a rapid exchange occurs between the chair form and another conformer. It is proposed that the conformation of ^b1^b coordinated to [SiW11CoⅡO39]6- in DMSO-d6 is close to a twist form.

• Geomechanics and Engineering
• /
• 재33권6호
• /
• pp.625-633
• /
• 2023

The volume changes associated with moisture or suction variation in expansive soils are of geotechnical and geoenvironmental design concern. These changes can impact the performance of infrastructure projects and lightweight structures. Assessment of unsaturated function for these materials leads to better interpretation and understanding, as well as providing accurate and economic design. In this study, expansive soils from different regions of Saudi Arabia were studied for their basic properties including gradation, plasticity and shrinkage, swelling, and consolidation characteristics. The unsaturated soil functions of saturated water content, air-entry values, and residual states were determined by conducting the tests for the entire soil water characteristic curves (SWCC) using different techniques. An attempt has been made to provide a prediction model for unsaturated properties based on the basic properties of these soils. Once the profile of SWCC has been predicted the time and cost for many tests can be saved. These predictions can be utilized in practice for the application of unsaturated soil mechanics on geotechnical and geoenvironmental projects.

• 한국가구학회지
• /
• 제17권4호
• /
• pp.1-13
• /
• 2006

This study attempted to identify the characteristics of chair design from furniture company, $K{\ddot{a}}llemo$, the furniture manufacturer in Sweden manufacturing mostly the limited edition of art furniture on the basis of the unique management philosophy. There are 12 artists manufactured chairs for $K{\ddot{a}}llemo$. Of them, this study selected 4 artists-Sigurdur Gustafsson, John Kandell, Komplot Design, Mats Theselius-who designed at least more than three chairs. Total 25 chairs were analyzed; 6 from Sigurdur Gustafsson, 8 from John Kandell, 3 from Komplot Design and 8 from Mats Theselius. The chair structure was divided into three parts, seat, back and structure and analyzed by material, color, type of legs and finishing. The following results were derived from the study. First, $K{\ddot{a}}llemo$ secured the regular customers who want to possess the chairs as the artistic works by continuing the small quantity mass-production system insisting that the maximum quantity of production is 360 pieces and the minimum quantity is 33 pieces. Second, the sufficient time and cost were invested in the initial phase of design. This approach seems to be deviated from the traditional business system that has to create the revenue at a glance, but ultimately induces the commercial success by exponentially increasing the revenue through the creation of various product lines. Third, $K{\ddot{a}}llemo$ provides the space that the artists who work for $K{\ddot{a}}llemo$ can sufficiently enjoy the mental composure and luxury required for the designers by strictly selecting the artists and providing the best environment for enabling the creative activities that look like the pure art area. This study enables the further analysis and research on other collections of $K{\ddot{a}}llemo$ that mass-produces the chairs on the basis of the unique philosophy in the world as well as in Sweden using more various kinds of analysis frameworks.

• 대한기계학회논문집A
• /
• 제34권5호
• /
• pp.527-533
• /
• 2010

인간 중심 제품의 개발을 위해서는 사용자가 제품을 사용하며 느끼는 사용감이 중요하다. 기존의 제품 개발 방법은 제품의 사용감을 평가하기 위해서 반드시 시제품을 제작하여야 하는 불편함이 있었다. 이러한 제품 개발 과정은 시제품을 햅틱 시뮬레이터로 대체함으로써 단순화할 수 있으며, 이러한 제품개발 방법을 햅틱보조설계 기법(Haptic-Aided Design, HAD)라고 한다. 본 논문은 맞춤형 의자의 제작에 효율적으로 사용될 수 있는 새로운 HAD 기법을 제안하였다. 햅틱의자와 직관적인 유저 인터페이스로 구성된 햅틱 시뮬레이터를 개발하였으며, 이를 이용하여 실시간으로 의자의 등판과 좌판의 임피던스를 조절하였다. 시제품을 대신하여 햅틱의자를 사용하여, 설계 초기에 설정된 의자의 등판과 좌판의 강성과 감쇠에 대한 안락감 평가를 실시하였다. 이를 통하여, 제안된 HAD 기법이 맞춤형 의자의 개발에 효율적으로 적용될 수 있고, 다른 제품의 개발에도 확장될 수 있다는 것을 보였다.

• 한국간호교육학회지
• /
• 제22권4호
• /
• pp.485-494
• /
• 2016

Purpose: The present research is a descriptive study aimed at understanding clinical nurses' Video display terminal (VDT) syndrome and identifying the factors that affect their VDT syndrome. Methods: Data were collected from 239 clinical nurses working in two metropolitan cities. Research tools included subject's VDT syndrome assessing musculoskeletal, ophthalmic, dermal, psychiatric, and whole body syndromes. The data were analyzed using frequency analysis, average and standard deviation, t-test, One-way ANOVA, and multiple regression analysis with the SPSS/WIN 20.0 program. Results: The subjects' VDT syndrome score was 1.34 out of 5. There were significant differences in participating subjects' VDT syndrome, hospital's size, working unit, health status, diagnosis of illness, having an Order Communication System (OCS), having an Electronic Medical Record (EMR) System, continuous VDT working for more than one hour, break time during VDT use, VDT use time, comfort of the chair, adjustability of the height of the chair, size of the VDT's desk, distance between the monitor and the user's eyes, resolution of the monitor, and frequency of eye exercise during VDT use. According to the research, influencing factors on VDT syndrome in clinical nurses included size of the VDT's desk, frequency of eye exercise during VDT use, having an EMR system, break time during VDT use, diagnosis illness, and having an OCS' system. Conclusion: The findings from this study can be used as a basis for future VDT syndrome prevention education and programs for clinical nurses.

• 한국운동역학회지
• /
• 제33권1호
• /
• pp.10-16
• /
• 2023

Objective: The purpose of this was to find out the muscle activity of the quadriceps femoris by gender when sitting on a chair while performing stairs gait (US; Up-stairs, DS; Down-stairs). Method: 13 male subjects (age: 22.00 ± 1.68 yrs, height: 174.85 ± 6.10 cm, weight: 68.15 ± 9.83 kg) and 15 female subjects (age: 21.17 ± 1.58 yrs, height: 168.20 ± 5.55 cm, weight: 55.73 ± 6.94 kg) participated in this study. The study used wireless three channel EMG. Results: In this study, there was no gender difference in quadriceps femoris activity during the US and DS periods, and there was no significant difference between the male group before and after postural maintenance during the US and DS periods. The quadriceps muscle of the female group also did not show a significant difference before and after US sitting. However, the vastus medialis muscle activity during DS in the female group was significantly lower after application than before application of maintaining a sitting posture (p<.05). There was no interaction effect between the 15-minute sitting position application and gender. Conclusion: Our results demonstrate that sitting in a chair affects the transient functioning of the quadriceps muscle in women. Therefore, emphasize the need for active rest when sitting in a chair for long periods of time.

• 한국화재소방학회:학술대회논문집
• /
• 한국화재소방학회 1996년도 학술발표회
• /
• pp.24-29
• /
• 1996

The objective of this research is to study on the formations of thermal stratification in a room in case of several furniture fires such as trashcan, chair, carpet, sofa, mattress and wardrobe as a fire starter in a residential room by performing the experimental studies. The uniformly distributed fire in case of carpet showed that the ignition and the initial growth period were relatively short while the fully developed period was considerably long. The concentrated fires such as the mattress and wardrobe showed that the ignitions and the initial growth periods were relatively long. When fire spread to only one direction, like the case for the trashcan with a regular shape, there was one peak of temperature profile, and for the irregular shaped furniture such as chair, sofa, mattress and wardrobe, there were two or more peaks. The interface heights for the furniture fires were around 1(m) mataining constant state. However, at the time of the maximum temperature, the interface height was lowered to 0.25(m)-0.75(m) from the floor

• 대한의용생체공학회:의공학회지
• /
• 제8권2호
• /
• pp.231-240
• /
• 1987

This Paper introduces a new design of motorized wheel chair for the disabled, which is intended to improve the quality of the disabled's indoor life. This vehicle was based on high manoeuvrability of the omnidirectional drive and saftey. Usually, the vehicle controlled by a joystick but also the voice control system to be prepared for the severely disabled. This voice control system responds to the result of voice recognition, state of system or warning of dangers with voices, which has real time response and 95.3% recognition ratio and satisfactory synthesis voice Quality Therefore this system is able to provide independency in driving and the disabled's daily life.

• 한국가구학회지
• /
• 제23권3호
• /
• pp.305-316
• /
• 2012

This study considered stools not just as a tool for sitting but with their symbolicity as well. Regarding the changes and meanings of general stools and X-stools, this paper studied their images and explanations as well as literatures by quoting as it limited their range from the ancient times till Neo-classicism. In conclusion, the origin of stools exists in consciousness and also the social hierarchy of authority. There still remain the elements of X in any way along with the functions. This proves that furniture has reason for existence even today not just for its functions but something beyond that. Along with the historic flow of X-stools, we should know that there is diversity of thinking in the area of stools. In understanding furniture design or furniture, now is the time to approach to it in various ways, and it is expected that new design can be born through that thinking.

• Bulletin of the Korean Chemical Society
• /
• 제12권2호
• /
• pp.224-227
• /
• 1991

The "frozen-out" $^{13}C-NMR$ spectrum of cyclooctanone conformer was detected at $-150^{\circ}$ and is reported for the first time. The stable conformation of cyclooctanone deduced by $^{13}C-NMR$ measurements was a unsymmetrical boat-chair conformation.