• Journal of applied mathematics & informatics
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• 제12권1_2호
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• pp.39-47
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• 2003

Sufficient conditions for asymptotic behavior of the solutions of nonlinear forced neutral delay differential equations with impulses are found. The results given in [2,4,6,7］are generalized and improved.

• Journal of the Korean Wood Science and Technology
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• 제18권3호
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• pp.42-52
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• 1990

In this study, thick 24mm glulams were composed of thick. 3, 4, 6, 8mm Larch laminas to study that the theoretical analysis and the experimental analysis regarding the location of neutral axis of the glulams were compared, and to study on the effect of location of neutral axis on mechanical properties of glulam. The variation of location of neutral axis after proportional limit(or elastical limit) was studied to offer basic data to make the better composition method of glulam. The result obtained can be summarized as follows: 1. The theoretical neutral axis was 0.547 in solid wood, and also 0.547 in glulams because glulams were composed of only Larch laminas. 2. In solid wood, the deviation of the theoretical and the experimental neutral axis location was 0.1%, But in glulams, the deviation from-12.2% to + 7.8% showed nonuniform pattern but no large deviation. Because laminas was only of Larch and so the mechanical properties of laminas were monotonous. 3. The neutral axis exerted no influance on the elasticity of glulam, which meaned that the maximum shear strength in the neutral axis showed no influance on elasticity limit. 4. The only minutely lower elasticities of glulam than that of solid wood were shown. This was because of influance of glue lines of glulam on the elasticlties. 5. The failure type of glulam was wholly simple tension failure and the horizontal shear failure near neutral axis was not taken place, which was that glue line was complete in bonding and the strength of the lamina was not various but uniform. 6. The ratio of tension strain($^{\varepsilon}t$) I compression strain($^{\varepsilon}c$) initially showed uniform level After the elasticity limit. the ratio was increased with the flow of time and so the tension strain was more increased than compression strain. So this proved tension lamination technique, which is that the mechanical properties of glulam could be improved, if the lamina of more superior strength would he added on the bottom side of the glulam.

• 한국식품과학회지
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• 제13권1호
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• pp.30-36
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• 1981

우리 나라에서 재배된 4가치 품종의 보리와 이들의 맥아를 클로로포름-메탄올-물로 추출한 총지방질중 중성지질의 조성을 관, 얇은막 및 기체-액체 크로마토그래피로 분석한 결과를 요약하면 다음과 같다. 1. 4가지 품종의 보리와 이들 맥아중의 총지방질의 평균함량은 각각 3.3% 및 2.9%였으며, 보리중의 총지방질은 맥아에서 평균 12.2%가 감소되었다. 2. 보리와 맥아중의 총지방질중 중성지질의 평균함량은 각각 73.8% 및 68.5%였으며, 보리중의 중성지질은 맥아에서 평균 7.2%가 감소 되었다. 3. 보리의 중성지질중 트리-글리세리드와 유리지방산의 평균함량은 각각 57.5% 및 15.4%였으나 맥아에서 트리-글리세리드의 양은 감소하였으나, 유리지방산의 양은 증가하였다. 그 외에 sterol ester, free sterol, 1,3 및 1,2-diglyceride가 보리와 맥아의 중성지질중 부성분으로 함유되어 있었으며, 맥아중의 이들 neutral non-triglyceride fraction의 함량은 보리에서 보다 증가하는 경향이었다. 4. 보리와 맥아의 총지방질의 주된 지방산은 리놀레산, 팔미트산및 올레산이었으며, 맥아는 보리보다 포화지방산의 함량은 증가하는데 반하여 불포화 지방산의 함량은 감소하는 경향이 었다.

• 반도체디스플레이기술학회지
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• 제7권2호
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• pp.63-67
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• 2008

The MgO protective layer plays an important role in plasma display panels (PDPs). Our previous work demonstrated that the properties of MgO thin film could be improved, which were deposited by ion beam assisted deposition (IBAD). However arc discharge always occurs during the IBAD process. To avoid this problem, oxygen neutral beam assisted deposition (NBAD) is used to deposit MgO thin films in this paper. The energy of the oxygen neutral beam was used as the parameter to control the deposition. The experimental results showed that the oxygen neutral beam energy was effective in determining in F/$F^+$ centers, crystal orientation, surface morphology of the MgO thin film, and the discharge characteristics of AC PDP. The lowest firing voltage $(V_f)$ and the highest secondary electron emission coefficient $(\gamma)$ were obtained when the neutral beam energy was 300 eV.

• 한국식품과학회지
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• 제21권1호
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• pp.17-24
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• 1989

가열처리 및 건조방법이 새우의 지방질 함량과 중성지방질에 미치는 영향을 밝히고자 하였다. 생새우의 총지방질 함량은 건물기준으로 6.0%였으며, 가열 및 건조방법에 따라 총지방질의 함량은 유의적인 변화가 없었다. 생새우의 중성, 당 및 인지방질의 함량비는 각각 36.8:21.5:41.7% 이었고 동결건조한 것은 열풍건조한 것보다 중성시방질의 함량이 유의적으로 많은 반면에 당 및 인지방질의 함량은 적었다. 중성지방질의 주요성불은 triglyceride, free sterol, free fatty acid 및 esterified sterol이었으며, 동결건조한 것은 열풍건조한 것보다 triglyceride 함량은 유의적으로 많았고 free fatty acid 함량은 적었는데, 이는 열풍건조중 triglyceride가 분해된 것으로 생각되었다. 생새우의 총지방질의 구성 주요지방산은 palmitoleic acid, eicosapentaenoic acid 및 docosahexaenoic acid이었고, 중성지방질의 구성 주요 지방산은 palmitic acid, palmitoleic acid, oleic acid, eicosapentaenoic acid 및 docasahexaenoic acid이었다.

• Journal of Electrical Engineering and Technology
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• 제13권5호
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• pp.1986-1995
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• 2018

In this paper, a novel neutral-point voltage balancing scheme for NPC three-level inverters using carrier-based sinusoidal pulse width modulation (SPWM) method is developed. The new modulation approach, based on the obtained expressions of zero sequence voltage in all six sectors, can significantly suppress the low-frequency voltage oscillation in the neutral point at high modulation index and achieve a fast voltage-balancing dynamic performance. The implementation of the proposed method is very simple. Another attractive feature is that the scheme can stably control any voltage difference between the two dc-link capacitors within a certain range without using any extra hardware. Furthermore, the presented scheme is also applicable to the single-phase NPC three-level inverter. It can maintain the neutral-point voltage balance at full modulation index and improve the voltage-balancing dynamic performance of the single-phase NPC three-level inverter. The performance of the proposed strategy and its benefits over other previous techniques are verified experimentally.

• Steel and Composite Structures
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• 제39권1호
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• pp.51-64
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• 2021

This paper presents a high-order shear and normal deformation theory for the bending of FGM plates. The number of unknowns and governing equations of the present theory is reduced, and hence makes it simple to use. Unlike any other theory, the number of unknown functions involved in displacement field is only four, as against five or more in the case of other shear and normal deformation theories. Based on the novel shear and normal deformation theory, the position of neutral surface is determined and the governing equilibrium equations based on neutral surface are derived. There is no stretching-bending coupling effect in the neutral surface-based formulation, and consequently, the governing equations of functionally graded plates based on neutral surface have the simple forms as those of isotropic plates. Navier-type analytical solution is obtained for functionally graded plate subjected to transverse load for simply supported boundary conditions. The accuracy of the present theory is verified by comparing the obtained results with other quasi-3D higher-order theories reported in the literature. Other numerical examples are also presented to show the influences of the volume fraction distribution, geometrical parameters and power law index on the bending responses of the FGM plates are studied.

• 대한음성학회:학술대회논문집
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• 대한음성학회 1996년도 10월 학술대회지
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• pp.207-207
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• 1996

The neutral tone is one of the most important distinguishing features in Beijing Mandarin, but there are two completely different views on its linguistic function: a special tone(Xu, 1980) versus weak stress(Chao, 1968). In this paper, the acoustic manifestation of the neutral tone will be explored to show that it is closely related to weak stress. 122 disyllabic words in which the second syllable carries the neutral tone, including 22 stress pairs, were uttered by a native male speaker of Beijing dialect and analysed by Kay Digital Sonagraph 5500-1. The results of the acoustic analysis are presented as follows: 1) The first two formants of the medial and the syllabic vowel moves towards that of central vowel with a greater magnitude in the syllable with the neutral tone than in the syllable with any of the four normal tones. Also the vowel ending, and nasal coda /n/ and / / in the syllable with the neutral tone tends to be deleted. 2) In the syllables with the neutral tone, there are strong carryover coarticulations between the medial and syllabic vowel and the preceding unvoiced consonant. In general, the vowel is affected to move towards the position of the central vowel with more greater magnitude by coronal consonant than by labial or velar consonant. 3) In the syllable with the neutral tone, when and only when it precedes a syllable with tone-4, the high vowel following [f], [ts'], [s], [ts'], [s], [tc'] or [c] tends to be voiceless. 4) It can be seen from the acoustical results of 22 stress pairs that the duration of the syllable with the neutral tone is on the average reduced to 55% of that of the syllable with the four normal tones, and the duration of the final in the syllable with neutral tone is on the average reduced to 45% of that of the final in the syllable with the four normal tones(Lin & Yan 1980). 5) The FO contour of the neutral tone is highly dependent on the preceding normal tone(Lin & Yan 1993). For a number of languages it has been found that the vowel space is reduced as the level of stress placed upon the vowel is reduced(Nord 1986). Therefore we reach the conclusion that the syllable with neutral tone is related to weak stress(Lin & Yan 1990). The neutral tone is not a special tone because the preceding normal tone.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.498-506
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• 2010

The neutral section was installed in order to prevent conflict with different phase angle source in electric railway catenary system. The speed of electric train reduced due to coasting operation by notch off when it passed the neutral section. And, the catenary wire was damaged and the accident might be happened because of the arc generation when the electric train passed the neutral section with notch on condition. This project has a goal to develop the automatic changeover system using by noncontactless semiconductor device in neutral section of catenary system so that the train pass as notch-on condition. In this first year, we obtain as following results such as domestic and international systems applications and completion requirements, development and analysis of stability for automatic changeover system, design of static switching device on automatic changeover system in neutral section and drawing up interface design and specifications according to equipment.

• 대한통합의학회지
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• 제5권1호
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• pp.67-74
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• 2017

Purpose : Forward head posture is typical neck disorders occur in all people. And this attitude causes a shortening and weakening of the muscles in the body. It also causes excessive extension acts as a reward. This attitude has to change if the pain occurs around the neck and shoulders, and are subjected to unusual stress. Patients with chronic neck pain associated with forward head posture was found to be the more severe the fall of the respiratory, forward head posture poor quality of much breath. The purpose of this study was to compare the effect of changes in forward head posture and neutral head posture on respiratory. Method : Forty volunteers were participated in study and divided into two groups [forward head posture group (n=20) and neutral head posture group (n=20)]. We measured cervical alignment with global postural system to find out a forward head posture. Respiratory function was measured with a SPIROVIT SP-1 equipment and we found out a forced vital capacity (FVC), forced expiratory volume at one second (FEV1) and FEV1/FVC. A pared t-test was used to determine a statistical significance for the pulmonary function variation and a independent t-test was used to determine a statistical significance in the two groups. Results : In the experimental group, FVC and FEV1 were significantly higher in the artificial neutral head posture than in the forward head posture. In the control group, FVC and FEV1 were significantly higher in the neutral head posture than in the forward head posture. FVC, FEV1, and FEV1/ FVC were significantly higher in the neutral head posture of control group than the artificial neutral head posture of experimental group and higher in the artificial forward head posture of control group than the forward head posture of experimental group. Conclusion : In conclusion, neutral head posture is considered to be an important factor in correct posture and improvement of lung function and continuous study of posture correction program for posture imbalance will be needed.