• 한국음향학회지
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• 제24권3호
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• pp.171-177
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• 2005

본 논문에서는 콘서트홀에서 확산체의 Early Stage Support (ST1)에 대한 영향을 알아보기 위하여 1:25 축소모형에서 8지점을 설정하여 ST1을 측정하였다. 무대 바닥에 의한 영향을 살펴보기 위하여 흡음천의 유무에 따라 ST1의 결과값의 차이를 살펴보았다. 무대측벽에 대한 영향을 살펴보기 위하여 기존의 확산체, 확산체를 제거한 경우와 반구 확산체의 3가지 형태의 확산체를 사용하여 측벽의 변화에 의한 ST1 값의 결과를 살펴보았다. 결과적으로 무대 바닥에서의 흡음천의 사용은 ST1에서 고주파의 저감을 일으켰으나 평균값에는 큰 차이가 없었으며, 3가지 형태의 확산체는 뚜렷한 차이를 보이지 않았으나 측정 지점에 따라 ST1 값의 차이가 발생하였고, 특히 반구 확산체에서는 ST1 값이 고르게 분포하였다. 따라서 무대 바닥은 상대적으로 ST1의 변화에 큰 영향을 주지 않았고, 무대 측벽의 형상은 확산현상에 의해 ST1의 분포에 영향을 주었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.551-554
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• 2005

This study uses a characteristic function to explain correlations between the objective function and design variables. Analysis of means and table of orthogonal array were carried out. The change of shape of diaphragm, thickness of diaphragm and voice coil weight based on the table of orthogonal array is made. Therefore this study carried to decide shape of diaphragm, voice coil weight and thickness of diaphragm for minimizing 1st natural frequency and maximizing 2nd natural frequency of diaphragm using design of experiments and characteristic function with constraints. we showed improved design factors that minimized 1st natural frequency and maximized 2nd natural frequency of diaphragm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.880_881
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• 2009

This paper improves the calculating method about the inductance with the high order frequency coreloss. It is different in which the analyzed inductance for calculating IPMSM and the measured thing for experiment. Due to this phenomenon, the expected input voltage differs from the inquired input voltage for operating the motor. This results from the coreloss margin which have both the 1st order and high order frequency value. For reducing the inductance error, after calculating the equivalence coreloss resistance with having the 1st order frequency Back_EMF and coreloss, designing the inductance with the high order frequency which occurred by the coreloss of high order frequency, and comparing the renovated inductance analysis value with the measured thing.

• Journal of Acupuncture Research
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• 제25권3호
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• pp.179-187
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• 2008

Objectives & Methods : This study was to investigate effect of low frequency electroacupuncture on NADPH-d positive neurons in the brain cortex of rat with adjuvant induced rheumatoid arthritis. Experimental groups were divided into 6 groups ; Normal, Control, $ST_{36}$, $SP_9$, $ST_{36}+SP_9$ and Non-Acupoint. Normal group, non-arthritic group, was injected normal saline, and the other groups were injected FCA. Each acupoint groups were treated by 2Hz electroacupuncture at each acupoints and NA group was treated by 2Hz electroacupuncture at non-acupoint. Each groups were evaluated by the number of NADPH-d positive neurons in primary somatosensory area(S1), secondary somatosensory area(S2), motor area and caudate putamen by using an image analyzer and a microscope. Results : 1. In S1, the number of NADPH-d positive neuron cells in the $ST_{36}$ group were significantly(p<0.05) increased compared with the control group. 2. In S2, the number of NADPH-d positive neuron cells in all electroacupuncture groups were not significantly changed compared with the control group. 3. In motor area, the number of NADPH-d positive neuron cells in $ST_{36}$ group, $SP_9$ group, NA group were significantly(p<0.05) increased compared with the control group. 4. In Caudate putamen, the number NADPH-d positive neuron cells in all electroacupuncture groups were significantly(p<0.05) decreased compared with the control group. Conclusions : Our result demonstrated that low frequency electroacupuncture on $ST_{36}$ & $SP_9$ normalized expression of NADPH-d positive neurons in the brain cortex of the rheumatoid arthritis model in rats.

• Clinical and Experimental Pediatrics
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• 제57권4호
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• pp.193-198
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• 2014

Purpose: This study aimed to evaluate the autonomic imbalance in syncope by comparing the baseline heart rate variability (HRV) between healthy children and those with vasovagal syncope. Methods: To characterize the autonomic profile in children experiencing vasovagal syncope, we evaluated the HRV of 23 patients aged 7-18 years and 20 healthy children. These children were divided into preadolescent (<12 years) and adolescent groups. The following time-domain indices were calculated: root mean square of the successive differences (RMSSD); standard deviation of all average R-R intervals (SDNN); and frequency domain indices including high frequency (HF), low frequency (LF), normalized high frequency, normalized low frequency, and low frequency to high frequency ratio (LF/HF). Results: HRV values were significantly different between healthy children and those with syncope. Student t test indicated significantly higher SNDD values (60.46 ms vs. 37.42 ms, P =0.003) and RMSSD (57.90 ms vs. 26.92 ms, P=0.000) in the patient group than in the control group. In the patient group, RMSSD (80.41 ms vs. 45.89 ms, P =0.015) and normalized HF (61.18 ms vs. 43.19 ms, P =0.022) were significantly higher in adolescents, whereas normalized LF (38.81 ms vs. 56.76 ms, P =0.022) and LF/HF ratio (0.76 vs. 1.89, P =0.041) were significantly lower in adolescents. In contrast, the control group did not have significant differences in HRV values between adolescents and preadolescents. Conclusion: The results of this study indicated that children with syncope had a decreased sympathetic tone and increased vagal tone compared to healthy children. Additionally, more severe autonomic imbalances possibly occur in adolescents than in preadolescents.

• 대한수의학회지
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• 제21권1호
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• pp.59-64
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• 1981

Holstein-Friesian cows(n=284) were given $100{\mu}g$ of gonadotropin-releasing hormone(GnRH) or saline solution by intramuscular injection at 10 to 22 days after parturition, and were investigated their reproductive performance and frequency of ovarian cysts. Among them 28 cystic cows were injected with $150{\mu}g$ of GnRH intramuscularly and examined the recovery rate. The results obtained in this study were summarized as follows: 1. The interval from calving to 1st ovulation was reduced from 28.2 days in controls to 16.5 days for cows given GnRH (p<0.01). 2. The intervals from calving to 1st estrus and from calving to conception were extended significantly in control group (p<0.05). 3. Inseminations per conception and conception rate at 1st insemination did not reveal difference between two groups. 4. Frequency of ovarian cysts was reduced from 14.0% in control to 4.20% for cows given GnRH (p<0.05). 5. Of the 28 cystic cows receiving $150{\mu}g$ of GnRH, 23(82.1%) responded to 1st treatment and returned to estrus $24.2{\pm}4.3$ days after treatment. 6. These data provide evidence for reduction in infertility and reproductive disorders in early postpartum dairy cows given GnRH as a prophylactic.

• 대한조선학회지
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• 제8권2호
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• pp.35-44
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• 1971

In terms of this paper, concerning primarily with the U-tube tank stabilizer, the authors' aim is to clarify and consolidate the theory as it has been developed thus far, and to provide with the certain additions which will make it more complete, more accurate, and more practical. And then we can know that the effect of the vertical tank position from the C.G., $a_{st}=1-w^2/{w^2}_{st}$, is very important, on account for the fact that the position factor, $a_{st}$, increase when the anti-rolling tank attaches to higher position vertically, but $a_{st}$ does not increase in proportion to the distance of the tank position. Measuring many characteristic coefficients by experiment, in the equation of the ship-tank system motion, such as the inertia coefficient, the damping coefficient, the natural frequency and so on, they can also give a guess that the higher position will accompany the non-linear motion of the tank water, but the non-linear effect will decrease the tank ability. In this study, they deal with not only the optimum damping coefficient of tank, which has very simply been expressed by the strength ratio, $\lambda$, but also the effect of the tank top, which has experimentally been treated when the water has hit the tank top. As this result, we can immediately find that the ability of the anti-rolling tank decrease at w/ws=0.9 generally low frequency.

• 전자공학회논문지D
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• 제36D권7호
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• pp.26-33
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• 1999

4빔 브릿지형 압저항형 실리콘 가속도 센서에서 빔의 위치가 가속도 센서의 특성에 어떤 영향을 주는지 조사하기 위해서 빔의 위치가 서로 다른 3가지 형태의 가속도 센서를 FEM(finite element method)을 사용하여 해석하고, SDB(silicon direct bonding) 웨이퍼를 사용하여 RIE(reactive ion etching)와 KOH(potassium hydroxide) 애칭 공정으로 제조하였다. 세가지 형태의 가속도 센서에 대한 FEM 해석 경과, 첫 번째 공진 주파수와 Z축 감도는 세구조 모두 같게 나타났으나, 두 번째와 세 번째의 공진 주파수 및 X, Y축의 감도는 다른 것으로 나타났다. 제조된 가속도 센서의 특성을 살펴볼 때, 세 가지 형태의 센서는 비록 첫 번째 공진 주파수와 Z축 감도가 정확하게 일치하지는 않았지만, 첫 번째 공진 주파수는 1.3 ~ 1.7 KHz, Z축 감도는 5 V 인가시 180 ~ 220 lN/G, 타축감도는 1.7 ~ 2 %를 가지는 것으론 나타났다.

• 한국결정학회:학술대회논문집
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• 한국결정학회 2002년도 정기총회 및 추계학술연구발표회
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• pp.36-36
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• 2002

To Establish of standard technique of length measurent in 2D plane, we develope AFM system. The XY scanner scans the sample only in XY plane, while the Z scanner scans the specimen only in Z-direction. Cantilever tip is controlled to has constant height relative to speciman surface by feedback of PSPD signal. To acquire high accuracy, Z-axis measuring sensor will be added.(COXI or others). In this paper we design XYZ stage suitable for this AEM system. For XY stage, single module parallel-kinnematic flexure stage is used which has high orthogonality and minimum out-of-plane motion. To obtain best performance optimal design is performed. For XY stage, to be robust about parasitic motion optimal design of maximizing Z and tilt stiffness is performed under the constraint of motion range and stage size. And for Z stage, optimal design of maximizing 1st resonant frequency is performed. Because if resonant frequency is get higher, scan speed is improved. So it makes reduce the error by sensor drift. Resultly XYZ stage each have 1st natural frequency of 115㎐, 201㎐, 2.66㎑ and range 109㎛, 110㎛, 12㎛.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권10호
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• pp.513-519
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• 2001

This paper proposed a random sigma-delta modulator(RSDM), which is constructed by a 1st order sigma-delta modulator(SDM) and a simple structured random binary generator(RBG). The 1st order SDM produces a switching pulse waveform which has the same low-frequency component as the reference input, while the RBG spreads the distribution of the number of sampling per switching cycle, and thus disperses the spectrum spikes in the output. The relationship between the harmonic spectra and the number of sampling per switching cycle is studied through computer simulations, and the frequency spectra of the RSDM are confirmed in an experimental setup.