• 한국수자원학회논문집
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• 제41권12호
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• pp.1173-1185
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• 2008

노면배수시설의 설계방법을 임계지속시간의 고려 여부와 등류 및 부등류의 해석 방법에 따라 4가지로 구분하고, 각 방법에 따른 설계결과를 비교·검토하였다. 임계지속시간을 고려하지 않는 방법에서 설계강우는 10분 지속시간의 강우강도로 정하나, 임계지속시간을 고려할 경우 설계강우는 강우의 지속시간과 유출의 도달시간이 유사해지는 경우를 시산적으로 찾아 결정한다. 4가지 설계방법으로 수립된 설계모형을 다양한 수로의 종단경사 및 길어깨 횡단경사를 가지는 노면배수시설에 적용하고, 그 설계결과를 비교 검토하였다. 10분 지속시간의 강우강도를 이용하는 경우, 부등류 해석을 기반으로 설계한 유출구 간격은 종단경사와 길어깨 횡단경사가 작은 경우에만 등류 해석보다 크게 산정되었다. 반면 도달시간을 산정하여 임계지속시간을 결정하는 경우에는 본 연구에서 고려된 모든 조건에서 부등류 해석을 기반으로 설계한 유출구 간격이 등류 해석보다 크게 산정되었다. 그러나 도달시간을 산정하여 임계지속시간을 결정하고 부등류 해석을 기반으로 설계한 유출구 간격은 10분 지속시간의 강우강도를 적용하고 등류 해석을 기반으로 설계한 값보다 항상 작은 것으로 조사되었다.

• Nuclear Engineering and Technology
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• 제11권2호
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• pp.111-117
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• 1979

Time of flight Technique를 사용한 coincidence spectrometer에 의해 액체 형광물질(liquid scintillator) NE213의 전자와 양자에 대한 빛 방출량을 측정하였다. 이 실험에서 양자에너지 (3.2Mev, 4Mev, 5Mev, 6Mev)는 2Mev에서 9Mev에 이르는 여러 에너지 분포를 갖고 있는 Am.Be 중성자원을 사용하여 중성자 탄성산란의 각도(45$^{\circ}$ and 60$^{\circ}$)와 측정기간의 거리를 조절하므로서 얻었다. NE213액체발광물질의 빛 방출량은 전자 에너지에 대해 선형적인 응답을 보였으며 양자에 대한 응답은 에너지 증가에 따라 비선형적이었다. 빛의 세기도 전자에 의한 응답이 양자에 의한 것보다 약 세배 가랑 컸다. 본 실험결과는 Batchelor et at 이 발표한 실험결과와 거의 비슷했다.

• 한국연소학회:학술대회논문집
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• 대한연소학회 2003년도 제27회 KOSCO SYMPOSIUM 논문집
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• pp.75-81
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• 2003

In this paper, the study of effects of flow variables on flame structure and NOx emission concentration was performed in co-axial laminar partially premixed methane/air flames. the objectives are to reveal its effect as parameters were varied and to understand the correlation between flame structure and NOx emission characteristics in the reaction zone. equivalence ratio(${\Phi}$), fuel split degree(${\sigma}$), and mixing distance(x/D) were defined as a premixing degree and varied within $1.36{\sim}3.17$(equivalence ratio), $50{\sim}100$(fuel split degree), and $5{\sim}20$(mixing distance). the image of $OH{\ast}$ and $CH{\ast}$, and NOx concentration were obtained with an ICCD camera and a NOx analyzer. additionally the maximum intensity location of $OH{\ast}$ chemiluminescence and $CH{\ast}$ chemiluminescence were measured to compare each flame structures. In conclusion flame structure and NOx emission characteristics were changed from diffused to premixed flame when mixing degree was on the increase. the main effect on flame structure and NOx production was at first equivalence ratio(${\Phi}$), and next fuel split degree(${\sigma}$), and finally mixing distance(x/D).

• 말소리와 음성과학
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• 제4권2호
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• pp.115-120
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• 2012

This study sought to compare breath competence in three different utterance conditions when reading a passage aloud, making a spontaneous speech, and singing. We tested 15 normal females (ages averaging $24{\pm}4.4$) and measured breath competence through an objective, aero-mechanical instrument called PAS (Phonatory aerodynamic system, model 6600, KAY Electronics, Inc). Breathing sets of inspiration and expiration were measured by breath group number, breath group duration, and the ratio of inspiration to expiration. The results from this study led us to the following conclusion: The breath group number and the breath group duration showed no significant difference. However, the only variance that we could find was in the ratio of inspiration and expiration. In significantly different speech patterns, singing resulted in the most varied ratio of inspiration and expiration, followed by reading a text aloud, and spontaneous speech. The average frequency rates and maximum intensity levels varied with regards to varying utterance conditions. This thus shows that breath competence and phonation competence have a closely interrelated relationship.

• 한국자동차공학회논문집
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• 제17권5호
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• pp.31-38
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• 2009

Supercharging system was adopted to investigate the influence of boost pressure on operating range and exhaust emissions by using a supercharger at low temperature diesel combustion (LTC) condition in a 5-cylinder 2.7 L direct injection diesel engine. The experimental parameters such as injection quantity, injection timing, injection pressure and exhaust gas recirculation (EGR) rate were varied to find maximum operating range in LTC condition. As a result of adopting increased boost pressure in LTC, wider operating range was achieved compared with naturally aspirated condition due to increased mixing intensity. Increased boost pressure resulted in lower hydrocarbon (HC) and carbon monoxide (CO) emissions due to increased swirl rate and mixing intensity, which induced complete combustion. Moreover, increased boost pressure in LTC resulted in much lower soot emissions compared with high speed direct injection (HSDI) condition.

• Food Quality and Culture
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• 제1권1호
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• pp.1-5
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• 2007

Physicochemical qualities and consumer acceptability of chocolate layer cake were studied with varied levels of rosemary powder at 0, 0.2, 0.4 and 0.6%. The ash content of the cake increased from 2.30 to 3.10%, as the amount of rosemary powder increased from 0 to 0.6%, and the carbohydrate content of the cake decreased as the addition of rosemary powder increased. There were no significant differences in moisture contents and pH values among the samples and the pH values of all samples were within the typical pH range of 7.5-8.0 for chocolate layer cakes. Water loss from the control cake was greater than that from the cakes with rosemary powder supporting the suggestion that the addition of rosemary powder to the chocolate layer cake could increase moisture retention of the cake. Consumer acceptability of all the samples showed higher preferences of more than 7 points. Rosemary aroma, mint flavor and after taste were highly positively correlated with the fat content. Fat and ash content of the cake, which tended to increase in proportion to the rosemary powder content, were negatively correlated with acceptance of herb flavor, sweet taste, moistness, softness and intensity of softness but positively correlated with intensity of herb flavor. With the results above, trials on chocolate layer cake using rosemary powder were successfully performed within the ranges tested.

• 분석과학
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• 제7권3호
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• pp.253-260
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• 1994

Low power-low flow 유도결합 플라즈마 원자방출 분광법(ICP-AES)에서 분석적 특성에 대해 연구하였다. Low power ICP에서는 moderate power ICP보다 알짜세기는 감소하지만 바탕세기도 감소하여 알짜세기에 대한 바탕세기의 비는 오히려 증가하였다. Low power ICP에서도 작동조건에 따라 moderate power와 비슷한 검출한계를 얻을 수 있으며, 검량곡선도 $10^4{\sim}10^5$ 정도의 직선성을 가질 수 있었다. 알칼리 금속에 의한 이온화 방해영향은 시료운반기체의 사용량을 증가시킬수록 증가하지만, RF power의 변화에 대해서는 큰 차이가 없었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 추계학술대회 논문집 학회본부
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• pp.168-171
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• 1988

The p-n homo junction diode of the III-V ternary alloy semiconductor $In_{1-x}Ga_xP$ : S grown by the temperature gradient solution (TGS) was fabricated by Zn-diffusion, and it's characteristics was investigated. The carrier concentration of $In_{1-x}Ga_xP$ doped with sulfur, 0.5 mol %, was $1{\times}10^{17}cm^{-3}$ and the mobility was varied with the composition. In the case that the diffusion time was constant as 30 minutes. The temperature dependence of diffusion coefficient was decreased from D= $4.2{\times}10^{-5}$ exp (-1.74/$k_{B}T$) to D= $2.5{\times}10^{-5}$ exp (-3.272/$k_{B}T$) with increasing of composition $\times$ from 0.43 to 0.98. The major peak of E.L spectrum was due to D-A pair recombination and the peak intensity was increased with the increasing of input current. And the E.L intensity was decreased with the increasing temperature, and shift to the long wavelength. The luminescence efficiencies measured at $5^{\circ}C$, atmosphere temperature, was decreased from $2.6{\times}10^{-4}$% to $9.49{\times}10^{-6}$ % with increasing of composition it from 0.39, direct transition region, to 0.98, indirect transition region.

• Applied Science and Convergence Technology
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• 제25권4호
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• pp.81-84
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• 2016

InP/InGaP quantum structures (QSs) grown on GaAs substrates by a migration-enhanced molecular beam epitaxy method were studied as a function of growth temperature (T) using photoluminescence (PL) and emission-wavelength-dependent time-resolved PL (TRPL). The growth T were varied from $440^{\circ}C$ to $520^{\circ}C$ for the formation of InP/InGaP QSs. As growth T increases from $440^{\circ}C$ to $520^{\circ}C$, the PL peak position is blue-shifted, the PL intensity increases except for the sample grown at $520^{\circ}C$, and the PL decay becomes fast at 10 K. Emission-wavelength-dependent TRPL results of all QS samples show that the decay times at 10 K are slightly changed, exhibiting the longest time around at the PL peak, while at high T, the decay times increase rapidly with increasing wavelength, indicating carrier relaxation from smaller QSs to larger QSs via wetting layer/barrier. InP/InGaP QS sample grown at $460^{\circ}C$ shows the strongest PL intensity at 300 K and the longest decay time at 10 K, signifying the optimum growth T of $460^{\circ}C$.

• 한국세라믹학회지
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• 제51권1호
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• pp.25-31
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• 2014

New green phosphor is synthesized by reducing $LiAlO_2:xEu^{3+}$ phosphors in a low pressure $H_2$ atmosphere. The $LiAlO_2:xEu^{3+}$ prepared by a solid state reaction method is reported as red phosphor. The effect of the reduction treatment on the $LiAlO_2:xEu^{3+}$ on the crystalline phase change and photoluminescence (PL) property are characterized. The reduced phosphor had a broad green light spectrum centered at 524 nm. The PL intensity of the reduced phosphor increased to a maximum at the reduction temperature of $1100^{\circ}C$. The PL intensity decreased with a further increase in the reduction temperature. The crystalline phase constituting the reduced phosphor varied with the temperature. A new crystalline phase $Li_2Al_4O_7$ was observed at $1100^{\circ}C$. The origin of the green-light emission is discussed in relation to the crystalline phase change.