• 천문학회지
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• 제37권4호
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• pp.285-288
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• 2004

Near-infrared imaging photometry supplemented by optical spectroscopy and narrow-band imaging of the H II region Sh 2-128 and its environment are presented. This region contains a developed H II region and the neighboring compact H II region S 128N associated with a pair of water maser sources. Midway between these, the core of a CO cloud is located. The principal ionizing source of Sh 2-128 is an 07 star close to its center. A new spectroscopic distance of 9.4 kpc is derived, very similar to the kinematic distance to the nebula. This implies a galactocentric distance of 13.5 kpc and z = 550 pc. The region is optically thin with abundances close to those predicted by galactocentric gradients. The $JHK_s$ images show that S 128N contains several infrared point sources and nebular emission knots with large near-infrared excesses. One of the three red Ks knots coincides with the compact H II region. A few of the infrared-excess objects are close to known mid- and far-infrared emission peaks. Star counts in J and $K_s$ show the presence of a small cluster of B-type stars, mainly associated with S 128N. The $JHK_s$ photometric properties together with the characteristics of the other objects in the vicinity suggest that Sh 2-128 and S 128N constitute a single complex formed from the same molecular cloud, with ages ${\~}10^6$ and < $3 {\times} 10^5$ years respectively. No molecular hydrogen emission was detected at 2.12 ${\mu}m$. The origin of this remote star forming region is an open problem.

• Current Optics and Photonics
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• 제4권4호
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• pp.380-390
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• 2020

In this study, the traditional electron-blocking layer (EBL) in (In,Ga)N/GaN light-emitting diodes is replaced by a circular EBL that is the same size as the n-pad. The three-dimensional (3D) nonlinear Poisson, drift-diffusion, and continuity equations are adopted to simulate current transport in the LED and its characteristics. The results indicate that the local carrier-density distribution obtained for the circular EBL design is more uniform than that for the traditional EBL design. This improves the uniformity of local radiative recombination and local internal quantum efficiency (IQE) at high injection levels, which leads to a higher lumped IQE and lower efficiency droop. With the circular EBL, the lumped IQE is higher in the outer active region and lower in the active region under the n-pad. Since most emissions from the active region under the n-pad are absorbed by the n-pad, obviously, an LED with a circular EBL will have a higher external quantum efficiency (EQE). The results also show that this LED works at lower applied voltages.

• 대한전자공학회논문지
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• 제21권1호
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• pp.62-70
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• 1984

비저항이 10Ω-cm, 두께가 13∼15mi1인 <111> oriented, p형 Si기판을 이용하여 N+PP+ BSF 전지와 에미터 영역이 N+N 고저 접합으로 이루어진 N+NPP+ HELEBSF(high low emitter bach surface field) 전지를 설계 제작하였다. 접합형 태양전지의 에미터 영역에서 고저 접합구조가 효율 개선에 미치는 영향을 검토하기 위해 HLEBSF 전지의 N영역을 제외하고는 같은 마스크와 동시 공정을 통해 N+PP-전지와 N+NPP+ 전지의 가영역에서 물리적 파라미터들(불순물 농도, 두께)을 동일하게 만들었다. 100mW/㎠의 인공조명에서 측정한 결과 N+PP+ 전지들의 전면적 (유효 수광면적) 평균 변환효율이 10.94%(12.16%)이었고, N+NPP+ 전지들의 평균 변환효율은 12.07% (13.41%)로 나타났다. N+NPP+ 전지의 효율개선은 N+N-고저 접합 에미터 구조가 N+ 에미터 영역에서 나타나는 heavy doping effects를 제거함으로써 에미터 재결합 전류의 증가를 억제하고 나아가 개방전압(Voc)과 단락전류(Ish)의 값을 증가시켜 준 결과로 볼 수 있다.

• 한국정밀공학회지
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• 제22권7호
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• pp.19-26
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• 2005

The objective of this study is to investigate the influence of process parameters, such as power of laser, cutting speed of laser and material thickness, on the practical cutting region and the kerfwidth fer the case of cutting of CSP IN sheet using high power Nd:YAC laser in continuous wave(CW) mode. In order to obtain the practical cutting region and the relationship between process parameters on the kerfwidth, several laser cutting experiments are carried out. The effective heat input is introduced to consider the influence of power and cutting speed of laser on the kerfwidth together. From the results of experiments, the allowable cutting region and the relationship between the effective heat input and kerfwidth fur the case of cutting of CSP 1N sheet using high power CW Nd:YAG laser have been obtained to improve the dimensionalaccuracyofthecutarea.

• 천문학논총
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• 제11권1호
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• pp.75-90
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• 1996

The vertical distribution of HCN, $HC_3N$ and $C_2N_2$ have been determined from a sequence of Voyager 1 IRIS limb tangent measurements over Titan's north polar region. This sequence yields gas distributions with ${\sim}200\;km$ altitude resolution over the 50-400 km range. The derived mixing ratios of HCN, $HC_3N$ and $C_2N_2$ are $5{\times}10^{-7}$, $7{\times}10^{-8}$ and $8{\times}10^{-9}$, respectively, at 120 km with a factor of 3 uncertainty.

• Animal Systematics, Evolution and Diversity
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• 제13권2호
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• pp.93-102
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• 1997

조간대와 수심 20m 미만의 조하대 모래틈에서 채집한 해양 완보류 2신종 - Batillipes longispinosus n. sp., B. orientalis n. sp. - 을 기재한다. 이들 2신종은 미성숙 개체와 성체 모두에서 몸통 뒷부분에 돌기가 없으며 머리에 난 여러 돌기들이 길다는 점, 제 4다리위에 긴돌기를 가진다는 점에서 특징적이다. B. longispinosus n. sp.는 Batillipes 속에 기록된 21종 중에서 B. tubernatis Pollock과 가장 유사하나 4번째 다리에 긴 돌기를 가지는 점에서 다르다. 또한 B. orientalis n. sp. 는 몸 측면 돌기를 가진다는 점에서 B. roscoffensis Kristensen와 닮았으나 머리의 모양과 4번째 다리에 긴 돌기를 가지는 점에서 뚜렷하게 구별된다.

• Nuclear Engineering and Technology
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• 제50권1호
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• pp.165-169
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• 2018

An assessment for determining N-16 activity concentrations during the operation condition of Bangladesh Atomic Energy Commission TRIGA Research Reactor was performed employing several governing equations. The radionuclide N-16 is a high energy (6.13 MeV) gamma emitter which is predominately created by the fast neutron interaction with O-16 present in the reactor core water. During reactor operation at different power level, the concentration of N-16 at the reactor bay region may increase causing radiation risk to the reactor operating personnel or the general public. Concerning the safety of the research reactor, the present study deals with the estimation of N-16 activity concentrations in the regions of reactor core, reactor tank, and reactor bay at different reactor power levels under natural convection cooling mode. The estimated N-16 activity concentration values with 500 kW reactor power at the reactor core region was $7.40{\times}10^5Bq/cm^3$ and at the bay region was $3.39{\times}10^5Bq/cm^3$. At 3 MW reactor power with active forced convection cooling mode, the N-16 activity concentration in the decay tank exit water was also determined, and the value was $4.14{\times}10^{-1}Bq/cm^3$.

• JSTS:Journal of Semiconductor Technology and Science
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• 제2권3호
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• pp.233-236
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• 2002

Some measures are provided for the optimum design of specific on-resistance $R_{on}$ and breakdown-voltage $V_B$ of interdigitated CB (Composite Buffer) MOSFET, including introducing opposite type impurity into the P region near the $N_＋$contact, separating P region from N region with an oxide film, and a groove in the N region near the $P_＋$ contact. The new relationship between the $R_{on}$ and $V_B$, which proved by numerical device simulation, are more exact and minute than the qualitative results before.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.457-457
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• 2013

Current-voltage (I-V) measurements of crystalline silicon solar cells was conducted under dark conditions with the temperature range of 260 K~350 K. Using the calculation method, we extracted the crucial factors of ideality factor (n) and activation energy (Ea) to investigate the carrier conducting path in the space charge region (SCR) and the quasi-neutral region (QNR). Values of n were decreased with increasing temperature in both SCR and QNR. We also conformed that the value of Ea of SCR was larger than that of QNR about 0.4 eV. The temperature dependence of n indicates that the carrier conducting path is dominated by carrier recombination-generation in the SCR region than in the QNR region.

• 한국전기전자재료학회논문지
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• 제20권5호
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• pp.403-409
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• 2007

In this paper, effects of the trench angle($\theta$) on the breakdown voltage according to the process parameters of p-base region and doping concentrations of n-drift region in a Trench Gate IGBT (TIGBT) device were analyzed by computer simulation. Processes parameters used by variables are diffusion temperature, implant dose of p-base region and doping concentration of n-drift region, and aspects of breakdown voltage change with change of each parameter were examined. As diffusion temperature of the p-base region increases, depth of the p-base region increases and effect of the diffusion temperature on the breakdown voltage is very low in the case of small trench angle($45\;^{\circ}$) but that is increases 134.8 % in the case of high trench angle($90\;^{\circ}$). Moreover, as implant dose of the p-base region increases, doping concentration of the p-base region increases and effect of the implant dose on the breakdown voltage is very low in the case of small trench angle($45\;^{\circ}$) but that is increases 232.1 % in the case of high trench angle($90\;^{\circ}$). These phenomenons is why electric field concentrated in the trench is distributed to the p-base region as the diffusion temperature and implant dose of the p-base increase. However, effect of the doping concentration variation in the n-drift region on the breakdown voltage varies just 9.3 % as trench angle increases from $45\;^{\circ}$ to $90\;^{\circ}$. This is why magnitude of electric field concentrated in the trench changes, but direction of that doesn't change. In this paper, respective reasons were analyzed through the electric field concentration analysis by computer simulation.