• 한국재료학회지
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• 제13권4호
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• pp.213-218
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• 2003

Fibrous monolithic control of$ Al_2$$O_3$ -$ZrO_2$composite was investigated by multi-pass extrusion process. To obtain sound $Al_2$$O_3$-X $O_2$sintered bodies, burning out and sintering process were carefully carried out. The sintered bodies showed continuous, fibrous monolithic microstructure without any swelling. Many microcracks were observed at the $Al_2$$O_3$-$ZrO_2$interfaces due to the mismatching of thermal expansion coefficient between $Al_2$$O_3$ and $ZrO_2$phase. Most of m- $ZrO_2$grains included twin defects such as (001), (010) and (011) type to accommodate the phase transformation induced stress.

• 대한기계학회논문집
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• 제14권5호
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• pp.1330-1336
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• 1990

The factors to act on atomization of liquid fuel are viscosity, geometric shape of nozzle, atomizing pressure, etc. Most of high viscous liquid fuels show decrease in viscosity by raising the preheat temperature, but the viscosity of liquid fuel like CWM does not readily change with fuel temperature. As an experimental study to investigate the atomizing characteristics of CWM, CWM fuel is atomizing with a twin-fluid atomizer, and the effects of the geometric shape of spray nozzle on atomization are investigated by measuring the Sauter`s Mean Diameter (SMD) of CWM. The summarized results obtained in this study are as follows ; (1) As the ratio of the mass flows of atomizing air to that of fuel (W$_{a}$ /W$_{1}$) increases, 능 decreases when fuel temperature is constant. (2) At the ratio (t/d) 4 of thickness (t) of spray nozzle hole to the diameter (d) of the hole, there is the best atomization. And SMD decreases when t/d is between 1 to 4 and increases when t/d > 4.

• 한국철도학회논문집
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• 제15권2호
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• pp.154-161
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• 2012

철도교량 동적 설계 및 동적 안전성을 해석적으로 평가하기 위해서는 교량의 감쇠비를 산정하는 것이 매우 중요하다. 본 연구에서는 국내 고속 및 일반철도에서 일반적으로 사용되고 있는 소수주형강합성교, PSC Box, Steel Box, PSC, IPC, Precom, Preflex에 대하여 실내 모형실험 및 운행 중 현장계측을 하였다. 이러한 고속 및 일반철도의 대표적 교량형식에 대한 실내외 시험을 통해 대수감소율을 적용하여 감쇠비를 분석하였다. 따라서 철도교량의 감쇠비는 하중크기, 가진주파수, 진폭에 영향을 받지 않는 것으로 분석되었다. 또한, 기존 철도설계기준에 제시된 감쇠비 하한치와 비교하여 PSC구조 및 강합성구조 철도교량의 경우 감쇠비 하한값을 1.0%로 적용하는 것이 합리적이라 판단되었다.

• 대한전자공학회논문지
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• 제23권1호
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• pp.83-90
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• 1986

A micro pH-ISFET probe, which can be applied to the in vivo measurements of the hydrogen ion concentration in blood, has been developed, and a measuring system equiped with this probe also developed. The pH-ISFET has been fatricated by employing the techniques of integrated circuit fabrication. Two kinds of micro electrode formed around the sensing gate during the wafer process, and the other is a capillary type of Ag/AfCl/sat. KCI reduced in size. This capillary electrode has shown its good performance characteristics so far in the application with ISFET as well as a commercial one. In order to form a micro pH-ISFET probe, this pH-ISFET and well as a commercial one. In order to form a micro pH-ISFET probe, this pH-ISFET and the capillary electrode were built together into a needle tip having 1 mm inner diameter. The chip size of a twin pH-ISFET is 0.8 mmx1.4 mm, the material of the sensing gate membrane is Si3N4, and the sensitivity of the developed probe is about 52mV/pH.

• 한국정밀공학회지
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• 제14권12호
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• pp.73-85
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• 1997

The rolling force and roll deformation behavior in the twin roll type strip continuous casting process has been computed to estimate the thermal charcteristics of a caster roll. To calculation of rolling force, the relationship between flow stress and strain for a roll material and casting alloy are assumed as a function of strain-rate and temperature because mechanical properties of a casting materials depends on tempera- ture. The three dimensional thermal dlastic-plastic analysis of a cooling roll has also been carried out to obtain a roll stress and plastic strain distributions with the commercial finite element analysis package of ANSYS. Temperature fields data of caster roll which are provided by authors were used to estimated of roll deformation. Roll life considering thermal cycle is calculated by using thermal elastic-plastic analysis results. Roll life is proposed as a terms of a roll revolution in the caster roll with and without fine failure model on the roll surface. To obtain of plastic strain distributions of caster roll, thermomechan- ical properties of roll sleeve with a copper alloy is obtained by uniaxial tensile test for variation of temperature.

• 한국임상수의학회지
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• 제23권3호
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• pp.320-324
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• 2006

The purpose of the present study was to compare pulsatile type(Twin Pulse Life Support; TPLS) with rotary type hemodialyzer(AK95) in order to reduce the dialysis time and to improve dialysis effect. Three healthy dogs(about 30 kg BW) were used. Experimental renal failure was induced by the ligation of bilateral renal artery. A pair of catheters were implanted in jugular vein for dialysis. Daily investigated parameters included clinical signs such as vomiting, fecal appearance and activity, and also laboratory data such as PCV, TP, BUN and creatinine. Hemodialysis was started above 90 mg/100 ml BUN level and, laboratory data were measured every an hour for 4 hours. Heparin was administered 300 IU/Kg before dialysis and 150 IU/Kg via IV route every 90 minutes during dialysis. Clinical signs after induction renal failure were shown severe vomiting, anorexia, diarrhea, mucous feces, ataxia, dilated pupil and episcleral hyperemia. The average of BUN value decreased hourly $99{\pm}12.1,\;84{\pm}12.2,\;72{\pm}8.0,\;58{\pm}7.1,\;48{\pm}5.2,\;and\;39{\pm}3.2mg/100ml$ by hemodialysis. The average of creatinine value decreased $7.8{\pm}0.61,\;6.4{\pm}0.40,\;5.3{\pm}0.42,\;4.5{\pm}0.23,\;4.0{\pm}0.41,\;and\;3.4{\pm}0.42mg/100ml$ according to hemodialysis an hour. There are not significantly differences BUN, creatinine, PCV and TP values between pulsatile and rotary type hemodialysis. These results suggested that effects of hemodialysis with Pulsatile type(TPLS) are not significantly difference as compared with hemodialysis of rotary type(AK95). Further research is needed in order to estimate the influence of cardiovascular and pulmonary system in hemodialysis of pulsatile type.

• 한국분무공학회지
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• 제13권3호
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• pp.134-142
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• 2008

In the case of heavy duty diesel engines, the Urea-SCR system is currently considered to reduce the NOx emission as a proved technology, and it is widely studied to get the high performance and durability. However, the nozzles to inject the urea-water solution into the exhaust pipe occur some problems, including the nozzle clogging, deposition of urea-water solution on the inner wall of the exhaust pipe, resulting in the production of urea salt. In this study, a swirl-type twin-fluid nozzle to produce more fine droplets was used as a method to solve the problems. The effect of the nozzle cap geometry, including the length to diameter ratio ($l_o/d_o$) and chamfer, on the spray characteristics were investigated experimentally. The length to diameter ratio of nozzle cap were varied from 0.25 to 1.125. The chamfer angle of the nozzle cap was constant at 90o. The mean velocity and droplet size distributions of the spray were measured using a 2-D PDA (phase Doppler analyzer) system, and the spray half-width, AMD (arithmetic mean diameter) and SMD (Sauter mean diameter) were analyzed. At result, The larger length to diameter ratio of nozzle cap were more small SMD and AMD. The effect of the chamfer did increase the radial velocity, while it did not affect the atomization effect.

• Asian-Australasian Journal of Animal Sciences
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• 제9권5호
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• pp.591-595
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• 1996

This paper presents results from a study of the age and weight at puberty of Thai does. A randomized block $3{\times}3$ factorial design was used. Factors were genotype (Thai Native; TN, 75% TN $\times$ 25% Anglo-Nubian; AN and 50 TN $\times$ 50% AN does), year of kidding (1989, 1990 and 1991) and birth type (single or twin) as a block. It was shown that there were no significant (p > 0.05) difference in age at puberty among genotypes ($167.6{\pm}6.0$, $157.6{\pm}7.0$ and 160.0 = 4.7 days for TN, 75% TN $\times$ 25% AN and 50% TN $\times$ 50% AN does, respectively) and between birth types. However, does kidded in 1991 had significantly (p < 0.01) longer age at puberty ($194.0{\pm}7.4$ days) than did does kidded in 1989 ($143.0{\pm}4.5$ days) or in 1990 ($148.1{\pm}5.7$ days). There was an interaction effect between genotype and year. Fifty % TN $\times$ 50% AN does had significantly (p < 0.05) higher weights at pubery ($17.2{\pm}0.4kg$) than those of TN($14.3{\pm}0.5kg$ and 75% TN $\times$ 25% AN ($14.4{\pm}0.6kg$) does. There was no significant difference in weights at puberty between TN and 75% TN $\times$ 25% AN does. There was no effect of birth type on weight at puberty. There was an interaction effect between genotype and year of kidding on age and weight at puberty and on growth rate from birth to weaning.

• Asian-Australasian Journal of Animal Sciences
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• 제10권5호
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• pp.491-494
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• 1997

The growth performance in the first year of life of 892 Black Bengal kids was studied in four different locations in Bangladesh, e. g. (1) Bhabakhali, (2) Trisal, (3) Aishara and (4) Akhrail. Birth weight of kids of region 1, 2 and 3 were almost similar (1.01 kg) with significantly lower birth weight in region 4 (0.88 kg). Effect of birth type and sex were significant with higher weights for single (1.03 kg) v. twin (0.98 kg) v. triplet (0.92 kg) and male kids (1.03 kg) v. female (0.93 kg). Monthly weights of kids followed the same pattern as birth weight. Monthly weights of kids in region 1, 2 and 3 were similar with significantly lower weight for region. 4 Birth type and sex affected monthly weights in different regions where single and male kids had significantly higher weights for all the regions. The analysis of variance reveals that regional significant differences for average daily gains were noticed for the periods from birth to 3 and 9 to 12 months of age. The highest gains were noticed for region 2 ($51.9{\pm}2.4kg$) and the lowest for region 1 ($38.2{\pm}2.3kg$) with similar values for region 4. From the results it is revealed that growth performance of Black Bengal kids varied in different regions, which might be caused by inappropriate management and inadequate feed availability around the year and stressful environmental conditions.

• 한국전기전자재료학회논문지
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• 제13권11호
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• pp.914-920
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• 2000

When the charge-trap type SONOS(polysilicon-oxide-nitride-oxide-semiconductor) cells are used to flash memory, the tunneling program/erase condition to minimize the generation of interface traps was investigated. SONOSFET NVSM(Nonvolatile Semiconductor Memory) cells were fabricated using 0.35 ㎛ standard memory cell embedded logic process including the ONO cell process, based on retrograde twin-well, single-poly, single metal CMOS(Complementary Metal Oxide Semiconductor) process. The thickness of ONO triple-dielectric for the memory cell is tunnel oxide of 24 $\AA$, nitride of 74 $\AA$, blocking oxide of 25 $\AA$, respectively. The program mode(V$\_$g/=7, 8, 9 V, V$\_$s/=V$\_$d/=-3 V, V$\_$b/=floating) and the erase mode(V$\_$g/=-4, -5, -6 V, V$\_$s/=V$\_$d/=floating, V$\_$b/=3 V) by MFN(Modified Fowler-Nordheim) tunneling were used. The proposed programming condition for the flash memory of SONOSFET NVSM cells showed less degradation(ΔV$\_$th/, S, G$\_$m/) characteristics than channel MFN tunneling operation. Also, the program inhibit conditins of unselected cell for separated source lines NOR-type flash memory application were investigated. we demonstrated that the phenomenon of the program disturb did not occur at source/drain voltage of 1 V∼12 V and gate voltage of -8 V∼4 V.