• 한국연소학회지
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• 제8권4호
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• pp.15-23
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• 2003

The zone conditional two-fluid equations are derived and validated against DNS database of a premixed turbulent flame. The conditional statistics of major flow variables are investigated to understand the mechanism of flame generated turbulence. The flow field in burned zone shows substantially increased turbulent kinetic energy, which is highly anisotropic due to reaction kinematics across thin f1amelets. The transverse component may be larger than the axial component for a distributed pdf of the flamelet orientation angle, while the opposite occurs due to redistribution of turbulent kinetic energy and flamelet orientation normal to the flow at the end of a flame brush. The major source or sink terms of turbulent kinetic energy are the interfacial transfer by the mean reaction rate and the work terms by fluctuating pressure and velocity on a flame surface. Ad hoc modeling of some interfacial terms may be required for further application of the two-fluid model in turbulent combustion simulations.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.380-380
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• 2006

Styrene-Butadiene diblock or styrene-butadiene-styrene triblock copolymers are industrially important materials for asphalt modification and adhesives. A kinetic modeling study on non-isothermal anionic styrene-butadiene diblock copolymerization system is presented. The model deals with the association/dissociation reaction of initiator and propagating ion pairs in its kinetic scheme. By comparing model calculation results with real plant data, it is possible to obtain useful ideas for more efficient plant operation. For example, the model clearly provides important relation between the reaction temperature profile and the conversion of monomers.

• 대한화학회지
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• 제25권5호
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• pp.291-299
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• 1981

용액중에서 화학반응을 설명하기 위하여 한개의 대표적인 입자의 반복적 충돌현상까지 고려한 동역학적인 이론을 경구모델을 사용하여 연구하였다. 반응성을 지닌 대표적인 입자의 상공간 밀도의 시간상관함수가 만족시키는 동역학방정식을 유도하였고 이로부터 비활성 용매 S중에서 일어나는 A + B ${\rightleftharpoons$ C + D 형태의 가역반응에 관계되는 반응속도 계수의 인자를 투영연산자방법으로 구하였다.

• Archives of Pharmacal Research
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• 제22권1호
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• pp.13-17
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• 1999

The kinetic constants and the reaction mechanism of the K228G mutant horse liver alcohol dehyrogenase isoenzyme E (HLADH-E) were compared to the wild-type enzyme. All the Km and Ki constants of the mutant enzyme for NAD+, ethanol, acetaldehyde and NADH were larger than those of the wild-type enzyme. The dissociation constants for the NADH and $NAD^{+}$ (Kiq and Kia) were greatly increased by 130-and 460-fold, respectively. The product inhibition patterns suggested that the reaction mechanism of the mutant enzyme was changed to Random Bi Bi. These results could attribute to the increase in the dissociation rate of coenzyme with the substitution at Lys-228 residue.

• Macromolecular Research
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• 제14권3호
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• pp.338-342
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• 2006

The kinetic features of polymerization with an active site comprising cobalt dihalides ($CoX_2$, where X=Cl, Br, I) activated by methylaluminoxane (MAO) were investigated in 1,3-butadiene polymerization. The catalytic system exhibited the characteristic features of living polymerization. The initiation ($k_i$) and propagation ($k_p$) rate coefficients were estimated using the kinetic model for slow initiation previously reported by Shiono et al. The energy of activation fur the propagation reaction was calculated to be 27-30 $kJmol^{-1}$. The marked changes in reaction rate observed with different halides could be adequately described in terms of variations in the initiation process, with the same Arrhenius curve fitting propagation rate coeffcients estimated from all three halides, suggesting that the halide does not participate in the growing chain end.

• 약학회지
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• 제43권5호
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• pp.606-613
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• 1999

To survey the possibility of replacing the pyrogen test with Limulus Amebocyte Lysate(LAL) test and to find out a standard methods suitable to our blood products made in Korea, 100 samples of 20% human serum albumin were tested by commercial LAL test kits and results of those were compared with rabbit pyrogen test. The LAL test is used both dinetic-chromogenically and kinetic-turbidimetrically. Both methods equally showed broad detection range (5.0~0.005 EU/ml), excellent sensitivity ($\geq$ 0.005 EU/ml) and predominant recovery rate within valid dilution range, but kinetic-turbidimetric method seemed to be more reproducible than kinetic-chromogenic method(kinetic-chromogenic method : S.D. = 15.88, kinetic-turbidimetric method : S.D. = 8.12). After heating the sample at 75$^{\circ}C$ for 15 min, the results showed a little elevated recovery rate with both methods. After performing the test on 100 albumin samples with both kits, the results were analysed using the USP standard (1.33 EU/ml). 7% of samples in kinetic-chromogenic methods and 1% of samples in kinetic-turbidimetric method exceeded the limit of endotoxin levels regulated for blood products in USA. Because this phenomenon was not observed in both methods at the same time and both methods have high sensitivity ($\geq$0.005 EU/ml), these results seemed to depend on nonspecific reaction. Considering its sensitivity and reproducibility, we could assure that LAL test is proper to detecting pyrogenic with good sensitivity.

• 한국운동역학회지
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• 제20권1호
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• pp.109-116
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• 2010

This study aims to comparatively analyze kinetic variables that affect high jump records and thus to provide the basic data for enhancement of physical education teachers' teaching skills and expertise. 10 students who were majoring in physical education in a college of education - five males and five females - were chosen for the experiment in which the 3D image analyzer and ground reaction force measuring unit were adopted. The kinetic variables of the groups, the characteristics and differences were analyzed, and the correlation between each variable and record in each group was examined. The results are as follows: As to the height of center of gravity from one step before stamping to landing, the vertical velocity of the center of gravity at take off, the vertical velocity of the limbs at take off, the angles of the hip joint and ankle joint of the jumping leg, it turned out that male were better than female. As to the angles of the hip joint and ankle joint of the lead leg, female recorded higher values than male. As to the maximum vertical ground reaction force, the maximum horizontal ground reaction force, the vertical impulse, it turned out that male were better than female.

• 대한기계학회논문집B
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• 제21권9호
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• pp.1174-1184
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• 1997

Extinction characteristics of pure hydrogen-oxygen diffusion flames, at high pressures in the neighborhood of the critical pressure of oxygen, is numerically studied by employing counterflow diffusion flame as a model flame let in turbulent flames in rocket engines. The numerical results show that extinction strain rate increases almost linearly with pressure up to 100 atm, which can be explained by comparison of the chain-branching-reaction rate with the recombination-reaction rate. Since contributions of the chain-branching reactions, two-body reactions, are found to be much greater than those of the recombination reactions, three-body reactions, extinction is controlled by two-body reactions, thereby resulting in the linearity of extinction strain rate to pressure. Therefore, it is found that the chemical kinetic behaviors don't change up to 100 atm. Consideration of the pressure fall-off reactions shows a slight increase in extinction strain rate, but does not modify its linearity to pressure. The reduced kinetic mechanisms, which were verified at low pressures, are found to be still valid at high pressures and show good qualitative agreement in prediction of extinction strain rates. Effect of real gas is negligible on chemical kinetic behaviors of the flames.

• 반도체디스플레이기술학회지
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• 제19권1호
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• pp.29-35
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• 2020

The cure characteristics of three kinds of naphthalene type epoxy resins(NET-OH, NET-MA, NET-Epoxy) with a 2-methyl imidazole(2MI) catalyst were investigated for preparing sheet epoxy molding compound(SEMC) for wafer level package(WLP) applications, comparing with diglycidyl ether of bisphenol-A(DGEBA) and 1,6-naphthalenediol diglycidyl ether(NE-16) epoxy resin. The cure kinetics of these systems were analyzed by differential scanning calorimetry with an isothermal approach, and the kinetic parameters of all systems were reported in generalized kinetic equations with diffusion effects. The NET-OH epoxy resin represented an n-th order cure mechanism as like NE-16 and DGEBA epoxy resins, however, the NET-MA and NET-Epoxy resins showed an autocatalytic cure mechanism. The NET-OH and NET-Epoxy resins showed higher cure conversion rates than DGEBA and NE-16 epoxy resins, however, the lowest cure conversion rates can be seen in the NET-MA epoxy resin. Although the NETEpoxy and NET-MA epoxy resins represented higher cure reaction conversions comparing with DGEBA and NE-16 resins, the NET-OH showed the lowest cure reaction conversions. It can be figured out by kinetic parameter analysis that the lowest cure conversion rates of the NET-MA epoxy resin are caused by lower collision frequency factor, and the lowest cure reaction conversions of the NET-OH are due to the earlier network structures formation according to lowest critical cure conversion.

• Bulletin of the Korean Chemical Society
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• 제25권4호
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• pp.517-524
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• 2004

Two simple and sensitive spectrophotometric methods were developed for the determination of carbocisteine, penicillamine, ethionamide and thioctic acid in bulk and in their pharmaceutical preparations using alkaline potassium permanganate as an oxidizing agent. The first one involves determination of ethionamide and thioctic acid by spectrophotometric investigation of the oxidation reaction of the two drugs. The second method involves determination of carbocisteine and penicillamine by kinetic studies of the oxidation reaction of these two drugs at room temperature for a fixed time of 20 minutes. The absorbance of the colored manganate ions was measured at 610 nm in both methods. 1-10 ${\mu}$g/mL of ethionamide and thioctic acid could be etermined by the spectrophotometric method with detection limits of 0.11 and 0.089 ${\mu}$g/mL for the two drugs respectively. 2-10 ${\mu}$g/mL of carbocisteine and penicillamine could be determined by the kinetic method with detection limits of 0.14 and 0.21 ${\mu}$g/mL respectively. The two methods were successfully applied for the determination of these drugs in their dosage forms.