• Bulletin of the Korean Chemical Society
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• v.34 no.1
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• pp.243-245
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• 2013

Rate equations are exactly solved for the reversible consecutive reaction of the first-order and the time-dependence of concentrations is analytically determined for species in the reaction. With the assumption of pseudo first-order reaction, the calculation applies and determines the concentration of product accurately and explicitly as a function of time in the unimolecular decomposition of Lindemann and in the enzyme catalysis of Michaelis-Menten whose rate laws have been approximated in terms of reactant concentrations by the steady-state approximation.

• Bulletin of the Korean Chemical Society
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• v.16 no.4
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• pp.310-315
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• 1995

The heterobimetallic anion, (OC)5CrMn(CO)5-M+ (M+=Na+, PPN+), which has a donor-acceptor metal-metal bond1, was reacted with allyl bromide to yield BrCr(CO)5- and Mn(CO)5(CH2CHCH2). The reaction mechanism has been proposed in terms of the consecutive reaction pathway in which Cr(CO)5(THF) is an important intermediate leading to the corresponding product. Counterion effect on this reaction was also evaluated and the results were compared with those of the corresponding reaction of the mononuclear carbonyl anion, Mn(CO)5-.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.1D
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• pp.65-72
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• 2011

When an expressway intersects another expressway, a unique connector needs to be designed between the two consecutive exit ramps. In such a case, it is important to design a connector such that there is enough distance for drivers to find their way safely. A current design manual in Korea prescribes the minimum length of the connector as 240 m. In this research, we have suggested a method for calculating the minimum length of a connector in order to check the feasibility of the currently prescribed length. For this purpose, we have attempted to determine the total perception-reaction time and lane-changing time required by a driver. For determining the driver's perception-reaction time, we have used the driver's decision time in addition to the conventional 2.5 s of perception-reaction time for stopping sight distances. We have considered both the design speed and the average travel speed for the calculation of the length. To evaluate the accuracy of the new method, we have chosen four sites on expressways for which relatively high accident rates were recorded. As a result, we could verify that the current limit (240 m) was sufficient for drivers to be able to change lanes in the given specific geometry. However, the prescribed limit should be revised in case the drivers' decision time is considered to be their perception-reaction time. All new approaches for calculating the ideal length of a connector have been carried out by taking into account the design speed as well as the average travel speed. Owing to the characteristics of the specific geometry for two consecutive exit ramps and the large difference between the design speed and the average travel speed in the objective areas, it is more realistic to use the proposed method by keeping the decision time equal to a driver's perception-reaction time, in order to determine the ideal distance that should be maintained between two consecutive exit ramps.

• Journal of the Korean Ceramic Society
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• v.15 no.1
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• pp.21-27
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• 1978

Hadong Kaolin (Halloysite) was granulated cylindrically and treated with 1N aqueous sodium hydroxide solution for 6-48 hrs at 60-10$0^{\circ}C$. The crystalling structure of surface of the products was studied by X-ray powder diffraction method. The reaction rate of halloysite to sodium A zeolite showed a gradual decrease from surface to inner layer. At the surface layer, the reaction mechanism was observed as first order consecutive reaction as follows: halloysitelongrightarrowamorphous aluminosilicatelongrightarrowsodium A zeolitelongrightarrowhydroxysodalite By applying the above reaction mechanism, the rate constants and activation energies was measured.

• Bulletin of the Korean Chemical Society
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• v.32 no.4
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• pp.1387-1390
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• 2011

• Journal of Applied Biological Chemistry
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• v.48 no.2
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• pp.97-100
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• 2005

Chiral dienophile 5 was synthesized from D-glucose by consecutive diisopropylidenation, partial deprotection, diol cleavage, and Wittig reactions. Under thermal conditions, asymmetric Diels-Alder reaction between chiral dienophile and cyclopentadiene gave four possible chiral norbornenes stereoisomers whose absolute configurations were determined through CADD and NMR.

• Bulletin of the Korean Chemical Society
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• v.15 no.6
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• pp.448-452
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• 1994

2-Hydroxymethyl-2,5-dihydrothiophene 1,1-dioxide (1) was prepared from thiophene-2-carboxylic acid by consecutive reactions involving the Birch reduction, esterification, reduction with lithium aluminum hydride, and oxidation with Oxone$^{\circledR}$. The esterification of alcohol 1 with various unsaturated carboxylic acids provided the precursors 8 for the intramolecular Diels-Alder reaction. The cheletropic expulsion of sulfur dioxide from the esters 8 followed by intramolecular Diels-Alder reaction furnished bicyclic ${\gamma}$-and ${\delta}$-lactones.

• Clinics in Shoulder and Elbow
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• v.27 no.1
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• pp.45-51
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• 2024

Background: It is essential to distinguish between symptomatic- and asymptomatic radiographic acromioclavicular (AC) osteoarthritis (OA) because AC-targeted physical examinations are dubious. This study aimed to determine the diagnostic value of a preoperative AC injection in discriminating between symptomatic- and asymptomatic radiographic AC OA based on patient arthroscopic distal clavicle resection (aDCR) outcomes. Methods: Forty-eight patients who underwent aDCR for AC OA were included. Their satisfaction was objectified using a 5-point Likert scale and patient willingness to repeat the surgery. The Oxford Shoulder Score (OSS), the Subjective Shoulder Value (SSV), and the Numerical Rating Scale (NRS) were used to assess postoperative shoulder function and pain. Patients were subdivided into groups based on their good or minimal reaction to an AC injection (good reaction: ≥7 consecutive days of pain reduction, Minimal reaction: <7 consecutive days of pain reduction). Results: Twenty-seven patients had a good reaction and 21 patients had a minimal reaction to the AC injection (median follow-up, 45.0 months; range, 31.0-52.8 months). No significant differences were found in level of satisfaction (P=0.234) or willingness to repeat the surgery (P=0.861). No significant differences were found in OSS (P=0.612), SSV (P=0.641), NRS at rest (P=0.684) or during activity (P=0.422). Conclusions: This study found no significant differences between patients with a good reaction or a minimal reaction to an AC injection after aDCR surgery. The outcomes of this study seem to suggest that a distinction between symptomatic and asymptomatic radiographic AC OA is unnecessary, as all patients were equally satisfied with the outcome.

• Bulletin of the Korean Chemical Society
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• v.34 no.5
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• pp.1477-1480
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• 2013

The Suzuki cross-coupling reactions proceeded in excellent yields when it was catalyzed by magnetically recyclable nanocatalyst. This nanocatalyst provided very high catalytic activity with low loading level (1 mol %), because the palladium nanoparticles were so small in size (~2 nm) and located on the surface of the nanocomposite. It was also easily recovered from the reaction mixture using a magnet and reused for six consecutive cycles.

• Bulletin of the Korean Chemical Society
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• v.15 no.7
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• pp.537-541
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• 1994

The reaction of the heterobimetallic anion, ${(OC)_5CrMn(CO)_5^-M^+ (M^+=Na^+, PPN^+)\;with\;CH_3I$ was proven to be overall 1st order with respect to $[(OC)_5CrMn(CO)_5^-]$ This reaction mechanism may be described in terms of the consecutive reaction pathway in which Cr$(CO)_5$(THF) may be an important intermediate, leading to the corresponding products such as MeMn$(CO)_5\;and\;ICr(CO)_5^-$, accordingly. The counterion effect on this reaction was also elucidated.