• 한국연소학회지
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• 제12권4호
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• pp.1-7
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• 2007

Carbon monoxide (CO) is not only an important intermediate species in chemical reaction mechanisms of hydrocarbon fuel combustion, but also a crucial pollutant species emitted from automotive engines. To better understand the physical processes impacting CO emissions, the development of laser-based measurement techniques that can visualize in-cylinder CO distributions is desirable. Among these techniques, Laser-Induced Fluorescence (LIF) is a sensitive and species-selective detection technique capable of good spatial resolution. However, some technical matters such as deep UV excitation, severe pressure dependency of the LIF signal, and potential interference from other species have been major challenges for CO LIF application. This study is focused on investigating the feasibility of CO two-photon LIF in a direct-injection diesel engine operating at typical pressure and temperature conditions with commercial grade diesel fuel. Spectroscopic analysis shows that the CO fluorescence signal can be separated from $C_2$ Swan band or broadband fluorescence from PAHs when the signal is collected near 483 nm. The signal-to-noise ratio of CO LIF deteriorate rapidly as pressure is increased, following $P^{-1.49}$ which matches the theoretical signal pressure dependency.

• Carbon letters
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• 제12권4호
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• pp.223-228
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• 2011

In this present work, the effect of additional heat-treatment (AHT) in the range from $1800^{\circ}C$ to $2400^{\circ}C$ on the chemical composition, morphology, microstructure, tensile properties, electrical resistivity, and thermal stability of commercial polyacrylonitrile (PAN)-based carbon fibers was explored by means of elemental analysis, electron microscopy, X-ray diffraction analysis, single fiber tensile testing, two-probe electrical resistivity testing, and thermogravimetric analysis (TGA). The characterization results were in agreement with each other. The results clearly demonstrated that AHTs up to $2400^{\circ}C$ played a significant role in further contributing not only to the enhancement of carbon content, fiber morphology, and tensile modulus, but also to the reduction of fiber diameter, inter-graphene layer distance, and electrical resistivity of "as-received" carbon fibers without AHT. The present study suggests that key properties of commercial PAN-based carbon fibers of an intermediate grade can be further improved by proprietarily adding heat-treatment without applying tension in a batch process.

• 아동학회지
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• 제34권2호
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• pp.83-99
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• 2013

The premise underpinning this research is that cognitive evaluation is the starting point of children's emotional experience. It then went on to investigate how parents' person-oriented guidance affects children's emotional intelligence. Additionally, children's ego-resilience was analyzed as a variable that affects children's emotional intelligence and as a mediator between parents' person-oriented guidance and children's emotional intelligence. A purposive sampling was conducted in 4 elementary schools in metropolitan areas and made use of 466 students in 4th and 5th grade as research subjects. The results are summarized as follows：firstly, the more frequently parents used person-oriented guidance, the more children exhibited higher levels of ego-resilience and emotional intelligence. Secondly, vitality, peer relations, optimism, curiosity, emotional regulation, maternal person-oriented guidance were found to affect emotional intelligence in the order of relative significance of that influence. Thirdly, children's ego-resilience was found to intermediate parents' person-oriented guidance and children's emotional intelligence. In conclusion, individual children's evaluations of parental verbal stimuli was found to influence children's emotional intelligence, especially more significantly through the mediation of children's ego-resilience.

• Journal of Yeungnam Medical Science
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• 제21권1호
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• pp.12-22
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• 2004

The management of coincident glaucoma and cataract is not only a common clinical challenge but also an important research topic in the ophthalmic surgical field. The purpose of this article is to compare the different surgical options on the basis of their achievable postoperative intraocular pressure (IOP) control, success rates, and complication rates reported in the related literature, and to give advice on how to manage typical situations of patients with both glaucoma and cataract. Main topics were focused on indications and rationale of 3 surgical options (only cataract surgery first and later trabeculectomy, only trabeculectomy first and later cataract surgery, or simultaneous combined surgery). Modern clear corneal cataract extraction techniques resulted in a modest intermediate-term reduction of IOP and has considerably improved the success rates of combined glaucoma and cataract surgery. It also enabled future trabeculectomy to be successfully performed at a later date if necessary. Trabeculectomy alone achieved better IOP regulation than phacotrabeculectomy (combined surgery), but subsequent cataract surgery may compromise preexisting filtering bleb. Combined surgery augmented with mitomycin C achieved a lower IOP than combined surgery alone but had a higher complication rate. In conclusion, the choice of the preferred surgical method should be determined according to the target pressure, the amount of glaucomatous damage, and the grade of visual disturbance caused by the cataract. Phacotrabeculectomy with adjunctive mitomycin C offers visual improvement and achieves the best IOP lowering of all types of combined glaucoma and cataract surgery currently used but is associated with potentially sight-threatening complications.

• The Korean Journal of Pain
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• 제19권2호
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• pp.192-196
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• 2006

Background: Epidural opioids are commonly used for postoperative analgesia. However, the side effects of epidural opioids include respiratory depression, sedation, pruritus, nausea, vomiting and urinary retention. Meperidine, due to its intermediate lipid solubility and local anesthetic properties, permits postoperative analgesia. The aim of this study was to compare meperidine alone to meperidine coupled with bupivacaine, and to determine the effects of epidural meperidine without bupivacaine, when used for epidural analgesia following hepatectomy abdominal surgery. Methods: Patients received thoracic epidural analgesia with meperidine alone (3.5 mg/ml in saline) or with additional bupivacaine (0.15%) for 2 days after surgery. Postoperative pain was assessed using a visual analog scale (VAS) pain score 2 days after the operation, with the incidence and dose supplementation also evaluated. Postoperative side effects were assessed using a 3 grade system. Results: No significant difference was found between the two groups in terms of age and weight, or in the pain scores, side effects, incidence and dose supplementation. Conclusions: 3.5 mg/ml epidural meperidine at a dose of 2 ml/hr provides effective postoperative analgesia.

• Fisheries and Aquatic Sciences
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• 제19권1호
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• pp.3.1-3.6
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• 2016

Phlorotannins are reported to have diverse biological properties. However, no analytical methods for the standardization of phlorotannin preparations have been reported. Herein, we developed and validated an analytical method for the determination of dieckol in phlorotannin extracts (PRT) using high-performance liquid chromatography (HPLC). The optimum HPLC conditions consisted of a Supelco Discovery C18 column stationary phase, a mobile phase (A: 15 % HPLC grade methanol in deionized water, B: methanol), UV detection at 230 nm, and a flow rate of 0.7 mL/min. The optimized chromatographic conditions were validated and exhibited good specificity and linearity ($R^2$ > 0.9994-1.0000). The recoveries were in the range of 100.9-102.3 %. The method had good intermediate (%RSD 1.2) and intra-day (%RSD 0.4-1.7) assay precisions. This HPLC method had good accuracy and quality in the determination of dieckol in PRT.

• 대한수학교육학회지:수학교육학연구
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• 제8권2호
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• pp.709-722
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• 1998

This thesis is to see if the classes using problem posing is effective to improve the students' grades in math. So I set up research subjects as follow. 1. Do the classes focused on problem posing have any influence on the students' achievement\ulcorner 2. Do the classes focused on problem posing have any different influence on the students' achievement according to their levels\ulcorner 3. Do the classes focused on problem posing have any different influence on the students' achievement according to the categories in math\ulcorner I close four classes in the first grade of K middle school in Kangnung, Kangwon province for this thesis. First I divided them into two groups. Each group consisted of two classes. One is the experimental group. The other is the comparative group. The experimental group was taken classes using problem posing. The comparative group was taken classes by the traditional teaching method. And then I analyzed the difference of the achievement between two groups. As a result of this research, I came to the conclusion as follow. First, the classes focused on problem posing is more effective than traditional teaching method for the improvement of the students` achievement Second, both the classes using problem posing and the traditional teaching method doesn`t affect to the advanced students. Third, the classes using problem posing is more effective to the intermediate students and lower level students than the traditional teaching method. Especially it is very effective in teaching the students the linear equation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 E
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• pp.1840-1842
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• 1998

Gyroscope is a very important core sensor, as a rotation sensor in inertial space, in inertial guidance and navigation system on aeronautics, plane, vessel and so on for civilian and millitary applications. Mechnical gyroscopes, adopting a principle of spinning a top, have been used in many application system. These mechnical gyroscopes need high power consumption, long warming time and complicated peripheral devices. But fiber-optic gyroscopes, based on the Sagnac effect, have novel advantages as small volume. simple scheme, low power consumption and high reliability. So we have developed a Intermediate grade All-fiber Optic Gyroscope, which has open-loop and minimum reciprocal configuration scheme. We have designed feedback circuits for stability of amplitude and phase using four lock-in amplifier(LIA) circuits and also used for noise limitation. This paper describes the scheme of optical part and electronic part and also test results of this all-fiber optic gyroscope. The performance have been achieved as long-term bias drift of $9.54^{\circ}/h$, random walk of $0.0317^{\circ}/\sqrt{h}$ and dynamic range of ${\pm}150\;deg/s$.

• 설비공학논문집
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• 제26권4호
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• pp.145-150
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• 2014

Many studies are being conducted with the aim of reducing the energy consumption in data centers, which are one of the highest consumers of energy. The use of an air-side economizer system that uses external air during intermediate and winter seasons is being considered for reducing the energy consumption of air conditioners. In this study, using the energy simulation, we evaluated the energy performance of a central chilled water cooling system and air-side economizer system in domestic data centers. Further, the cost-effectiveness of the air-side economizer was analyzed through Life-Cycle Cost Analysis. The results showed that with the use of air-side economizer systems, the energy costs increased as the applied filter grade increased; however, unlike existing central chilled water systems, it would break even within 2 years.

• 아동학회지
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• 제35권1호
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• pp.17-41
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• 2014

This study explored the sandplay therapy case of a 5th grade boy who was living in a small income fatherless family from the viewpoints of both sandplay theory and related literatures. The goal of the therapy was to lessen his difficulties under the free and protected space of sandplay therapy. This study comprised 59 sessions of sandplay therapy. The subject exhibited his situations in the initial parts of therapy(1~5, the preparation for war against enemies) by putting miniatures related to Egypt and by placing Indians who were keeping the house from enemies. In the intermediate sessions(6~47, holding a ceremony), he repeated burning rituals, played finding treasures, and exhibited both struggle and construction. In the final parts(48~59, integration), he showed integration by expressing the adaptation to the collective. This study indicated the effectiveness of sandplay therapy, because his maladjustments in both school and home were reduced.