• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.1
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• pp.47-57
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• 2010

Subgrid scale stabilization method is applied to Woo and Liu(2004)'s extended Boussinesq FEM numerical model to eliminate the 2dx wiggles. In order to optimize the computational efficiency, Hessian operator is introduced and the matrix of velocity vector is combined to one matrix for solving matrix equations. The mass lumping technique is also applied to the matrix equations of auxiliary variables. The newly developed code is applied to simulate Vincent and Briggs(1989)' wave transformation experiments and the results show that the numerical solution is almost wiggle-free and it matches very well with experimental data. Due to improvement of computational efficiency and wiggle reduction, it is plausible to apply this model to a realistic problem such as harbor oscillation problems.

• Korean journal of food and cookery science
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• v.18 no.2
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• pp.200-205
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• 2002

Corn starch was modified by the oxidation with sodium hypochlorite(NaOCl) and the changes in the distribution of molecular weight were examined. Corn starch was oxidized with 0.25, 0.5, 0.75, 1.0, and 1.5% active Cl/g of starch at pH 7.0 and 25$^{\circ}C$ for 10 min. Oxidation of corn starch caused a change in the molecular weight distribution of amylopectin. The fraction of highest molecular weight in native starch decreased gradually and the fraction of lower molecular weight increased with increasing oxidation. Also, λ$\sub$max/ and iodine binding capacities of oxidized starches decreased and the soluble carbohydrate content increased by oxidation. The differential scanning calorimetric results of oxidized starches showed that the temperature and enthalpies of gelatinization were not changed by oxidation; however, the more the starch was oxidized, the greater the extent of retrogradation.

• Applied Chemistry for Engineering
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• v.24 no.6
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• pp.611-615
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• 2013

Vanadium oxide ($VO_2$) and tungsten-doped vanadium oxide (W-$VO_2$) powder, well known as thermochromic materials, were prepared from vanadium pentoxide ($V_2O_5$) and oxalic acid dihydrate by hydrothermal and calcination process. The crystal structure and thermochromic property of samples were analyzed using FE-SEM, XRD, XPS, DSC, and UV-Vis-NIR spectroscopy. With increasing the doping amount of W, the phase transition temperature of W-$VO_2$ sample decreased from $70^{\circ}C$ to $42^{\circ}C$. When heating W-$VO_2$ sample above the phase transition temperature, the UV-Vis-NIR spectrum was not changed in the visible range and shifted towards a low transparency in the full name (NIR) region.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.10 no.1
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• pp.1-10
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• 1985

Solar energy has its advantages not to be interruped by anything, which is wing to not only limitlessness in its source but shortness in its wave. Availing of tha advantages, we can look forword to vast allication. This study whose aim is to raise the effectuality of it by means of chasing the source correctly, which is to be acheved by the circularty of sensor. The consequence has been gained by two sensors is amplified and transfered to TTL leveland becomes "INPUT DATA" of INTE 8080CPU. The INTEL 8080CPU whose system is machinated to give cotrol pulse to moter driving circuit has the source and the sensors placed correctly on the basis of the data. DC motor taskes the advantage not to be in need of UP/DOWN counter, which is defferent from stepping motor. The system is composed of light detector, A/C converter, INPUT Interface, INTEL 8080 CPU, OUTPUT Interface, notor driving circiut. We can give correct chase to light experimentally as far as an error is the space of 1.2.ce of 1.2.

• Polymer(Korea)
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• v.31 no.5
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• pp.393-398
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• 2007

We studied the mechanism of liquid crystal alignment on polyvinylfluorocinnamate (PVCN-F) films which were irradiated by UV using polarized fourier transform infrared (FT-IR) spectroscopy and ultraviolet/visible (UV/Vis) spectroscopy. UV irradiation of PVCN-F films caused decrease of vinylene -C=C- stretching peak area at $1638cm^{-1}$ and shift of conjugated C:0 stretching vibration at $1712cm^{-1}\;to\;1734cm^{-1}$ which is caused by nonconjugated C=O stretching nitration. To study the orientation direction of 5CB liquid crystal (LC) molecules in the liquid crystal cell with PUV irradiation, rubbing treatment or without any treatment on the PVCN-F alignment layer, we used polarized FT-IR dichroism technique. We successfully measured 5CB LC alignment directions, which are perpendicular to the irradiated PUV polarization direction and parallel to the rubbing direction in the liquid crystal cell without using dichroic dyes.

• Polymer(Korea)
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• v.31 no.5
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• pp.374-378
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• 2007

Water-soluble terpolymer of acrylamide, diacetone acrylamide, and acrylic acid was prepared by redox initiators in aqueous medium. One component photoresist was synthesized by reaction of terpolymer with 4-azidoaniline. By blending the aqueous acrylamide/diacetone acrylamide copolymer solution with bisazide, 4,4'-diazidostilbene -2,2'-disulfuric acid sodium salt, two component photoresist was prepared. The photosensitivity per azido group unit mole of one component photoresist was 4 times higher than that of two component photoresist. The dot-type pattern was successfully achieved with one component photoresist at low exposure energy, which is prospective to be used as black matrix negative photoresist.

• Elastomers and Composites
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• v.44 no.4
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• pp.416-422
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• 2009

4-(6-bromohexyloxy)benzoic acid was synthesized from benzyl 4-Hydroxybenzoate and 1,6-dibromohexane. It was reacted with hydroquinone to obtain a new mesogenic ester having an bromine group. One kind of new photoresponsive coumarin compound was prepared by the reaction of mesogenic ester with coumarin sensitive to the ultraviolet. Structures of the compound were identified by FT-IR and $^1H$-NMR spectroscopies. Their phase transition temperatures and thermal stability were also investigated by differential scanning calorimetry (DSC), polarized optical microscopy (POM) and x-ray diffraction analysis. From optical polarizing microscopy, the prepared compound was found to show enantiotropic liquid crystallinity with smectic and nematic textures.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.33 no.4
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• pp.55-73
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• 2020

Objectives : We investigated the effectiveness and safety of intranasal phototherapy for allergic rhinitis (AR). Methods : We searched 8 electronic databases (PubMed, Cochrane Library, CNKI, CiNii Articles, OASIS, NDSL, KISS, KMbase) to identify randomized controlled trials (RCTs) that reported the use of intranasal phototherapy for AR from their inception until May 30, 2020. Two investigators independently searched, collected, and screened the RCTs. We performed data extraction and evaluation for risk of bias using the Cochrane risk-of-bias tool. Results : This study included 12 RCTs; six studies compared intranasal and sham phototherapy, of which four studies reported a significant inter group difference and two studies reported a significant difference partially. No significant changes in symptoms were observed between the phototherapy and conventional therapy groups. The phototherapy and concurrent acupuncture treatment group showed a significantly higher effectiveness rate compared with the group that received only acupuncture. Both the phototherapy and laser acupuncture group showed significant improvement in the symptom severity scale scores. Six studies reported mild adverse effects, such as dryness and nasal pain in the intranasal phototherapy group; however, no severe adverse effects were reported. Conclusions : This study confirmed the safety and effectiveness of intranasal phototherapy for symptom relief and improved quality of life in patients with AR. However, further studies are needed on this topic in order to demonstrate it clearly.

• The Transactions of the Korea Information Processing Society
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• v.6 no.4
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• pp.1098-1105
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• 1999

The caches in distributed shared memory systems enhance the performance by reducing memory access latency and communication overhead, but they must solve the cache coherence problem. This paper proposes a new directory protocol to solve the cache coherence problem and to improve the system performance in distributed shared memory systems. To maintain the cache coherence of shared data, processors within a limited distance reduce the communication overhead by using a bit-vector like the full directory scheme. Processors over a limited distance store pointers in a directory pool. Since the bit-vector and the directory pool remove the unnecessary cache invalidations, the proposed scheme reduces the communication traffic and improves the system performance. The dynamic limited directory scheme reduces the communication traffic up to 66 percents compared with the limited directory scheme and the number of directory access up to 27 percents compared with the dynamic pointer allocation scheme.

• Journal of the Korean Chemical Society
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• v.29 no.6
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• pp.575-581
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• 1985

Ultraviolet spectrophotometric investigations have been carried out on the systems of benzene, naphthalene and phenanthrene with iodine in carbon tetrachloride. The results reveal the formation of the one to one molecular complexes. The equilibrium constants were obtained in consideration of that absorption maxima due to the formation of the charge transfer complexes shift to blue with increasing temperature. Thermodynamic parameters for the formation of the charge transfer complexes were calculated from these values. These results indicate that the stabilities of the complexes formed between polynuclear aromatics and iodine increase with the number of aromatic rings. This may be a measure of the relative basicities of polynuclear aromatics toward iodine, which is explained in terms of the resonance of the interaction between aromatics and iodine. The results in this study were, additionally, compared with those of the polymethylbenzene series to be discussed the reason for them.