• 제목/요약/키워드: R-404A

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Preparation and Structure of $CH_2CH_2OOCCHCH_2SnCl_3$

  • Jung Ok-Sang;Lee Young-A;Jeong, Jong Hwa;Sohn Youn Soo
    • Bulletin of the Korean Chemical Society
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    • v.13 no.4
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    • pp.404-406
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    • 1992
  • A new estertin, $CH_2CH_2OOCCHCH_2SnCl_3$, was prepared and its structure was determined by X-ray crystallography ($P2_12_12_1$; a = 9.439(l), b = 9.601(l), c = 10.779(I) $\AA$, Z = 4) and refined to R = 0.0356. The coordination geometry around the tin atom approximates to a trigonal bipyramid with the intramolecularly coordinated oxygen O(1), (Sn-O(1), $2.482(6){\AA})$ and Cl(2) occupying mutually trans positions (O(1)-Sn-Cl((2), $176.4(2)^{\circ}$).

A SOLUTION OF EGGERT'S CONJECTURE IN SPECIAL CASES

  • KIM, SEGYEONG;PARK, JONG-YOULL
    • Honam Mathematical Journal
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    • v.27 no.3
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    • pp.399-404
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    • 2005
  • Let M be a finite commutative nilpotent algebra over a perfect field k of prime characteristic p and let $M^p$ be the sub-algebra of M generated by $x^p$, $x{\in}M$. Eggert[3] conjectures that $dim_kM{\geq}pdim_kM^p$. In this paper, we show that the conjecture holds for $M=R^+/I$, where $R=k[X_1,\;X_2,\;{\cdots},\;X_t]$ is a polynomial ring with indeterminates $X_1,\;X_2,\;{\cdots},\;X_t$ over k and $R^+$ is the maximal ideal of R generated by $X_1,\;X_2,{\cdots},\;X_t$ and I is a monomial ideal of R containing $X_1^{n_1+1},\;X_2^{n_2+1},\;{\cdots},\;X_t^{n_t+1}$ ($n_i{\geq}0$ for all i).

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Rubbing Angle Effect on Response Time of the Fringe Field Switching (FFS) TFT-LCD using the Liquid Crystal with Negative Dielectric Anisotropy

  • Noh, Jeong-Dong;Kim, Hyang-Yul;Kim, Jin-Mahn;Lee, Won-Gun;Park, Hae-Sung;Lee, Seung-Hee
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.401-404
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    • 2002
  • We have studied on response time of the fringe-field switching (FFS) TFT-LCD using the LCs with negative dielectric anisotropy related to rubbing angle. Simulation and experimental results shows that when a rubbing angle approached $45^{\circ}$, a slope of voltage-dependent curve is decreased such that the operation voltage is increased, however the whole response characteristic between inter-gray levels have a trend to be fast.

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Low Temperature Synthesis of Willemite Powder (Willemite 분말의 저온합성)

  • Son, Se-Gu;Lee, Ji-Hyeon;Lee, Jeong-Mi;Kim, Young-Do
    • Journal of the Korean Ceramic Society
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    • v.45 no.7
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    • pp.401-404
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    • 2008
  • Willemite ($Zn_2SiO_4$) are a wide range of applications such as a phosphor host and an important crystalline phase in glass ceramics, electrical insulators, glazes, and pigments. In this study, Willemite precursors were synthesized with zinc silicate gels from mixture of zinc nitrate solution and various sodium silicate solution by the geopolymer technique. To examine the crystallization behavior, precursors were have been monitored by the XRD. A pure willemite phase was obtained at $900^{\circ}C$. TEM investigations revealed that the sample with 50 nm particle size was obtained via heat-treated at $900^{\circ}C$ for W-3.

Experimental study on the performance of R-502 alternative refrigerant mixtures (R-502 대체 혼합냉매의 성능에 관한 실험적 연구)

  • Park, D.M.;Jeoung, D.S.;Kim, J.B.;Kang, D.J.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.9 no.2
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    • pp.198-209
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    • 1997
  • This paper is concerned about the performance of alternative refrigerants of R-502 which has been widely used in transport and low temperature refrigeration. A breadboard heat pump was constructed with counterflow heat exchangers and tested with R-502 and transitional alternatives of R-402A and R-402B and long-term alternatives of R-404A and R-507 to compare the performance of each refrigerant. Measurements were conducted at two different condensing temperatures of $43.3^{\circ}C$ and $52.0^{\circ}C$ and the evaporating temperature was varied over a range from $-25^{\circ}C$ to $-5^{\circ}C$. The evaporator superheat and condenser subcooling were maintained constant at about $5^{\circ}C$ for all tests. Test results showed that all alternative fluids tested in this research work can be used as 'drop-in' fluids to replace R-502 without any major problem. It is also found that in the long run HFC alternatives are to be used due to their favorable environmental characteristics and better performance.

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Dietary inflammatory index is associated with serum C-reactive protein and protein energy wasting in hemodialysis patients: A cross-sectional study

  • Kizil, Mevlude;Tengilimoglu-Metin, M. Merve;Gumus, Damla;Sevim, Sumeyra;Turkoglu, Inci;Mandiroglu, Fahri
    • Nutrition Research and Practice
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    • v.10 no.4
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    • pp.404-410
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    • 2016
  • BACKGROUND/OBJECTIVE: Malnutrition and inflammation are reported as the most powerful predictors of mortality and morbidity in hemodialysis (HD) patients. Diet has a key role in modulating inflammation and dietary inflammatory index (DII) is a new tool for assessment of inflammatory potential of diet. The aim of this study was to evaluate the application of DII on dietary intake of HD patients and examine the associations between DII and malnutrition-inflammation markers. SUBJECTS/METHODS: A total of 105 subjects were recruited for this cross-sectional study. Anthropometric measurements, 3-day dietary recall, and pre-dialysis biochemical parameters were recorded for each subject. Subjective global assessment (SGA), which was previously validated for HD patients, and malnutrition inflammation score (MIS) were used for the diagnosis of protein energy wasting. DII was calculated according to average of 3-day dietary recall data. RESULTS: DII showed significant correlation with reliable malnutrition and inflammation indicators including SGA (r = 0.28, P < 0.01), MIS (r = 0.28, P < 0.01), and serum C-reactive protein (CRP) (r = 0.35, P < 0.001) in HD patients. When the study population was divided into three subgroups according to their DII score, significant increasing trends across the tertiles of DII were observed for SGA score (P = 0.035), serum CRP (P = 0.001), dietary energy (P < 0.001), total fat (P < 0.001), saturated fatty acids (P < 0.001), polyunsaturated fatty acids (P = 0.006), and omega-6 fatty acids (P = 0.01) intakes. CONCLUSION: This study shows that DII is a good tool for assessing the overall inflammatory potential of diet in HD patients.

Runoff Characteristics of Refractory Organic Matters from Kyongan River Watershed during Rainfall Event and Dry Season (경안천 유역의 강우 시, 비 강우 시 난분해성 유기물질 유출 특성)

  • Kim, Taewon;Gil, Kyungik
    • Journal of Korean Society on Water Environment
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    • v.27 no.4
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    • pp.397-404
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    • 2011
  • This research investigates the runoff characteristics of refractory organic matters from Kyongan river watershed. Samples were taken 27 times during dry season, 4 times during rain events and analyzed into flow rate, Dissolved Organic Carbon (DOC), Particulate Organic Carbon (POC), Refractory Dissolved Organic Carbon (R-DOC), Refractory Particulate Organic Carbon (R-POC). R-DOC during dry season was the lowest in winter and showed a rising tendency in spring and R-POC changes less than R-DOC. The mass loading of Refractory Total Organic Carbon (R-TOC) in summer takes approximately 80% of 1 year mass loading. During rainy season, EMC of R-DOC was similar to R-DOC in dry season. But maximum EMC of R-POC was 12 times higher than that of R-POC in dry season. Results of the survey show that enhanced management of R-DOC in dry season and R-POC in rainy season is needed.

Comparison of Clinical Characteristics Between Respiratory and Non-Respiratory Subtypes of Panic Disorder (공황장애 호흡기 아형과 비호흡기 아형의 임상 특성 비교)

  • Ha, Ju-Won;Lim, Se-Won;Oh, Kang-Seob
    • Korean Journal of Biological Psychiatry
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    • v.16 no.1
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    • pp.46-52
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    • 2009
  • Objectives : The goal of this study was to compare the clinical characteristics of panic disorder respiratory subtype(PD-R) and non-respiratory subtype(PD-NR). Methods : 84 patients with panic disorder were enrolled and divided into 2 groups, 29 PD-R and 55 PD-NR. Diagnosis of panic disorder was evaluated using Diagnostic and Statistical Manual of Mental Disorders $4^{th}$ edition and Mini International Neuropsychiatric Interview. They were also measured with Hamilton Rating Scale for Anxiety(HAM-A), Hamilton Rating Scale for Depression(HAM-D), and Panic Disorder Severity Scale (PDSS). Results : PD-R group showed significantly higher scores in PDSS than those of PD-NR group(p=.027). After controlling for the severity of panic disorder and gender, PD-R group showed higher HAM-D and somatic anxiety subscale of HAM-A than those of PD-NR group. Furthermore, results of logistic regression analysis suggested that the somatic anxiety was a possible risk factor of PD-R(OR=1.404,p=0.009). Conclusion : These results suggest that somatic anxiety and depressive symptom would be important clinical characteristics of PD-R.

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Study on 3-Phase Isolated PFC Converter for the Electric Vehicle Charger (전기자동차 충전기를 위한 3상 절연형 PFC 컨버터의 회로 연구)

  • Kim, Yoon-Jae;Lee, Jun-Young;Lee, Il-Oun;Lee, Byung-Kwon;Choi, Seung-Won;Hong, Young-Gun
    • The Transactions of the Korean Institute of Power Electronics
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    • v.22 no.5
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    • pp.404-413
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    • 2017
  • This paper suggests an isolated PFC converter for electric vehicle (EV) chargers with wide-output voltage range. The proposed converter is based on voltage-fed full-bridge structure. All the harmonic and output controls are performed by secondary and primary switches are only operated under a fixed frequency with 50% duty-ratio. In addition, harmonic modulation technique is adopted to obtain a near unity power factor without input current monitoring. The feasibility of the proposed charger has been verified with a 10-kW prototype.