• Bulletin of the Korean Chemical Society
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• 제26권11호
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• pp.1795-1802
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• 2005

Potential energy curves and internuclear (M-X) distance variations for dissociation reactions of $[MX_4]^{2-}$ into ($[MX_3]^-$ + $X^-$) have been calculated using ab initio Hartree-Fock (HF), second order M$\ddot{o}$ller-Plesset perturbation (MP2), and Density Functional Theory (DFT) methods with a triple zeta plus polarization (TZP) basis set. The equilibrium geometrical structures of $[MX_4]^{2-}$ are optimized to tetrahedral geometry for $[NiX_4]^{2-}$ and square planar geometry for ($[PdX_4]^{2-}$ and $[PtX_4]^{2-}$). The bond (M-X) distances of $[NiCl_4]^{2-}$, $[NiBr_4]^{2-}$, $[PdCl_4]^{2-}$, $[PdBr_4]^{2-}$, $[PtCl_4]^{2-}$, and $[PtBr_4]^{2-}$ at the DFT level are 2.258, 2.332, 2.351, 2.476, 2.367, and 2.493 $\AA$, respectively. The dissociation energies for the bond dissociation of ($[MX_3]^-$${\cdot}{\cdot}{\cdot}$$X^-$) at the DFT level are found to be 4.73 eV for $[NiCl_4]^{2-}$, 4.89 eV for $[NiBr_4]^{2-}$, 4.93 eV for $[PdCl_4]^{2-}$, 5.57 eV for $[PdBr_4]^{2-}$, 5.44 eV for $[PtCl_4]^{2-}$, and 5.87 eV for $[PtBr_4]^{2-}$. As the (M${\cdot}{\cdot}{\cdot}$X) distance of ($[MX_3]^-$${\cdot}{\cdot}{\cdot}$$X^-$) increases, the distance variation (Rt) of trans (M-X) bond at the trans-position is shorter than those (Rc) of two cis (M-X) bonds at the cisposition. Simultaneously the atomic charge variation of trans-X atom is more positive than those of equilibrium $[MX_4]^{2-}$ structures, while the variation of leaving X group is more positive.

• 한국결정성장학회지
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• 제18권6호
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• pp.237-241
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• 2008

AlN 소결체를 제조함에 있어서 $Y_2O_3$를 소결 첨가제로 하여 일축 가압 소결법을 적용하여 소결 조제 첨가량의 변화와 소결 시간의 변화에 따른 소결 특성, 미세구조 및 열전도도 측성에 대하여 조사하였다. $Y_2O_3$의 첨가로 인하여 AlN의 치밀화가 첨가하지 않은 경우보다 증진됨을 확인할 수 있었으며, 결정립계 및 결정립계 삼중점에서 YAG 이차상을 형성함으로써 AlN 결정 격자 내의 산소 결함 농도를 낮춰 열전도도를 향상시킴을 알 수 있었다. 특히, 소결 시간을 증대함에 따라 결정립 성장 및 열전도도의 방해 요소인 YAG 이차상이 고온에서 휘발됨에 따라 열전도도가 크게 향상됨을 확인할 수 있었다.

• 공업화학
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• 제27권4호
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• pp.343-352
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• 2016

지구상에는 1조 6880억 배럴의 원유매장량으로 현재 추세로 채굴하면 향후 53.3년 채굴 가능할 것으로 예측되고 있다. OPEC은 원유값이 10년 내에는 $100이 넘지 않을 것으로 예상하지만, 감산 정책의 정치적 이슈가 등장하면 원유값은 급격히 상승할 수도 있다. 따라서 일반 원유의 고갈에 대비해 비재래형 원유자원인 오일샌드나 비튜맨과 같은 중질유에 대한 관심이 높아지고 있다. 중질유는 일반적으로 레진이나 아스팔텐이라 부르는 탄소수가 60이 넘는 분자량이 높은 화합물 함량이 높아 점도가 높고 끓는점이 높다. 일반 원유를 감압 증류할 때 부생되는 감압잔사유(vacuum residue)는 물리화학적 물성들이 중질유와 비슷하다. 중질유의 채굴을 위해서는 점도를 낮추는 기술이 중요한데 본 리뷰논문은 상업적으로 사용되고 있는 aquathermolysis 기술을 검토하여 보았고 감압잔사유에 적용하여 보았다. 감압잔사유에는 니켈(Ni)과 바나듐(V)과 같은 전이금속이 함유되어 있는데, 이를 고도화하기 위해서는 전이금속 제거가 선행되어야 한다. 본 리뷰 논문에서는 감압잔사유로부터의 전이금속 제거 기술에 대한 최근 연구결과를 정리하여 보았다.

• 한국세라믹학회지
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• 제41권12호
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• pp.929-932
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• 2004

페로브스카이트 단일상의 PMN 계 복합화합물을 제조하기 위하여 일반적으로 소량의 MgO가 과잉으로 사용되며, 잉여 MgO는 주로 입내에 석출되며 소결을 저해하는 것으로 알려져 있다. 본 연구에서는 MgO 대신 $(MgCO_3)_4{\cdot}Mg(OH)_2{\cdot}5H_{2}O$을 사용하여 고상법으로 제조한 PMN-PT-BT(PBT) 전구체 분말을 $500^{\circ}C/1h$에서 열처리한 후, MgO 졸로 표면 개질하여, 과잉의 MgO가 소결 및 물성에 미치는 영향을 조사하였다. 소량의 MgO 졸($0.5{\sim}1.0wt\%$)은 $1000^{\circ}C$ 이하의 온도에서 소결을 크게 촉진시켰다. $0.5wt\%$의 졸이 사용된 PBT 분말은 $900^{\circ}C/2h$ 소결로 소결밀도 $7.62g/cm^3$, 유전율 14800, 유전손실 $1.1\%$를 나타내었으며, 이는 PBT의 $1000^{\circ}C/2h$ 소결체의 물성과 흡사하였다. 또한 MgO 졸로 첨가된 과잉의 MgO는 삼중점과 입계에 주로 석출되어 입성장을 제어함을 알 수 있었다.

• 대한핵의학회지
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• 제25권2호
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• pp.165-176
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• 1991

The purpose of this study was to assess the ability of quantitative Tl-201 tomography to identify and localize coronary artery disease (CAD). The study population consisted of 41 patients (31 males, 10 females; mean age $55{\pm}7$ yr) including 14 with prior myocardial infarction who underwent both exercise Tl-201 myocardium SPECT and coronary angiography for the evaluation of chest pain. From the short axis and vertical long axis tomograms, stress extent polar maps were generated by Cedars-Sinai Medical Center program, and the % stress defect extent (SDE) was quantified for each coronary artery territory. For the purpose of this study, the coronary circulation was divided into 6 arterial segments, and the "myocardial ischemic score" (MIS) was calculated from the coronary angiogram. Sensitivity for the detection of CAD ($\geq50%$ coronary stenosis by angiography) by angiography) by stress extent polar map was 95% in single vessel disease, and 100% in double and triple vessel deseases. Overall sensitivity was 97%. Sensitivity and specificity for the detection of individual diseased vessels were, respectively, 87% and 90% for the left anterior descending artery (LAD), 36% and 93% for the left circumflex artery (LCX), and 71% and 70% for the right coronary artery (RCA). Concordance for the detection of individual diseased vessels between the coronary angiography and stress polar map was fair for the LAD (kappa=0.70), and RCA (kappa=0.41) lesions, whereas it was poor for the LCX lesions (kappa : 0.32). There were siginificant correlations between the MIS and SDE in LAD (rs=0.56, p=0.0027), and RCA territory (rs=0.60, p=0.0094). No significant correlation was found in LCX territory. When total vascular territories were combined, there was a significant correlation between the MIS and SDE (rs=0.42, p=0.0116). In conclusion, the quantitative analysis of Tl-201 tomograms appears to be accurate for determining the presence and location of CAD.

• Asian Pacific Journal of Cancer Prevention
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• 제16권6호
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• pp.2465-2472
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• 2015

Background: The Quality Audit (BQA) program of the Breast Surgeons of Australia and New Zealand (NZ) collects data on early female breast cancer and its treatment. BQA data covered approximately half all early breast cancers diagnosed in NZ during roll-out of the BQA program in 1998-2010. Coverage increased progressively to about 80% by 2008. This is the biggest NZ breast cancer database outside the NZ Cancer Registry and it includes cancer and clinical management data not collected by the Registry. We used these BQA data to compare socio-demographic and cancer characteristics and survivals by ethnicity. Materials and Methods: BQA data for 1998-2010 diagnoses were linked to NZ death records using the National Health Index (NHI) for linking. Live cases were followed up to December $31^{st}$ 2010. Socio-demographic and invasive cancer characteristics and disease-specific survivals were compared by ethnicity. Results: Five-year survivals were 87% for Maori, 84% for Pacific, 91% for other NZ cases and 90% overall. This compared with the 86% survival reported for all female breast cases covered by the NZ Cancer Registry which also included more advanced stages. Patterns of survival by clinical risk factors accorded with patterns expected from the scientific literature. Compared with Other cases, Maori and Pacific women were younger, came from more deprived areas, and had larger cancers with more ductal and fewer lobular histology types. Their cancers were also less likely to have a triple negative phenotype. More of the Pacific women had vascular invasion. Maori women were more likely to reside in areas more remote from regional cancer centres, whereas Pacific women generally lived closer to these centres than Other NZ cases. Conclusions: NZ BQA data indicate previously unreported differences in breast cancer biology by ethnicity. Maori and Pacific women had reduced breast cancer survival compared with Other NZ women, after adjusting for socio-demographic and cancer characteristics. The potential contributions to survival differences of variations in service access, timeliness and quality of care, need to be examined, along with effects of comorbidity and biological factors.

• Radiation Oncology Journal
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• 제31권4호
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• pp.222-227
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• 2013

Purpose: This study was performed to evaluate prognostic factors for survival from first relapse (SFFR) in stage I-III breast cancer patients. Materials and Methods: From June 1994 to June 2008, 3,835 patients were treated with surgery plus postoperative radiotherapy and adjuvant chemotherapy for stage I-III breast cancer at Samsung Medical Center. Among them, a total of 224 patients died by June 2009, and 175 deaths were of breast cancer. Retrospective review was performed on medical records of 165 patients who met the inclusion criteria of this study. Univariate and multivariate analysis were done on survivals according to variables, such as age, stage, hormone status of tumor, disease-free interval (DFI), sites of first failure, number of organs involved by recurrent disease (NOR), application of salvage treatments, and existence of brain or liver metastasis (visceral metastasis). Results: Patients' median overall survival time was 38 months (range, 8 to 123 months). Median SFFR was 17 months (range, 5 to 87 months). Ninety percent of deaths occurred within 40 months after first recurrence. The patients with SFFR ${\leq}1$ year had tendency of triple-negativity, shorter DFI (${\leq}2$ years), larger NOR (>3), visceral metastasis for first relapse than the patients with SFFR >1 year. In multivariate analysis, longer DFI (>2 vs. ${\leq}2$ years), absence of visceral metastasis, and application of salvage treatments were statistically significant prognosticators for longer SFFR. Conclusion: The DFI, application of salvage treatments, and visceral metastasis were significant prognostic factors for SFFR in breast cancer patients.

• 한국결정성장학회지
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• 제19권1호
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• pp.33-38
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• 2009

AIN 소결에 있어서 ${Y_2}{O_3}$를 소결 조제로하여 $1,700{\sim}1,900^{\circ}C$의 온도에서 상압소결하엿을 때 ${Y_2}{O_3}$ 첨가와 소결 유지 시간이 소결 특성, 미세 구조 및 열전도도에 미치는 영향에 관하여 평가하였다. ${Y_2}{O_3}$의 첨가에 따라 AIN 시편은 치밀화가 증진되고 열전도도가 증가됨을 확인할 수 있었다. 이러한 결과는 AIN 분말 표면의 ${Al_2}{O_3}$와 ${Y_2}{O_3}$의 반응으로 형성된 이차상에 기인한 것으로, 첨가된 ${Y_2}{O_3}$는 ${Al_2}{O_3}$와의 반응으로 치밀화에 기여를 하여 고온에서 액상의 형성으로 급속히 치밀화를 증진시키며, AIN 결정격자 내부로 유입될 수 있는 산소의 양을 감소시킴으로써 AIN 시편의 열전도도를 증가시키는 것을 알 수 있었다. 또한 소결시간의 증가에 따라 열전도도는 급격히 증가하였는데 이는 결정립계의 이차상이 고온에서 휘발되어 그 양이 감소함에 기인하는 것으로 파악되었다. $1,900^{\circ}C$ 5시간 소결한 시편의 열전도도는 약 $141\;Wm^{-1}K^{-1}$ 값을 나타내었고 이는 1시간 소결한 시편과 비교하여 20% 이상 증가된 값이었다.

• 한국사회복지학
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• 제59권3호
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• pp.147-174
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• 2007

본 연구는 내부노동시장 및 외부노동시장과 분절된 근로빈곤노동시장의 경로제약성이 취업과 취업의 질에 누적적인 영향을 미쳐, 장기간 근로빈곤노동시장에 머물게 함으로써 근로빈곤탈출을 저해하는 악순환의 고리가 되는지 분석하였다. 자료는 한국노동패널 $3{\sim}7$차이고, 분석방법은 Markov 이행확률과 이산시간분석을 활용하였다. 분석결과 우리나라 노동시장은 내부노동시장과 외부노동시장 그리고 근로빈곤노동시장의 삼중 구조로 이루어져 있었다. 근로빈곤유형은 최근으로 올수록 취업빈곤층은 계속 감소하는 반면, 비경활 빈곤층은 점점 증가하여 근로빈곤층의 주된 유형이 되었다. 근본적으로 빈곤층에 대한 노동수요가 부족하며, 빈곤층의 취업자체를 저해하는 노동시장의 구조적 장벽이 존재함을 볼 수 있다. 회귀분석에서는 근로빈곤노동시장 참여기간이 길어질수록 근로빈곤 이탈률이 감소하였다. 이는 한번 근로빈곤노동시장에 편입되면 그 굴레를 벗어나지 못하고 근로빈곤노동시장 내에서 폐쇄적으로 이동하여, 다시 빈곤으로 연결되는 악순환을 보여주는 것이다. 따라서 적절한 근로조건을 보장하는 노동수요 활성화정책과, 근본적인 노동시장구조 개혁 및 빈곤층 노동에 대한 부정적 사회인식과 차별완화 정책이 필요하다.

• 동의생리병리학회지
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• 제17권3호
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• pp.617-623
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• 2003

The following conclusions are drawn from a review on the theory of correlation between the jang-bu organs in 'Ojangchunchaklon(五臟穿鑿論)' which is quoted in 'Uihakipmoon(醫學入門)' and 'Donguibogam(東醫寶鑑)'. The three yangs and three yins are trisections each of yang ki and y1n ki. They represent three aspects of change in powers of yin ki and yang ki. The theory of Kaehapchu(開闔樞 the opening, closing and pivot) is thought to be the concept which explains the three states of jang-bu organs and meridians in terms of three yangs and three yins. The three yangs and three yins are assigned to twelve months according to the generation, prosperity and vanishment of the water, the fire, the wood and the metal in the circulation of nature with the lapse of time. Most of all, the change of the water and the fire is the main guide to the assignment. Both the theory of exterior-interior relations in jang-bu organs and meridians and the theory of Kaehapchu are founded on the assignment of three yangs and three yins to twelve months. The correlation between jang-bu organs is based on the monthly assignment of three yangs and three yins described in 'Internal classic(內經)' and the theory of Kaehapchu. In the correlations between jang-bu organs and meridians, the exterior-interior relations are the correspondences of Hand to Hand and Foot to Foot. but the relations of Kaehapchu are those of Hand to Foot and Foot to Hand. Jeesan's diagram of pulse is grounded on the correlations between jang-bu organs. On the left of the diagram, jang organs are arranged in the order of hierarchic positions in body. On the right, bu organs are disposed according to the correlations with the jang organs. Jeesan's diagram includes the principles of triple harmony and diagonal groups in twelve earthly branches(十二支). Jeesan's diagram is the frame through which correlations of jung-ki-shin-hyul, five jang and six bu organs, twelve meridians and six intrinsic factors can be observed at once.