• Bulletin of the Korean Chemical Society
• /
• v.32 no.3
• /
• pp.889-893
• /
• 2011

The energetics and transition state (TS) structures of the reactions of six substrates, $R_1R_2P$(=O or S)Cl-type where $R_1=R_2$=Me and/or MeO, with ammonia in acetonitrile are theoretically investigated at the level of CPCM-MP2/6-31+G(d) and CPCM-MP2/6-311+G(3df,2p). The degrees of distortion of TS from the ideal trigonal bipyramidal pentacoordinate, ${\Delta}{{\delta}}_{{\neq}b}$ for a backside and ${\Delta}{{\delta}}_{{\neq}f}$ for a frontside attack, are calculated. The results of calculation suggest that the feasibility of a frontside attack for P=S is greater than that for P=O system when the two ligands, $R_1$ and $R_2$, becomes larger. The experimental and calculated results of anilinolyses of $R_1R_2P$(=O or S)Cl-type show the consistent tendencies.

• Proceedings of the Membrane Society of Korea Conference
• /
• 2004.05a
• /
• pp.94-97
• /
• 2004

Micro/nano-sized L $a_{0.6}$S $r_{0.4}$Co $O_{3-}$$\delta$/ particles are considered to improve oxygen permeability in highly selective inorganic oxygen separation membrane. A L $a_{0.7}$S $r_{0.3}$G $a_{0.6}$F $e_{0.4}$ $O_{3-}$$\delta$/ membrane with perovskite structure is fabricated by a conventional solid-state reaction. As the oxygen permeation flux of the L $a_{0.7}$S $r_{0.3}$G $a_{0.6}$F $e_{0.4}$ $O_{3-}$$\delta$/ membrane was lower than commercial gas separation membranes, we coated the L $a_{0.6}$S $r_{0.4}$Co $O_{3-}$$\delta$/ particles to enhance the oxygen permeation flux. It has been demonstrated that the effective area of reactive free surface is an important factor in determining the effectiveness of the introduction of coating layer for oxygen permeation. The introduction of micro/nano L $a_{0.6}$S $r_{0.4}$Co $O_{3-}$$\delta$/ particles was very effective for increasing oxygen flux, as the flux was as much as 2 to 6 times higher than that of an uncoated L $a_{0.7}$S $r_{0.3}$G $a_{0.6}$F $e_{0.4}$ $O_{3-}$$\delta$/ membrane.\delta$/ membrane.>/ membrane.brane.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.6 no.1
• /
• pp.77-87
• /
• 1996

In order to compare the difference of the measurement of delta aminolevulinic acid(${\delta}$-ALA) in urine between HPLC method(HALA) and colorimetric method(CALA), and also to provide useful information for the new diagnostic criteria of ${\delta}$-ALA in urine in lead poisoning, if at all possible in the future, authors studied 234 male lead workers who were selected from 7 storage battery factories, 3 secondary smelting industries, and 2 litharge making industries. Study subjects were selected on the basis of blood Zinc protoporphyrin(ZPP) level from low to high concentration to cover wide range of lead exposure. Study variables for this study were ${\delta}$-ALA measured by two different methods, blood lead(PbB), and blood ZPP. The results were as follows: 1. There was very high correlation between ${\delta}$-ALA measured by two method(r = 0.989 : HALA = -0.8194 + 0.8110 ${\times}$ CALA), but the value of CALA was measured about 2mg/L greater than HALA. 2. While the correlations of ${\delta}$-ALA by two method with blood lead and blood ZPP were 0.46 and 0.37 respectively, they were increased to 0.63 and 0.57 if ${\delta}$-ALA values were log-transformed. 3. Simple linear regression of ${\delta}$-ALA measured by two method on ZPP were as follows: CALA = 2.0421 + 0.0341 ${\times}$ ZPP ($R^2=0.1385$ p = 0.0001) HALA = 0.8006 + 0.0280 ${\times}$ ZPP ($R^2=0.1389$ p = 0.0001) 4. Simple linear regression of ${\delta}$-ALA measured by two method on PbB were as follows: CALA = - 0.4134 + 0.1545 ${\times}$ PbB ($R^2=0.2085$ p = 0.0001) HALA = -1.2893 + 0.1287 PbB ($R^2=0.2154$ p = 0.0001), 5. Simple linear regression of log-transformed ${\delta}$-ALA by two method on ZPP and PbB were as follows: logHALA = 0.3078 + 0.0060 ZPP ($R^2=0.3329$ p = 0.0001) logCALA = 1.0189 + 0.0044 ZPP ($R^2=0.3290$ p = 0.0001) logHALA = -0.0221 + 0.0246 PbB ($R^2=0.4046$ p = 0.0001) logCALA = 0.7662 + 0.0184 PbB ($R^2=0.4108$ p = 0.0001) 6. The cumulative percent of colorimetric method to detect lead workers whose value of PbS and ZPP were over screening level such as $40{\mu}/dl$ and $100{\mu}/dl$ respectively was higher than HPLC method if cut-off level of ${\delta}$-ALA for screening of lead poisoning was 5 mg/L. But if cut-off level of ${\delta}$-ALA measured by HPLC was reduced to 3 mg/L which is compatible to 5 mg/L of ${\delta}$-ALA measured by colorimetric method, there were good agreement between two methods and showed dose-response relationship with other lead exposure indices such as PbB and ZPP.

• Journal of Ocean Engineering and Technology
• /
• v.9 no.1
• /
• pp.92-100
• /
• 1995

The effect of different anisotropy and stress ratio on fatigue crack propagation behavior was investigated under various stress ratio(R=-0.4, -0.2, 0.2, 0.2, 0.4) using pure titanium sheet used in aerospace, chemical and food industry. The rack closure behavior under constant load amplitude fatigue crack propagation test was examined. Fatigue crack propagation rate da/dN was estimated in terms of effective stress intensity factor range, $\Delta$K$_{eff}$, regardless of various stress ratio but was influenced by anisotropy. Also, it was found that the effect of anisotropy was considerably decreased but still not negligible when he da/dN was evaluated by a conventional parameter, $\Delta$$K_{eff}$/E and when the modified da/dN.$\sqrt{\varepsilon}_f$ was evaluated by $\Delta$$K_{eff}$/E. On the other hand, da/dN could be evaluated uniquely by effective new parameter, $\Delta$K$_{eff}$/$sigma_{ys}$, regardless of anisotropy, as int he following equation da/dN=C''[\frac{{\Delta}K_{eff}}{{\sigma}_{ys}}]^{n''}. And effective stress intensity factor range ratio, U was estimated by the following equation with respect to the ratio of reversed plastic zone size, $\Delta r_{p}$ to monotonic plastic zone size, $r_p$ regardless of stress ratio and anisotropy. U=-4.45$(\Delta r_{p}/r_{p})^{2}$+4.1$(\Delta r_{p}/r_{p})$+0.245_{p})$+0.245

• Journal of the Korean Wood Science and Technology
• /
• v.8 no.1
• /
• pp.22-27
• /
• 1980

Quantitative assessment of edge blunting of saw-teeth was carried out by TALYSURF. 1. Using the following equation, the real shape of a saw-tooth can be traced on the graph of TALYSURF. ${\frac{{\Delta}h}{h}}={\frac{V{\Delta}_x}{V_x}}$ {${\Delta}h$: vertical distance of stylus h: vertical distance in chart $V{\Delta}_x$: Velocity of stylus $V_x$: velocity of chart} 2. As shown on Fig 2, the error from stylus itself can be calculated by following equation. i) 13.8${\mu}{\leqq}$x<20.4${\mu}$ y=-0.2246x+4.59${\mu}$ ii) 0${\leqq}$x<13.8${\mu}$ y=${\sqrt{(-18{\mu})^2-x^2}}-1.42x+32.7{\mu}}$ 3. The relationship between profile of saw-tooth and error from stylus itself can be calculated by following equation. $E(%)=\frac{f(r){\times}{\frac{4}{18{\mu}}}}{f(R){\times}{\frac{R}{18.5{\mu}}}-f(r){\times}{\frac{r}{18{\mu}}}}{\times}100$ {E(%)${\frac{error\;of\;stylus}{dullness\;of\;saw\;tooth}}{\times}100$ r: radius of stylus tip R: radius of tip which is drawn in graph of talysurf f(r) : error of stylus f(R) : dullness of tip which is drawn in graph of talysurf} 4. The graph of maximum error and profile of saw-tooth was parabola.

• East Asian mathematical journal
• /
• v.16 no.1
• /
• pp.89-96
• /
• 2000

In this paper, a differential polynomial ring $R[x;\delta]$ of ring R with a derivation $\delta$ are investigated as follows: For a reduced ring R, a ring R is Baer(resp. quasi-Baer, p.q.-Baer, p.p.-ring) if and only if the differential polynomial ring $R[x;\delta]$ is Baer(resp. quasi-Baer, p.q.-Baer, p.p.-ring).

• IMMUNE NETWORK
• /
• v.5 no.1
• /
• pp.23-29
• /
• 2005

Background: Interleukin-7 receptor (IL-7R) ${\alpha}$-deficient mice have small numbers of B cells and ${\alpha}{\beta}$T cells in periphery, they totally lack ${\gamma}{\delta}$T cells. In addition, the V-J recombination and transcription of TCR ${\gamma}$ genes is also severely impaired in IL-7R ${\alpha}$-deficient mice. Stat5, a signaling molecule of the IL-7R, induces germline transcription in the TCR ${\gamma}$ locus, and promotes V-J recombination and ${\gamma}{\delta}$T cell development. However, the roles for IL-7R signaling pathway in thymic or extrathymic ${\gamma}{\delta}$T cell development are largely unknown. Methods: To clarify the role of the IL-7 receptor in proliferation and survival of ${\gamma}{\delta}$T cells, we introduced the TCR ${\gamma}{\delta}$ transgene, $V_{{\gamma}2}/V{\delta}_5$, into IL-7R ${\alpha}$-deficient mice, and investigated the development of ${\gamma}{\delta}$T cells. Results: We found that $V_{{\gamma}2}/V{\delta}_5$ transgene restored ${\gamma}{\delta}$T cells in the epithelium of the small intestine (IEL) but not in the thymus and the spleen. Further addition of a bcl-2 transgene resulted in partial recovery of ${\gamma}{\delta}$T cells in the thymus and the spleen of these mice. Conclusion: Taken together, this study revealed that the IL-7R ${\alpha}$ is indispensable for proliferation and survival mainly in thymic ${\gamma}{\delta}$T cell development.

• International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
• /
• v.21 no.1
• /
• pp.17-30
• /
• 1993

The basic processes responsible for the generation of oceanic fronts were reviewed. In particular the process of a shelf sea front produced by tidal stirring was identified from the one dimensional model of the water column in the coastal area, which incorporates the microscale process for the formation of a tidal front. Also a new criterion to predict its location was suggested. The time evolutions of the distributions of density and turbulent kinetic energy calculated from the model show that the criterion for the formation of a thermocline can be predicted as $R{\delta}^4$~ constant for large $\delta$ ($\delta$＞0.5), but the dependence on $\delta$ decreases as $\delta$ goes to O, where $R=H^4Q/{K_b}^3$,{\;}{\delta}=1-Do/H$, Q is the buoyancy flux at the surface, $K_b$ is the eddy diffusivity maintained at the bottom and Do is the depth of a thermocline in the absence of bottom mixing. The depth of a thermocline was found to decrease as the bottom mixing increases for a given value of Do. The results were interpreted in comparison with the previous studies.

• Asian Pacific Journal of Cancer Prevention
• /
• v.17 no.9
• /
• pp.4451-4456
• /
• 2016

Background: In this study, we examined epidemiological aspects of dynamic changes in incidences of laryngeal cancer in male and female populations in Kazakhstan. Materials and Methods: Primary data were for registered patients with malignant laryngeal tumors in the whole country during the period of 1999-2014. Evaluation of changes in laryngeal cancer incidence in the population of Kazakhstan was performed using component analysis. Results: It was determined that the number of patients with laryngeal cancer in the whole country is decreasing although with conflicting impacts of different factors. Despite population growth (all - ${\Delta}_P=+66.1%$, men - ${\Delta}_P=+70.9%$ and women - ${\Delta}_P=+46.4%$), and aging (all - ${\Delta}_A=+45.1%$, men - ${\Delta}_A=+54.3$ and women - ${\Delta}_A=+22.2$), the reduction in risk of developing the disease (all - ${\Delta}_R=-165.6%$, men - ${\Delta}_R=-170.9%$ and women - ${\Delta}_R=-141.0%$) was overwhelming. Conclusions: This investigation was the first epidemiological study of dynamics of laryngeal cancer by component analysis in population of Kazakhstan. Implementation of the results of the study is recommended in management of anti-cancer activities for laryngeal cancer.

• Bulletin of the Korean Mathematical Society
• /
• v.55 no.1
• /
• pp.51-61
• /
• 2018

In this article, we mainly use Nevanlinna theory to investigate some special difference equations of malmquist type such as $f^2+({\Delta}_cf)^2={\beta}^2$, $f^2+({\Delta}_cf)^2=R$, $f{^{\prime}^2}+({\Delta}_cf)^2=R$ and $f^2+(f(z+c))^2=R$, where ${\beta}$ is a nonzero small function of f and R is a nonzero rational function respectively. These discussions extend one related result due to C. C. Yang et al. in some sense