• Communications of the Korean Mathematical Society
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• v.38 no.3
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• pp.741-754
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• 2023

In this paper, we study the existence and nonexistence of solutions for a class of Hamiltonian strongly degenerate elliptic system with subcritical growth $$\left{\array{-{\Delta}_{\lambda}u-{\mu}v={\mid}v{\mid}^{p-1}v&&\text{in }{\Omega},\\-{\Delta}_{\lambda}v-{\mu}u={\mid}u{\mid}^{q-1}u&&\text{in }{\Omega},\\u=v=0&&\text{ on }{\partial}{\Omega},}$$ where p, q > 1 and Ω is a smooth bounded domain in ℝ^N, N ≥ 3. Here Δ_λ is the strongly degenerate elliptic operator. The existence of at least a nontrivial solution is obtained by variational methods while the nonexistence of positive solutions are proven by a contradiction argument.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.7
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• pp.1068-1076
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• 2020

Objective: In the present study, we determined efficiency of incorporating caffeine, melatonin or omega-3 polyunsaturated fatty acid in the diluent on mitigating consequences of (a) liquid chilled- and (b) cryo-storage of ram spermatozoa. Methods: In the first experiment, ejaculates (n = 30) were collected from 5 adult rams and were pooled, diluted (1:10) with Tris-citric acid (base diluent) and were split into 4 aliquots assigned for: control (untreated), caffeine (0.1 mM), melatonin (0.3 mM) or omega-3 fatty acids (0.3 mM) (T₀). The diluted specimens were stored at 4℃ for 48 h, during which sperm physical and cytological properties were evaluated along with oxidative stress indices (T₂₄, T₄₈). In the second experiment, 15 ejaculates (3 per male) were pooled, diluted with glycerolized base diluent (4% glycerol, v/v) and were split corresponding to the same previous treatment groups before being processed for cryopreservation. Post-thaw physical and kinematic sperm properties were assessed by a computer-assisted sperm analysis system. Results: The results clarified superiority of both melatonin and omega-3 supplementation on maintaining (p<0.05) sperm properties, while reducing (p<0.05) lipid peroxidase reaction and enzymatic activities of alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase in preservation medium, compared to caffeine either during liquid-chilled storage or cryopreservation of spermatozoa. Conclusion: Melatonin and omega-3 are regarded efficient alternatives to caffeine when processing ram spermatozoa for application of artificial insemination or in vitro fertilization.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.3
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• pp.195-202
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• 1998

The LPCVD system of batch type for the massproduction of semiconductor fabrication has a problem of phosphorous concentration uniformity in the boat. In this paper we study an improvement of the uniformity for phosphorous concentration and sheet resistance. These property was improved by using the nitrogen process and modified long nozzle for gas injection tube in the doped polysilicon deposition system. The phosphorous concentration and its uniformity for polysilicon film are measured by XRF(X-ray Fluorescence) for the conventional process condition and nitrogen process. In conventional process condition, the phosphorous concentration, it uniformity and sheet resistance for polysilicon film are in the range of 3.8~5.4$\times$10\ulcorner atoms/㎤, 17.3% and 59~$\Omega$/ , respectively. For the case of nitrogen process the corresponding measurements exhibited between 4.3~5.3$\times$10\ulcorner atoms/㎤, 10.6% and 58~81$\Omega$/ . We find that in the nitrogen process the uniformity of phosphorous concentration improved compared with conventional process condition, however, the sheet resistance in the up zone of the boat increased about 12 $\Omega$/ . In modified long nozzle, the phosphorous concentration, its uniformity and sheet resistance for polysilicon films are in the range of 4.5~5.1$\times$10\ulcorner atoms/㎤, 5.3% and 60~65$\Omega$/ respectively. Annealing after $N_2$process gives the increment of grain size and the decrement of roughness. Modification of nozzle gives the increment of injection amount of PH$_3$. Both of these suggestion result in the stable phosphorous concentration and sheet resistance. The results obtained in this study are also applicable to process control of batch type system for memory device fabrication.

• Archives of Pharmacal Research
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• v.26 no.5
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• pp.367-374
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• 2003

In the course of screening neuraminidase inhibitors from herbal medicines, Reynoutria elliptica exhibited high inhibitory activity. Four active compounds were isolated from the ethyl acetate soluble fraction by consecutive purification using sillica gel, Sephadex LH-20 chromatography, and recrystallization. The chemical structures of these compounds were identified as 1,3,8-trihydroxy-6-methylanthraquinone (emodin) 1,8-dihydroxy-3-methoxy-6-methylanthraquinone (emodin 3-methyl ether; physcion), 1,3,8-trihydroxy-6-hydoxymethylanthraquinone ($\omega$-hydroxyemodin), and 3,5,4 -trihydroxystilbene (trans-resvertrol) by spectral data including MS, $^1 H-, and ^{13}C-NMR. The IC_{50}$ values of emodin, emodin 3-methyl ether, $\omega$-hydroxyemodin, and trans-resvertrol were 2.81, 74.07, 10.49, and 8.77 $\mu$M, respectively. They did not inhibit other glycosidase such as glucosidase, mannosidase, and galactosidase, indicating that they were relatively specific inhibitors of neuraminidase.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.9
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• pp.1246-1254
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• 2004

Two separate trials were designed to determine effects of dietary level of whole flaxseed (WFS) on fatty acid composition of serum, and subcutaneous, perirenal, intermuscular, and intramuscular adipose tissues of Korean Hanwoo cattle. Twentyone bulls (trial 1) and 15 cows (trial 2) were assigned to diets containing 0, 10 or 15% WFS. Relative treatment effects were similar between bulls and cows. The proportion of C18:3 in serum and to a lesser extent in adipose tissues were increased by dietary inclusion of WFS, reflecting supplemented lipid composition of WFS that escaped ruminal biohydrogenation. Animals fed WFS had a lower proportion of saturated fatty acids in serum and adipose tissues than animals fed diets without WFS, while the opposite trend was observed in unsaturated fatty acids with little differences between two WFS groups. WFS-fed animals had higher proportions of C18:1, 18:2, 18:3, 20:3, and 22:3 and lower proportions of C12:0, 14:0, 16:0 and 18:0 in intramuscular fat than animals fed diets without WFS. Furthermore, feeding WFS increased proportions of both $\omega$-3 and $\omega$-6 fatty acids but decreased the ratio of $\omega$-6/$\omega$-3 substantially. In conclusion, feeding WFS can be an effective method of increasing absorption of unsaturated fatty acids, and subsequent deposition in adipose tissues.

• Korean Chemical Engineering Research
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• v.50 no.4
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• pp.614-620
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• 2012

Polyurethane prepolymers were prepared from poly (carbonate diol), isophrone diisocyanate and dimethylol propionic acid. Then, aniline terminated waterborne polyurethane dispersion (ATPUD) was synthesized by capping the NCO group of the prepolymer with aniline monomer. Subsequently, ATPUD and waterborne polyurethane dispersion (PUD), respectively, were blended with conducting polymer, poly (3,4-ethylenedioxythiophene)/polystyrene sulfonate [PEDOT/PSS], to yield antistatic coating solutions, and the mixture was coated on the polycarbonate substrates. At adequate addition amounts of PEDOT/PSS less than or equal to 2.5 g, the surface resistances ($1.0{\times}10^{11}{\sim}2.5{\times}10^8{\Omega}/cm^2$) of coating films from ATPUD showed better electronic conductivities than those ($5.0{\times}10^{11}{\sim}6.3{\times}10^9{\Omega}/cm^2$) from PUD. However, at excess amount of PEDOT/PSS of 3.0 g, the surface resistance from ATPUD showed similar electronic conductivity with that from PUD.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.11
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• pp.791-803
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• 2001

Mach-Zehnder type traveling-wave Ti：LiNb $O_3$ optical modulators were designed and fabricated. Optimum parameters of optical waveguides were calculated by means of the FDM. Design of CPW traveling-wave electrodes were performed by the FEM in the active region and by the CMM in the input/output section to obtain the conditions of MW effective index and impedance matching. From the measured S parameters, MW characteristics of the traveling-wane electrodes were extracted to be ${\alpha}_m$=0.05426 $\sqrt{f}$, $N_{eff}$=2.2025, and $Z_{c}$=39 ${\Omega}$. The calculated optical response R($\omega$) showed the 3 dB bandwidth of 10 GHz.z..

• International Journal of Aeronautical and Space Sciences
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• v.13 no.3
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• pp.307-316
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• 2012

Numerical simulations of 3D aircraft configurations are performed in order to understand the effects of turbulence models on the prediction of aircraft's aerodynamic characteristics. An in-house CFD code that solves 3D RANS equations and two-equation turbulence model equations are used. The code applies Roe's approximated Riemann solver and an AF-ADI scheme. Van Leer's MUSCL extrapolation with van Albada's limiter is also adopted. Various versions of Menter's $k-{\omega}$ SST turbulence models as well as Coakley's $q-{\omega}$ model are incorporated into the CFD code. Menter's $k-{\omega}$ SST models include the standard model, the 2003 model, the model incorporating the vorticity source term, and the model containing controlled decay. Turbulent flows over a wing are simulated in order to validate the turbulence models contained in the CFD code. The results from these simulations are then compared with computational results from the $3^{rd}$ AIAA CFD Drag Prediction Workshop. Numerical simulations of the DLR-F6 wing-body and wing-body-nacelle-pylon configurations are conducted and compared with computational results of the $2^{nd}$ AIAA CFD Drag Prediction Workshop. Aerodynamic characteristics as well as flow features are scrutinized with respect to the turbulence models. The results obtained from each simulation incorporating Menter's $k-{\omega}$ SST turbulence model variations are compared with one another.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.506-506
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• 2013

Ag (Silver) 박막은 낮은 전기 저항과 높은 가시광대의 반사율을 가져 T-OLED (Top Emission-Organic Light Emitting Diode)의 Anode로 각광 받고 있지만, 일반적인 Ag 박막의 일함수는 4.3 eV 이하로 T-OLED의 Anode로 사용하기에는 낮은 단점이 있다. 따라서 이를 극복하기 위한 방법으로 Ag 박막 표면을 산화시켜 일함수를 증가시키기 위한 연구가 진행중에 있다. 하지만 연구는 단순히 일함수를 증가시키는 것에 한정되어 있을 뿐 UV 처리된 박막의 nano-mechanics 특성에 대한 연구는 현재 전무하다. 따라서 본 연구에서는 순도 99.9%의 Ag 타겟을 이용하여 rf magnetron sputter 장비를 통해 Ag 박막을 증착 하였고, 이후 UV (Ultra-Violet) 램프를 통해 시료 표면을 산화시켰다. 특히, 이 논문의 주요 관심사인 박막의 nano mechanics 특성 분석을 위하여 nano indenter와 SPM (Scanning Probe microscope) 장치를 활용 하였다. 실험 결과 후처리 시간이 3분 이하인 경우 박막이 비결정질의 silver oxide로 성장하는 것을 확인하였으며, 이때 박막의 면저항은 $0.16{\Omega}$/sq.에서 $0.55{\Omega}$/sq.로 증가하는 것을 관찰할 수 있었고, 3분 이후, 비결정질의 silver oxide가 conducting 특성을 갖는 silver oxide 결정을 이루면서 면저항이 $0.55{\Omega}$/sq.에서 $0.21{\Omega}$/sq.로 감소하는 것을 보았다. 또한 결정질의 박막이 자라는 3분이상의 박막에서 surface hardness는 급격하게 증가($3.57{\rightarrow}9.47$ GPa)했으며, 6분 이후에는 감소하는($9.47{\rightarrow}3.46$ GPa) 경향을 보였다. 이러한 경향은 silver oxide의 결정 크기가 Ag 결정 보다 크므로 상대적인 압축응력을 받아 표면 경도가 증가됐다. 처리시간 6분 이후, 경도 감소는 박막의 표면 물성이 불안정해졌기 때문이다.

• Journal of the Korean Applied Science and Technology
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• v.13 no.3
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• pp.15-24
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• 1996

Essentiality was proposed in the field of lipid by Burr and Burr in 1929. When rats were raised on the fat-free diet, their growth retarded and their skin and tails showed the characteristic deficient symptoms, which were relieved by the addition of ${\omega}6(n-6)$ polyunsaturated fatty acids as linoleic(LA) and arachidonic(AA) acids to the basal diet. LA is dehydrogenated to ${\gamma}-linolenic$ acid(GLNA) by ${\Delta}6$ desaturase, then GLNA is 2 carbon chain elongated by elongase to $dihomo-{\gamma}-linolenic$ acid(DGLNA), which is desaturated by ${\Delta}5$ desaturase to AA. These acids are called LA family or ${\omega}6(n-6)$ polyunsaturated fatty acids(PUFA). ${\alpha}-Linolenic$ acid(ALNA) is converted through the series of desaturation and elongation steps to docosahexaenic acid(DHA) via eicosapentaenoic acid(EPA). These acids belong to ALNA family or ${\omega}3(n-3)$PUFA. Human who consume large amounts of EPA and DHA, which are present in fatty fish and fish oils, have increased levels of these two fatty acids in their plasma and tissue lipids at the expense of LA and AA. Alternately, vegetarians, whose intake of LA in high, have more elevated levels of LA and AA and lower levels of EPA and DHA in plasma lipids and in cell membranes than omnivores. AA and EPA are metabolized to substances called eicosanoids. Those derived form AA are known as prostanocids(prostaglandins and prostacyclins) of the 2-types and leukotrienes of the 4-series, whereas those derived from EPA are known as prostanoids of the 3-types and leukotrienes of the 5-series. DGLNA is a precursor of the 1-types of prostaglandins. The metabolites of AA and EPA have competitive functions. Ingestion of EPA from fish or fish oil replaces AA from membrane phospholipids in practically all cells. So this leads to a more physiological state characterized by the production of proatanoids and leukotrienes that have antithrombic, antichemotactic, antivasoconstrictive and antiinflammatory properties. It is evident that ${\omega}3$ fatty acids can affect a number of chronic diseases through eicosanoids alone.