치밀층으로 코팅된 다공성 엔지니어링 세라믹스에서의 접촉응력에 의한 균열 거동

김상겸,김태우,김도경,이기성,Kim, Sang-Kyum,Kim, Tae-Woo,Kim, Do-Kyung,Lee, Kee-Sung 한국세라믹학회 2005 한국세라믹학회지 Vol.42 No.8

The engineering ceramic needs the properties of high strength, hardness, corrosion-resistance and heat-resistance in order to withstand thermal shock or applied nonuniform stresses without failure. The densely coated porous ceramics can be used for machine component, electromagnetic component, bio-system component and energy-system component by their high-performances from superior coating properties and light-weight characteristics due to the structure including pore by itself. In this study we controlled the porosity of silica and alumina, $8.2\~25.4\%$ and $23.4\~36.0\%$, respectively, by the control of sintering temperature and starting powder size. We made bilayer structures, consisting of a transparent glass coating layer bonded to a thick substrate of different porous ceramics by a thin layer of epoxy adhesive, facilitated observations of crack initiation and propagation. The elastic modulus mismatch could be controlled using different porous ceramics as the substrate layer. Then we applied 150 N force using WC sphere with a radius of 3.18 mm by Hertzian indentation. As a result, the crack initiation in the coating layer was delayed at lower porosity in the substrate layer, and the damage in the coating layer was relatively smaller at the bilayer structure coated on higher elastic substrate.

마우스 간의 황함유 아미노산 대사에 미치는 베타인의 용량의존성 영향

김상겸,Kim, Sang-Kyum 대한약학회 2009 약학회지 Vol.53 No.2

Acute betaine treatment induces time-dependent changes in the hepatic glutathione (GSH), cysteine and S-adenosylmethionine (SAM) levels. Our previous study demonstrated that betaine administered $1{\sim}4$ hours prior to sacrifice decreased hepatic GSH levels, but these levels were increased when measured 24 hours following the treatment. The present study was aimed to determine dose-dependent effects of betaine on hepatic metabolism of sulfur amino acid in mice. Mice were sacrificed 2.5 or 24 hours after intraperitoneal treatment with betaine at different dose levels ranging from 50 to 1000 mg/kg. The concentrations of methionine and SAM were increased by a betaine dose of 100 mg/kg, and the concentrations of GSH and cysteine were decreased by a betaine dose of 200 mg/kg at 2.5 hours. These changes were augmented with increasing doses of betaine. At 24 hours following betaine treatment, increased GSH and decreased taurine levels were observed from dose levels of 400 mg/kg. Changes in hepatic activities of cystathionine beta-synthase, gammaglutamylcysteine ligase and cysteine dioxygenase were observed from dose levels of $200{\sim}400$ mg/kg of betaine administered 24 hours prior to sacrifice.

알루미나에 YSZ가 나노코팅된 층상형 시스템의 인덴테이션 특성평가

김상겸,김태우,김철,신태호,한인섭,우상국,이기성,Kim, Sang-Kyum,Kim, Tae-Woo,Kim, Chul,Shin, Tae-Ho,Han, In-Sub,Woo, Sang-Kuk,Lee, Kee-Sung 한국세라믹학회 2005 한국세라믹학회지 Vol.42 No.1

전자 범 물리적 증착법(Electron Beam Physical Vaper Deposition, EB-PVD)으로 알루미나 상용기판 위에 나노 크기의 YSZ입자를 포함하고 있는 층을 코팅하여 층상형 시스템을 제조하였으며, 이때 기판층의 온도를 600, 700, $800^{circ}C$로 변화시켜 증착되는 YSZ층이 서로 다른 미세구조가 형성되도록 제어하여, 코팅층 미세구조의 변화에 따른 인덴데이션 거동을 고찰하였다 인덴테이션 거동으로는 비커스 인덴테이션과 헤르찌안 인덴테이션으로 피라미드형 압자 혹은 초경 구를 압입하였으며 압입 하중 및 코링층 구조에 따른 경도와 인덴테이션 응력-변형률 곡선을 구하였고, 미세구조와 하중의 증가에 따른 손상 및 파괴거동을 고찰하였다. 기판층의 온도가 향상됨에 따라 증착된 입자의 크기가 보다 증가하고 각진 입자가 형성됨을 알 수 있었고, 서로 다른 미세구조가 인덴테이션 거동에 영향을 주어, $800^{circ}C$에서 증착된 YSZ/A12달 구조가 상대적으로 우수한 특성을 나타내었다. YSZ layer containing nano-sized particles has been deposited on the commercial A1203 substrate by Electron Beam Physical Vapor Deposition (EB-PVD). The role of coating rnjcrostructures of YSZ to indentation damage is studied. The different coating microsouctures are prepared by varying the substrate temperatures from $600^{circ}C$ to $800^{circ}C$ during the deposition. Microhardness test and Hertzian indentation are conducted on the $YSZ/Al_{2}O_{3}$ layered systems. The damage and flilure behaviors have been investigated according to the effect of microstructures and indentation loads. With increasing the substrate temperature during EB-PVD, the overall grain sizes are coarser and more faceted, which microsoucture ultimately influences on the indentation behavior, thus, YSZ/Al_{2}O_{3}$ layered system prepared at the substrate temperature of $800^{circ}C$ shows relatively higher damage tolerance.

인슐린 매개성 Microsomal Epoxide Hydrolase의 발현증가에서 Akt의 역할

김상겸,김봉희,오정민,윤강욱,김충현,강건욱,Kim, Sang-Kyum,Kim, Bong-Hee,Oh, Jung-Min,Yun, Kang-Uk,Kim, Chung-Hyeon,Kang, Keon-Wook 대한약학회 2007 약학회지 Vol.51 No.5

The present study examines the effect of dominant-negative Akt on the insulin-mediated microsomal epoxide hydrolase (mEH) induction in rat hepatocytes. We also assessed the role of insulin in the expression of soluble epoxide hydrrolase (sEH). Insulin increased mEH levels and the enzyme activities, whereas sEH protein expression was unaffected by insulin. The specific PI3K inhibitors or p70 S6 kinase inhibitor ameliorated the insulin-mediated increase in mEH protein levels. Infection with adenovirus expressing dominant-negative and kinase-dead mutant of Akt1 effectively inhibited the insulin-mediated increase in mEH expression and mEH activity. These results suggest that mEH and sEH are differentially regulated by insulin and PI3K/Akt/p70S6K are active in the insulin-mediated regulation of mEH expression.

절식이 랫트 간의 황함유 아미노산 대사에 미치는 영향

김상겸,Kim, Sang-Kyum 대한약학회 2009 약학회지 Vol.53 No.2

Food deprivation decreases hepatic glutathione (GSH) levels, which is ascribed to alterations in availability of hepatic cysteine, a rate limiting factor for the GSH synthesis. The present study examines the effects of food deprivation on hepatic metabolism of sulfur amino acid in male rats. In rats fasted for 24 or 48 hours, hepatic GSH levels were decreased from $6.70{\pm}0.16{\mu}mol/g$ liver to $4.02{\pm}0.20$ or $4.06{\pm}0.07{\mu}mol/g$ liver, respectively. Hepatic S-adenosylmethionine levels were also decreased in fasted rats, but S-adenosylhomocysteine levels were increased. Hepatic methionine levels were not changed by food deprivation for 48 hours. On the other hand, hepatic cysteine or taurine levels were increased from $106.2{\pm}4.1$ to $130.0{\pm}2.7$ nmol/g liver or from $2.45{\pm}0.43$ to $5.07{\pm}0.78{\mu}mol/g$ liver, respectively, in 48-hour fasted rats. Activity of cystathionine beta-synthase catalyzed homocysteine to cystathionine, was markedly decreased, but activity of betaine homocysteine methyltransferase was increased in fasted rats, indicating that methylation of homocysteine to methionine is activated. Also activity of cysteine dioxygenase, involved in taurine synthesis, was increased. These results suggested that hepatic methionine levels were maintained in rats fasted for 48 hours through increase in homocysteine methylation, and hepatic GSH may serve as a cysteine supplier reservoir in fasting state.

환경세 정책의 이중배당가설에 대한 새로운 접근: 노동시장의 변화를 중심으로

김상겸 ( Sang Kyum Kim ) 한국환경정책평가연구원 2011 환경정책연구 Vol.10 No.3

환경세의 이중배당가설은 1980년대 중반 처음 제기된 이래, 최근까지 그 실현가능성에 대한 논의가 매우 활발한 연구주제이다. 이중배당가설의 실현가능성에 대해 부정적 입장을 견지하였던 2세대 연구들과는 달리, 3세대 연구들은 가설이 실현될 수 있는 조건에 초점을 맞추어 왔다. 3세대 연구들은 함수적 가정이나 환경세 부과대상 재화의 성질, 그리고 초기 조세체계에 대한 가정 등 다양한 경로를 통해 이중배당이 가능함을 주장하고 있다. 하지만 한 가지 흥미로운 점은, 3세대 연구들은 외형적으로 전혀 다른 접근방법을 취하고 있는 것으로 보이지만 그 작동기제를 살펴보면 노동시장에 유사한 영향을 미친다는 점에서 공통점이 발견된다는 것이다. 본 논문은 이러한 점에 착안하여 수행되었으며, 환경세 정책이 노동시장에 미치는 영향에 논의의 초점을 맞추고 이론적, 수리적 분석을 시도하였다. 분석결과는 이와 같은 이론적 직관과 일치하는 것으로 나타났다. 즉, 이중배당가설의 성립 여부는 정책변화가 노동시장에 미치는 영향이 매우 중요하며, 특히 가설이 성립하기 위해서는 환경세 정책이 노동공급의 증가를 유발해야 한다는 것이다. The double dividend hypothesis of environmental taxes has been a very widely debated research topic since its introduction in the mid-80s. Unlike the second generation studies, which stated that the double dividend environmental taxes were impossible to realize, the third generation researchers of today are focused on assumptions or conditions that make the hypothesis viable. The third generation studies state that the double dividend hypothesis is possible through functional form assumptions, such as the characteristics of taxes levied on polluting goods and the overall tax efficiency of the initial tax systems. The most notable, however, is the fact that the working mechanisms of third generation studies, upon closer inspection, give homogeneous effect on the labor markets, although at first glance the third generation studies take seemingly unrelated approaches. This thesis stems from such idea, and it attempts to analyze the effects of environmental taxes on the labor market. After a thorough analysis, the results match the intuition, as the viability of the double dividend hypothesis of environmental taxes largely depends on the effects that policy changes generate on the labor market. In order for the hypothesis to be plausible, environmental tax policies have to increase the labor supply.

법치국가(法治國家)와 효과적(效果的)인 권리보호(權利保護)

김상겸 ( Sang Kyum Kim ) 동의대학교 지방자치연구소 1999 공공정책연구 Vol.15 No.-

정부자문위원회에 관한 헌법적 연구

김상겸(Kim Sang-Kyum) 한국헌법학회 2005 憲法學硏究 Vol.11 No.2

We have to abolish useless committees, whose achievement is low and which can be replaced by inter-committee cooperation, integrate those whose function is similar. And it is also needed to clarify the organization and responsibility of the committee. Especially, a means of control by the national assembly is needed, considering the committee as a policy maker and administration organ. It is necessary to enact a basic law regarding the set-ups, operation and control of a committee to straighten out those points mentioned above. In this point, the governmental advisory committee bill is proper in its need and justice. This act clarifies its aim in article one that it regulates useless set-ups of the central administrative advisory committee, and thus pursuing an efficient operation. And concerning article of the same act, some may bring up a question about the separation of powers, but in the point of legalism of administrative organ, it is acceptable. This article is a kind of pre-regulation, and in this cases the legal state and authority of the committee can be a problem. In addition, the binding power toward the result is questionable, provided that the set-up of the committee is merely a matter for discussion. Article 6 of the same act states that the committee should go through a discussion with the national assembly if they in tend to have an expert or more than 10 people, setting standards of organization. But this is not practical in its effect in that it only requires discussion. Therefore, it is reasonable to make the committee get approval of the national assembly. And article 8 of the same act states the national assembly can suggest abolition to the committee under certain conditions. But suggestions without any legal binding force is questionable in its effectiveness, so it should be granted a strong legal force. And the act should also clarify the basis and limit of the responsibility of the committee's member since it is not stated at present.

헌법상의 남북관련조항에 관한 연구-헌법 제3조와 제4조의 헌법해석론 관점에서-

김상겸(Sang-Kyum Kim) 한국헌법학회 2004 憲法學硏究 Vol.10 No.3

The 21th century is when globalization becomes general all over world What our technique has brought us is the fact that the only word is not a certain nation's property, not to mention a certain union's, but that our world exists in the age of peace, where all nations get along Of course, the meaningless sacrifices caused by local warfares makes the humankind feel pain Nonetheless Will the efforts for world peace continue, and consequently, the era of reunification, bringing peace to our nation is drawing rear If our efforts for peace and unification must continue, it is meaningless to ask that this has to be done In the area of our constitution The constitutional law already legalizes some articles based on this The current constitutional law proclains through territorial article that the korean peninsula is our tern tory, This territorial article ascertains the certain boundary of our nation, consequently forming the nation's Identity, This is simultaneously a preparation for the unification in our near future Through this article, our consitutional law ascertains the principle of unification In our words, the principle that unification was to be based on the liberal-democratic order formed on the basis of people's agreement, But the reality does not form the atmosphere to pursue the constitutional order If the constitutional reality violates the substantial core, crossing the line beyond the Innate restrictive characteristics of its own, it is evidenty violating the constitution The meaning within the desision of 'National Security Act' Indicator in solving the problems of realty According to this, the principle gl anted to us is, cannot change under liberal-demociatic order which our constitution pursues And that anything beyond this cannot be accepts even In the matter of south and north, and unification Therefore, discussion and people's agreement has to be limited In the constitutional order When we come to this part, we must always consider a certain limit that exists between the constitutional law and the government But one thing is evident, As Germany enacted basic laws and articles for their unification, our constitutional law is already accepting peace-unification and order.

사회적할인율 변화가 편익-비용분석 결과에 미치는 영향에 대한 연구: 예비타당성조사의 사례분석

김상겸 ( Sang Kyum Kim ) 경희대학교 사회과학연구원 2013 社會科學硏究 Vol.39 No.3

본 논문은 사회적할인율의 변화가 공공투자사업의 경제적 타당성 분석결과에 미치는 영향에 대해 살펴본 연구이다. 본 연구에서는 기 수행된 실제 예비타당성조사 보고서의 사업별편익과 비용자료를 활용하여 기간별 편익과 비용발생 흐름을 살펴보았으며, 사회적할인율 변동에 따른 총할인편익과 비용의 변화 형태를 분석하였다. 본 연구의 분석결과에 따르면, 사회적할인율의 인하조정은 편익과 비용의 총할인가치 모두를 증가 시키지만, 그 영향은 대칭적이지 않기 때문에 경제적 타당성 분석결과에도 의미있는 영향을 미치는 것으로 나타났다. 실제로 사회적할인율이 현행 수준 대비, 1%p. 인하조정되는 경우 편익은 평균적으로 20%증가되는 반면 비용의 증가폭은 평균 10%에 미달하기 때문에 편익/비용 비율로 측정되는 사업의 경제적 타당성은 평균 9.5% 가량 개선될 수 있는 것으로 분석되었다. 또한 이러한 영향은 사회적할인율의 인하폭이 더 커지는 경우 보다 뚜렷해지는 것으로 분석되었는데, 사회적할인율이 현행 대비 3%p. 인하조정되는 경우 편익/비용 비율은 평균적으로 33%가량 높아지는 것으로 나타났다. This study analyzes the effect of social discount rate change on the results of economic feasibility test for a public investment project. By reviewing actual reports from previously performed preliminary feasibility study in Korea, this study derives typical forms of benefit and cost flows over the time periods, across specific categories of public investment projects. According to the results of the study, 1%p. decreasing in social discount rate will lead 20% increasing in benefits while the rate of increasing in costs remains less than 10%. The assymetric changes between benefit and cost sides achieve meaningful changes in the economic feasibility test result. Analytic result of this study shows that 1%p. of downward change in social discount rate will increase the B/C ratio roughly by 9.5% on average, and it goes up higher as the social discount rate degraded more.