Acrylic Urethane수지의 경화속도에 관한 연구

서차수 釜山工業大學校 1995 論文集 Vol.37 No.-

UV-curable acrylic urethane resins widely used in the coating industry possess a distinct feature of rapid cure rate, which transforms a liquid resin almost instantly into a solid polymer. However, the cure rate and physical properties of the cured films are affected in a complicated fashion by the choice of photo-initiator, monofunctional monomer, polyfunctional monomer and polymer, and the proportion in which they are combined. Hence, relatively few systematic studies have been carried out on the UV-curable resin system so far. The effects of the molcular weight (MW) of the reactive oligomer, the functionality (f) and content of the reactive monomer, and the type and amount of the photo-initiators on the curing rate and physical properties of cured films were investigated in the present study using the UV radiation. The conclusions drawn from this study are as follows. In the curing reaction of HDDA (f-2) with three kinds of urethane acrylate oligomer (UAO) differing in MW, the initial rate of increase in % conversion of carbon-carbon acrylate double bonds, as determined by the change of the IR absorption peaks at 810 cm1 with UV irradiation time suing a time driver, was in the order of UAO-2>UAO-3>UAO-1 whereas the maximum % conversion of acrylate double bonds and %gel fraction approached about 70% and 100%, respectively, for all three cases. On the other hand, in the reaction of UAO-2 (MW=1200) with mono-, di-, and tri- functional monomers the initial conversion rate of acrylate double bonds decreased in the order of TMPTA(f=3)> HDDA(f=2)> EHA(f=1), but at a later reaction stage (above 60% conversion) the TMPTA case showed the lower reaction rate than HDDA probably due to the effect of molecular constraints imposed by highly corss-linked points. The % gel fractions approached nearly 100% at a final reaction stage for all three cases, the initial rate of increase being the greatest for TMPTA. The TMPTA system exhibited the strongest tensile strength, but the poorest elongation as expected. Tensile properties (strength and elongation) did not vary greatly with monomer content until 40%, but after then decreased with increasing monomer content because of the homopolymers produced in large amounts.

체질 안료에 따른 에폭시 도료의 전기화학적 특성 평가

서차수 ( Cha Soo Suh ),박재현 ( Jae Hyeon Park ),문명준 ( Myung Jun Moon ) 한국공업화학회 2004 공업화학 Vol.15 No.4

메탈 프탈로시아닌의 마이크로파 합성

서차수(Cha Soo Suh),박성수(Seong Soo Park),정기석(Ki Suck Jung),이종영(Jong Young Lee),박진환(Jin Hwan Park),이근대(Gun Dae Lee) 한국공업화학회 2001 공업화학 Vol.12 No.7

N/A N/A

신경회로망을 이용한 용접잔류응력 예측에 관한 연구

차용훈,김일수,김하식,이연신,김덕중,성백섭,서준열 韓國工作機械學會 2000 한국생산제조학회지 Vol.9 No.6

In order to achieve effective prediction of residual stresses, the series experiment were carried out and the residual stress-es were measured using the backpropagation algorithm from the neural network and the sectional method. Using the experimental results, the optiomal control algorithms using a neural network should be developed in order to reduce the effect of the external disturbances on residual stresses during GMA welding processes. The results obtained from the comparison between the measured and calculated results, showed that the neural network based on backpropagation algorithm can be used in order to control weld quality. This system can not only help to under-stand the interaction between the process parameters and residual stress, but also, improve the quantity control for welded structures. The development of the system is goal in this study.

Risk of Interval Cancer in Fecal Immunochemical Test Screening Significantly Higher During the Summer Months: Results from the National Cancer Screening Program in Korea :

Cha, Jae Myung,Suh, Mina,Kwak, Min Seob,Sung, Na Young,Choi, Kui Son,Park, Boyoung,Jun, Jae Kwan,Hwang, Sang-Hyun,Lee, Do-Hoon,Kim, Byung Chang,Lee, You Kyoung,Han, Dong Soo American College of Gastroenterology 2018 The American journal of gastroenterology Vol.113 No.4

<P>CONCLUSIONS: The positivity rate of FIT was lower in the summer, and the performance of the FIT screening program was influenced by seasonal variations in Korea. These results suggest that more efforts to reduce interval cancer during the summer are needed in population-based screening programs using FIT, particularly in countries with high ambient temperatures.</P>

Improving Accuracy and Reliability of Hearing Tests: An Exploration of International Standards

Suh Michelle J.,Lee Jihyun,Cho Wan-Ho,Jin In-Ki,Kong Tae Hoon,Oh Soo Hee,Lee Hyo-Jeong,Choi Seong Jun,Cha Dongchul,Park Kyung-Ho,Seo Young Jun 대한청각학회 2023 Journal of Audiology & Otology Vol.27 No.4

his study explores the internal standards for hearing tests and benefits of implementing international standard protocols, including the International Organization for Standardization (ISTO) and International Electrotechnical Commission (IEC), and discusses how ISO and IEC standards provide a framework for designing, calibrating, assessing hearing test instruments and methods, and exchanging and comparing data globally. ISO and IEC standards for hearing tests improve accuracy, reliability, and consistency of test results by applying standardized methods and environments. Moreover, they promote international harmonization and data interoperability, enabling information exchange and research collaboration. Those standards for hearing tests are beneficial but have challenges and limitations, such as variation in equipment and calibration, lag in updating standards, variation in implementation and compliance, and lack of coverage of clinical aspects, cultural diversity, and linguistic diversity. These affect the quality and interpretation of test results. Adapting ISO or IEC standards locally would improve their applicability and acceptability, while balancing customization and compatibility with global standards.

Rewarding and reinforcing effects of 4-chloro-2,5-dimethoxyamphetamine and AH-7921 in rodents

Cha, Hye Jin,Jeon, Seo Young,Jang, Hwa Jin,Shin, Jisoon,Kim, Young-Hoon,Suh, Soo Kyung Elsevier 2018 Neuroscience Letters Vol.676 No.-

<P><B>Abstract</B></P> <P>New psychoactive substances (NPSs), i.e., newly designed substances with chemical residues that are slightly different from those of known psychoactive substances, have been emerging since the late 2000s, and social problems related to the use of these substances are increasing globally. Two such NPSs are 4-chloro-2,5-dimethoxyamphetamine (DOC), a psychedelic substance that is structurally related to amphetamine, and AH-7921, an opioid analgesic that is used for recreational purposes and has a potency similar to that of morphine. Currently, scientific evidence for the dependence liability or toxicity of NPSs is lacking. Therefore, in this study, we performed animal behavioral tests to evaluate the dependence liability of DOC and AH-7921. The rewarding and reinforcing effects of DOC and AH-7921 were evaluated using the conditioned place preference (CPP) paradigm in mice and the self-administration (SA) procedure in rats. Both DOC and AH-7921 increased the preference for the drug-paired compartment in the CPP test at a dose of 0.3 mg/kg and increased the number of responses to the active lever in the SA test at 0.01 mg/(kg·infusion). Collectively, the data suggest that DOC and AH-7921 may have both rewarding and reinforcing effects. Further studies are needed to confirm the reinforcing effects in broader dose ranges with various schedules.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The dependence liability of DOC and AH-7921 were evaluated in rodents. </LI> <LI> Conditioned place preference and self-administration (SA) tests were performed. </LI> <LI> DOC and AH-7921 increased place preference to the drug-paired compartment. </LI> <LI> Both substances increased the number of active lever presses in the SA test. </LI> <LI> These new psychoactive substances may have both rewarding and reinforcing effects. </LI> </UL> </P>

Rewarding effects of 2-desoxypipradrol in mice

Cha, Hye Jin,Kim, Jin Mook,Kim, Young-Hsoon,Suh, Soo Kyung Elsevier/North-Holland 2019 Neuroscience letters Vol.705 No.-

<P><B>Abstract</B></P> <P>Desoxypipradrol (2-DPMP), a new psychoactive substance (NPS), acts as a norepinephrine-dopamine reuptake inhibitor (NDRI). NDRIs can be addictive due to their action mechanisms similar to cocaine and methamphetamine. However, there is a lack of scientific information regarding the exact dependency of 2-DPMP. Thus, the purpose of this study was to evaluate rewarding and reinforcing effects of 2-DPMP in rodents. The effective dose range of 2-DPMP was determined by climbing behavior test. To evaluate rewarding effects of 2-DPMP, conditioned place preference (CPP) test was performed at selected doses in mice. Self-administration (SA) test was then undertaken at two doses that caused the highest effects in the CPP test. Dopamine level changes were analyzed using synaptosomes in order to investigate effects of 2-DPMP on the central nervous system (CNS). Significant responses were observed in the climbing behavior test at doses of 0.1, 0.5, and 1 mg/kg by intraperitoneal injection (i.p.). In the CPP test, mice i.p. administered 2-DPMP at 1 mg/kg showed a significant preference in drug-paired compartment. In the SA test, mice intravenously given 0.1 mg/kg/infusion showed significantly higher active lever responses. Further, dopamine was increased in a dose-dependent manner. Taken together, these results suggest that 2-DPMP may act on the CNS and induce rewarding and reinforcing effects, indicating its dependence liability.</P> <P><B>Highlights</B></P> <P> <UL> <LI> 2-DPMP increased place preference to the drug-paired compartment. </LI> <LI> 2-DPMP increased the number of responses to the active lever. </LI> <LI> 2-DPMP has rewarding effects, and dopaminergic pathway plays a role in the properties. </LI> </UL> </P>

방식도막의 새로운 평가법

서차수,박진환 한국공업화학회 2001 공업화학 Vol.12 No.7

Receptor Binding Affinities of Synthetic Cannabinoids Determined by Non-Isotopic Receptor Binding Assay

Cha, Hye Jin,Song, Yun Jeong,Lee, Da Eun,Kim, Young-Hoon,Shin, Jisoon,Jang, Choon-Gon,Suh, Soo Kyung,Kim, Sung Jin,Yun, Jaesuk Korean Society of ToxicologyKorea Environmental Mu 2019 Toxicological Research Vol.35 No.1

A major predictor of the efficacy of natural or synthetic cannabinoids is their binding affinity to the cannabinoid type I receptor ($CB_1$) in the central nervous system, as the main psychological effects of cannabinoids are achieved via binding to this receptor. Conventionally, receptor binding assays have been performed using isotopes, which are inconvenient owing to the effects of radioactivity. In the present study, the binding affinities of five cannabinoids for purified $CB_1$ were measured using a surface plasmon resonance (SPR) technique as a putative non-isotopic receptor binding assay. Results were compared with those of a radio-isotope-labeled receptor binding assay. The representative natural cannabinoid ${\Delta}^9$-tetrahydrocannabinol and four synthetic cannabinoids, JWH-015, JWH-210, RCS-4, and JWH-250, were assessed using both the SPR biosensor assay and the conventional isotopic receptor binding assay. The binding affinities of the test substances to $CB_1$ were determined to be (from highest to lowest) $9.52{\times}10^{-3}M$ (JWH-210), $6.54{\times}10^{-12}M$ (JWH-250), $1.56{\times}10^{-11}M$ (${\Delta}^9$-tetrahydrocannabinol), $2.75{\times}10^{-11}M$ (RCS-4), and $6.80{\times}10^{-11}M$ (JWH-015) using the non-isotopic method. Using the conventional isotopic receptor binding assay, the same order of affinities was observed. In conclusion, our results support the use of kinetic analysis via SPR in place of the isotopic receptor binding assay. To replace the receptor binding affinity assay with SPR techniques in routine assays, further studies for method validation will be needed in the future.