• Macromolecular Research
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• 제16권5호
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• pp.446-456
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• 2008

A recent theoretical approach based on the coupling of both the Flory-Huggins (FH) and the Association Equilibria thermodynamic (AET) theories was modified and adapted to study the miscibility properties of a multi-component system formed by two polymers (a proton-donor and a proton-acceptor) and a proton-acceptor solvent, named copolymer(A)/solvent(B)/polymer(C). Compatibility between polymers was mainly attained by hydrogen-bonding between the hydroxyl group on the phenol unit of the poly(styrene-co-vinyl phenol) (PSVPh) and the carbonyl group of the biodegradable and environmentally friendly poly(3-hydroxybutyrate) (PHB). However, the self-association of PSVPh and specific interactions between the PSVPh and the H-acceptor group (an ether oxygen atom) of the epichlorohydrin (ECH) solvent were also established in a lower extension, which competed with the polymer-polymer association. All the binary specific interactions and their dependence with the system composition as well as with the copolymer content were evaluated and quantified by means of two excess functions of the Gibbs tree energy, ${\Delta}g_{AB}$ and ${\Delta}g_{AC}$. Experimental results from fluorescence spectroscopy were consistent with the theoretical simulations derived with the model, which could also be applied and extended to predict the miscibility in solution of any polymer blend with specific interactions.

• 한국전문물리치료학회지
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• 제14권3호
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• pp.48-56
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• 2007

Environmental Enrichment (EE) alone is not capable of enhancing the fine digit and the forelimb functions. Therefore, we applied modified constraint-induced movement therapy (mCIMT) under the influence of EE to assess its effect on promoting improved forelimb sensorimotor functions. Focal ischemic brain injury was produced in Sprague-Dawley rats (60 rats, $250{\pm}50$ g) through middle cerebral artery occlusion (MCAO). Before MCAO induction, all rats were trained in modified limb placing tests and reaching tasks for 1 week. Then they were randomly divided into three groups: Group I: application of standard environment (SE) after MCAO induction (n=20), Group II: application of EE after MCAO induction (n=20), Group III: MCAO+EE, mCIMT and task-oriented training that was initiated at 10th day after MCAO induction (n=20). We also applied mCIMT (between 9 AM and 5 PM/daily) which included restraining the forelimb ipsilateral to the lesion using the 'Jones & Schallert' method. We assessed the change of modified limb placing, single pellet reaching test and the immunoreactivity of BDNF by immunohistochemistry (pre, 1st, 5th, 10th and 20th day). Group I showed no improved outcome, whereas group II and III significantly improved on the use of the forelimb and the immunoreactivity. The qualitative analysis of the skilled reaching test, of group III showed the greatest improvement in the fine digit and the forelimb function. These results suggest that EE combined with mCIMT is more functional in promoting enhanced fine digit and forelimb functional movements.

• 공업화학
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• 제34권2호
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• pp.199-205
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• 2023

Arsenic is a highly toxic element, and its contamination is widespread around the world. The natural materials with high selectivity and efficiency toward pollutants are important in wastewater treatment technology. In this study, the mesoporous synthetic hectorite was synthesized by facile hydrothermal crystallization of gels comprising silica, magnesium hydroxide, and lithium fluoride. Additionally, the naturally available clay was modified using zirconium at room temperature. Both synthetic and modified natural clays were employed in the removal of arsenate from aquatic environments. The materials were fully characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier transform-infrared (FT-IR) analyses. The synthesized materials were used to remove arsenic (V) under varied physicochemical conditions. Both materials, i.e., Zr-bentonite and Zr-hectorite, showed high percentage removal of arsenic (V) at lower pH, and the efficiency decreased in an alkaline medium. The equilibrium-state sorption data agrees well with the Langmuir and Freundlich adsorption isotherms, and the maximum sorption capacity is found to be 4.608 and 2.207 mg/g for Zr-bentonite and Zr-hectorite, respectively. The kinetic data fits well with the pseudo-second order kinetic model. Furthermore, the effect of the background electrolytes study indicated that arsenic (V) is specifically sorbed at the surface of these two nanocomposites. This study demonstrated that zirconium intercalated synthetic hectorite as well as zirconium modified natural clays are effective and efficient materials for the selective removal of arsenic (V) from aqueous medium.

• 한국물환경학회지
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• 제33권6호
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• pp.769-779
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• 2017

Nutrient (i.e., nitrogen and phosphorus) budgets are required under a 'Livestock Excreta Survey'. A nutrient budget is one of the agri-environmental indicators that calculates the difference between the inputs and outputs of the amount of nutrients within a certain boundary and for a certain time period (e.g., 1 year). In this study, a nutrients budget model was developed to effectively determine the surplus of nutrients within a region in Korea. The C# program language was used in order to facilitate the deployment of a graphical user interface (GUI) and to enhance compatibility. Also, the model was developed on Windows OS, which is the commonly used operating system in Korea. The model was based on the OECD/Eurostat nutrient budget method, and it was modified to consider manure composting procedures as well. There are key features of the nutrient budget model, including directly use of the original data sets from various input and output sources, and a collectively exchange of the address in different formats. The model can quickly show the results of various spatial and temporal resolutions with the same data, as well as perform a sensitivity analysis with coefficients and easily compareresults using tables and graphs. Further, it would be necessary to study the extension of the scope of utilization, such as the application of various nutrient budget methods. It would also be helpful to investigate both pre and postprocessing information such as linking input data through online systems.

• Journal of Korean Neurosurgical Society
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• 제65권2호
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• pp.204-214
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• 2022

Objective : Osteoporosis result from age-related decline in the number of osteoblast progenitors in the bone marrow. Probiotics have beneficial effects on the host, when administered in appropriate amounts. This study investigated the effects of probiotics expressing specific genes, especially the effects of genetically modified bone morphogenetic protein (BMP)-2-expressing Lactobacillus plantarum CJNU 3003 (LP) on ovariectomized rats. Methods : Twenty-eight female Wistar rats (250-300 g, 12 weeks old) were divided into four groups : the sham (control), the ovariectomy (OVX)-induced osteoporosis group (OVX), the OVX and LP (OVX/LP), OVX and genetically modified BMP-2-expressing LP (OVX/LP with BMP) groups. The three groups underwent bilateral OVX and two of these groups were administered two different types of LP via oral gavage daily. At 16 weeks post-OVX, blood was collected from the heart and the bilateral tibiae were extracted and were scanned by ex-vivo micro-computed tomography and stained with hematoxylin-and-eosin (H&E) and Masson's trichrome stain for pathological assessment. The serum levels of osteocalcin (OC), rat C-telopeptide of type I collagen (CTX-I), BMP-2, and receptor activator of nuclear factor-ĸB ligand (RANKL) were measured. Results : The 3D-micro-computed tomography images showed that the trabecular structure in the OVX/LP with BMP group was maintained compared with OVX and OVX/LP groups. No significant differences were detected in trabecular thickness (Tb.Th) between control and OVX/LP with BMP groups (p>0.05). Furthermore, a tendency toward increased BMD, trabecular bone volume, Tb.Th, and trabecular number and decreased trabecular separation was found in rats in the OVX/LP with BMP groups when compared with the OVX and OVX/LP groups (p>0.05). The H&E and Masson's trichrome stained sections showed a thicker trabecular bone in the OVX/LP with BMP group compared with the OVX and OVX/LP groups. There was no difference in serum levels of OC, CTX and RANKL control and OVX/LP with BMP groups (p>0.05). In contrast, significant differences were found in OC and CTX-1 levels between the OVX and OVX/LP with BMP groups (p<0.05). Conclusion : Our results showed that the expression of genetically modified BMP-2 showed inhibition effect for bone loss in a rat model of osteoporosis.

• 대한조선학회논문집
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• 제34권4호
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• pp.61-71
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• 1997

본 연구에서는 일정속도로 자유수면상을 항주하는 수중익쌍동선의 저항성능을 모형시험 및 수치계산에 의하여 해석하였다. 대상선형은 Wigley선형을 변형한 비대칭형 트랜섬(transom) 선미의 단동체(demihull)를 갖는 수중익쌍동선으로서 전진속도 Fn = 0.2 ~ 1.0의 범위 및 수중익의 입사각도를 $0.0^{\circ}$에서 $3.0^{\circ}$까지 변화시켜 가며 실험과 계산을 수행하였다. 실험은 인하대학교의 선형시험수조에서 수행되었으며, 수치계산은 유한차분법(Finite Difference Method)에 의하여 수행되었다. 모형시험 및 수치계산결과는 포일(foil)을 부착하지 않았을 때의 결과와 비교, 검토되었다. 수치계산결과와 실험결과는 정성적으로 일치함을 보였으며, 포일의 형태와 각도에 따라 항주자세와 저항성능의 변화를 확인하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.555-560
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• 2003

Korean High Speed Train(KHST) has been tested on the high speed test line in Osung site of Korea High Speed Rail Construction Authority (KHRC). since it was developed as G7 Project Plan In 2002. This paper introduces the dynamic test devices in KHST and shows the comparison between the results of test and theoretical computing results which derive from the new model for KHST dynamic behavior. Previous computer simulation model for KHST was developed to review wether the vehicle system was satisfied with the dynamic performance requirements during the design procedure. But It should be applied the results of the parts test for suspension elements in order to compare between the results of computation and real test. Using VAMPIRE Program made by AEA Technology in UK. the new model also was modified. This paper shows that the static wheel loads calculated from new model is similar to test results. For test on high speed line, we prepared the test devices for evaluating the dynamic performances. which was consisted of the accelerometers( based on Kisler Co.) and the data aquisition systems (based on National instrument Co.), and test program coded by LabView 6i program. These lest devices and programs are flexible to extension the channels for adding sensors and connect to the ethernet network. The acceleration of car bodies, bogie frames and axle boxes were compared between the results of computation and test at 150km/. This paper shows that the results of test were high in high frequency band range but similar frequency band range. It might be considered that these differences were caused by the test which did not performed at constant speed for comparison analysis. Also. It will be able to understand the differences and make better results through a lot of tests planed in future.

• Journal of Chest Surgery
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• 제31권10호
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• pp.919-923
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• 1998

연구배경: 인체에 이식된 동종 혹은 이종조직은 궁극적으로 석회화 변성이 일어난다. 저자들은 독자적인 항석회화 처리법을 이용해 석회화에 내구성을 가진 심혈관용 조직첨포를 개발하였다. 재료 및 방법:도축장에서 채취한 신선한 소의 심막을 Hank 용액에 담아 실험실로 이송하였다. 불필요한 부분을 절제해 낸 심낭조직을 0.65% glutaraldehyde 용액(4$^{\circ}C$)에 1주일 동안 저장한 다음 phophate-buffered saline 용액(pH 7.4)로 세척하였다. 이후 2.5% 술폰산화 폴리에틸렌옥사이드(PEO-SO3) 용액으로 실온에서 2일 동안 처리한 다음 4$^{\circ}C$ NaBH4용액으로 16시간 동안 환원시켰다. 실험은 글루타르알데하이드 용액으로만 처리한 심막첨포와 항석회화 처리된 심막첨포를 각각 대조군(GA군, n=4)과 실험군(PEO-SO3군, n=4)으로 나누어 혈관벽에 이식하여 석회화 변성 정도를 비교하였다. 실험모델은 성견의 폐동맥과 대동맥 벽의 일부를 절제한 후 심막첨포로 재건하는 방법을 이용하였고, 수술 후 평균 1개월 째에 이식된 첨포를 적출하여 조직병리 변화와 칼슘 및 인 함량을 측정하였다. 결과: 실험군이 대조군에 비해 조직 위축 변성, 칼슘(폐동맥; 1.55$\pm$0.29 vs. 6.72$\pm$0.70 mg/g, 대동맥; 7.10$\pm$1.05 vs. 13.81$\pm$2.33 mg/g) 및 인의 침착량 (폐동맥; 2.58$\pm$0.40 vs. 12.60$\pm$3.40 mg/g, 대동맥; 8.11$\pm$1.07 mg/g vs. 19.33$\pm$4.31 mg/g)이 현저하게 적었다 (P<0.01). 결론:이상의 결과에서 PEO-SO$_3$로 처리한 조직첨포는, 비록 단기관찰 결과이지만, 충분한 석회화 내성을 보이며 이 조직첨포의 장기적인 안정성과 적합성에 대해서는 계속적인 연구가 필요할 것이다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.415-417
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• 2003

we analyzed the electromagnetic behavior of a superconducting fault current limiter (SFCL) under the quench state using FEM. The analysis model used in this work is 5.5 KVA meander-line type SFCLs. Meshes of 3,650 triangular elements were used in the analysis of this SFCL. Analysis results showed that the distribution of current density was concentrated to inner curved line in meander-line type-SFCL and the maximum current density was 14.61 $A/m^2$ and also the maximum Joule heat was 2,030 $W/m^2$ in this region. We think that the new and the modified structure must be considered for an uniform distribution of the electromagnetic field.

• 벤처창업연구
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• 제2권2호
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• pp.49-68
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• 2007

본 연구는 인터넷 쇼핑몰 창업 시 활용할 수 있는 비즈니스 모델 사전 자가 평가 방법론을 개발하는 것이다. 자가 평가 방법론은 Bruce Merrifield 박사가 제안한 BMO 모형을 인터넷 쇼핑몰에 맞도록 재구성하였으며, 평가 항목이 변형을 위해 인터넷 비즈니스의 특징, 인터넷 비즈니스 모델의 사업성 평가에 관한 이론, e-business의 성공 실패요인, 벤처기업의 성공 실패요인, 기술가치 평가 요인, 인터넷 쇼핑몰의 성공 실패요인 등에 관한 선행연구들을 고찰하였다. 재구성된 사업매력도 평가항목은 매출규모, 시장성장성, 경쟁력, 위험분산도, 업계 재구축 가능성, 특별한 사회적 상황이며, 자사회의 적합성 평가항목은 경영자특성, 컨텐츠제공력, 상호작용성 구현 및 운영, Commerce, Fulfillment, 마케팅력이다. 재구성된 BMO모형으로 인터넷 쇼핑몰 사업을 진출하고자 하는 I사, D사, G사를 대상으로 사례연구를 하였다. 본 연구는 자가평가를 통한 부적격한 인터넷 쇼핑미로 비즈니스 모델의 사업화 방지, 인터넷쇼핑몰 비즈니스 모델의 평가를 통해 사업을 점검하고 실행할 수 있는 지침 제공, 인터넷 쇼핑몰 비즈니스 모델이 실행에 필요한 자원의 수준과 확보의 용이성 평가에 활용될 수 있다.