http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
The Difficulties In Teaching English by Means of the Oral Approach In Korea
Shin, Sungchul 大田工業高等專門學校 1967 論文集 Vol.2 No.-
"Language is a custom." According to that meaning of the word, learning English is simply forming the habit of expressing our ideas instead of in Korean. However, how have the students been English in their schools? They have studied English for years and still can neither speak nor understand English as much as we have expected. They learn rules of grammar and memorize vocabulary. They them translate sentences from English into their native language. The method is easy to teach, but they don't learn to speak English nor to understand it when it is spoken. Neither do the students learn to read fluently, for the emphasis is on the transalation. Thus English is difficult enough for Korean students to sutdy, and I would like to point out the problems procuced in the process of teaching English by means of the oral approach, one of the typical newmethods, and some suggestions will be made. There are many methods that have been used to teach a second lanauage. All of them have certain mertis as methods of teaching a second language since they are based on experience and on elaborate studies. Each has its advantages and disadvantages and it is a difficult task to determine which method is best. In the grammar-translation method, which has been used in Korea, all insturctions are given in the native language of the students. By using rules of grammar, they are to translate sentences in the textbook. The direct methods is based on the idea that the native language is not spoken and emphasis is put on speaking and understanding. The natural method maintains that they should learn, English in the same way that they learneed their native language. In an oral approach, the pupil's language can be used, if necessary, in order to make sure that explannations are thoroughly understood. The psychological method uses techniques similar to those of the natural method, but doesn't adequately prepare the student for reading and writing about anything except practical everyday events. In the phonetic method, the teaching of a language must be proceeded by pronunciation drill. The students learn the language written in phonetic symbols. The reading methods in available only for the senior grades, and doesn't stress oral work, grammar or composition. Insteat it teaches them to read directly as in the native language for over-all comprehension. The practice method stresses repeated practices through easy materials selceted from everyday conversation. The textbook is composed mainly of question-and -answer drill. In the combination method, the best features of several of the above methods are combined.
Matrix-Assisted Three-Dimensional Printing of Cellulose Nanofibers for Paper Microfluidics
Shin, Sungchul,Hyun, Jinho American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.31
<P>A cellulose nanofiber (CNF), one of the most attractive green bioresources, was adopted for construction of microfluidic devices using matrix-assisted three-dimensional (3D) printing. CNF hydrogels can support structures printed using CAD design in a 3D hydrogel environment with the appropriate combination of rheological properties between the CNF hydrogel and ink materials. Amazingly, the structure printed freely in the bulky CNF hydrogels was able to retain its highly resolved 3D features in an ultrathin two-dimensional (2D) paper using a simple drying process. The dimensional change in the CNF hydrogels from 3D to 2D resulted from simple dehydration of the CNFs and provided transparent, stackable paper-based 3D channel devices. As a proof of principle, the rheological properties of the CNF hydrogels, the 3D structure of the ink, the formation of channels by evacuation of the ink, and the highly localized selectivity of the devices are described.</P>
Transparent cellulose nanofiber based open cell culture platform using matrix-assisted 3D printing
Shin, Sungchul,Kwak, Hojung,Hyun, Jinho Elsevier 2019 Carbohydrate polymers Vol.225 No.-
<P><B>Abstract</B></P> <P>Carboxymethylated hydrophilic CNF (Hphil-CNF) was modified with methyltrimethoxysilane into hydrophobic CNF (Hphob-CNF) and used as a printing matrix. The Hphil-CNF hydrogel was printed at the surface of the Hphob-CNF hydrogel, forming an immiscible, distinct 3D structure. Fabrication of channel systems in the CNF platform was performed by matrix-assisted 3D printing of petroleum jelly ink in the Hphil-CNF-patterned Hphob-CNF hydrogel. After the dehydration process followed by removal of the ink from the CNF film, the CNF hydrogels became a dense platform embedding fluidic channels. The CNF platform exhibited selective diffusion of fluorescein isothiocyanate-dextran from the channels in the Hphil-CNF patterns, indicating transport of bioactive molecules to cells cultured at the platform surface. The applicability of the open cell culture platform was investigated with A549 lung cancer cells by injecting cisplatin, a model drug into the channel.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The transparent CNF platform enabled direct observation of cell growth. </LI> <LI> The hydrophilic CNF patterns were created on the hydrophobic CNF hydrogel. </LI> <LI> The microfluidic system was fabricated in CNF hydrogel. </LI> <LI> The CNF platform was fabricated by matrix assisted 3D printing. </LI> <LI> The effect of cisplatin on the death of lung cancer cells was examined. </LI> </UL> </P>
Shin, Sungchul,Kwak, Hojung,Hyun, Jinho American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.28
<P>It is not easy to design structures with transparent solutions, especially in light projection three-dimensional (3D) printing, since the penetration of light in solution is limitless. Here, silk fibroin incorporated with melanin nanoparticles (SFM) is used as a transparency modifier of poly(ethylene glycol)-tetraacrylate (PEG4A) solution. The incorporation of melanin into the SF hydrogel is performed in the range of 0.05-0.2% (w/v), and the SFM was added to the PEG4A precursor solution at 0.25-1.0% (w/v). The printing accuracy was examined by comparing the printed and designed feature sizes. The addition of 1.0% (w/v) SFM to a 4% (w/v) PEG4A (PEG4A/SFM) precursor solution effectively reduces the transparency of the solution and improves the printing resolution by confining the light beam to a designed region. This enables the fabrication of hard-to-express features such as hollow blood vessels or vacant tubes. Furthermore, the elastic modulus of the printed PEG4A/SFM composite hydrogel increases 2.5-fold higher than the PEG4A hydrogel without SFM. For the bio-ink, PEG4A/SFM-containing cells show non-cytotoxicity and improve the proliferation rate of embedded cells, confirming the high biocompatibility of PEG4A/SFM hydrogels.</P> [FIG OMISSION]</BR>
구조용 접착제 수명예측 기법 정립을 위한 기계적 물성과 분석물성간의 상관관계 분석 연구
신성철(Sungchul Shin),류성우(Seongwoo Ryu),김성겸(Sungkyum Kim) 한국자동차공학회 2022 한국자동차공학회 부문종합 학술대회 Vol.2022 No.6
As the proportion of plastic materials such as CFRP, SMC, PC-ABS, etc., used as a vehicle body increases, the number of cases where the vehicle body is joined only with adhesive without mechanical bonding has increased. Therefore, securing the durability of adhesives and predicting the life expectancy has become more important. Until now, there was no way to know how the experimentally established Arrhenius life equation matches the adhesive life applied to the actual vehicle. In this paper, by formulating the correlation between mechanical properties such as adhesion, which is reduced by aging, and analytical properties such as crosslinking, oxidation, and Tg, mechanical properties can be inferred only by analysis of field applications. In addition, the purpose of this study is to check whether the established correlation formula matches the established Arrhenius lifetime formula and to study ways to further improve the accuracy of the existing Arrhenius formula.
원심펌프의 임펠러와 볼루트 케이싱 간 간극이 자동차용 워터펌프 성능에 미치는 영향에 대한 연구
신성철(Sungchul Shin),강훈철(Huncheol Kang),양시원(Siwon Yang) 한국자동차공학회 2019 한국자동차공학회 부문종합 학술대회 Vol.2019 No.5
In the automotive electric water pump, the gap height between the closed type impeller and the volute casing is inevitable due to part’s injection molding and the product assembly process. Therefore, In this study, we investigated the effect of the clearance of the pump on the performance in the same closed type impeller. Numerical analysis was performed using CFD for different the gap height models, and hydraulic performance tests were conducted using our test bench. As a result, it was confirmed that the gap height is closely related to the leakage amount inside the centrifugal pump, which greatly affects the hydraulic performance of the pump. Throughout this study, we proposed the optimal gap height.