• Macromolecular Research
• /
• 제9권2호
• /
• pp.92-99
• /
• 2001

Silica-filled rubber compounds have slower cure characteristics than carbon black-filled ones due to the adsorption of curatives on the silica surface. Fatty acid was used as a cure activator along with zinc oxide in a sulfur cure system. Poly(ethylene glycol), PEG, was used in silica-filled rubber compounds to prevent adsorption of the curatives on the silica surface. In this study, influence of the size of fatty acid and PEG on properties of silica-filled NR compounds was investigated. It was found that the size of fatty acid and PEG affected the curt: characteristics and physical properties. The cure rate becomes faster as the PEG size increases. By increasing the size of fatty acid or PEG, the delta torque of the compound decreases while the Mooney viscosity increases. The modulus of the vulcanizate decreases with increasing the molecular weight of fatty acid or PEG. The experimental results were explained by the filler dispersion and by the prevention of the curative-adsorption on the silica surface.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
• /
• pp.548-551
• /
• 1999

The cure characteristics of metal particle filled DGEBA/MDA/SN/ zeolite epoxy resin composite system for EMI shielding were investigated by dynamic DSC run method and FT-lR spectroscopy. As the heating rate increased, the peak temperature on dynamic DSC curve increased because of the rapid cure reaction. From the straight line of the Kissinger plot, the curing reaction activation energy and pre-exponential factor could be obtained. As the post-curing time at 15$0^{\circ}C$ increased, the glass increased the glass transition temperature or the thermal stability increased. When the post curing time is too long, the system filled with metallic Al particle can be thermally oxidized by the catalytic reaction of metal filler and the thermal stability of the composite for the EMI shielding application may be decreased.

• 한방안이비인후피부과학회지
• /
• 제32권4호
• /
• pp.13-28
• /
• 2019

Objectives : The purpose of this study is to report the effectiveness of Korean medical treatment on 222 patients with alopecia areata. Methods : The subjects of this study were 222 patients who had received Korean medical treatment among the patients who visited the Balmer's Korean Medicine Clinic from January 1, 2016 to December 31, 2017. The extent of the alopecia areata was measured every month to determine the improvement. We analyzed the relationship between the types of alopecia areata, the extent of hair loss, duration of illness, age at first visit, and the treatment of alopecia areata. Results : 1. There were 100 males(45.0%) and 122 females(55.0%). The mean age of patients was 35.3 years old. 2. Of the 222 patients, 142(64%) were "cured". 31(14%) showed "good", 21(9.5%) showed "fair", 28(12.6%) showed "poor" improvement. 3. According to clinical records, of the 64 patients with alopecia areata(AA), 48(75.0%) were cured. Of the 100 patients with alopecia areata multiplex(AAM), 68 patients (68.0%), 12(50.0%) out of 24 patients with ophiasis, 5(55.6%) out of 9 with alopecia semi-totalis(AST), 3(50.0%) out of 6 patients with alopecia totalis(AT), 6(31.6%) out of 19 patients with alopecia universalis(AU) were cured. 4. Patients with the wider hair loss extent and with more severe type of alopecia areata required longer treatment period to cure, and the cure rate was lowered(p<0.05). 5. The shorter duration of the disease was related to the higher cure rate(p<0.05). If the treatment was started after six months of the duration, the cure rate was lowered. Therefore, beginning treatment within six months of the onset is recommended. 6. The period until terminal hair showed was 1.5 months for AA, 1.7 months for AAM, 1.6 months for ophiasis, 1.9 months for AST, 2.3 months for AT, 3.2 months for AU. 7. The treatment period to cure was 4.9 months for AA, 7.3 months for AAM, 7.7 months for ophiasis, 6.8 months for AST, 7.7 months for AT, 16.3 months for AU. 8. The major prognostic factors were extent and type of alopecia, duration of the disease and relapse. Conclusions : We analyzed the effectiveness of Korean medical treatment through cure rate according to the prognostic factors. This study will provide useful data for the treatment of alopecia areata.

• 혜화의학회지
• /
• 제19권2호
• /
• pp.57-64
• /
• 2011

Parkinson's disease is a degenerative disease of a cranial nerve and has a main symptoms of irregular movement of muscle, stiffening, trembling which occurred by about 1% of population in the age of over 65. Moreover, the and prevalence rate and attack rate are soaring according to increase of elderly population. However, allopathy and surgery were done through dopamine and anticholinergic medicine for treatment but it developed a lot of complications due to medicine and progress since it makes slow progress or can't stop the treatment. Hereupon, I report that there is a case on one of the patients Young Jin Oriental Medical Clinic. The patient who is in state of treatment termination who doesn't need any further remedy and no worsening of symptoms after conduction of therapies of dialectic and 5 upright life cure regulations. 5 upright life cure regulations means five practive way for improvement of nature healing power. Upon undertaking the 5 upright life cure regulations, there were found significant results in such tests as Unified Parkinson Disease Rating Scale (UPDRS), Hoehn & Yahr Staging Scale, and Activity of Daily Living (ADL), and the ingestion of Benztropine 1mg and Requip 0.25mg was decreased from 3 times to 0 times. The study offers objective clinical data on Oriental Medicine treatment for Parkinson's disease which is one of representative neuro-degenerative diseases and thus broadens the application range of Oriental Medical treatment and presents the fundamental data on the clinical research on Parkinson's disease by adopting evidence-based medicine (EBM).

• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2002년도 추계학술발표대회 논문집
• /
• pp.265-268
• /
• 2002

In this work, the blend system of epoxy and PMR-15 polyimide is investigated in terms of the cure behaviors and thermal stabilities. The cure behaviors are studied in DSC measurements and thermal stabilities are also carried out by TGA analysis. DDM (4, 4'-diamino diphenyl methane) is used as curing agent for EP and the content of PMR-15 is varied within 0, 5, 10, 35, and 20 phr to neat EP. As a result, the cure activation energy ($E_a$) is increased at 10 phr of PMR-15, compared with that of neat EP. From the TGA results of EP/PMR-15 blend system, the thermal stabilities based in the initial decomposed temperature (IDT) and integral procedural decomposition temperature (IPDT) are increased with increasing the PMR-15 content. The fracture toughness, measured in the context of critical stress intensity factor ($K_{IC}$) and critical strain energy release rate ($G_{IC}$), shows a similar behavior with $E_a$. This result is probably due to the crosslinking developed by the interactions between intermolecules in the polymer chains.

• 응용통계연구
• /
• 제17권2호
• /
• pp.253-267
• /
• 2004

임상시험중에는 소아암연구에서와 같이 환자 중의 상당수에서 사망 또는 재발이 오랜 기간 일어나지 않고 완치된 것으로 보이는 경우가 있다. 이 경우 연구자는 생존함수의 전반적인 비교보다는 치료율의 비교에 더 관심이 있을 것이다. 본고에서는 치료율의 비교를 위한 여러 모수적, 비모수적 방법들을 소개하고, 생존분포, 치료율, 중도절단을 등을 다양하게 설정한 모의실험을 통하여 각 방법들의 검정력과 유의수준을 비교하였다.

• 한국재료학회지
• /
• 제8권9호
• /
• pp.797-801
• /
• 1998

Diglycidy1 ether of bisphenol A (DEGBA)/4, 4'-methylene dianiline(MDA) 계의 반응속도에 미치는 10 phr의 pheny1 glycidy1 ether(PGE)-acetamide(AcAm)의 영향을 살펴보았다. PGE-AcAm이 첨가됨으로 인해서 승온적 DSC 곡선에서 최대 발열피크의 온도와 피크 시작 온도가 감소하였다. PGE-AcAm의 첨가 여부에 관계없이 전화율 곡선은 s-자 형상이었고, 이는 DGEBA/MDA 계와 DGEBA/MDA/PGE-AcAm 계가 자촉대 반응을 한다는 것을 의미한다. 또한 PGE-AcAm이 10 phr 첨가됨으로 인해서 1.2-1.4배 증가하였는데, 이는 PGE-AcAm의 수산기가 촉매로 작용하기 때문이다.

• 한국재료학회지
• /
• 제9권5호
• /
• pp.467-472
• /
• 1999

Neopentyl glycoI(NPG) 의 함량변화에 따른 diglycidyl ether of bisphenol A (DGEBA)/4,4' -methylene dianiline (MDA) 계의 등온적 경화거동을 DSC를 이용하여 분석하였다. DGEBA/MDA 계의 경화속도를 증가시키기 위하여 NPG를 첨가하였다. NPG 함량에 관계없이 전화율 곡선이 s-자 모양이었으며, 이것은 DGEBA/MDA/NPG 계의 경화반응이 자촉매 반응 메커니즘에 따른다는 것을 의미한다. NPG의 함량이 증가함에 따라 경화속도가 증가하였으며, 이것은 NPG가 가지고 있는 두 개의 hydroxyl 기가 촉매로 작용하기 때문이다.

• Macromolecular Research
• /
• 제17권2호
• /
• pp.121-127
• /
• 2009

The cure kinetics of the epoxy-layered, silicate nanocomposites were studied by differential scanning calorimetry under isothermal and dynamic conditions. The materials used in this study were o-cresol novolac epoxy resin and phenol novolac hardener, with organically modified layered silicates. Various kinetic parameters, including the reaction order, activation energy, and kinetic rate constants, were investigated, and the storage stability of the epoxy-layered silicate nanocomposites was measured. To synthesize the epoxy-layered silicate nanocomposites, the phenolic hardener underwent pre-intercalation by layered silicate. From the cure kinetics analyses, the organically modified layered silicate decreased the activation energy during cure reaction in the epoxy/phenolic hardener system. In addition, the storage stability of the nanocomposite with the pre-intercalated phenolic hardener was significantly increased compared to that of the nanocomposite with direct mixing of epoxy, phenolic hardener, and layered silicate. This was due to the protective effect of the reaction between onium ions and epoxide groups.

• Design & Manufacturing
• /
• 제17권1호
• /
• pp.1-5
• /
• 2023

In multi-material injection molding, since two or more materials with different process conditions are used, it is essential to maximize process efficiency by operating the cooling or heating system to a minimum. In this study, Liquid silicone rubber (LSR) that can be cured at a low temperature suitable for the multi-material injection molding was selected and the cure behavior according to the process conditions was analyzed through differential scanning calorimetry (DSC). Dynamic measurement results of DSC with different heating rate were obtained, and through this, the total heat of reaction when the LSR was completely cured was calculated. Isothermal measurement results of DSC were derived for 60 minutes at each temperature from 80 ℃ to 110 ℃ at 10 ℃ intervals, and the final degree of cure at each temperature was calculated based on the total heat of reaction identified from the Dynamic DSC measurement results. As the result, it was found that when the temperature is lowered, the curing start time and the time required for the curing reaction increase, but at a temperature of 90 ℃ or higher, LSR can secure a degree of cure of 80% or more. However, at 80 ℃., it was found that not only had a relatively low degree of curing of about 60%, but also significantly increased the curing start time. In addition, in the case of 110 ℃, the parameters were derived from experimental result using the Kamal kinetic model.