• Elastomers and Composites
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• 제36권4호
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• pp.237-245
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• 2001

고무의 충전제로 사용되는 실리카의 보강효과를 높이기 위해 실란 커플링제인 bistriethox ysilyipropyltetrasulfide(Si 69)와 ${\gamma}$-mercaptopropyltrimethoxy silane(MPS)를 사용하여 실리카의 화학처리를 건식법과 습식법으로 행하였으며, 실란 커플링제를 직접 실리카와 혼합하는 건식법보다 혼합하기 전에 화학적으로 처리하는 건식법이 분산성, 젖음성, 동적특성 및 안정성에서 더욱 우수하였다. 화학처리된 실리카를 SBR 배합에 니더와 믹싱롤을 사용하여 균일하게 혼련하였고 측정한 물성으로부터 비교, 검토하였으며, 실란 커플링제를 사용하지 않을 때보다 물성이 현저히 증가하였으며, 실험으로부터 건식법의 경우 Si 69와 MPS의 최적 사용량은 2 w/w%이지만. 습식법의 경우 EA 및 TGA 분석으로부터 4 w/w% 이였다.

• 비파괴검사학회지
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• 제32권1호
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• pp.27-33
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• 2012

광탄성법은 실험역학에서 응력 또는 변형률을 해석하기 위한 여러 실험방법 중의 하나이며, 다양한 종류의 구조물의 응력 분포를 실험적으로 결정하는 기법이다. 광탄성법은 광탄성 영상의 등색 프린지와 등경 프린지로부터 광탄성 시편에 나타나는 전체의 응력장 분포를 정밀하게 측정할 수 있다. 본 논문에서는 여러 가지 광탄성 기법중 8단계 위상이동법(8-step phase-shifting method)에 관한 이론을 살펴보고, 경사균열이 있는 평판 시편에 인장을 가하여 나타난 광탄성 프린지로부터 경사균열 선단주위의 응력분포를 8단계 위상이동법으로 결정한 후, 이들 결과를 유한요소법(FEM)에 의한 결과와 비교하였다. 8단계 위상이동법을 이용한 실험에 의해 측정된 프린지 차수는 유한요소법에 의한 계산된 프린지 차수값에 근접하였다.

• 대한화장품학회지
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• 제25권4호
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• pp.111-121
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• 1999

Acne vulgaris, the most common skin disease. can be formed as only a few comedons or severe inflammatory lesions. The pathogenesis of acne involves various factors; excessive androgen, excessive sebum production, abnormal alteration of follicular epithelium, proliferation of Propionibacterium acnes, and inflammation. We investigated acne therapy using oriental herbs described in the Korean traditional medical book(Dong-ui-bo-gam). Oriental herbs(Angelica daurica, Arctium lappa, Coptidis rhizoma, and Glycyrrhiza glabra) were chosen based on their respective property of sebum control, anti-inflammatory activity, and anti-bacterial activity. We examined the effect of acne treatment, in terms of chemotactic inhibition, lipogenesis inhibition, and anti-bacterial activity for P. acnes. 1. Neutrophil chemotaxis assay; P. acnes secrete chemotactic factors and other pro-inflammatory extracellular products. Neutrophil chemotactic activity of P. acnes was measured by 48-well chemotaxis method. Angelica daurica clearly suppressed chemotactic activity of P. acnes. 2. Using sebaceous gland of hamster ear lipogenesis assay; Sebaceous lipogenesis was measured using ear biopsies by incubation or $C^{14}$-acetate in culture media. The $C^{14}$-labeled lipids were extracted and determined by liquid scintilation counting. Coptidis rhizoma markedly inhibited sebum production. 3. Anti-bacterial assay for P. acnes(MIC test); Glycyrrhiza glabra showed anti-bacterial activity. P. acnes did not develop resistance against Glycyrrhiza glabra. Retinoids are effectively to inhibit sebum production and regulate follicular keratinization process, with little anti-inflammatory activity. Angelica daurica suppressed neutrophil chemotaxis, Coptidis rhizoma inhibited sebum production, and Glycyrrhiza glabra showed anti-bacterial activity against P. acnes. A combined formulation of Angelica daurica, Coptidis rhizoma. and Glycyrrhiza glabra is expected to provide effective acne treatment.

• Asian Pacific Journal of Cancer Prevention
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• 제14권10호
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• pp.5753-5759
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• 2013

Curcumin and curcumin containing polyherbal preparations have demonstrated anti-microbial and antiviral properties in pre-clinical studies. Till date no therapeutic intervention has been proved to be effective and safe in clearing established cervical human papillomavirus (HPV) infection. The present study evaluated the efficacy of Basant polyherbal vaginal cream (containing extracts of curcumin, reetha, amla and aloe vera) and of curcumin vaginal capsules to eliminate HPV infection from cervix. Women were screened by Pap smear and HPV DNA test by PCR. HPV positive women without high grade cervical neoplasias (N=287) were randomized to four intervention arms to be treated with vaginal Basant cream, vaginal placebo cream, curcumin vaginal capsules and placebo vaginal capsules respectively. All subjects were instructed to use one application of the assigned formulation daily for 30 consecutive days except during menstruation and recalled within seven days of the last application for repeat HPV test, cytology and colposcopy. HPV clearance rate in Basant arm (87.7%) was significantly higher than the combined placebo arms (73.3%). Curcumin caused higher rate of clearance (81.3%) than placebo though the difference was not statistically significant. Vaginal irritation and itching, mostly mild to moderate, was significantly higher after Basant application. No serious adverse events were noted.

• Asian Pacific Journal of Cancer Prevention
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• 제14권5호
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• pp.3363-3368
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• 2013

Background: The burden due to cancers is an emerging public health concern especially in resource-limited countries like Nigeria. The WHO estimates that cancer kills more people than tuberculosis, HIV/AIDS and malaria combined. As people in Nigeria and other developing countries are beginning to survive infectious diseases, there is an observed epidemiologic transition to chronic diseases, such as cancers. In 2008, 75 out of 1,000 Nigerians died of cancer. Despite the rising incidence and public health importance, Nigeria lacks an organized and comprehensive strategy to deal with cancers. Materials and Methods: This article reviewed 30 peer-reviewed manuscripts on cancer care in four countries. It highlights the limitations to cancer care in Nigeria; due to lack of awareness, low health literacy, absence of organized screening programs, inadequate manpower (in terms of quality and quantity) as well as limited treatment options. Results: This review led to the formulation of a proposal for Nigerian National Cancer Policy, mainly drawn from effective strategies used in Canada, Brazil and Kenya. This is a vertical cancer program that is patient-centered with an emphasis on tobacco control and cancer disease screening (similar to Canada and Brazil). Additionally, it emphasizes primary cancer prevention (similar to Kenya). Its horizontal integration with other disease programs like HIV/AIDS will improve affordability in a poor resourced country like Nigeria. Capacity building for health professionals, hub-and-spoke implementation of screening services, as well as investment in effective treatment options and increased research in cancer care are essential. International 'twinning collaborations' between institutions in richer countries and Nigeria will enhance effective knowledge translation and improve the quality of patient care. Conclusions: A national cancer policy must be developed and implemented in Nigeria in order to overcome the present limitations which help contribute to the observed increases in cancer morbidity and mortality rates. Cancer control is feasible in Nigeria if the nation was to consider and employ some of the cost-effective strategies proposed here.

• 대한토목학회논문집
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• 제12권3호
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• pp.91-105
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• 1992

절점(節點)의 횡변위(橫變位)(sidesway)가 있는 고층(高層)라멘의 해석(解釋)을 위해서 고전적(古典的) 구조해석(構造解釋)에서는 적절한 방법(方法)이 없다고 볼 수 있다. 잘 알려진 처짐해석(角法)이나 모멘트분배법(分配法) 등도 엄청난 계산량(計算量)이 소요(所要)되기 때문에 효율적(效率的)인 방법(方法)은 못 된다. 본(本) 연구(硏究)는 절점(節點)의 횡변위(橫變位)를 수반하는 고층건물(高層建物)뼈대의 해석(解釋)에 관한 직접적(直接的)인 방법(方法)을 개발한 것이다. 이 절점(節點)의 횡변위(橫變位)는 횡하중(橫荷重)을 받는 경우, 또는 구조물(構造物)이나 수직하중(垂直荷重)이 비대칭(非對稱)인 경우에 일어난다. 여기 제시(提示)된 방법(方法)은 모멘트분배과정(分配過程)에 수차적(遂次的) 수정법(修正法)의 개념(槪念)을 도입하여 수학적(數學的)으로 간단한 방정식(方程式)을 유도(誘導)한 것이다. 수치예(數値例)에 의하면 본(本) 연구(硏究)에 의한 결과치(結果値)는 정해(正解)와 아주 잘 맞고 있음을 나타내고 있다. 이 새로운 방법(方法)은 말할 필요(必要)도 없이 절점변위(節點變位)가 없는 구조(構造)뼈대나 연속(連續)보의 해석(解析)에 훨씬 더 쉽게 적용(適用)할 수 있다.

• Structural Engineering and Mechanics
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• 제75권5호
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• pp.541-557
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• 2020

A novel family of controllable, dissipative structure-dependent integration methods is derived from an eigen-based theory, where the concept of the eigenmode can give a solid theoretical basis for the feasibility of this type of integration methods. In fact, the concepts of eigen-decomposition and modal superposition are involved in solving a multiple degree of freedom system. The total solution of a coupled equation of motion consists of each modal solution of the uncoupled equation of motion. Hence, an eigen-dependent integration method is proposed to solve each modal equation of motion and an approximate solution can be yielded via modal superposition with only the first few modes of interest for inertial problems. All the eigen-dependent integration methods combine to form a structure-dependent integration method. Some key assumptions and new techniques are combined to successfully develop this family of integration methods. In addition, this family of integration methods can be either explicitly or implicitly implemented. Except for stability property, both explicit and implicit implementations have almost the same numerical properties. An explicit implementation is more computationally efficient than for an implicit implementation since it can combine unconditional stability and explicit formulation simultaneously. As a result, an explicit implementation is preferred over an implicit implementation. This family of integration methods can have the same numerical properties as those of the WBZ-α method for linear elastic systems. Besides, its stability and accuracy performance for solving nonlinear systems is also almost the same as those of the WBZ-α method. It is evident from numerical experiments that an explicit implementation of this family of integration methods can save many computational efforts when compared to conventional implicit methods, such as the WBZ-α method.

• 한국축산식품학회지
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• 제37권1호
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• pp.52-61
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• 2017

The objective of this study was to investigate the effects of different concentrations of WSP (wheat sprout powder) and ISP (isolated soy protein) on the quality of breakfast sausage. Treatments were formulated as follows: Control, T1 (2.0% ISP), T2 (1.5% ISP + 0.5% WSP), T3 (1.0% ISP + 1.0% WSP), T4 (0.5% ISP + 1.5% WSP) and T5 (2.0% WSP). The treatments were analyzed for color, pH, cooking loss, emulsion stability, protein solubility, viscosity, texture properties and sensory evaluation. Lightness and redness were reduced and yellowness was increased as increased level of WSP, due to the dark green color of WSP (p<0.05). The pH values of all samples were affected by WSP which has lower pH (p<0.05). The emulsion stability and cooking loss of treatments were improved with increasing level of WSP (p<0.05). The protein solubility, viscosity and overall texture properties of the sausage indicated significant differences in relation to the level of WSP and ISP (p<0.05). The sensory evaluation indicated that the greatest flavor and overall acceptability in sausage was achieved at WSP 1% combination with ISP 1% (T3) (p<0.05). Therefore, these results indicate that breakfast sausage containing 1% WSP and 1% ISP is the optimal formulation, taking into consideration the overall physico-chemical properties and sensory evaluation.

• Structural Engineering and Mechanics
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• 제4권5호
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• pp.513-527
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• 1996

In this paper, both an approximate expression and an exact expression for the contribution factor of an element to the natural frequency of the finite element discretized system of a structure in general and a membrane in particular have been derived from the energy conservation principle and the finite element formulation of structural eigenvalue problems. The approximate expression for the contribution factor of an element is used to predict and determine the elements to be removed in an iteration since it depends only on the quantities associated with the old system in the iteration. The exact expression for the contribution factor of an element makes it possible to check whether the element is correctly removed at the end of an iteration because it depends on both the old system and the new system in the iteration. Thus, the combined use of the approximate expression and the exact expression allows a considerable number of elements to be removed in a single iteration so that the efficiency of the evolutionary structural optimization method can be greatly improved for solving the natural frequency optimization problem of a structure. A square membrane with different boundary supports has been chosen to investigate the general evolutionary path for the fundamental natural frequency of the structure. The related results indicated that if the objective of a structural optimization is to raise the fundamental natural frequency of the structure to an optimal value, the general evolutionary path during its optimization is that the elements are gradually removed along the direction from the area surrounded by the contour of the highest value to that surrounded by the contour of the lowest value.

• 한국물환경학회지
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• 제24권5호
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• pp.603-610
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• 2008

A mathematical model was developed to understand how the presence of plants affects vertical profiles of electron acceptors, their reduced species, and trace metals in the wetland sediments. The model accounted for biodegradation of organic matter utilizing sequential electron acceptors and subsequent chemical reactions using stoichiometric relationship. These biogeochemical reactions were affected by the combined effects of oxygen release and evapotranspiration driven by wetland plants. The measured data showed that $SO_4{^{2-}}$ concentrations increased at the beginning of the growing season and then gradually decreased. Based on the measured data, it was hypothesized that the limitation of the solid phase sulfide in direct contact with the roots may result in the gradual decrease of $SO_4{^{2-}}$ concentrations. With the dynamic formulation for the limitation of the solid phase sulfide, model simulated time variable sulfate profiles using published model parameters. Oxygen release from roots produced divalent metal species (i.e. $Cd^{2+}$) as well as oxidized sulfur species (i.e. $SO_4{^{2-}}$) in the sediment pore water. Evapotranspiration-induced advection increased flux of divalent metal species from the overlying water column into the rhizosphere. The increased divalent metal species were converted to the metal sulfide with sufficient FeS around the rhizosphere, which contributed to the decrease of bioavailability and toxicity of divalent metal activity in the pore water. Since the divalent metal activity is a good predictor of the metal bioavailability, this model with a proper simulation of solid phase sulfide plays an essential role to predict the dynamics of trace metals in the wetland sediments.