• Title/Summary/Keyword: stabilizers

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Microstructure and Phase Stability of $\beta$-Dicalcium Silicate ($\beta$형 Dicalcium Silicate 광물의 상 안정성 및 미세구조변화)

  • 박춘근
    • Journal of the Korean Ceramic Society
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    • v.34 no.9
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    • pp.957-962
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    • 1997
  • Dicalcium silicate has many polymorphs according to temperature. $\beta$-dicalcium silicate which exists in cement is stabilized by minor components drived from raw materials regardless of temperature, such as high temperature and room temperature. K2O, SO3 and B2O3 are effective stabilizers for $\beta$-dicalcium silicate at room temperature. B2O3 was the most effective stabilizer. Transformation from $\beta$ to ${\gamma}$ phase causes dicalcium silicate to change volume, resulting in dusting phenomenon. When B2O3 was used the phase transformation is the least than any other stabilizers. In addition, the starting temperature of quenching influences phases transformation : low temperature of quenching presented much phase transformation and decreased size of parameter of $\beta$-dicalcium silicate.

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Effect of Acoustical Excitation and Flame Stabilizer on a Diffusion Flame Characteristics (음향가진과 보염기형상이 확산화염의 특성에 미치는 영향)

  • Jeon, C.H.;Chang, Y.J.
    • Journal of the Korean Society of Combustion
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    • v.3 no.1
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    • pp.1-10
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    • 1998
  • Lots of techniques are adopted for a flame stabilization and a high-load combustion. But the techniques being used were passive control method which have to change combustor shape like pilot flame, flame stabilizer, pressure profile, etc. Active control method which is not necessary to transform its shape is employed. Acoustical excitation is broadly used for its convenience in changing frequency and intensity. Both acoustical excitation and flame stabilizers were adopted to study their relationship. So, we investigated flammability limits. Flame visualization. And mean temperature in the condition of various frequencies, intensities, and flame stabilizers. As a consequence, flammability limit were advanced in acoustically excited flame at some frequencies. Coherent structure was extended to the downstream region through acoustical excitation and a size of vortice was curtailed. Also width of recirculation zone was magnified. In addition, Effects of acoustical excitation was stood out at 25mm flame stabilizer rather than another ones.

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Effects of Various Stabilizers on the Production of hGM-CSF in Transgenic Nicotiana tabacum Suspension Cell Cultures (형질전환된 담배세포배양을 이용한 hGM-CSF 생산에서 여러 가지 단백질 안정제가 미치는 영향)

  • Cho, Jong-Moon;Kim, Dong-Il
    • KSBB Journal
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    • v.22 no.4
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    • pp.185-190
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    • 2007
  • Productivity of secreted recombinant protein depends largely on its stability in the extracellular environment with protease. Most hGM-CSF produced by transgenic tobacco cell cultures and secreted to the medium was confirmed to be rapidly degraded by protease in medium. To increase the productivity, therefore, various protein stabilizers such as gelling agents such as carrageenan and alginate, polymers, polyols, and amino acids have been tested. The stability of hGM-CSF in spent medium without cells was improved by the presence of gelling agents. However, the reason for the enhanced production by the addition of gelling agents may be due to the increased expression level and permeability rather than stability. The addition of DMSO inhibited the cell growth, but improved specific yield. The others were not effective for stability as well as hGM-CSF production.

Effect of Emulsifiers and Stabilizers on the Emulsion Stability of Mayonnaise (유화 . 안정제 사용이 Mayonnaise의 유화안정성에 미치는 영향)

  • 이영엽
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.27 no.1
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    • pp.115-120
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    • 1998
  • The effects of oil concentration and stabilizers and emulsifiers on the emulsion stability of mayonnaise were studied. The highest viscosity of mayonnaise and the least amount of oil separation were by the additon of soluble starch, but when it was added below 0.6%, the viscosity of a mayonnaise decreased sharply during storage at 3$0^{\circ}C$. The stability of mayonnaise was increased only when the soluble starch was added to mayonnaise above 0.9%. When xanthan gum was added at the concentration of 0.05~0.1%, the viscosity of mayonnaise was increased considerably and the emulsion stability was improve. But if it was added more than at 0.2% on the contrary, the emulsion stability was reduced and the texture of mayonnaise was changed. When both 0.1%-xanthan gum and 0.3%-soluble starch were added, the most stable mayonnaise was obtained.

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New Low-Order Stabilizers and Its Application to the First-Order and PID Controllers with Time Response Specifications (새로운 저차 안정화기와 시간응답을 위한 1차 및 PID 제어기 설계)

  • Kim, Young-Chol;Cho, Tae-Shin;Kim, Keunsik
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.55 no.1
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    • pp.1-13
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    • 2006
  • This paper presents the problems of designing low-order controller for a linear time-invariant(LTI) system in parameter space, wherein both transient response requirements and stability shall be considered in the same space. For a LTI system, we, (1) develop a method determining the existence of low-order stabilizers of the first-order and PID structures, (2) develop an algorithm of finding such a stabilizing region. (3) Both procedures are carried out by means of a parametric approach in the same frame work. This leads to easily obtain a subset of controller gains from the stabilizing set, that meet good time response requirements. It is illustrated by examples.

Dynamic Embedded Optimization Applied to Power System Stabilizers

  • Sung, Byung Chul;Baek, Seung-Mook;Park, Jung-Wook
    • Journal of Electrical Engineering and Technology
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    • v.9 no.2
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    • pp.390-398
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    • 2014
  • The systematic optimal tuning of power system stabilizers (PSSs) using the dynamic embedded optimization (DEO) technique is described in this paper. A hybrid system model which has the differential-algebraic-impulsive-switched (DAIS) structure is used as a tool for the DEO of PSSs. Two numerical optimization methods, which are the steepest descent and Broyden-Fletcher-Goldfarb-Shanno (BFGS) algorithms, are investigated to implement the DEO using the hybrid system model. As well as the gain and time constant of phase lead compensator, the output limits of PSSs with non-smooth nonlinearities are considered as the parameters to be optimized by the DEO. The simulation results show the effectiveness and robustness of the PSSs tuned by the proposed DEO technique on the IEEE 39 bus New England system to mitigate system damping.

Change of Prescribing Pattern after Clozapine Discontinuation: A Retrospective Chart Review (클로자핀 중단 이후 처방 패턴의 변화: 후향적 의무기록 분석)

  • Kang, Shi Hyun
    • Korean Journal of Schizophrenia Research
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    • v.24 no.1
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    • pp.36-43
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    • 2021
  • Objectives: Despite the high discontinuation rate of clozapine in refractory schizophrenia, there is limited evidence regarding the suggested treatment after clozapine discontinuation. Methods: The medical records of 37 patients who discontinued clozapine were retrospectively reviewed. The prescription patterns of antipsychotics, mood stabilizers, and antidepressants were compared at three points before and after clozapine treatment and at the most recent visit. Results: After clozapine discontinuation, 75.6% of the subjects were receiving antipsychotic polypharmacy, and 32.4% were taking more than 3 antipsychotics. The frequently used antipsychotics were olanzapine (21.5%), quetiapine (21.5%), and paliperidone (12.7%). The rates of augmentation with mood stabilizers and antidepressants were 43.2% and 29.7%, respectively. Furthermore, valproate was the most commonly used mood stabilizer (87.5%). Conclusion: Antipsychotic polypharmacy and augmentation are inevitable in schizophrenia patients for whom clozapine has been discontinued. Further research is required to improve the outcomes of polypharmacy and augmentation in schizophrenia patients.

STABILIZERS ON SHEFFER STROKE BL-ALGEBRAS

  • Katican, Tugce;Oner, Tahsin;Saeid, Arsham Borumand
    • Honam Mathematical Journal
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    • v.44 no.1
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    • pp.78-97
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    • 2022
  • In this study, new properties of various filters on a Sheffer stroke BL-algebra are studied. Then some new results in filters of Sheffer stroke BL-algebras are given. Also, stabilizers of nonempty subsets of Sheffer stroke BL-algebras are defined and some properties are examined. Moreover, it is shown that the stabilizer of a filter with respect to a/n (ultra) filter of a Sheffer stroke BL-algebra is its (ultra) filter. It is proved that the stabilizer of the subset {0} of a Sheffer stroke BL-algebra is {1}. Finally, it is stated that the stabilizer St(P, Q) of P with respect to Q is an ultra filter of a Sheffer stroke BL-algebra when P is any filter and Q is an ultra filter of this algebra.

Pharmacological Treatment Strategies for Acute Bipolar Depression (급성기 양극성우울증 약물치료 전략)

  • Kim, Se Joo
    • Journal of Korean Neuropsychiatric Association
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    • v.57 no.4
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    • pp.287-300
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    • 2018
  • Of the different phases of bipolar disorder, bipolar depression is more prevailing and is more difficult to treat. However, there is a deficit in systemic research on the pharmacological treatment of acute bipolar depression. Therefore, consensuses on the pharmacological treatment strategies of acute bipolar depression has yet to be made. Currently, there are only three drugs approved by the Food and Drug Administration for acute bipolar depression : quetiapine, olanzapine-fluoxetine complex, and lurasidone. In clinical practice, other drugs such as mood stabilizers (lamotrigine, lithium, valproate) and/or the other atypical antipsychotics (aripiprazole, risperidone, ziprasidone) are frequently prescribed. There remains controversy on the use of antidepressants in bipolar depression. Here, we summarized the evidence of current pharmacological treatment options and reviewed treatment guidelines of acute bipolar depression from recently published studies.