• 제목/요약/키워드: intrinsic

검색결과 3,843건 처리시간 0.031초

Intrinsic Viscosity and Unperturbed Dimension of Poly(DL-lactic acid) Solution

  • Lee, Jae-Sung;Kim, Sung-Chul;Lee, Hwan-Kwang
    • Macromolecular Research
    • /
    • 제16권7호
    • /
    • pp.631-636
    • /
    • 2008
  • The intrinsic viscosities were determined for poly(DL-lactic acid) (PDLLA) solutions in 1,2-dialkyl phthalate at temperatures ranging from 30 to $60^{\circ}C$. A series of dialkyl phthalate, in which the alkyl group was changed from methyl to propyl, was used as the solvent to control the solvent quality systematically. The intrinsic viscosity of the PDLLA solution was higher in the better quality solvent, with a higher molecular weight of PDLLA, and at lower temperatures. The unperturbed dimensions of the PDLLA molecule and polymer-solvent interaction parameter of PDLLA in dialkyl phthalate were deduced using extrapolation methods based on the temperature-dependent intrinsic viscosities. Slight shrinkage in the unperturbed chain dimension was observed, which resulted from a change in polymer conformation with temperature. It was also observed that the polymer-solvent interaction became more favorable with the dialkyl phthalate containing a shorter alkyl chain.

Default Bayesian testing for normal mean with known coefficient of variation

  • Kang, Sang-Gil;Kim, Dal-Ho;Le, Woo-Dong
    • Journal of the Korean Data and Information Science Society
    • /
    • 제21권2호
    • /
    • pp.297-308
    • /
    • 2010
  • This article deals with the problem of testing mean when the coefficient of variation in normal distribution is known. We propose Bayesian hypothesis testing procedures for the normal mean under the noninformative prior. The noninformative prior is usually improper which yields a calibration problem that makes the Bayes factor to be defined up to a multiplicative constant. So we propose the objective Bayesian hypothesis testing procedures based on the fractional Bayes factor and the intrinsic Bayes factor under the reference prior. Specially, we develop intrinsic priors which give asymptotically same Bayes factor with the intrinsic Bayes factor under the reference prior. Simulation study and a real data example are provided.

A Novel Trench Electrode BRT with Intrinsic Region for High Blocking Voltage (고내압 특성을 위한 진성영역과 트렌치 구조를 갖는 베이스 저항 사이리스터)

  • 강이구;성만영
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 한국전기전자재료학회 2001년도 추계학술대회 논문집
    • /
    • pp.243-246
    • /
    • 2001
  • In this paper, we have proposed a novel trench electrode Base Resistance Thyristor(BRT) and trench electrode BRT with a intrinsic region. A new power BRTs have shown superior electrical characteristics including snab-back effect and forward blocking voltage more than the conventional BRT. Especially, the trench electrode BRT with intrinsic region has obtained high blocking voltage of 1600V. The blocking voltage of conventional BRT is about 400V at the same size. Because the breakdown mechanism of BRT is avalanch breakdown by impact ionization, the trench electrode BRT with intrinsic region has suppressed impact ionization, effectively. If we use this principle, we can develope super high voltage power devices and applicate to another power devices including IGBT, EST and etc.

  • PDF

Persistence length calculation from light scattering and intrinsic viscosity of dilute semiflexible polyimide solutions with different degree of imidization

  • Hansol Cho;Kim, Youn-Cheol;Kim, Sang-Ouk;Chung, In-Jae
    • Korea-Australia Rheology Journal
    • /
    • 제12권1호
    • /
    • pp.69-76
    • /
    • 2000
  • We have derived the translation diffusion coefficient and the intrinsic viscosity formula adopting the Kholodenko's theory using 3+1 dimensional Dirac propagator in the Kirkwood and Riseman scheme. We also performed static light scattering experiments and intrinsic viscosity measurement of dilute solutions of polyimides with different rigidities. In the framework of Kholodenko's theory, we can easily measure the persistence length of polyimide. We prepared five different polyamic acids and polyimides with different degree of imidization by controlling imidization temperatures. From experimental results, we obtained molecular weights and persistence lengths according to the Kholodenko's plot. The molecular weight and the intrinsic viscosity decreased and then increased with the imidization temperature but the persistence length increased monotonically and then leveled off. The persistence lengths calculated from intrinsic viscosities showed very good agreement with those from light scattering experiments.

  • PDF

Cross-Interaction Constant and Intrinsic Reaction Barrier

  • Lee, Ik Chun;Lee, Hae Hwang
    • Bulletin of the Korean Chemical Society
    • /
    • 제22권7호
    • /
    • pp.732-738
    • /
    • 2001
  • The cross second-derivative of the activation energy,${\theta}$G${\neq}$ , with respect to the two component thermodynamic barriers, ${\theta}$G˚X and ${\theta}$G$^{\circ}C$Y, can be given in terms of a cross-interaction constant (CIC), $\betaXY(\rhoXY)$, and also in terms of the intrinsic barrier,${\theta}$G${\neq}$ , with a simple relationship between the two: $\betaXY$ = $-1}(6${\theta}$G${\neq}$).$ This equation shows that the distance between the two reactants in the adduct (TS, intermediate, or product) is inversely related to the intrinsic barrier. An important corollary is that the Ritchie N+ equation holds (for which $\betaXY$ = 0) for the reactions with high intrinsic barrier. Various experimental and theoretical examples are presented to show the validity of the relationship, and the mechanistic implications are discussed.

Current understanding of cancer-intrinsic PD-L1: regulation of expression and its protumoral activity

  • Yadollahi, Pedram;Jeon, You-Kyoung;Ng, Wooi Loon;Choi, Inhak
    • BMB Reports
    • /
    • 제54권1호
    • /
    • pp.12-20
    • /
    • 2021
  • In the last decade, we have witnessed an unprecedented clinical success in cancer immunotherapies targeting the programmed cell-death ligand 1 (PD-L1) and programmed cell-death 1 (PD-1) pathway. Besides the fact that PD-L1 plays a key role in immune regulation in tumor microenvironment, recently a plethora of reports has suggested a new perspective of non-immunological functions of PD-L1 in the regulation of cancer intrinsic activities including mesenchymal transition, glucose and lipid metabolism, stemness, and autophagy. Here we review the current understanding on the regulation of expression and intrinsic protumoral activity of cancer-intrinsic PD-L1.

Interrelationship between Diabetic Control and Related Factors of Dietary Compliance in Diabetic Patients (당뇨병 환자의 당뇨병 조절과 식사요법 실천 관련요인과의 상관성)

  • Choe, Ji-Eun;Seo, Jeong-Suk
    • Journal of the Korean Dietetic Association
    • /
    • 제11권2호
    • /
    • pp.137-146
    • /
    • 2005
  • This study was carried out to investigate the relationship between diabetic control and related factors of the practice of diet therapy which affects mostly diabetic patients’ dietary compliance. A questionnaire survey was conducted on 128 diabetic patients who had visited Internal medicine endocrinology clinic at University Medical Center of Daegu area. The questionnaires including clinical characteristics, meal regularity and food intake which shows dietary compliance, intrinsic barriers to the practice of diet therapy and knowledge of diet therapy were asked and analyzed. The factor which affects HbA1c was intrinsic barriers and HbA1c became higher as the level of intrinsic barriers was increasing. The education on diet therapy had no influence on the intrinsic barriers, but the level of knowledge on diet therapy was shown higher in the educated patients. The above results suggest that the practice of diet therapy should be leaded to develop behavioral aspects through resonable motivation on dietary compliance along with removing intrinsic barriers rather than simply providing information.

  • PDF

Behavior of Intrinsic Viscosity and Moisture Content of Antistatic Polyethyleneterephthalate by Thermal Stabilizer (열안정제에 의한 제전성 폴리에틸렌테레프탈레이트의 고유점도 및 수분율의 거동 변화)

  • Kim, Moon-Chan;Lee, Cheal-Gyu
    • Applied Chemistry for Engineering
    • /
    • 제10권5호
    • /
    • pp.707-710
    • /
    • 1999
  • Moisture content and intrinsic viscosity of antistatic polyethyleneterephthalate(PET) depending on the thermal stabilizer content was studied. The terminal moisture content of antistatic PET was a function of drying temperature rather than drying time. Intrinsic viscosity drop of antistatic PET after melt spinning increased with increasing moisture content of it. After melt spinning, intrinsic viscosity of antistatic PET was decreased due to the thermal degradation of polyoxyalkyleneglycol(POAG) component of antistatic agent. Triphenylphosphate(TPP) was more effective as a thermal stabilizer than trimethylphosphate(TMP). A little intrinsic viscosity drop after melt spinning was found in PET containing 300 ppm of TPP as a thermal stabilizer.

  • PDF

The Role of Transformational Leadership toward Work Performance through Intrinsic Motivation: A Study in the Pharmaceutical Field in Vietnam

  • NGUYEN, Ha Minh;MAI, Lam Tung;HUYNH, Tam Luong
    • The Journal of Asian Finance, Economics and Business
    • /
    • 제6권4호
    • /
    • pp.201-212
    • /
    • 2019
  • The study aims to identify the role of transformational leadership toward work performance through intrinsic motivation in pharmaceutical field by a survey of 220 pharmacists in Vietnam. The pharmaceutical industry in Vietnam is experiencing rapid growth, accompanied by the need for a change in leadership for managers. The transformational leadership creates a proactive, positive attitude, passion, interest or an increase in intrinsic motivation of employees, thereby affecting work performance. This study performed reliable verification by Cronbach's Alpha coefficient, then the factors are analyzed by EFA before conducting multivariate regression analysis. The results showed that the transformational leadership style includes such factors as: idealized influence (attributed and behavior), inspirational motivation, intellectual stimulation, individualized consideration have a positive impact on intrinsic motivation and thereby positively affecting work performance. It confirms that employees will have a higher intrinsic motivation level when working under transformational leadership from their leaders. It makes employees work more efficiently. According to the research results, the pharmacist has an intrinsic motivation to work hard on tasks that contribute to the group overall goal of. That requires managers to have a task assignment strategy to connect the goals of the members together as well as of the members to the group.

Change of Intrinsic Brightness Temperatures of Compact Radio Jets

  • Lee, Sang-Sung
    • The Bulletin of The Korean Astronomical Society
    • /
    • 제39권2호
    • /
    • pp.57.1-57.1
    • /
    • 2014
  • We present results of our investigation of intrinsic brightness temperatures of compact radio jets at radio frequencies. The intrinsic brightness temperatures of about 100 compact radio jets at 2, 5, 8, 15, and 86 GHz are estimated based on large VLBI surveys conducted in 2001-2003 (or in 1996 for the 5 GHz sample). The multi-freqeuncy intrinsic brightness temperatures of the sample of the jets are determined with a statistical method relating the observed brightness temperatures with the maximal apparent jet speed, assuming one representative intrinsic brightness temperature for the sample at each observing frequency. With investigating the observed brightness temperatures at 15 GHz in multiple epochs, we found that the determination of the intrinsc brightness temperature for our sample is affected by variability of individual jets in flux density at the time scales of a few years. This implies an importance of contemporaneity of the multi-frequency VLBI observations for the statistical method. Since our analysis is based on the VLBI observations conducted in 2001-2003, the results are less affected by the flux density variability. We found that the intrinsic brightness temperature $T_0$ increases as $T_0{\propto}{\nu}^{\epsilon}$ with ${\epsilon}{\approx}0.7$ below a critical frequency ${\nu}_c{\approx}10GHz$ where energy losses begin to dominate the emission, and above the critical frequency, $T_0$ decreases with ${\epsilon}{\approx}-1.2$ supporting for the decelerating jet model.

  • PDF