Enhanced electromechanical properties of (1-x)BiFeO₃-BaTiO₃-xLiNbO₃ ceramics by quenching process

Ahmed Malik, R.,Hussain, A.,Kwon Song, T.,Kim, W.J.,Ahmed, R.,Soo Sung, Y.,Kim, M.H. Elsevier 2017 CERAMICS INTERNATIONAL Vol.43 No.suppl1

A new lead-free piezoelectric ceramics (1-x) (0.67Bi<SUB>1.05</SUB>FeO<SUB>3</SUB> - 0.33BaTiO<SUB>3</SUB>)-x LiNbO<SUB>3</SUB>, abbreviated as BFBT-LNx (x = 0.00-0.030), were fabricated by conventional mixed oxide route following by quenching process and crystal structure and electromechanical properties were discussed. X-ray diffraction pattern showed that LiNbO<SUB>3</SUB> addition into 0.67Bi<SUB>1.05</SUB>FeO<SUB>3</SUB> - 0.33BaTiO<SUB>3</SUB> system did not caused any significant change in crystal structure. However, an obvious variation in electrical properties was observed. It is revealed from electrical properties that the modification of LiNbO<SUB>3</SUB> induces a phase transition from a ferroelectric to relaxor state in the 0.67Bi<SUB>1.05</SUB>FeO<SUB>3</SUB> - 0.33BaTiO<SUB>3</SUB> system. At optimum composition (x = 0.010), enhanced field-induced strain with large dynamic piezoelectric constant S<SUB>max</SUB>/E<SUB>max</SUB> = d<SUP>*</SUP><SUB>33</SUB> = 500pm / V at a relatively low field of 3.5kV / mm with lower hysteresis loss of 40% was recorded. For this composition, a high Curie temperature T<SUB>C</SUB> ~ 390<SUP>o</SUP>C was found. These properties suggests that the synthesized system is promising for high temperature actuator applications.

Critical behavior of the resistivity of GaMnAs near the Curie temperature

Yuldashev, Sh.U.,Yunusov, Z.A.,Kwon, Y.H.,Lee, S.H.,Ahuja, R.,Kang, T.W. Pergamon Press ; Elsevier Science Ltd 2017 Solid state communications Vol.263 No.-

<P>The effect of the magnetization fluctuations on the resistivity of GaMnAs near the Curie temperature T-C was experimentally studied. It is shown that the determination of T-C from the maximum of the temperature derivative of the resistivity is valid for the samples with a high concentration of free carries. Whereas, for the samples with low concentration of free carriers the T-C coincides with the resistivity maximum. The magnetic specific heat for T > T-C demonstrates the crossover from the one dimensional to the three dimensional critical behavior when the temperature become closer to the Curie temperature. This is explained by the formation of the ferromagnetic phase in the paramagnetic side of the phase transition which is started from Mn-Mn dimers oriented along one direction.</P>

유지혈액투석 환자에 있어 영양상태와 염증지표의 관계에 대한 연구

한상엽(S. Y. Han),조상경(S. K. Jo),윤종우(J. W. Yoon),신진호(J. H. Shin),이소영(S. Y. Lee),차대룡(D. R. Cha),권영주(Y. J. Kwon),조원용(W. Y. Cho),표희정(H. J. Pyo),정태시(T. S. Jung) 대한신장학회 2000 Kidney Research and Clinical Practice Vol.19 No.2

N/A Malnutrition is known to be an independent risk factor of morbidity and mortality in hemodialysis patients. The causes of malnutrition were obsucure. Several catabolic cytokines such as interleukin-1β(IL-1β), interleukin-6(IL-6), and tumar necrosis fac-tor-α(TNF-α) were reported to be elevated in hemo-dialysis patients with malnutrition, To evaluate the nutritrional status and relationship among cytokines IL-1β, TNF-α, and various parameters, we performed a cross-sectional study in maintenance hemodialysis patients who have undergone for six months at least. Patients who were taking steroid. showed any sign of infection, or had residual renal function were excluded from the study. Nutritional status was classified into well nourished(A), mild to moderate malnutrition(B), and severe malnutrition(C) by using subjective global assessment(SGA). Patients were divided into two groups (I: A, II: B and C) based on SGA. The level of IL-10, TNF-a were estimated by ELISA. Total patients were 23(M/F:15/8 mean age 52.0±1.56yrs). There were significant differences in weight changes for 6 months, CRP, and SGA between two groups based on the level of serum albumin(using 4.0g/dL as a cutoff value). Moreover, based on SGA, there were significant differences in age, BMI, CRP, and albumin between the group I and IL Serum albumin levels was directly correlated with transferrin(r=0.302, p=0.04), and was inversly correlated with age(r=-0.329, p=0.007). TNF- u was inversly correlated with Kt/Vueea(r=-0.291, p= 0.047), and directly correlated with the duration of maintenance hemodialysis(r=0,346, p=0.036), BMI(r-0.453, p<0.05). These data support the fact that albumin and CRP can be a good marker of nutritional status in maintenance hemodialysis patient. However cytokines and transferrin might not be related to nutritional status.

식이 콜레스테롤에 대한 인지도 및 섭취현황 조사

권혁희,이달수,권오란,이혜영,박계각,송주완,김욱희 국립보건연구원 1994 국립보건원보 Vol.31 No.2

한국식품의 營養成分에 관한 硏究 : 나트륨, 칼륨 함량 측정 Determination of Sodium and Pstassium Concentrations

權赫姬,金達秀,金素姬,權五蘭,金吉女,尹寶奎,崔惠淑 국립보건연구원 1992 국립보건원보 Vol.29 No.2

사과의 감압저장법의 개발

손태화,윤형식,홍순영,서정훈,김광수,박용태,이갑랑,권태종 慶北大學校 生産技術硏究所 1970 生産技術 Vol.4 No.-

Rolls, Janathan, and American Summer Pearmain were used in this experiment. This experiment was conducted under 0˚ and 20℃ at subatmospheric pressure, respectively. we found to examine physiological changes of apple under storage and the rate of respiration of apple in order to decide the time of harvesting. The summary results were as follows. A. Physiological Changes of Apples Stored Under Reduced Atmospheric Pressure. 1. Rate of Respiration (1) Lower rates of respiration were observed under reduced atmospheric pressure than under normal atmospheric pressure other storage conditions being equal. (2) American Summer Pearmain apples showed the biggest rate of respiration, followed by Jonathan apples. Rolls apples showed the smallest rate of respiration among three varieties. (3) The rate of respiration of apples stored under reduced atmospheric pressure changed less remarkably than that of apples stored under normal atmospheric pressure when these apples were taken out of the storage rooms, and their surrounding temperature and atmospheric pressure were changed. (4) change of the rate of respiration was more marked in an O^2-chamber than in an air-chamber. A serious physiological breakdown was observed in a N_2-chamber and in a CO_2-chamber. 2. Production of Ethylene (1) The action of ethylene as a ripening hormone for apples was supressed by reducing the atmospheric pressure of the storage chamber. (2) The order of amount of ethylene production was American summer Pearmain, Jonathan, and Rolls. The ethylene production was larger under reduced atmospheric pressure than under normal atmospheric pressure without respect to the variety of apples. (3) Ethylene production of apples was reduced by lowering the temperature of the storage chamber (4) The rate of ethylene formation increased markedly when apples were stored in a cold chamber and than the temperature and atmospheric pressure were changed. This phenomenon, however, was less marked for the apples stored in the reduced atmospheric pressure chamber than for those in the normal atmospheric pressure chamber. (5) The ethylene production in the O_2-storage chamber was about 80 times as large as that in air-storage chamber at 20℃. The rate of ethylene production reached a maximum in 12 days in the O_2-chamber, but the ethylene production increased continuously in the air-chamber. In the N_2-chamber and the CO_2-chamber ethylene production was small. Generally the ethylene concentration in the atmosphere of the storage chamber was smaller under reduced atmospheric pressure than under normal atmospheric pressure. 3. Acidity Acidity was lowered from 0.68% to 0.36%, 0.50%, or 0.56% when Jonathans were stored in an uncontrolled atmospheric chamber, a cold and uncontrolled atmospheric pressure chamber, and a cold and reduced atmospheric pressure chamber respectively. 4. Change of Weight Decrease in weight under the same conditions as the above 3, was 6.2%, 3.6% and 2.8% when stored in an uncontrolled chamber, in a cold and uncontrolled atmospheric pressure, chamber, and in a cold and reduced atmospheric pressure chamber respectively. 5. Decaying Decaying ratio showed also the same order as 4, and was 18.5%, 7.4%, and 3.6% in an uncontrolled chamber, in a cold and uncontrolled atmospheric pressure chamber, and in a cold and reduced atmospheric pressure chamber respectively. 6. Enzyme Activity (1) Catecholase activity of apples decreased with storage duration. (2) The order of catecholase activity was Rolls, American summer Pearmain and Jonathan. (3) Catecholase activity was higher in apples stored under reduced atmospheric pressure than in those stored under normal atmospheric pressure regardless of the variety. B. Preliminary Investigations for Practical Uses 1. It is possible to calculate the concentration of carbon dioxide in a storage chamber atmosphers since the rate of carbon dioxide production was almost constant according to the storage conditions. Therefore the storage chamber was successfully maintained at 5% carbon dioxide by controlling ventilation. 2. With a simple automatic controller, the storage chamber atmosphere was maintained at an appropriate reduced pressure. 3. Poly ethylene film, which is most permeable for gases among several common plastic films, was found to be adoptable as an apple wrapper for reduced atmospheric pressure storage. C. Investigation of the Time of Harvest Observations of the rate of respiration of apple during growing made in possible to predict the optimal time of harvest. The optimal times of harvest are around September 23 and October 26 for Jonathan and Rolls apples respectively.

Chimeric protein of internally duplicated α-type carbonic anhydrase from Dunaliella species for improved expression and CO₂ sequestration

Ki, M.R.,Nguyen, T.K.M.,Kim, S.H.,Kwon, I.,Pack, S.P. Elsevier Applied Science 2016 PROCESS BIOCHEMISTRY Vol.51 No.9

An internally duplicated α-type carbonic anhydrase (CA) from Dunaliella species (Dsp-CA) has been expressed as single-domain derivatives, N- and C- half domains. Although both derivatives have structures similar to that of a known CA (PDB ID: 1y7w), only the C-half domain (Dsp-CA-c) exhibited enzymatic activity, albeit with low solubility. In order to increase the solubility of Dsp-CA-c, its proximal N-terminal amino acids 1-11 were substituted with VSEPHDYNYEK (NT11) of the N-half domain (Dsp-CA-n) which exhibits a high soluble expression yield. The new chimeric gene products, Dsp-nCA-c displayed approximately 2-fold the solubility and activity shown by Dsp-CA-c. Dsp-nCA-c showed increased thermal stability (ΔT<SUB>m</SUB>>10<SUP>o</SUP>C) by multimerization compared to Dsp-CA-c. Finally, the chimeric protein effectively catalyzed the conversion of CO<SUB>2</SUB> into its calcite form in the presence of CaCl<SUB>2</SUB>. These findings indicate that the substituted NT11 may contribute to soluble expression and enhanced activity of Dsp-nCA-c and cause multimerization which can confer increased thermostability to Dsp-nCA-c. Therefore, N-terminal engineering can be an effective strategy for improving soluble production yield and thermostabillity of CA without disrupting catalytic activity, and the engineered CA could be usefully employed for the development of an efficient enzymatic CO<SUB>2</SUB> sequestration system.

WO3 의 염화반응성에 관한 연구

원창환,조통래,서동희,권호영 대한금속재료학회(대한금속학회) 1988 대한금속·재료학회지 Vol.26 No.2

Chlorination behaviours of tungsten oxide (WO₃) were investigated by means of a thermogravimetric analysis. The rate of chlorination was increased with increasing the mixed ratio of carbon as a reducing agent. the flow. rate of chlorine gas, reaction temperature, and the amount of calcium fluoride as an additive. It was found that experimental results fit well Valensi equation, 1-2/3R-(1-R)^(2/3) = Kt and the rate of chlorination is controlled by a diffusion process, the activation energy of which is 26.0 KJ/mole. Discussion of the chlorination mechanism is also given in the text.

Physiological mechanism of drought tolerance in transgenic rice plants expressing Capsicum annuum methionine sulfoxide reductase B2 (CaMsrB2) gene

Siddiqui, Z. S.,Cho, J. I.,Kwon, T. R.,Ahn, B. O.,Lee, K. S.,Jeong, M. J.,Ryu, T. H.,Lee, S. K.,Park, S. C.,Park, S. H. POLISH ACADEMY SCIENCES WARSAW 2014 ACTA PHYSIOLOGIAE PLANTARUM Vol.36 No.5

The methionine sulfoxide reductase B2 (MsrB2) gene catalyzes the reduction of free and protein-bound methionine sulfoxide to methionine and is known to provide tolerance to biotic and abiotic environmental stresses. There are yet to be any reports that MsrB2 enhances drought tolerance. Two drought-tolerant transgenic rice lines, L-8 (single copy) and L-23 (two copy), expressing the Capsicum annuum MsrB2 (CaMsrB2) gene were selected for stress tolerance phenotyping under drought stress conditions. CaMsrB2 enhanced relative water content, maintained substantial quantum yield (F (v) /F (m) ratio), and subsequently improved photosynthetic pigments. Interestingly, L-23, carrying two-copy T-DNA insertion, showed greater drought tolerance through more effective stomatal regulation, carotenoid concentration, and osmotic potential than the wild type. High-tech infrared technology (FLIR SC620) was used for the selection of stress-tolerant physiotypes. Later, the IR results were correlated with other tested physiological parameters. The IR images, average plant temperature, and physiological parameters of the treated plants are discussed in detail.

Partitioning of Na⁺, K⁺, Proline and Total Soluble Sugar in Relation to the Salinity Tolerance of Brassica juncea and Brassica rapa

Kwon T.R.,Harris P.J.C.,Bourne W.F. 한국원예학회 1998 원예과학기술지 Vol.16 No.3