Measurement of neutron cross sections and resonance parameters of ¹⁶⁹Tm below 100 eV

Wen-Ming, Wang,Xia, Li,Zhi-Xiang, Zhao,Zu-Ying, Zhou,Hong-Wei, Yu,Hai-Cheng, Wu,Yi-Xiang, Wei,Wang, T. F.,Kim, G. N.,Lee, M. W.,Kim, K. S.,Cho, M. H.,Ko, I. S.,Namkung, W. science press 2010 Chinese physics. C Vol.34 No.2

<P>The neutron total cross-sections of thulium (<SUP>169</SUP>Tm) were measured in the neutron energy region from 0.01 eV to 100 eV by using the time-of-flight method at the Pohang Neutron Facility, which consists of an electron linac, a water-cooled tantalum target with a water moderator, and a 12 m time of flight path. Two thulium plates with different thicknesses were used for the neutron transmission measurement. The background level was determined by using a notch-filter of Co, In, and Cd sheets. The present measurement was compared with the previous ones, and a new set of resonance parameters of <SUP>169</SUP>Tm isotope was obtained from the transmission rate by using the SAMMY code, with a comparison with the recommended parameters by Mughabghab.</P>

Induced quadrupolar singlet ground state of praseodymium in a modulated pyrochlore

van Duijn, J.,Kim, K. H.,Hur, N.,Ruiz-Bustos, R.,Adroja, D. T.,Bridges, F.,Daoud-Aladine, A.,Fernandez-Alonso, F.,Wen, J. J.,Kearney, V.,Huang, Q. Z.,Cheong, S.-W.,Perring, T. G.,Broholm, C. American Physical Society 2017 Physical Review B Vol.96 No.9

<P>The complex structure and magnetism of Pr2-xBixRu2O7 was investigated by neutron scattering and extended x-ray absorption fine structure. Pr has an approximate doublet ground state and the first excited state is a singlet. While the B-site (Ru) is well ordered throughout, this is not the case for the A-site (Pr/Bi). A broadened distribution for the Pr-O-2 bond length at low temperature indicates the Pr environment varies from site to site even for x = 0. The environment about the Bi site is highly disordered ostensibly due to the 6s lone pairs on Bi3+. Correspondingly, we find that the non-Kramers doublet ground-state degeneracy, otherwise anticipated for Pr in the pyrochlore structure, is lifted so as to produce a quadrupolar singlet ground statewith a spatially varying energy gap. For x = 0, below TN, the Ru sublattice orders antiferromagnetically, with propagation vector k = (0,0,0) as forY(2)Ru(2)O(7). No ordering associated with the Pr sublattice is observed down to 100 mK. The low-energy magnetic response of Pr2-xBixRu2O7 features a broad spectrum of magnetic excitations associated with inhomogeneous splitting of the Pr quasidoublet ground state. For x = 0 (x = 0.97), the spectrum is temperature dependent (independent). It appears disorder associated with Bi alloying enhances the inhomogeneous Pr crystal-field level splitting so that intersite interactions become irrelevant for x = 0.97. The structural complexity for the A-site may be reflected in the hysteretic uniform magnetization of B-site ruthenium in the Neel phase.</P>

Polymorphysims of CYP17-I Gene in the Exons Were Associated with the Reproductive Endocrine of Japanese Flounder (Paralichthys olivaceus)

Ma, R.Q.,He, F.,Wen, H.S.,Li, J.F.,Mu, W.J.,Liu, M.,Zhang, Y.Q.,Hu, J.,Qun, L. Asian Australasian Association of Animal Productio 2012 Animal Bioscience Vol.25 No.6

The cytochrome P450c17-I (CYP17-I) is one of the enzymes critical to gonadal development and the synthesis of androgens. Two single nucleotide polymorphisms (SNPs) were detected within the coding region of the CYP17-I gene in a population of 75 male Japanese flounder (Paralichthys olivaceus). They were SNP1 (c.C445T) located in exon2 and SNP2 (c.T980C (p.Phe307Leu)) located in exon5. Four physiological indices, which were serum testosterone (T), serum $17{\beta}$-estradiol ($E_2$), Hepatosomatic index (HSI), and Gonadosomatic index (GSI), were studied to examine the effect of the two SNPs on the reproductive endocrines of Japanese flounder. Multiple comparisons revealed that CT genotype of SNP1 had a much lower T level than CC genotype (p<0.05) and the GSI of individuals with CC genotype of SNP2 was higher than those with TT genotype (p<0.05). Four diplotypes were constructed based on the two SNPs and the diplotype D3 had a significantly lower T level and GSI. In conclusion, the two SNPs were significantly associated with reproductive traits of Japanese flounder.

Emodin accentuates atrial natriuretic peptide secretion in cardiac atria

Zhou, G.H.,Zhang, F.,Wang, X.N.,Kwon, O.J.,Kang, D.G.,Lee, H.S.,Jin, S.N.,Cho, K.W.,Wen, J.F. North-Holland ; Elsevier Science Ltd 2014 european journal of pharmacology Vol.735 No.-

Emodin, an active anthraquinone constituent isolated from the rhubarb, a traditional Chinese herbal medicine which is widely used in clinical treatment, has cardiovascular protective properties. However, it remains unclear whether the cardiovascular protective actions of emodin are related to an activation of cardiac natriuretic hormone secretion. The purpose of the present study was to explore the effect of emodin on the secretion of ANP, a member of the family of cardiac natriuretic hormones, and its mechanisms involved. Experiments were performed in isolated perfused beating rabbit atria allowing measurement of ANP secretion, atrial pulse pressure, and stroke volume. Emodin increased ANP secretion concomitantly with a decrease in atrial pulse pressure and stroke volume in a concentration-dependent manner. These effects were reversible. Inhibition of K<SUP>+</SUP> channels with tetraethylammonium and glibenclamide attenuated the emodin-induced changes in ANP secretion and atrial dynamics. Furthermore, the emodin-induced changes in ANP secretion and atrial dynamics were attenuated by inhibition of L-type Ca<SUP>2+</SUP> channels with nifedipine. Atropine, methoctramine, tertiapin-Q, and pertussis toxin had no significant effect on the emodin-induced changes in ANP secretion and mechanical dynamics. The present study demonstrates that emodin increases ANP secretion via inhibition of L-type Ca<SUP>2+</SUP> channels through an activation of K<SUP>+</SUP><SUB>ATP</SUB> channel in isolated beating rabbit atria. The results also provide a rationale for the use of emodin in the treatment of impairment of the regulation of the cardiovascular homeostasis.

Formation of a Wide Area of Diamond Film Using HFCVD: Ⅱ. Effect of Applied Negative Bias on Nucleation

Song, G.H.,Yoon, J.H.,Shin, K.S.,Kim, H.S.,Sun, C.,Huang, R.F.,Wen, L.S. 국립7개대학공동논문집간행위원회 2003 공업기술연구 Vol.3 No.-

The nucleation and nucleus shape of diamond films on silicon (100) has been investigated by varying the negative bias value applied to substrate during Hot Filament Chemical Vapor Deposition (HFCVD). Results showed that the nucleation density increased, peaked and then decreased with increase of the applied bias value. it seemed that there was an optimum bias value. The nucleation of diamond film by HFCVD is a competitive process of deposition and etchings (sputtered) due to the particles impinging on the substrate. The magnitude of the energy, quantity of the particles and the ratio of carbon to hydrogen in reactive gas plasma controlled the competitive process and determined which process was primary. The deposition rate and the nucleation density gradually increased reaching to a maximum with the increment of the energy of the adatoms. With further increment of the energy of the adatoms, however, the deposition process was suppressed by strengthened particle impact on the substrate and the etching or sputtering became the primary process. Experimental results also showed the nucleus crystal shape of diamond films sequentially changed from cubic to dodecahedron, and then to irregular shape with the increment of the bias value. The change of the nucleus crystal shape of diamond films with substrate bias is thought to be related to the each process of the H+ ion with different kinetic energy, as well as the process of the diffusion and migration of the adatoms.

Ursolic acid increases the secretion of atrial natriuretic peptide in isolated perfused beating rabbit atria

Cui, H.Z.,Wen, J.F.,Choi, H.R.,Li, X.,Cho, K.W.,Kang, D.G.,Lee, H.S. North-Holland ; Elsevier Science Ltd 2011 european journal of pharmacology Vol.653 No.1

Ursolic acid is reported to have beneficial effects on the regulation of cardiovascular homeostasis. However, the effects of ursolic acid on cardiac hormone secretion are yet to be defined. The present study was designed to test the effects of ursolic acid on the secretory and contractile functions of the atria. Experiments were conducted in isolated perfused beating rabbit atria. We measured the changes in atrial dynamics, pulse pressure, stroke volume, cAMP efflux, as well as the secretion of atrial natriuretic peptide (ANP). Ursolic acid increased ANP secretion and mechanical dynamics in a concentration-dependent manner. The inhibition of L-type Ca<SUP>2+</SUP> channels with nifedipine attenuated the ursolic acid-induced increase in ANP secretion but not mechanical dynamics. The inhibition of K<SUP>+</SUP><SUB>ATP</SUB> channels with glibenclamide attenuated the ursolic acid-induced increase in ANP secretion-but not atrial dynamics-in a concentration-dependent manner. The selective Na<SUP>+</SUP>-K<SUP>+</SUP>-ATPase inhibitor ouabain blocked the ursolic acid-induced increase in atrial dynamics but not ANP secretion. These findings show that ursolic acid increases ANP secretion via its activation of K<SUP>+</SUP><SUB>ATP</SUB> channels and subsequent inhibition of Ca<SUP>2+</SUP> entry through L-type Ca<SUP>2+</SUP> channels in rabbit atria. These data also suggest that ursolic acid increases atrial dynamics via its inhibition of Na<SUP>+</SUP>-K<SUP>+</SUP>-ATPase activity.

Cardiovascular effects of ethanol extract of Rubus chingii Hu (Rosaceae) in rats: an in vivo and in vitro approach.

Su, X H,Duan, R,Sun, Y Y,Wen, J F,Kang, D G,Lee, H S,Cho, K W,Jin, S N The Society 2014 Journal of physiology and pharmacology Vol.65 No.3

<P>Rubus chingii Hu (Rosaceae) is an important traditional Chinese medicine that has been used to improve function of the kidney and treat excessive polyuria. However, the effects of Rubus chingii on the cardiovascular system and its pharmacological mechanisms of action have not been studied. The aim of the present study was to evaluate the cardiovascular effects of ethanol extract of Rubus chingii (ERC) in rats. The changes in systolic blood pressure and heart rate of rats and vascular tone of aortic rings in in vitro were measured using pressure transducer and force transducer, respectively, connected to a multichannel recording system. ERC decreased systolic blood pressure and heart rate in a concentration-dependent manner. ERC induced vasorelaxation in a concentration-dependent manner. The ERC-induced vasorelaxation was not observed in the absence of the endothelium. The vasorelaxant effect of ERC was significantly attenuated by inhibition of endothelial NO synthase (eNOS), soluble guanylyl cyclase (sGC), or Ca(2+) entry from extracellular sources with L-NAME, ODQ, diltiazem, or extracellular Ca(2+) depletion, respectively. Similarly, an inhibition of Akt with wortmannin attenuated the ERC-induced vasorelaxation. Modulators of the store-operated Ca(2+) entry, thapsigargin, Gd(3+), and 2-aminoethyl diphenylborinate markedly attenuated the ERC-induced vasorelaxation. Furthermore, 4-aminopyridine an inhibitor of voltage-dependent K(+) (KV) channel, significantly attenuated the ERC-induced vasorelaxation. However, tetraethylammonium and glibenclamide, had no significant effect on the ERC-induced vasorelaxation. Indomethacin, atropine, and propranolol had no effects on the ERC-induced vasorelaxation. The present study demonstrates that ERC induces vasorelaxation via endothelium-dependent two-step signaling: an activation of the Ca(2+)-eNOS-NO signaling in the endothelial cells and then subsequent stimulation of the NO-sGC-cGMP-KV channel signaling in the vascular smooth muscle cells. The Akt-eNOS pathway is also suggested to be involved in this relaxation. Also, the findings suggest that the ERC-induced vasorelaxation is closely related to the hypotensive action of the agent.</P>

Process and property characterization of La-Al-B-O/Al2O3 glass ceramic composites

Wen-Cheng J. Wei,Chih-Lung Chen,S.F. Wang 한양대학교 세라믹연구소 2006 Journal of Ceramic Processing Research Vol.7 No.1

A LAB glass with a composition of 10 mol% La2O3 + 10 mol% Al2O3 + 80% B2O3 made into a composite with 30-50% Al2O3 filler was prepared and investigated. Processing optimization and several engineering properties used for microwave substrates are reported, including densification, interaction with Ag electrodes, dielectric properties as a function of frequency, acid dissolution and microstructure. The glass ceramic composite, i.e. L30A, without lead and alkali, can be densified by two-step sintering to a density better than 99% with minimal glass residue. The densified composite does not react with Ag up to 950 oC in 1 h, and does not dissolve in an acid solution (pH=3.5) in 2 h. The dielectric constant and loss are in the range of 5.6-5.9 and 1.4 × 10−3-5.5 × 10−3, respectively. The coefficient of thermal expansion (CTE) and thermal conductivity of the composite are reported.

Analysis of a three-dimensional FEM model of a thin piezoelectric actuator embedded in an infinite host structure

Zeng, Xiaohu,Yue, Zhufeng,Zhao, Bin,Wen, S.F. Techno-Press 2014 Advances in materials research Vol.3 No.1

In this paper, we adopted a two-dimensional analytical electro-elastic model to predict the stress distributions of the piezoelectric actuator in 3D case. The actuator was embedded in an elastic host structure under electrical loadings. The problem is reduced to the solution of singular integral equations of the first kind. The interfacial stresses and the axial normal stress in both plane stress state and plane strain state were obtained to study the actuation effects being transferred from the actuator to the host. The stress distributions of the PZT actuator in different length and different thickness were analyzed to guarantee the generality. The validity of the present model has been demonstrated by application of specific examples and comparisons with the corresponding results obtained from the Finite Element Method.

THE TAOS PROJECT: RESULTS FROM SEVEN YEARS OF SURVEY DATA

Zhang, Z.-W.,Lehner, M. J.,Wang, J.-H.,Wen, C.-Y.,Wang, S.-Y.,King, S.-K.,Granados, Á,. P.,Alcock, C.,Axelrod, T.,Bianco, F. B.,Byun, Y.-I.,Chen, W. P.,Coehlo, N. K.,Cook, K. H.,de Pater, I.,Kim American Institute of Physics 2013 The Astronomical journal Vol.146 No.1

<P>The Taiwanese-American Occultation Survey (TAOS) aims to detect serendipitous occultations of stars by small (~1 km diameter) objects in the Kuiper Belt and beyond. Such events are very rare (<10<SUP>–3</SUP> events per star per year) and short in duration (~200 ms), so many stars must be monitored at a high readout cadence. TAOS monitors typically ~500 stars simultaneously at a 5 Hz readout cadence with four telescopes located at Lulin Observatory in central Taiwan. In this paper, we report the results of the search for small Kuiper Belt objects (KBOs) in seven years of data. No occultation events were found, resulting in a 95% c.l. upper limit on the slope of the faint end of the KBO size distribution of q = 3.34-3.82, depending on the surface density at the break in the size distribution at a diameter of about 90 km.</P>