2,967 research outputs found
Synthesis and characterization of several cesium zirconates and a study of their relevance to fission product chemistry
Investigations of the reaction of CsI with excess ZrO(,2) in various containers at 400-850(DEGREES)C have successfully demonstrated the formation of ZrI(,4) and Cs(,2)ZrO(,3) in low yields (\u3c35%) based upon the analytical evidence from X-ray fluorescence and atomic absorption techniques;To further investigate the chemistry, macroscopic amounts of the cesium zirconates have been synthesized from reactions of Cs-Zr-O(,2) in silver crucibles or of Cs-CsO(,2)-ZrO(,2) and CsO(,2)-Zr in welded silver tubing at 600-750(DEGREES)C for one to two weeks. These reactions have produced four new compounds: Cs(,2)ZrO(,3) and Cs(,4)ZrO(,4) each in 95-100% yield, and two evidently ZrO(,2)-richer cesium zirconates of unknown composition and structure in 40-50% yield;The crystal structures of the first two phases have been solved by single crystal methods. The Cs(,2)ZrO(,3) is structurally related to K(,2)ZrO(,3) or Cs(,2)PrO(,3) and crystallizes in the orthorhombic space group Cmcm with a = 11.256(6), b = 7.738(5) and c = 5.967(7) (ANGSTROM), Z = 4 (R = 5.2%). Its structure consists of infinite chains along the c-axis formed by square pyramidal Zr(O)O(,4/2) units sharing opposite basal edges and represents the second zirconate reported with five-coordinate zirconium. The compound Cs(,4)ZrO(,4) crystallizes in the monoclinic space group P2(,1)/c with a = 7.163(1), b = 19.919(2), c = 7.158(1) (ANGSTROM) and (beta) = 103.05(8)(DEGREES), Z = 4 (R = 3.2%). The structure contains isolated and slightly distorted tetrahedral ZrO(,4) units. The third zirconate crystallizes in a triclinic cell with a = 10.254(1), b = 10.416(2), c = 10.104(1) (ANGSTROM), (alpha) = 106.45(1)(DEGREES), (beta) = 98.51(1)(DEGREES), and (gamma) = 100.17(1)(DEGREES). Volume relationships suggest a composition near 3Cs(,2)O(.)7ZrO(,2). The fourth zirconate evidently crystallizes with a monoclinic cell, a = 9.926(5), b = 15.359(8), c = 20.642(8) (ANGSTROM), (beta) = 103.28(3)(DEGREES);The thermal stabilities of Cs(,2)ZrO(,3) and Cs(,4)ZrO(,4) have been investigated both in vacuo and in sealed silver containers. The compounds Cs(,2)ZrO(,3) and Cs(,4)ZrO(,4) decompose into Cs(,2)O and ZrO(,2) or Cs(,2)ZrO(,3) at near 915(DEGREES)C and 260-280(DEGREES)C under high vacuum, whereas in sealed silver containers they are stable to above 900(DEGREES)C and to 730 (+OR-) 20(DEGREES)C, respectively. The relevance of the formation and properties;of these zirconates to the distribution of fission products is also discussed; *DOE Report IS-T-1253. This work was performed under contract No. W-7405-Eng-82 with the U.S. Department of Energy
Direct Observation of Long-Term Durability of Superconductivity in YBaCuO-AgO Composites
We report direct observation of long-term durability of superconductivity of
several YBaCuO-AgO composites that were first prepared and
studied almost 14 years ago [J. J. Lin {\it et al}., Jpn. J. Appl. Phys. {\bf
29}, 497 (1990)]. Remeasurements performed recently on both resistances and
magnetizations indicate a sharp critical transition temperature at 91 K. We
also find that such long-term environmental stability of high-temperature
superconductivity can only be achieved in YBaCuO with AgO
addition, but not with pure Ag addition.Comment: to be published in Jpn. J. Appl. Phy
Inequalities Detecting Quantum Entanglement for Systems
We present a set of inequalities for detecting quantum entanglement of
quantum states. For and systems, the
inequalities give rise to sufficient and necessary separability conditions for
both pure and mixed states. For the case of , these inequalities are
necessary conditions for separability, which detect all entangled states that
are not positive under partial transposition and even some entangled states
with positive partial transposition. These inequalities are given by mean
values of local observables and present an experimental way of detecting the
quantum entanglement of quantum states and even multi-qubit pure
states.Comment: 6 page
Autonomic Dysfunction Because of Severe Tetanus in an Unvaccinated Child
Tetanus is rare in a country with a national vaccination program. When it does occur, the associated autonomic dysfunction is a challenge for physicians. We report here a case of an unvaccinated 5-year-old boy who suffered from tetanus complicated by autonomic dysfunction, which was successfully controlled by the infusion of magnesium sulfate. This is the first case that demonstrated the therapeutic effect of magnesium sulfate in a child with tetanus. This case highlights the importance of implementing a vaccination program
Apoptosis signal-regulating kinase 1 mediates denbinobin-induced apoptosis in human lung adenocarcinoma cells
In the present study, we explore the role of apoptosis signal-regulating kinase 1 (ASK1) in denbinobin-induced apoptosis in human lung adenocarcinoma (A549) cells. Denbinobin-induced cell apoptosis was attenuated by an ASK1 dominant-negative mutant (ASK1DN), two antioxidants (N-acetyl-L-cysteine (NAC) and glutathione (GSH)), a c-Jun N-terminal kinase (JNK) inhibitor (SP600125), and an activator protein-1 (AP-1) inhibitor (curcumin). Treatment of A549 cells with denbinobin caused increases in ASK1 activity and reactive oxygen species (ROS) production, and these effects were inhibited by NAC and GSH. Stimulation of A549 cells with denbinobin caused JNK activation; this effect was markedly inhibited by NAC, GSH, and ASK1DN. Denbinobin induced c-Jun phosphorylation, the formation of an AP-1-specific DNA-protein complex, and Bim expression. Bim knockdown using a bim short interfering RNA strategy also reduced denbinobin-induced A549 cell apoptosis. The denbinobin-mediated increases in c-Jun phosphorylation and Bim expression were inhibited by NAC, GSH, SP600125, ASK1DN, JNK1DN, and JNK2DN. These results suggest that denbinobin might activate ASK1 through ROS production to cause JNK/AP-1 activation, which in turn induces Bim expression, and ultimately results in A549 cell apoptosis
Novel Technology for Bio-diesel Production from Cooking and Waste Cooking Oil by Microwave Irradiation
AbstractIn the transitional process, acid or base catalysts are common technology to produce bio-diesel from waste cooking oil; however, the catalysts only can be use one time. Highly reaction time is requirement for the transitional technology. For improvement these concern issues, this study applied a novel technology to create bio-diesel product from cooking oil and waste cooking oil by microwave irritation. The microwave irradiation can provide strong power and reach reaction temperature in a short time. The SrO catalyst is a heterogeneous catalyst which is not dissolution into any liquid solution therefore, it can be recycling and reusing again.In this research, the optimum conditions were using commercial SrO, 40 to 180seconds reaction time, around 80oC reaction temperature, 6 methanol to oil ratio, and 1000W microwave power output. 99% and 93% biodiesel conversion efficiency for cooking oil and waste cooking oil were reached within in these conditions. The determined specifications of obtained biodiesel according to ASTM D6751 and EN14214 standards were in accordance with the required limits. As a conclusion, the present study indicates that derived fuel promises being an alternative for diesel, and could be used in engines without a major modification due to its qualifications
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