Anomalous Magnetic-Field-Hysteresis of Quantum Oscillations in κ-(BETS)2FeBr4

Shubnikov-de Haas (SdH) oscillations are measured in the organic conductor, κ-(BETS)₂FeBr₄. In the canted antiferromagnetic (CAF) phase (μ₀ H < μ₀ H _c =5.2 T), hysteresis is clearly observed in both the background resistance and oscillation amplitude. The analyses of the Dingle temperatures in the CAF phase show that some disorder is induced in the down sweep from the field above H _c . A possible origin of the excess scattering is discussed.     

Investigations of Quantum Oscillations in Θ- and ΘT-(BEDT-TTF)2I3

Thequasi-two-dimensional (Q2D) organic conductor (BEDT-TTF)₃Cl₂·2H₂O is metallic at 300 K and it undergoes ametal-insulatortransition (MIT) at T∼140 K as revealed from magnetic susceptibility and electric conductivity measurements. Using¹³C-NMR measurement, we observed a split of the NMR spectrum which corresponds to a charge rich and poor site below the MIT temperature and concluded that the insulator state is in achargeordered (CO) state, instead of achargedensitywave (CDW) formation proposed previously.     

(Quantum) chaos in Bose-Einstein condensates

I discuss chaos in classical and quantum (wave) dynamics, extending this to considering chaotic dynamics in nonlinear wave equations, in particular how chaotic dynamics in the Gross-Pitaevskii equation relate to particle depletion from an initial Bose-Einstein condensate.     

Field Tuning and Quantum Criticality in Ytterbium Based Heavy Electron Compounds

We review here the results of magnetization, specific heat, and inelastic neutron scattering measurements conducted on Yb₃Pt₄, Yb₂Pt₂Pb, Yb₅Pt₉, and YbRh₂Pb, which indicate that the Yb moments in these heavy electron compounds are appreciably localized, at least in their paramagnetic states. The magnetic ground states in each are isolated magnetic doublets, and we show that magnetic fields suppress long ranged magnetic order and lead to a characteristic magnetic field-temperature phase diagram where order vanishes suddenly above a critical value for the field. We argue that the stability of magnetic order in these compounds arises from the competition between the Zeeman splitting gμ _B H of the ground state doublet, which favors a spin polarized state with minimal entropy and without long range order, and the exchange splitting Δ of the doublet, which enables long ranged magnetic order.     

SU(2) and SU(1,1) Rotation Transformation and Pseudo-vector Model in Quantum Optics

Abstract

We construct a pseudo-vector model and realize the rotation transformation for the SU(2) and SU(1,1) dynamics. We introduce concepts of the pseudo-scalar and the scalar product in quantum optics. Several equivalents of the SU(2) and SU(1,1) unified rotation operator are given. By using this method, the two- and three-level Jaynes-Cummings model is discussed in the non-rotating wave approximation.     

Synthesis and photopolymerization of 2-(acryloyloxy) ethyl bis (2-(acryloyloxy) ethyl)carbamate

A low viscosity urethane diacrylate monomer of 2-(acryloyloxy) ethyl bis (2-(acryloyloxy) ethyl)carbamate (AEBAC) was prepared via a nonisocyanate route. The photopolymerization kinetics of this urethane acrylate was studied by real-time FTIR. The influences of light intensity, photoinitiator type, and concentration on the polymerization kinetics were discussed. The photopolymerization kinetic results indicated that the relationship between the polymerization rate (R _p) and the incident light intensity (I ₀) was R _p∞I ₀ ^0.5 and the maximum rate of polymerization (R _p,max) was proportional to [A]^0.5 ([A] was the molar concentration of initiator). The dynamic mechanical analysis (DMA) results indicated that the glass transition temperature (T _g) of the curing product of AEBAC was about 80°C.     

重金属氧化物玻璃的应用与研究

本文分析了重金属氧化物玻璃与传统氧化物玻璃的主要区别，展示了重金属氧化物玻璃的应用领域与潜在的应用前景，引出了对重金属氧化物玻璃进行研究的重要意义     

量子振动系统的高阶微扰理论(续)

根据一维玻色量子振动系统的湮灭算符和产生算符的实么正变换理论 ,SU(1,1)Lie代数 ,对量子振动系统的高阶微扰理论进行详细研讨。结果表明 ,一维量子振动系统的高阶微扰理论是精确的     

Heavy metals removal from automobile shredder residues (ASR)

The fate of heavy metals during a separation process for automobile shredder residues (ASR) was investigated. A washing method to remove heavy metals from the ASR was also investigated. Although the separation process was not designed for removal of heavy metals, but for the recovery of reusable materials, the heavy metal content in the ASR was efficiently decreased. The concentrations of Pb, Cr and Cd in ASR were effectively reduced by a nonferrous metals removal process, and the As concentration was reduced by the removal of light dusts during the separation process. Five heavy metals (As, Se, Pb, Cr, Cd) remaining in the ASR after the separation process satisfied the content criteria of the Environmental Quality Standards for Soil (EQSS), while the concentrations of As, Se, Pb in the leachate from the remaining ASR did not satisfy the elution criteria of the EQSS. After additional washing of the remaining ASR with a pH 1 acid buffer solution, the As, Se, and Pb concentrations satisfied the EQSS for elution. These results indicate that an ASR residue can be safely recycled after a separation process, followed by washing at acidic pH.     

(PANI)98-(PEG)136-(PANI)98三嵌段共聚物的自组装

采用化学氧化法合成了(PANI)98-(PEG)136-(PANI)98三嵌段共聚物,使用激光光散射研究了它在选择性溶剂中的聚集行为, 并用扫描电镜观察了嵌段共聚物在选择性溶剂中的自组装行为.结果表明在DMF溶剂中,732个(PANI)98-(PEG)136-(PANI)98三嵌段共聚物形成了结构稳定的球形胶束.在不同的选择性溶剂中, (PANI)98-(PEG)136-(PANI)98三嵌段共聚物能形成球形、棒状、囊泡、花瓣状等不同的自组装结构.     

Self-assembly deposition and luminescence properties of TiNbO5(-) and TiTaO5(-) nanosheets

Through a novel mechanical cleavage technology, TiNbO5(-) and TiTaO5(-) nanosheets were obtained by the exfoliation of the layered KTiTaO5 and KTiNbO5. Lamellar aggregates of the pre-prepared nanosheets accommodating Eu3+ ions have been fabricated by flocculation of colloidal nanosheet. A series of methods including X-ray diffraction (XRD), transmission electron microscopy (TEM) were used to analyze the structure of the as-obtained composites. The results indicated that the restacking nanosheets could form a uniform layered structure. Meanwhile, the Eu3+ ions could enter into the interlayer of the flocculated nanosheets. The Photoluminescence (PL) spectra were also employed to investigate the optical property of the hybrids. The characteristic emission from the composites either by exciting the nanosheet host with UV light or by directly exciting RE at a longer wavelength were studied in details.     

Electro-optical properties of poly(1-(difluorophenyl)-2-(4-alkylcyclohexyl phenyl)acetylene) organic light-emitting diodes

For organic light-emitting diodes (OLEDs) applications, we have investigated novel polymers, using substituted polyacetylenes (PA), poly(1-(fluorophenyl)-2-(alkylcyclohexylphenyl)acetylene) (PDPA-nF) (n = 1 or n = 2) which exhibit air stability, better solubility in common organic solvent and higher luminescence than polyacetylene. In this study, we have used poly[(1-(3,4-difluorophenyl)-2-(4-pentylcyclohexylphenyl)acetylene)] (PDPA-2F) as an emitter in OLEDs and their performance was determined by measuring the current-voltage-luminance characteristic. The devices have a maximum brightness of 827 candela (cd)/m² at 12 V and a maximum current efficiency of 0.78 cd/A at 9 V with a maximum luminescence at 536 nm. Influence of the metal electrode on the charge injection was studied using several cathode configurations (Ca, Al and Au) for the devices. Furthermore, the charge injection and transport processes were correlated to the presence of traps inside the polymer, determined by deep level transient spectroscopy (DLTS).     

1,1-二(对-二乙氨基苯基)-4-(α-萘基)-4-苯基-1,3-丁二烯的合成及其光电性能研究

以α-溴代萘和苯乙酮为主要原料合成了1-(α-萘基)-1-苯基-3-氯丙烯,该化合物与4,4'-双(二乙氨基)二苯甲酮经Grignard反应,脱水后得到目标产物1,1-二(对-二乙氨基苯基)-4-(α-萘基)-4-苯基-1,3-丁二烯(CT),产品纯度98.86%,收率36.4%.通过质谱与核磁共振对产物的结构进行了表征,并对其进行X-射线单晶衍射分析,确定了分子构型.以Y-TiOPc为电荷产生材料,CT为空穴传输材料制备的功能分离型光导体光导性能参数为:V0=-850V,VR=-20V,Rd=17.5V,E1/2=0.60lx·s,表明CT具有优良的空穴传输特性.     

Optical and differential scanning calorimetry studies of the (Na2B4O7)-(CuO)-(CeO2) glass system

A series of glass samples was prepared from an admixture of sodium tetraborate, copper and cerium based on the system (Na2B4O7)98-(CuO)2-x-(CeO2)x where x=0.5, 1 and 1.5 mol%, and results of optical absorption, infrared absorption spectra and differential scanning calorimetry are reported as a function of copper and cerium contents. It was found that increasing the CuO content and decreasing the CeO2 content shifted the fundamental absorption edge to longer wavelengths. It was also found that the incorporation of CuO and CeO2 did not affect the limits of the ultraviolet absorption edge of the base glass. This revised version was published online in November 2006 with corrections to the Cover Date.