Chemiluminescence excited photoelectrochemistry using graphene-quantum dots nanocomposite for biosensing

Chemiluminescence was used as the exciting light source to construct a universal photoelectrochemical platform based on a reduced graphene oxide-CdS nanocomposite, which greatly improves the photovoltaic transfer efficiency and leads to excellent performance for the photoelectrochemical immunoassay.     

Sol–gel synthesis of Eu<Superscript>3+</Superscript> incorporated CaMoO<Subscript>4</Subscript>: the enhanced luminescence performance

In order to develop high efficiency red emitting phosphors, Ca_0.76MoO₄: Eu _0.24 ³⁺ samples are investigated via sol–gel and solid state reaction. The XRD analysis reveals that both methods can synthesize phosphors with tetragonal CaMoO₄ phase successfully. Smaller crystal size of samples prepared by sol–gel can be observed, and the grain size of these samples are around 100–200 nm, which is also smaller than the one prepared by solid state reaction. All phosphors present a red emission at 616 nm wavelength and one sol–gel synthesized sample exhibits the strongest emission intensity because of the higher quantum efficiency. It is attributed to the removal of lattice defects by sol–gel, in which way luminescent efficiency is enhanced. This can be reflected by the longer fluorescent lifetime of phosphors.     

Scenario tree generation approaches using K-means and LP moment matching methods

We consider in this paper the efficient ways to generate multi-stage scenario trees. A general modified K-means clustering method is first presented to generate the scenario tree with a general structure. This method takes the time dependency of the simulated path into account. Based on the traditional and modified K-means analyses, the moment matching of multi-stage scenario trees is described as a linear programming (LP) problem. By simultaneously utilizing simulation, clustering, non-linear time series and moment matching skills, a sequential generation method and another new hybrid approach which can generate the whole multi-stage tree right off are proposed. The advantages of these new methods are: the vector autoregressive and multivariate generalized autoregressive conditional heteroscedasticity (VAR-MGARCH) model is adopted to properly reflect the inter-stage dependency and the time-varying volatilities of the data process, the LP-based moment matching technique ensures that the scenario tree generation problem can be solved more efficiently and the tree scale can be further controlled, and in the meanwhile, the statistical properties of the random data process are maintained properly. What is more important, our new LP methods can guarantee at least two branches are derived from each non-leaf node and thus overcome the drawback in relevant papers. We carry out a series of numerical experiments and apply the scenario tree generation methods to a portfolio management problem, which demonstrate the practicality, efficiency and advantages of our new approaches over other models or methods.     

A novel red phosphor BaZn2(PO4)2:Sm3+, R+ (R=Li,Na, K)

BaZn₂(PO₄)₂:Sm³⁺ phosphor was synthesized by a high temperature solid-state reaction in atmosphere. BaZn₂(PO₄)₂:Sm³⁺ phosphor can be efficiently excited by ultraviolet and blue light, and the emission spectrum consists of three emission peaks at 568, 606 and 660 nm. By increasing the Sm³⁺ doped content, the emission intensity of the phosphor can reach the maximum at 0.02 mol Sm³⁺, then the concentration quenching occurs. By introducing the compensator charge R⁺ (R=Li, Na, K) into the BaZn₂(PO₄)₂:Sm³⁺ phosphor, its emission intensity can be enhanced. The Commission International de l'Eclairage (CIE) chromaticity coordinates of Ba_0.96Zn₂(PO₄)₂:0.02Sm³⁺, 0.02K⁺ phosphor were (x=0.623, y=0.361). The results indicate that BaZn₂(PO₄)₂:Sm³⁺, R⁺ (R=Li, Na, K) may be a promising red phosphor for white light-emitting diodes.     

Volumetric Properties of the Binary System Trihexyltetradecylphosphonium Bromide (CYPHOS IL 102) + N,N-Dimethylformamide (DMF) at Temperatures from T=293.15 to 313.15 K at Atmospheric Pressure

Volumetric properties for the trihexyltetradecylphosphonium bromide (CYPHOS IL 102) + N,N-dimethylformamide (DMF) binary system were determined at temperatures from T=293.15 to 313.15?K and ambient pressure (p=0.7 atm). Densities were measured by means of a vibrating tube densimeter (VTD). These measurements covered the full range of compositions along with the pure compounds; expansion coefficients, excess molar volumes, and partial molar volumes were calculated from the experimental densities. Excess molar volumes were fitted to a Redlich?CKister type equation. The excess molar volumes exhibit negative deviations from ideal behavior.     

Enhanced Performance of Organic Photovoltaic Cells Fabricated with a Methyl Thiophene‐3‐Carboxylate‐Containing Alternating Conjugated Copolymer

A new donor‐acceptor copolymer, containing benzodithiophene (BDT) and methyl thiophene‐3‐carboxylate (3MT) units, is designed and synthesized for polymer solar cells (PSCs). The 3MT unit is used as an electron acceptor unit in this copolymer to provide a lower highest occupied molecular orbital (HOMO) level for obtaining polymer solar cells with a higher open‐circuit voltage (V_OC). The resulting bulk heterojunction PSC made of the copolymer and [6,6]‐phenyl‐C71‐butyric acid methyl ester (PC₇₁BM) exhibits a power conversion efficiency (PCE) up to 4.52%, a short circuit current (J_SC) of 10.5 mA·cm‐², and a V_OC of 0.86 V.     

Quantitative HPLC method for determining two of the major active phthalides from Ligusticum porteri roots

Z-Ligustilide (1) and Z-6,6',7,3'-alpha-diligustilide (2), two of the major active phthalides of the medicinal plant Ligusticum porteri (osha), were chosen for the development and validation of an HPLC-diode array detection method suitable for QC of the crude drug. The method used gradient elution to achieve separation on a Hibar RT LiChrospher 100 C18 column. The LOD values were 29 and 45 microg/mL, and the LOQs were 89 and 125 microg/mL, respectively. The method showed good intraday precision (%RSD: 0.7 for 1 and 3.1 for 2) and interday precision (%RSD: 1.2 for 1 and 1.8 for 2). The method was used for the analysis of 1 and 2 in crude drug samples and several herbal preparations from Mexico and the United States. Quantitative analysis showed that the content of the two phthalides varied significantly among the samples. All the samples contained higher concentrations of 1 (0.15-2.5%) than 2 (0.002-1.0%). The profiles of volatile compounds in the essential oil obtained by hydrodistillation and solid-phase microextraction of L. porteri roots were analyzed by GC-MS. Thirty one chemical constituents (> 99.7% of the total content) were identified in the essential oil, which was characterized by the presence of a high percentage of phthalides (44.61%) and sesquiterpenes (10.69%). The major light volatile components extracted by solid-phase microextraction were monoterpenes.     

Comparative investigation of long-wave infrared generation based on ZnGeP2 and CdSe optical parametric oscillators

Long-wave infrared(IR) generation based on type-II(o→e+o) phase matching ZnGeP 2(ZGP) and CdSe optical parametric oscillators(OPOs) pumped by a 2.05 μm Tm,Ho:GdVO 4 laser is reported.The comparisons of the birefringent walk-off effect and the oscillation threshold between ZGP and CdSe OPOs are performed theoretically and experimentally.For the ZGP OPO,up to 419 mW output at 8.04 μm is obtained at the 8 kHz pump pulse repetition frequency(PRF) with a slope efficiency of 7.6%.This ZGP OPO can be continuously tuned from 7.8 to 8.5 μm.For the CdSe OPO,we demonstrate a 64 mW output at 8.9 μm with a single crystal 28 mm in length.     

Hybrid theoretical,experimental and numerical study of vibration and buckling of composite shells with scatter in elastic moduli

Hybrid theoretical, experimental and numerical method is proposed for free vibration and buckling of composite shell with unavoidable scatter in elastic moduli. Based on the Goggin’s measurement techniques, the elastic moduli for material T300-QY8911 are measured, and a set of experimental points are obtained. The measurements of elastic moduli are quantified by either (1) the smallest ellipsoid and (2) the smallest four-dimensional uncertainty hyper-rectangle. Then uncertainty propagation in vibration and buckling problems of composite shell by ellipsoidal analysis and interval analysis are, respectively, studied from the theoretical standpoint. Comparison between these analyses is performed numerically.     

水在二氧化钚表面吸附行为的模拟

采用Kinetic Monte Carlo方法对水在PuO₂表面的吸附行为进行数值模拟研究,通过对Statebake,Haschke等的实验数据进行数值拟合得到水的脱附活化能:0~0.5层为200 kJ·mol^-1,0.5~1层为135 kJ·mol^-1,1~2层为47·6 kJ.mol^-1,2~3层为43.8 kJ·mol^-1,3层以后为41.1 kJ·mol^-1;采用这些参数对不同升温速率下的热脱附谱以及不同温度、水分压下的吸附等温线和等压线进行预测.