Sargassum fusiforme Polysaccharide-Based Hydrogel Microspheres Enhance Crystal Violet Dye Adsorption Properties

In this study, a polysaccharide-based hydrogel microsphere (SFP/SA) was prepared using S. fusiforme polysaccharide (SFP) and sodium alginate (SA). Fourier transform infrared spectroscopy (FT-IR) demonstrated that SFP was effectively loaded onto the hydrogel microsphere. Texture profile analysis (TPA) and differential scanning calorimetry (DSC) showed that, with the increase of SFP concentration, the hardness of SFP/SA decreased, while the springiness and cohesiveness of SFP/SA increased, and the thermal stability of SFP/SA improved. The equilibrium adsorption capacity of SFP/SA increased from 8.20 mg/g (without SFP) to 67.95 mg/g (SFP accounted 80%) without swelling, and from 35.05 mg/g (without SFP) to 81.98 mg/g (SFP accounted 80%) after 24 h swelling. The adsorption of crystal violet (CV) dye by SFP/SA followed pseudo-first order and pseudo-second order kinetics (both with R² > 0.99). The diffusion of intraparticle in CV dye was not the only influencing factor. Moreover, the adsorption of CV dye for SFP/SA (SFP accounted 60%) fit the Langmuir and Temkin isotherm models. SFP/SA exhibited good regenerative adsorption capacity. Its adsorption rate remained at > 97% at the 10th consecutive cycle while SFP accounted for 80%. The results showed that the addition of Sargassum fusiforme polysaccharide could increase the springiness, cohesiveness and thermal stability of the hydrogel microsphere, as well as improve the adsorption capacity of crystal violet dye.     

p-型层状氧化锌的热电性质研究

采用第一性原理和玻尔兹曼输运理论,我们系统的研究了p-型二层氧化锌的热电性质.基于对单层氧化锌的晶格优化,计算得到其无虚频的声子谱,证明了它的热力学稳定性.由此构建了热力学性质稳定的二层氧化锌.采用实空间有限差分法生成了二层氧化锌的二阶和三阶力常数,然后得到了其声子散射和晶格热导率,使用两种计算方法得到了其晶格热导率在室温下分别为κ_ι~(BTE)=2.65 W/m·K和κ_ι~(RTA)=2.38 W/m·K.并且得到了p-型二层氧化锌在300 K至900 K等差温度下的热电优值为0.052～0.601,证明通过调节温度可以获得较高的热电优值.     

Phase formation and magnetic properties of Nd2Fe14B-type Nd16Co76B8−xCx alloys and their hydrides

An attempt is made to synthesize Nd₂Co₁₄C compound by mechanical alloying Nd₁₆Co₇₆B_8−xC_x (0x8) alloys and subsequent annealing. Phase formation and magnetic properties of Nd₂Fe₁₄B-type Nd₁₆Co₇₆B_8−xC_x alloys and their hydrides are investigated. The Nd₂Co₁₄(B,C) phase with Nd₂Fe₁₄B-type structure is formed for Nd₁₆Co₇₆B_8−xC_x (0x7) alloys, while NdCo₇C_δ phase with TbCu₇-type structure is observed in Nd₁₆Co₇₆C₈ alloy. The lattice parameter c of the Nd₂Co₁₄(B,C) phase decreases with increasing the carbon content. A limit volume of the unit cell to form the Nd₂Fe₁₄B-type structure is estimated to be 0.870 nm³. The spin-reorientation temperature T_SR increases with increasing the carbon content, due to an enhancement of magnetocrystalline anisotropy caused by carbon substitution for boron. After hydrogenation, the lattice expansion is observed for Nd₁₆Co₇₆B_8−xC_x (0x7) alloys. The spin-reorientation temperature of Nd₁₆Co₇₆B_8−xC_xH_y (0x7) is much lower than that of the host alloys. Some structural and magnetic properties of hypothetic Nd₂Co₁₄C and Nd₂Co₁₄CH_y compounds are estimated by extrapolation.     

New Properties of the Wigner Function of the Tripartite Entangled State

For entangled three particles one should treat their wave function as a whole, there is no physical meaning talking about the wave function (or Wigner function) for any one of the tripartite, therefore thinking of the entangled Wigner function (Wigner operator) is of necessity, we introduce the entangled Wigner operator related to a pair of mutually conjugate tripartite entangled state representations and discuss some of its new properties, such as the trace product rule, the size of an entangled quantum state and the upper bound of the three-mode Wigner function. Deriving wave function from its corresponding tripartite entangled Wigner function is also presented. Those new properties of the tripartite entangled Wigner function play significant role in quantum physics because they provide us deeper insight into the shape of quantum states.     

Modeling natural gas market volatility using GARCH with different distributions

In this paper, we model natural gas market volatility using GARCH-class models with long memory and fat-tail distributions. First, we forecast price volatilities of spot and futures prices. Our evidence shows that none of the models can consistently outperform others across different criteria of loss functions. We can obtain greater forecasting accuracy by taking the stylized fact of fat-tail distributions into account. Second, we forecast volatility of basis defined as the price differential between spot and futures. Our evidence shows that nonlinear GARCH-class models with asymmetric effects have the greatest forecasting accuracy. Finally, we investigate the source of forecasting loss of models. Our findings based on a detrending moving average indicate that GARCH models cannot capture multifractality in natural gas markets. This may be the plausible explanation for the source of model forecasting losses.     

TiO2 Nanotube Array/Monolayer Graphene Film Schottky Junction Ultraviolet Light Photodetectors

Schottky junctions made from a titanium dioxide nanotube (TiO₂NT) array in contact with a monolayer graphene (MLG) film are fabricated and utilized for UV light detection. The TiO₂NT array is synthesized by the anodization and the MLG through a simple chemical vapor deposition process. Photoconductive analysis shows that the fabricated Schottky junction photodetector (PD) is sensitive to UV light illumination with good stability and reproducibility. The corresponding responsivity (R), photoconductive gain (G), and detectivity (D*) are calculated to be 15 A W^?1, 51, and 1.5 × 10¹² cm Hz^1/2 W^?1, respectively. It is observed that the fabricated PD exhibits spectral sensitivity and a simple power‐law dependence on light intensity. Moreover, the height of the Schottky junction diode is derived to be 0.59 V by using a low temperature I–V measurement. Finally, the working mechanism of the TiO₂NT array/MLG film Schottky junction PD is elucidated.     

Identification of functionally key residues in maltose transporter with an elastic network model-based thermodynamic method

Periplasmic binding protein-dependent maltose transport system (MBP-MalFGK₂) of Escherichia coli, an important member of the Adenosine triphosphate-binding cassette transporter superfamily, is in charge of the transportation of maltoses across cellular membrane. Studies have shown that this transport processes are activated by the binding of maltose and are accompanied by large-scale cooperative movements between different domains which are mediated by a network of important residues related to signal transduction and allosteric regulation. In this paper, the functionally crucial residues and long-range allosteric pathway of the regulation of the system by substrate were identified by utilising a coarse-grained thermodynamic method proposed by our group. The residues whose perturbations markedly change the binding free energy between maltoses and MBP-MalFGK₂ were considered to be key residues. In result, the key residues in 62 clusters distributed in different subdomains were identified successfully, and the results from our calculation are highly consistent with experimental and theoretical observations. Furthermore, we explored the long-range cooperation within the transporter. These studies will help us better understand the physical mechanism of the effects of the maltose on MBP-MalFGK₂ by long-range allosteric modulation.     

Large Strain Tensile Deformation and Failure in Oriented Isotactic Polypropylene/Clay Nanocomposite: Role of Voiding and Molecular Orientation

Plane strain compression of isotactic polypropylene iPP)/clay nanocomposite in a channel die at 140 and 160°C, respectively, has been adopted to prepare oriented samples with well-controlled structure for comparative studies. Molecular orientation in the amorphous phase, independent of clay loadings, decreases with increasing preparation temperature, whereas crystallographic orientation is nearly the same for all oriented samples. Severer voiding and void coalescence during stretching, mostly induced by the crystals and inter-chain sliding in the amorphous phase, respectively, is suggested to be responsible for higher volume dilatation and lower failure strain in the oriented samples prepared at higher temperature (e.g., 160°C). Fracture toughness is well correlated with the molecular orientation and crystal-dependent voiding in the oriented samples with respect to preparation temperatures. Furthermore, debonding of clay in the iPP matrix, especially in the oriented samples prepared at 140°C, is another contributor to the enhanced toughness.     

Preparation of Highly Stable and Photoluminescent Cadmium-Free InP/GaP/ZnS Core/Shell Quantum Dots and Application to Quantitative Immunoassay

Indium phosphide (InP) quantum dots (QDs) are ideal substitutes for widely used cadmium-based QDs and have great application prospects in biological fields due to their environmentally benign properties and human safety. However, the synthesis of InP core/shell QDs with biocompatibility, high quantum yield (QY), uniform particle size, and high stability is still a challenging subject. Herein, high quality (QY up to 72%) thick shell InP/GaP/ZnS core/shell QDs (12.8 ± 1.4 nm) are synthesized using multiple injections of shell precursor and extension of shell growth time, with GaP serving as the intermediate layer and 1-octanethiol acting as the new S source. The thick shell InP/GaP/ZnS core/shell QDs still keep high QY and photostability after transfer into water. InP/GaP/ZnS core/shell QDs as fluorescence labels to establish QD-based fluorescence-linked immunosorbent assay (QD-FLISA) for quantitative detection of C-reactive protein (CRP), and a calibration curve is established between fluorescence intensity and CRP concentrations (range: 1–800 ng mL⁻¹, correlation coefficient: R² = 0.9992). The limit of detection is 2.9 ng mL⁻¹, which increases twofold compared to previously reported cadmium-free QD-based immunoassays. Thus, InP/GaP/ZnS core/shell QDs as a great promise fluorescence labeling material, provide a new route for cadmium-free sensitive and specific immunoassays in biomedical fields.