Preparation and performance of lipophilic α-zirconium phosphate with high thermal stability and its application in thermal-plastic polymers

To prepare lipophilic α-zirconium phosphate with high grafting ratio and thermal stability(OZrP-HT) and explore its potential application in thermal-plastic polymers,a novel method was developed by surface lipophilicity enhancement strategy.The commercial a-zirconium phosphate(a-ZrP) was pre-intercalated by n-propylamine(PA) and grafted by silane coupling agents.Then the pre-intercalated PA was removed by heattreatment,and the obtained OZrP-HT was utilized to fabricate the phosphorous-containing polyester(P-co-PET)/OZrP-HT nanocomposites by melt-blending method.The prepared OZrP-HT and P-co-PET/OZrP-HT nanocomposites were characterized by Wide Angle X-ray Diffraction(WAXD),Fourier Transform Infrared Spectroscopy(FTIR),Thermogravimetric Analysis(TGA),Transmission Electron Microscope(TEM),etc.The results show that OZrP-HT with high grafting ratio(13.78 wt%) and thermal stability(T_(onset)= 368℃) was successfully prepared via this novel method and was uniformly intercalated by P-co-PET molecular chains.OZrP-HT had no significant effect on the fiber processability of P-co-PET polymer,and flame retardant properties of(P-co-PET)/OZrP-HT nanocomposites were improved.This method may be suitable for organic modification of general inorganic layered compounds and could extend the potential applications in thermo-plastic polymers.     

Hydrothermal synthesis, characterization and nonlinear optical effect of orthorhombic phase Ca2B6O11 · H2O

Hydrothermal treatment of calcium oxide and boric acid mixtures at temperatures between 234 °C and 300 °C has produced a colorless, transparent, orthorhombic compound Ca₂B₆O₁₁ · H₂O. Of the seven known members of the series of hydrated dicalcium hexaborate containing boron-oxygen six-membered ring anionic group (B₃O₈)^-7, only the title compound has been found to have the nonlinear optical effect. The second harmanic generation (SHG) effect of its crystal is larger than that of KH₂PO₄ (KDP). The reflection spectrum has shown that this compound has no absorption in the experimental wavelength range (800–240 nm). Its crystal structure is favorable for generating the nonlinear optical effect.     

Hydrothermal synthesis,characterization and nonlinear optical effect of orthorhombic phase Ca2B6O11·H2O

Hydrothermal treatment of calcium oxide and boric acid mixtures at temperatures between 234℃ and 300℃ has produced a colorless,transparent,orthorhombic compound Ca2B6O11.H2O.Of the seven known members of the series of hydrated dicalcium hexaborate containing boron-oxygen six-membered ring anionic group (B3O8)7-,only the title compound has been found to have the nonlinear optical effect.The second harmanic generation (SHG) effect of its crystal is larger than that of KH2PO4 (KDP).The reflection spectrum has shown that this compound has no absorption in the experimental wavelength range (800-240 nm).Its crystal structure is favorable for generating the nonlinear optical effect.     

Design and implementation of an optical simulation environment for bioluminescent tomography studies

As a challenging task for bioluminescent tomography simulation, a virtual optical environment is needed to solve the forward problem accurately, that is, to achieve a high precision for bioluminescent signal synthesis on the external body surface of a small animal. The molecular optical simulation environment named MOSE is implemented using the C programming language and the OpenGL techniques, including a user-friendly interface with interactive tools facilitating users' operations. The accuracy of the virtual optical environment is verified by error analysis of mesh simplification and comparison between MOSE results and experimental data. This virtual optical environment is accurate, flexible and efficient to simulate the photon propagation in complicated tissues, which has a great potential to become a software platform for bioluminescent tomography studies and other molecular imaging applications.     

Approximate solution for nonlinear model of the second and half order reactions in porous catalyst by decomposition method

The problem of the process of coupled diffusion and reaction in catalyst pellets is considered for the case of second and half order reactions. The Adomian decomposition method is used to solve the non-linear model. For the second, half and first order reactions, analytical approximate solutions are obtained. The variation of reactant concentration in the catalyst pellet and the effectiveness factors at φ＜10 are determined and compared with those by the BAND's finite difference numerical method developed by Newman. At lower values of φ, the decomposition solution with 3 terms gives satisfactory agreement with the numerical solution; at higher values of φ, as the term number in the decomposition method is increased, an acceptable agreement between the two methods is achieved. In general, the solution with 6 terms gives a satisfactory agreement.     

The roles of π electrons in the electronic structures and optical properties of graphyne

The electronic structures and optical properties of graphyne consisting of sp-and sp 2-hybridized carbon atoms are studied using first-principles calculations.A tight-binding model of the 2p z orbitals are proposed to describe the electronic bands near the Fermi level.The results show that the natural band gap of graphyne originates from the inhomogeneous bindings between differently-hybridized carbon atoms.The interlayer interactions of bulk graphyne narrow the band gap to 0.16 eV and result in redshift of the optical spectral peaks as compared to single-layered graphyne.     

Tunable amplification and absorption properties in double-Λ system of GaAs/AlGaAs multiple quantum wells

We study the optical amplification and absorption properties in a double-Λ four level system of GaAs/AlGaAs multiple quantum wells(MQWs) under realistic experimental conditions.The amplification and absorption responses of two weak fields can be achieved by adjusting the relative phase,the probe detuning,and the two pump Rabi frequencies appropriately.The investigation is much more practical than its atomic counterpart because of its flexible design and the wide adjustable parameters.It may provide a new possibility in technological applications for the light amplifier working on quantum coherence effects in MQWs solid-state system.     

Design, Development and Implementation of Three Gorges Project Management System

1Introduction　TheThreeGorgesProject (TGP)makesafeatureofalargeinvestment,alongconstructionperiod ,widely involv ingaspects,agreatdealofworkindataandinformationprocessingandacom plicatedmanagementsystem .Ascien tificandefficientmanagementsystemisurgentlyneededtomanagetheprojectinasystematic ,all roundandmodernmanner.TheChinaYangtzeThreeGorgesProjectDevelopmentCorporation(CTGPC)decidedtocooperatewithaCanadacounterpartinbuildingTGPMSbyintroducingmoderncomputerizedin formationtechnology…     

Structural and optical properties of Zn1−xNixTe thin films prepared by electron beam evaporation technique

Zn1-xNixTe thin films with different composition(x=0.0, 0.05, 0.10, 0.15 and 0.20) were deposited on glass substrate by electron beam evaporation technique followed by its characterization using advanced structural and optical analysis techniques. Structural properties of the prepared thin films were studied by X-ray diffraction(XRD). The XRD patterns revealed that the binary compounds transformed into a ternary compound with cubic structure having preferred orientation along the c-direction with(111) planes. Composition analysis of the films was determined by energy dispersive analysis of X-rays(EDAX) and found to be in agreement with the precursor composition. Optical properties such as extinction coefficient(k) and band gap energy of these films were examined by using a spectroscopic ellipsometer. It was found that the extinction coefficient(k) increased with the addition of Ni content in the alloy. In comparison, the band gap energy was also determined by using transmission spectra and found to be agreed with that of the ellipsometric results. These analyses confirm that the band gap energy decreases with the increase of Ni content in the alloy.     

Influence of Ag content on the microstructure,mechanical, and tribological properties of TaVN-Ag films

A series of TaVN-Ag nanocomposite films were deposited using a radio-frequency magnetron sputtering system. The microstructure, mechanical properties, and tribological performance of the films were investigated. The results showed that TaVN-Ag films were composed of face-centered cubic (fcc) TaVN and fcc-Ag. With increasing Ag content, the hardness of TaVN-Ag composite films first increased and then decreased rapidly. The maximum hardness value was 31.4 GPa. At room temperature, the coefficient of friction (COF) of TaVN-Ag films decreased from 0.76 to 0.60 with increasing Ag content from 0 to 7.93at%. For the TaVN-Ag films with 7.93at% Ag, COF first increased and then decreased rapidly from 0.60 at 25℃ to 0.35 at 600℃, whereas the wear rate of the film increased continuously from 3.91×10-7 to 19.1×10-7 mm3/(N·mm). The COF of the TaVN-Ag film with 7.93at% Ag was lower than that of the TaVN film, and their wear rates showed opposite trends with increasing temperature.     

“Twits-Up”,Transform of Spin Flows and Physics of Process

1 Introduction Due to theoretical difficulties and technologicalobstacles, very few people have been braveenoughtoforecast disastroustorrential rains of 100mmor higher . Because of our success withthesekinds of disastrous weather systems , manyscholars and front-line meteorologists have askedus questions like : Without first going intotheoretical details ,what is the difference betweenyour method and the traditional ,but well appliedmethod? To this end,our answer is our methodmakes use of some…     

Local electronic structure and magnetic properties of （Ga,Cr）N

Modern electronic devices utilize the charge degree of freedom of electrons to process information in semiconductors and the spin degree of freedom to store information in magnetic materials. For example, inte- grated circuits and high–frequency devices …     

Facile synthesis of Ca-α-SiAlON:Eu2+ phosphor by the microwave sintering method and its photoluminescence properties

Pure Ca-SiAlON:Eu2+ was synthesized by microwave sintering method at a relatively low temperature of 1550℃.Photoluminescence intensity of the resultant phosphor was higher than those of the samples synthesized by conventional gas-pressure sintering technique at 1750℃.When it was excited at 450 nm,the as-prepared yellow Ca-SiAlON:Eu2+ sample had an external quantum efficiency of 42%,comparable to the sample synthesized at 1750℃ under 0.5 MPaN2 gas pressure by the GPS method reported in reference.The experimental results demonstrated that the microwave sintering method was also an interesting approach for synthesizing nitride phosphors,which promises lower firing temperature than those by carbothermal reduction and nitridation (CRN) methods,higher heating rate and shorter duration time compared with those by gas-pressure sintering.     

Evaluation of the microstructure,secondary dendrite arm spacing,and mechanical properties of Al-Si alloy castings made in sand and Fe-Cr slag molds

The microstructure and mechanical properties of as-cast A356 (Al-Si) alloy castings were investigated. A356 alloy was cast into three different molds composed of sand, ferrochrome (Fe-Cr) slag, and a mixture of sand and Fe-Cr. A sodium silicate-CO₂ process was used to make the necessary molds. Cylindrical-shaped castings were prepared. Cast products with no porosity and a good surface finish were achieved in all of the molds. These castings were evaluated for their metallography, secondary dendrite arm spacing (SDAS), and mechanical properties, including hardness, compression, tensile, and impact properties. Furthermore, the tensile and impact samples were analyzed by fractography. The results show that faster heat transfer in the Fe-Cr slag molds than in either the silica sand or mixed molds led to lower SDAS values with a refined microstructure in the products cast in Fe-Cr slag molds. Consistent and enhanced mechanical properties were observed in the slag mold products than in the castings obtained from either sand or mixed molds. The fracture surface of the slag mold castings shows a dimple fracture morphology with a transgranular fracture nature. However, the fracture surfaces of the sand mold castings display brittle fracture. In conclusion, products cast in Fe-Cr slag molds exhibit an improved surface finish and enhanced mechanical properties compared to those of products cast in sand and mixed molds.     

Mineral magnetic properties of surface sediments at Bei’anhe, Beijing, and its environmental significance

A multiparameter investigation of surface sediments from the Bei＇anhe section （Beijing） has been conducted using environmental magnetic approaches. The studied sedimentary sequence consists of pluvial and lacustrine silts and clay of the Holocene age. Magnetite, hematite and pyrrhotite were identiffed as the dominant magnetic minerals. The mineral magnetic characteristics are considered to reflect the Holocene paleoenvironmental processes of the studied area, which are different from the mineral magnetic properties of typical polluted sections reported in the Beijing area. The low-field magnetic susceptibility and saturated isothermal remanence magnetization of the section decrease gradually with increasing depth. This indicates that the concentration of magnetic minerals in the strata decreases down the section. Values of interparametric ratios, such as ARM/SIRM, XARM/Xand SIRM/X, gradually increase with increasing depth, which indicates a down-section decreasing trend in the magnetic grain size of the sediments. Pyrrhotite occurs below the depth of 22 cm, suggesting the existence of redox interface. The magnetic variations of the Bei＇anhe surface sediments might be controlled by two geological processes： reductive diagenesis and pedogenesis. Our findings may have provided a reference point for magnetic investigation of polluted surface sediments in the Beijing area.     

Microstructure,mechanical, and corrosion properties of extruded low-alloyed Mg–xZn–0.2Ca alloys

The microstructure, mechanical, and corrosion properties of extruded low-alloyed Mg-xZn-0.2Ca (x=0, 1.0, 2.0, 3.0) alloys were investigated in this study. Findings from scanning electron microscope, X-ray diffraction and transmission electron microscopy results indicate that the amount of ternary Ca₂Mg₆Zn₃ phase, as the only secondary phase in 1.0Zn, 2.0Zn, and 3.0Zn alloys, gradually increases with the addition of Zn, while the Mg₂Ca phase was observed in the Mg-0.2Ca alloy only. Zn has a strong effect on the orientation and intensity of textures, which also influence mechanical behaviors, as revealed by electron back-scatter diffraction. Among all the alloys, the Mg-2.0Zn-0.2Ca alloy obtains the maximum tensile strength (278 MPa) and yield strength (230 MPa). Moreover, Zn addition has an evident influence on the corrosion properties of Mg-xZn-0.2Ca alloy, and Mg-1.0Zn-0.2Ca alloy exhibits the minimum corrosion rate. This paper provides a novel low-alloyed magnesium alloy as a potential biodegradable material.     

Synthesis, structure and photo-physical properties of coordination polymer of Pr( Ⅲ ), Yb( ⅢⅢ )

采用水热合成的方法,以肉桂酸为配体,合成了2种Ln(Ⅲ)的配合物[Pr(C9 H7O2)3]n(1)和[Yd(C9 H7O2)3]n(2) (C9H7O2=肉桂酸根),通过X—射线单晶衍射仪确定了配合物1和2的晶体结构.结构分析表明,1和2均是以(C9 H7O2)为桥连配体而形成的1D无限链状结构,但不同构.1是三斜晶系,R3c空间群,晶胞参数为:a=2.2630(4)nm,b=2.2630(4) nm,c=0.787 6(3) nm,α=90°,β=90°,γ=120°;2是单斜晶系,P2(1)空间群,晶胞参数为:a=1.15336(16) nm,b=0.78421(11) nm,c=1.30222(18) nm,α=90°,β=94.371(2)°,γ=90°.在室温下测定了2种配合物固态粉末的IR光谱,UV-Vis-NIR光谱以及荧光激发和发射光谱,并进行了分析指认.这2种配合物IR光谱的主要谱带极为相似,它们的UV-ViS-NIR吸收光谱均表现出配体的π→π(')跃迁吸收带和稀土离子的f-f特征吸收带.此外,重点讨论了它们的发光性质,尤其是配合物2在NIR区表现出Yb(Ⅲ)的特征发射.     

The amplified fluorescence quenching of heteroatomic conjugated polymers based on the “molecular wire”effects

One of the most important components of chemicalsensor is sensing material, which selectively binds ananalyte and signals the binding. In conventional sensorresearch, the sensitivity and reversibility of sensor arelargely determined by the association constant of thebinding. An approach to enhancing the association con-stant can be benefit for sensitivity, but disadvantageous to reversible response. Therefore, the search for new sensing materials with the high sensitivity, good selectivity and…     

Review and Comment of the Book“Syntax,a Minimalist Program”

In the present article I will first give a brief summary of the content of the book.Then I discuss some limitations of the book as well as my personal viewpoint about what the book fails to clarify and explain.