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Argyrodite sulfide solid electrolytes, such as Li6PS5Cl (LPSC), have received much attention due to their high ionic conductivity (>1 mS cm–1) and success in all-solid-state batteries (long cycle p...

All-solid-state lithium–sulfur batteries (ASSLSBs) possess higher safety, longer lifespan, and elevated energy density compared to the traditional liquid lithium–sulfur batteries (LLSBs). However, the ion-electron insulating nature along with the large volume changes of sulfur and Li2S significantly hinder the full exploitation of their high theoretical specific capacities, especially in ASSLSBs. In this work, dense composite sulfur carbon (S/C) cathodes featuring sulfurized polyacrylonitrile (SPAN) supported by a macroporous carbon (MaPC) conductive matrix (SPAN@MaPC) are prepared to solve the above issues. ASSLSBs consisting of the SPAN@MaPC-Li6PS5Cl-vapor grown carbon fiber (VGCF) composite cathode are evaluated. With ∼1 mg cm−2 pure sulfur loading in the cathode, the assembled ASSLSBs achieved a high reversible capacity of 1396.2 mA h g−1 under an applied current of 0.1C at room temperature and still retained 715.5 mA h g−1 after 200 cycles. The reason it has achieved such performance is that the sulfur in SPAN, which is uniformly dispersed at the atomic level and covalently bonded to the polyacrylonitrile (PAN) carbon skeleton, has higher electrochemical reactivity. Further, the electrochemical behavior of SPAN@MaPC in the first cycle is revealed. Also, it is evidenced that the irreversible C–Li bonding contributes partially to the super-theoretical capacity.

NASICON-type LiZr2(PO4)3 (LZP) has a high bulk ionic conductivity (∼10−4 S cm−1) and a wide electrochemical stability window between 0 and 5.5 V. However, LZP suffers from a problem in which its desirable rhombohedral phase transforms to the triclinic phase (∼10−8 S cm−1) below 50 °C. In this work, we reported a rhombohedral-structured LiZr2(PO4)3 (α-LZP) at room temperature with a high total Li-ion conductivity (2.8 × 10−6 S cm−1) by a microwave sintering process. Moreover, this approach realized a drastic reduction in the sintering temperature from the typical 1200 °C–900 °C with only a 4 h holding time. Using this approach, we also demonstrated the successful synthesis of Ca-incorporated Li1.2Ca0.1Zr1.9(PO4)3 (LCZP) with an ionic conductivity of 1.7 × 10−5 S cm−1.

Lithium–sulfur batteries based on a solid-state sulfide electrolyte show great promise in achieving the next generation of rechargeable chemical power sources with high energy density and long lifespans. However, the poor solid–solid contacts within the electrode and at the electrode/electrolyte interface, as well as lithium dendrite formation and its interaction with sulfide electrolytes during cycling, are significant challenges that must be overcome before the full potential of sulfide electrolyte-based lithium–sulfur batteries can be realized. Here, we propose a [Li(triglyme)]+[TFSI]− (LiG3) solvent-salt complex with an excellent stabilizing effect towards Li10GeP2S12 electrolyte and demonstrate its application in a high-performance solid-state lithium–sulfur battery. A small quantity of LiG3 added into the cathode material dramatically enhanced the Li+ ion transfer and facilitated the transition from a solid–solid redox reaction involving sulfur species to a solid–liquid dual-phase redox reaction. Simultaneously, we achieved a stabilized solid electrolyte interphase layer at the lithium anode side by the in situ electrochemical reduction of LiG3 complex. The solid-state lithium–sulfur cells demonstrated high specific capacities of 1100 mA h g−1 at 0.2C and 650 mA h g−1 at 1.0C. Furthermore, pouch cells with dimensions of 4 × 5 cm2 were successfully fabricated, indicating the promising practical application of these cells in energy storage.

Searching for an efficient and cost effective electrochemical catalyst is regarded as the key challenge for the hydrogen evolution reaction (HER). Both the active sites and electrical conductivity of the catalysts should be carefully engineered to improve their HER performance. In this work, S-doped MoSe2-decorated graphene/graphene nanoribbon aerogel (S-MoSe2@GGNR) hybrids have been fabricated as high-performance electrocatalysts for HER. The unique nanoribbon-interconnected-nanosheet structure of the graphene/graphene nanoribbon aerogel (GGNR) provides an open structure for fast ion diffusion and conductive channels for fast electron transport. GGNR as a substrate could prevent MoSe2 nanosheets from agglomeration and fully expose the active sites of MoSe2, while further S-doping can modify its electronic and crystalline structure, which can improve the activity of the catalytic sites. Consequently, the S-MoSe2@GGNR hybrids exhibit outstanding electrochemical activity with a potential of −153 mV vs. reversible hydrogen electrode to achieve a current density of 10.0 mA cm−2 and a small Tafel slope of 46 mV per decade. The good performance of the S-MoSe2@GGNR hybrids can be credited to synergistic effects between the unique hierarchical architecture of carbon aerogels and positive effect of S-doping, which makes them promising electrocatalysts for hydrogen production. The authors are grateful for the financial support from the National Natural Science Foundation of China (21704014, 51433001, and 21674019), Science and Technology Commission of Shanghai Municipality (16520722100), the Fundamental Research Funds for the Central Universities (2232017D-06), Shanghai Municipal Education Commission (17CG33), Shanghai Sailing Program (17YF1400200), and Program of Shanghai Academic Research Leader (17XD1400100).

The high temperature dielectrics properties of unfilled tungsten bronze ceramics, Ba4SmFe0.5Nb9.5O30, were studied. The temperature dielectric properties and the variable temperature XRD data, in addition to the XPS data indicated that BSFN ceramics have no phase changes from 25 °C to 450 °C; the high temperature relaxation behaviour around 350 °C is closely related to the oxygen defects. Frequency dependence of temperature electrical conductivity relaxation of Ba4SmFe0.5Nb9.5O30 ceramics was well fitted by the Arrhenius relationship with Ea ~ 0.65 eV.

Carbon nanomaterials have received much attention due to their good electrochemical performance as electrode materials and as substrates for pseudocapacitive materials. Herein, the graphene–carbon nanotube aerogel (GCA) has been constructed by direct cryodesiccation from the aqueous dispersion of a graphene oxide–carbon nanotube hybrid, the so-called “sol-cryo” method, followed by high-temperature carbonization. The as-obtained GCA with a unique sheet-scroll conjoined architecture not only displays an excellent electrical double-layer capacitive performance but also performs as an ideal three-dimensional template for the perpendicular immobilization of Ni(OH)2 nanosheets. The capacitance of Ni(OH)2@GCA is 1208 F g–1 at 1 A g–1 with 88% retention after 2000 cycles. The Ni(OH)2@GCA//GCA asymmetric supercapacitor exhibits a high energy density of 30 Wh kg–1 at a power density of 820 W kg–1. In addition, this template-free sol-cryo method possesses simplicity and large-scale availability, which provides a nov...

ZnO nanowire-reduced graphene oxide nanocomposites have been prepared and used to detect ammonia at room temperature successfully. The nanocomposites are synthesized through hybridization of ZnO nanowires and graphene oxide sheets, which have been produced in large scale through mechanical mixing and low-temperature thermal reduction process. The micro ammonia sensors based on the as-prepared nanocomposites are subsequently constructed by dip-dropping method. The resultant device exhibits excellent response (∼19.2%) to NH 3 at room temperature, which is much better than pure reduced graphene oxide based gas sensors. It is revealed that ZnO nanowires can provide pathways for electron transfer on reduced graphene oxide sheets, thus the ZnO nanowire-reduced graphene oxide nanocomposites based sensors show excellent overall sensing performance with high response, short response and recovery time, good stability and excellent selectivity. Moreover, the sensor has a very small size and low power consumption, which are critical for system integration and portable equipment. Our work can hold a great potential for realistic applications in ammonia detection fields.

Carbon-based materials have emerged as the promising templates of electrocatalysts for hydrogen evolution reaction (HER). In order to enhance the HER activity, the structure of carbon-based materials needs to be carefully engineered to maximize the exposure of active sites, improve the electrical conductivity and shorten the ion diffusion pathway of catalysts. In this work, high-performance electrocatalysts for HER have been constructed based on the graphene/graphene nanoribbon (GGNR) aerogels. In the GGNR aerogels, graphene nanosheets act as the main building blocks of the monolithic aerogels, while large amounts of graphene nanoribbons tightly bridge different graphene nanosheets, which allows intrinsically good electrical contact with electroactive materials. Moreover, the three-dimensional porous framework with large surface-to-volume ratio can be tuned by adjusting the amount of graphene nanoribbons, which guarantees the ultrafast and sufficient mass transfer in the catalytic process. All the above factors make GGNR aerogels ideal templates for immobilization of MoS 2 nanosheets, a typical noble metal-free hydrogen evolution catalyst. The optimal GGNR@MoS 2 hybrid exhibits excellent HER performance, with a low onset potential of −105 mV, a small Tafel slope of 49 mV per decade and a large current density (10.0 mA cm −2 at η = 183 mV), making them promising and highly efficient electrocatalyst for hydrogen evolution reaction.

In order to found new dielectrics ceramics in tungsten bronze structure, unfilled tungsten bronze (TB) ceramics with nominal formula Ba4PrFe0.5Nb9.5O30 were prepared by the solid state reaction method. The microstructure and dielectric properties were studied using powder X-ray diffraction, field emission scanning electron microscope, and variable temperature dielectric test system. The results show that the ceramics have a single phase and belong to the space group of P4bm with the cell of a = b = 12.4839(3) A, c = 3.9409(5) A, V = 614.192(2) A3. The frequency dependent dielectrics properties show that the ceramics have a Debye-like relaxation at room temperature, while the temperature dependent dielectrics properties indicate that the ceramics are a relaxor and the relaxation is due to the nanopolars and oxygen vacancies. The ceramics have a potential application in electronic ceramics as temperature-stable multilayer ceramic capacitors.

Unfilled tungsten bronze ceramic Ba3.5Sm1.5Fe0.75Nb9.25O30 was prepared by a conventional solid-state reaction method. Its structure, microstructure, and dielectric properties were investigated. Dielectric behaviors indicate that the ceramics are ferroelectric at room temperature with a remnant polarization ~1.61 μC/cm2 and a coercive field ~13.91 kV/cm. Ba3.5Sm1.5Fe0.75Nb9.25O30 ceramics have temperature stability with a high dielectric constant (er) varying from 172 to 202 at the temperature range −55 to 200°C (at 1 MHz). Capacitance change rate of the sample is less than 15%. These results indicate that Ba3.5Sm1.5Fe0.75Nb9.25O30 ceramics might be promising in temperature-stable multi-layer ceramic capacitors.

Unfilled tungsten bronze ceramics with a composition of Ba 4 SmFe 0.5 Nb 9.5 O 30 were prepared by the conventional solid-state sintering method. The phase, microstructure, dielectric and ferroelectric properties were studied. Room temperature XRD results indicated that the ceramic occurs in the tetragonal space group P4bm phase with cell parameters of a = b =12.4712(2) A and c =3.9430(2) A. The temperature-dependent dielectric properties, XRD data and Raman spectra data indicated that BSFN ceramics exhibit no phase changes from 35 °C to 450 °C. Fitting of a Vogel-Fulcher relationship with an activated energy E a of 0.11 eV indicates an unambiguous dielectric relaxor state near room temperature. Furthermore, the BSFN ceramics exhibited residual polarization and coercive field of 3.45 µC/cm 2 and 24.65 kV/cm, respectively.

Artificial manipulation of electronic degrees of freedom is the key point to realize modern electronic devices. Both charge and spin of electron have been widely studied and applied to logic circuits and information storage devices. Valley, the unique degree of freedom of crystal electrons, has also attracted great attention of the researchers in the past decade. The valleytronics progress benefits from the tremendous improvements of the two-dimensional atomic layer material growth technologies and in-depth explorations of valley properties. Valleytronic materials, represented by two-dimensional transition metal dichalcogenides, have become an excellent platform for the research and design of new electronic devices due to their special optical responses and distinctive electronic transport properties. The valley devices have the advantages of fast operation, low energy consumption, less information loss, high integration and long transmission distance.In this review, we first introduce the basic concepts and properties of the energy valley, such as the valley Hall effect and the valley circular dichroism. Second, we describe the crystal structures and energy band diagrams of the two-dimensional transition metal dichalcogenides. Third, the progress in artificial manipulation of the valley effects is summarized. Some approaches which can break the inversion symmetry and therefore induce the valley degree of freedom are introduced. Fourth, we discuss the methods of realizing valley polarization. Fifth, the developments of valleytronic devices in recent years are reviewed. Finally, a summary and an outlook are given.

In this study, graphene oxide reinforced regenerated cellulose/polyvinyl alcohol (GO-RCE/PVA) ternary hydrogels were successfully prepared via a repeated freezing and thawing method in NaOH/urea aqueous solution. The effect of GO content on the mechanical properties, swelling behavior, water content of composite hydrogels was investigated. It was found that the mechanical properties of GO-RCE/PVA ternary hydrogels were largely enhanced relative to RCE/PVA hydrogels. With the addition of 1.0wt% GO, the tensile strength was increased by 40.4% from 0.52MPa to 0.73MPa, accompanied by the increase of the elongation at break (from 103% to 238%). Meanwhile, GO-RCE/PVA ternary hydrogels performed the excellent pH-sensitivity, and the higher pH leaded to higher swelling ratio. With 0.8wt% GO loading, the swelling ratio of GO-RCE/PVA ternary hydrogel was improved from 150% (pH=2) to 310% (pH=14). In addition, a slight increase in the water content of the ternary hydrogel was achieved with increasing concentrations of GO. It is believed that this novel ternary hydrogels is a promising material in the application of biomedical engineering and intelligent devices.

A ZnO nanowire-reduced graphene oxide (ZnO-rGO) based portable ammonia (NH3) gas sensing electron device working at room temperature has been demonstrated for the first time. The sensor is developed on a microelectrode of micro-electromechanical systems and supported by peripheral circuits and a hosting computer, which enables the real-time detection of NH3 at room temperature. In contrast to the traditional sensors based on pure graphene or ZnO nanowires alone, the ZnO-rGO based gas sensing electron device can detect low-concentration (1 ppm) NH3 with higher sensitivity ( $\sim 7.2$ %). Besides, this sensor exhibits satisfying properties at sensing NH3 with the concentration as low as 500 ppb at room temperature.

Solid-state batteries (SSBs) exhibit a promising prospect due to their potential in terms of safety and energy densities. As an oxide electrolyte, cubic garnet solid electrolyte (cubic-Li7La3Zr2O12) attracts wide attention due to the high ionic conductivity. However, the problem of poor contact between garnet solid electrolyte and lithium impairs the development of solid electrolytes. Herein, we demonstrate an effective modification method to cope with the interface issue between electrolyte and Li metal by introducing an Ag@WSe2 composite layer. By applying this method, the interfacial resistance between the garnet electrolyte and Li metal is reduced to ~12.5 Ω cm2, which is nearly 150 times lower than the value of 1900 Ω cm2 before modification. The WSe2 acts as a framework to immobilize Ag, while Ag forms an Ag–Li alloy with lithium for lithium ions transportation. And other Ag@TMDs (transition metal dichalcogenides) composites have also been proven to have similar effects. In addition, the Li | Ag@WSe2-LLZO | LFP full cell demonstrates a satisfactory capacity and excellent cycle stability (500 cycles with 90% capacity retention rate) at room temperature.

Solid-state lithium batteries (SSLBs) exhibit numerous advantages including high safety, high energy density and power density, etc., and therefore become the most promising candidate for next-generation batteries. However, constructing an intimate contact within the composite electrode and the electrode/electrolyte interface via simple mixing and cold-pressing processes is still challenging. Herein, a novel fabrication process for homogeneous composite electrodes used in SSLBs is successfully demonstrated. An in-situ liquid-phase approach employing the [Li(triglyme)]+[TFSI]- (LiG3) solvent-salt complex with excellent stability to modify the sulfide-based solid-state electrolyte interfaces, is introduced into the SSLBs system, which enables SSLBs to work efficiently at lower external pressures. The quasi-solid-state prototype cells with Li4Ti5O12 (LTO) active material deliver excellent room-temperature performance, generating a super high capacity of 160 mA h g−1 and high capacity retention of 91.4% for 1500 cycles under 0.25 C. This work gives new insight into the interface engineering, processing and more positive impact on the industrial production of SSLBs.

Micro fluidized bed is a promising reactor for a variety of industrial processes. It is important to understand the hydrodynamics of gas-solid fluidization of the micro fluidized beds with different oblique angles. This study numerically investigated the effects of oblique angle on the fluidization behavior and pressure drop in the micro fluidized beds by Computational Particle-Fluid Dynamics (CPFD) models. The results show that the oblique angle of the bed affects strongly the particles, fluidized gas and pressure distribution in the micro fluidized bed due to strong wall effects. The bed with oblique angle of 0° can achieve better gas-solid contact than the inclined beds. The pressure drops in the micro fluidized beds decrease linearly with increasing oblique angles of the beds when the oblique angles are beyond 15°. The oblique angle of the bed has a great influence on the fluidization behavior and pressure drop in the micro fluidized bed.

Unfilled tungsten bronze ceramics with general formula KBa3RNb10O30 (R = La, Pr, Nd, Sm, Eu, Gd) were prepared by the conventional solid state reaction method. XRD patterns show that all ceramics are pure tungsten bronze phase. Dielectric characterization indicates that the ceramics except KBa3GdNb10O30 are relaxors with strong frequency dispersion, while KBa3GdNb10O30 shows diffuse phase transition and belongs to classical ferroelectrics. At room temperature, the KBa3RNb10O30 compounds (R = La, Pr, Nd) are paraelectrics while the KBa3RNb10O30 compounds (R = Sm, Eu, Gd) are ferroelectrics. Among them, KBa3GdNb10O30 has the highest remnant polarization (2P r ) of 8.2 μC/cm2. Phase transition temperature, remnant polarization (2P r ) and tetragonality of the compounds increase with the decrease of ionic radius of the rare earths.

WC-17Co cermet coatings were deposited on Ni718 alloys using the high-velocity oxygen fuel (HVOF) technique. These coatings were then heat treated by different processes (150 °C, 10 h; 300 °C, 10 h; 450 °C, 10 h). The effects of heat treatment on microhardness, elasticity modulus, and fracture toughness were studied by an indentation method. The residual stresses of the coated specimens were evaluated by the Almen strip method. The results show that the phase constitution and the structure of the WC-17Co coatings exhibit no obvious change in 150, 300, and 450 °C heat-treatment. The microhardness, elasticity modulus, and fracture toughness of the WC-17Co coatings decrease with the increase of heat treatment temperature. The descent tendency of the mechanical properties is attributed to the decline in compressive residual stresses after isothermal heat treatment.

4-dodecyloxy-phenyl-4′,4″-diaminotriphenylamine(DPDTA) containing triphenylamine were successfully synthesized.Polyimides(PIs) containing triphenylamine units in the main chain were synthesized with the co-condensation of DMMDA,DPDTA and aromatic dianhydride 4,4′-oxydiphthalic anhydride(ODPA) by thermal imidization.The structures of the PIs were confirmed by FT-IR.The alignment behavior of PIs as liquid crystal alignment layers was also examined with polarized optical micrograph(POM).The properties of the PIs were characterized by TGA,UV-Vis and DSC etc.It was found that side chain density of PIs had important influence on properties of liquid crystal alignment film.Before rubbing,PI containing 25% DPDTA could induce uniform vertical alignment and a pretilt angle of 89.7°.The liquid crystal was not aligned on the surface of PI film which contained 10% DPDTA without the rubbing treatment.After the rubbing process,the pretilt angle of liquid crystal was 2.4,when PI film contained 25% DPDTA and the pretilt angle of liquid crystal was 1.8°,when PI contained 10% DPDTA.The transmittances of the PIs in 500～800 nm wavelengths are more than 80%,and their glass transition temperatures are above 230 ℃.

A novel functional diamine(H8-c) with thick ring and long alkoxy was synthesized from 3,5-dinitrobenzoyl chloride,estradiol and 1-Bromooctane.A polyimide(PI),applied in liquid crystal(LC) vertical orientation agent,was prepared from p-phenylenediamine(PDA),1,2,3,4-cyclobutanetetracarboxylicdianhydride(CBDA) and H8-c.The PI possessed excellent vertical alignment for nematic LC.The vertical alignment of LC cell which was kept at 120 ℃ for 12 h was still stable.It could be seen that the thermal stability of the vertical alignment of LC was excellent.The temperature at 5% weight loss of the PI(T5) is as high as 400 ℃ in nitrogen.The temperature at 10% weight loss of the PI(T10) is as high as 480 ℃ in nitrogen.The PI film exhibited high transparency(95%) at wavelengths above 400 nm.

Polyimide(PI) was synthesized by copolymerization of PMDA,MDA and TBCA in this paper.The films prepared by PI can induce the same vertical alignment before and after rubbing.The effect of content of TBCA on the alignment property was discussed,the relative content of surface side chains was observed by the ATR-FTIR spectra of the PI films' surface,and the effect of the microgrooves on the liquid crystal was investigated by atomic force microscope(AFM).The PI films without microgrooves before rubbing can align liquid crystal molecules.Moreover,the content of surface side chains of this PI films before rubbing is the same as that after rubbing.

The first series of polyimides with different ratio of side chain were copolymerized from 4-octyloxy-biphenyl-3,5-diaminobenzoate(C8),3,3′-dimethyl-4,4′-methyl-enedianiline(DMMDA) and 4,4-oxydiphthalic(ODPA) via one-step method.The effect of the diamine content of these PIs on their solubility,alignment,pretilt angle and thermal stability was investigated.Similarly,the second series of polyimides with different main chain were copolymerized from C8,DMMDA and different dianhydrides which include ODPA,pyromellitic dianhydride(PMDA),3,3′,4,4′-dibenzophenonetetracarboxylic dianhydride(BTDA) via one-step method.The effect of dianhydride structure on the solubility and thermal stability was explored.

We carried out a theoretical study on the geometries, electronic structures, and frontier molecular orbitals of vinyl thiophene group conjugated spirooxazines (SO-SO3) using density functional theory (DFT) at the B3LYP/6-31G* level. The calculated results show that the equalization of bond lengths at the left and right parts of the open-forms occurred during the ring-opening process. A large conjugated system was formed and this significantly narrowed the energy gap. The conjugated system became larger and its electrons flowed easily because of the introduction of different lengths of vinyl thiophene conjugation moieties into the spirooxazine molecule. The electrons and energy efficiently transferred from the vinyl thiophene to naphthoxazine. The orbital contribution rate of the vinyl thiophene group in the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) increased obviously. Time-dependent DFT (TD-DFT) calculations showed that as the conjugated vinyl thiophene unit reached 2-3 the first singlet excited state of SO2 and SO3 resulted from the electron transition from the HOMO to the LUMO, which were also assigned to the π-π transition. Meanwhile, λmax 1847 Acta Phys. ⁃Chim. Sin. 2011 Vol.27 was between 466 and 540 nm with an obvious red-shift while the λmax of O-SO2 and O-SO3 reached 605 and 647 nm, respectively.

This paper presents a computational fluid dynamics approach for micro droplet impacting on a flat dry surface. A two-phase flow approach is employed using FLUENT VOF multiphase model to calculate the flow distributions upon impact. The contact line velocity is tracked to calculate the dynamic contact angle through user defined function program. The study showed that the treatment of contact line velocity is crucial for the accurate prediction of droplet impacting on poor wettability surfaces. On the other hand, it has much less influence on the simulation of droplet impacting on good wettability surfaces. Good fit between simulation results and experimental data is obtained using this model.

Selective excitation of coherent anti-Stokes Raman scattering from the benzene solution is achieved by adaptive pulse shaping based on genetic algorithm, and second harmonic generation frequency-resolved optical gating (SHG-FROG) technique is adopted to characterize the original and optimal laser pulses. The mechanism for two-pulse coherent mode-selective excitation of Raman scattering is experimentally investigated by modulating the pump pulse in the frequency domain, and it is indicated that two-pulse coherent mode-selective excitation of Raman scattering mainly depends on the effective frequency components of the pump pulse related to specific vibrational mode. The experimental results suggest that two-pulse CARS has good signal-to-background ratio and high sensitivity, and it has attractive potential applications in the complicated molecular system.

High resolution mode-selective excitation in the mixture of C6H6 (992cm−1) and C6D6 (945 cm−1) is experimentally achieved by adaptive femtosecond pulse shaping based on the genetic algorithm (GA), and second harmonic generation frequency-resolved optical gating (SHG-FROG) is adopted to characterize the original and optimal laser pulses, and its mechanism is experimentally validated by tailoring the frequency components of the pump pulses at the Fourier plane. It is indicated that two-pulse coherent mode-selective excitation of the Raman scattering mainly depends on the effective frequency components of the pump pulse related to specific molecular vibrational mode. The experimental results have attractive potential applications in the complicated molecular system.

High pressure method was used for the first time to produce rectorite clay (REC)/phenolic resin (PF) and organic rectorite clay (OREC)/phenolic resin and montmorillonite (MMT)/phenolic resin (PF) nanocomposites. The structure of the material phase was studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), and atomic force microscopy (AFM). The experimental results show that intercalated clay/resin nanocomposites could form under normal temperature and high pressure conditions by the intercalation of polymeric molecules rather than interlayer polymerization.

Effects of water to binder ratio (mW/mB), types and addition content of mineral admixtures on the autogenous relative humidity (ARH) change of concrete resulting from self-desiccation were studied. The parameters of coefficient of mineral self-desiccation-effect k and efficient water to binder ratio re were proposed, and experimental results were fitted non-linearly and analyzed using these proposed parameters. The experimental results indicate that ARH reduction of concrete at different ages increases with the decrease of mW/mB. The ARH change laws of concrete with mW/mB lower than 0.4 can be expressed with a non-linear equation. The extent of the effect of types and addition content of mineral admixtures on ARH reduction of concrete resulting from self-desiccation can be reflected by the non-linear equation with the parameter of efficient water to binder ratio re effectively.

Nonlinear optical properties of 75TeO2–20Nb2O5–5ZnO glasses doped with CeO2 have been investigated with a self-diffracted time-resolved degenerate four-wave mixing (DFWM) technique at different excitation intensities and lattice temperatures. The DFWM signal exhibits three peaks at higher excitation intensities, where a main peak appears at zero delay time and two rather weak side peaks are located symmetrically at the negative and positive time delay. Due to destructive interferences between the fifth- and third-order polarizations, the line-shape of the main peak around the zero time delay evolves from single peak into a double-peak structure with increasing excitation intensity. Two side peaks emerge at the positive and negative time delay and gradually intensify with increasing excitation intensity or lattice temperature and their positions are independent of the pulse duration, temperature and excitation intensity, which are attributed to the many-body Coulomb interaction.

Using a nonperturbative scattering theory, we study the photoelectron angular distributions (PADs) of Kr atoms irradiated by an infinite sequence of intense single-cycle pulses of circular polarization. We demonstrate the inversion asymmetry of PADs and the dependence of PADs on the carrier-envelope phase of the single-cycle pulses. The inversion asymmetry is caused by the interference between transition channels where the different channels are characterized by different combinations of absorbed-photon numbers in the ionization process. Our results provide a possible method to determine the value of carrier-envelope phase by the detected PADs.

Neodymium doped phosphate glasses have been prepared by the semi-continuous melting technique. Their absorption and emission spectra have been recorded at room temperature. The Judd-Ofelt theory has been applied to evaluate the stimulated emission cross sections of 4F3/2→4I11/2 transition for Nd3+. The higher stimulated emission cross section, 4.0×10-20cm2, is obtained. The fluorescence decays of the 4F3/2→4I11/2 transition of Nd3+ are measured for the samples doped (0.7-10) wt% of Nd2O3 at room temperature. The concentration quenching of Nd-doped phosphate glass is mainly attributed to cross-relaxation and energy migration. The site-dependent properties of fluorescence spectra and the fluorescence lifetime of the Nd3+-doped phosphate glass (with 2.2wt% Nd2O3) are studied using laser-induced fluorescence line narrowing techniques and the site-to-site variations of optical properties are observed at low temperature.

Multiple order self-diffractions by femtosecond laser-induced transient grating in CeO2 doped 75TeO2–20Nb2O5–5ZnO glass are investigated by pump-probe technique. The glass structure and component are investigated by Raman and visible–NIR absorption spectra. It is showed that there exists Ce3+ ion in tellurite glass and the transient grating is created by the optical Kerr effects and improved by the excited particle grating from the resonant absorption of the 1S0→1F3 electronic energy transition of Ce3+ ion and the conversion efficiency of the first order diffraction signal reaches about 11%. The results indicate that CeO2 doped 75TeO2–20Nb2O5–5ZnO glass has potential applications in ultra-fast all-optical switching.

Some properties of nano SiO2 modified PVF adhesive were studied. The experimental results show that nano SiO2 can improve the properties of PVF adhesive very well. Meanwhile the modification mechanism of nano SiO2 to PVF adhesive and the applications of this adhesive in paper-plastic composite, concrete and fire-proof paint were discussed by using IR and XRD determination.

The n-type nonstoichiometric Pb 0.55 Te 0.45 materials were prepared by melting and quenching combined with a subsequent high pressure high temperature (HPHT) sintering. After adequately annealed at 623 K in the argon atmosphere, the microstructures and thermal transferring performance of the prepared samples have been systematically investigated. The results show that the grains of samples were apparently refined, as well as a large quantity of twisty layered structure and numerous particles with a size of ∼200nm distributing in the grain boundary can be observed. These refined microstructures significantly block the transports of phonons, and result in a remarkable reduction of the lattice thermal conductivity compared with the corresponding melting ingots.

The n-type nonstoichiometric Pb0.55Te0.45 materials were prepared by melting and quenching combined with a subsequent high pressure high temperature (HPHT) treatment. After adequately annealed at 623 K in the argon atmosphere, the thermoelectric transport properties of the prepared samples have been systematically investigated. The results show that the pressure effectively adjusts the carrier concentration and its transport properties, and hence commendably tunes thermoelectric performances of the samples. Therefore, the maximum ZT of the sample treated by 2 GPa reaches 0.84 at 580 K, which is ~ 400% improvement in comparison with the melting ingot.

We report the results of the hyperfine structure (HFS) of the 23Π1g state in Na2. The relative ultraviolet and visible fluorescence spectra of molecular sodium were measured by means of a Doppler-free two-photon spectroscopy technique. The HFS of the 23Πg(v = 78, J = 37, Ω = 1) level was first observed and its HFS constant was measured to be C = -4.92±0.26 MHz. The intermediate enhancing and upper energy levels were labelled by the experimental and theoretical methods.

Composite ZnO/SnO2nanocrystalline particles (ZnO/SnO2) were synthesized by sol-gel method and with treatment of high pressure at 6 GPa. The crystallinity and the particle size of the prepared samples were analyzed by X-ray diffraction (XRD) spectroscopy. The results indicated that all the samples had the good crystallinity, and the particle size of ZnO and ZnO/SnO2decreased after high-pressure treatment. The infrared (IR) spectra showed that the distance of crystal lattice was shortened after high-pressure treatment, and the size distribution became more uneven afterSnO2doping. With the high-resolution transmission electron microscope (HRTEM), we got some morphology information and evidence to support the IR and XRD analysis results. The results of ultraviolet-visible absorption (UV-Vis) spectra showed that ZnO/SnO2might improve the photocatalytic property of the samples after high-pressure treatment.

The real-time observation of atomic motion in space and time is of great importance for natural science research. Ultrafast electron diffraction (UED) technique, which is equipped with both the high temporal resolution of femtosecond laser pulses and the high spatial resolution of electron diffraction, can provide an effective approach to study the structural change of matter in atomic scale. In this review, we make an introduction of the development history, experimental methods, related applications and future prospects of UED technique.

In the magnetic confinement fusion device, the first wall as plasma facing components will directly affect the performance of high temperature plasma. And the interaction of plasma and materials also affect the life of the first wall. Liquid lithium first wall receives more and more attention due to the properties of repairing itself and effectively inhibiting boundary particle recycling. So the research of the interaction between liquid lithium wall and plasma is particularly important. Erosion and deposition characteristics of lithium and its influence on the performance of plasma during lithium limiter experiment in HT-7 device are studied in-depth in this paper. Experimental results show that when the interaction between Li and plasma is weak, Li enters into the plasma mainly by weak surface evaporation and sputtering. During this process, Li line emission is strengthened, impurity and hydrogen recycling is decreased resulting in the improvement of plasma performance. When the interaction between Li and plasma becomes extremely strong, it is found so many big scale Li droplets ejected from liquid lithium surface to cause intense Li efflux into plasma, leading to plasma discharge disruption. Li atoms coming from Li limiter are ionized in the scrape-off layer (SOL), and entered into hot plasma column as ions (Li+, Li2+, Li3+) and transported in plasma. After the experiment, it can be found that a lot of white spots distributed in the vacuum chamber wall, with its main composition being Li2CO3 by XPS analysis. Through observing Li spot distribution and analyzing the lithium film thickness by scanning electron microscopy (SEM) in different samples, it is observed that the lithium is primarily deposited around the limiter, but the number of Li spots is more at the low field side than that at the high field side of the device, and the Li film gradually becomes thinner along the toroidal direction of the HT-7 device, leading to the non-uniformity of impurity and hydrogen recycling. The experiment may provide a reference for studying the interaction of plasma and liquid lithium first wall and the application of liquid lithium first wall in future tokamak device.

We have shown that r.f. sputtered Si films crystallized by cw Ar/sup +/ laser irradiation is a suitable material for fabrication of polysilicon TFTs. Polycrystalline Si film with proper annealing condition has a high Hall mobility up to 120 cm/sup 2//V-s in p-type samples. The dependence of dark conductivity on temperature suggests that much reduced trap density in laser-annealed Si films is the reason for the high mobility, despite the fact that the grain size is only 30 nm.

The temperature of the remaining cold 87Rb atoms confined in a vapor cell magneto-optical trap after two-step photoionization has been measured. In the two-step photoionization process, the first excitation laser is served by the cooling laser and the second excitation laser is served by a continuous semiconductor laser with a wavelength of 450 nm. The results show that the temperature of the remaining cold atoms decreases as the intensity of the second excitation laser increases. Moreover, the relationship between the temperature T and number N of the remaining cold atoms generally follows a power law, while it deviates from the well-known T ∝ N1/3 and the power factor is smaller than 1/3. We propose that ion-atom collisions occurring during a photoionization process strongly influence the temperature scaling law in an optically dense magneto-optical trap in the presence of an ionization laser. In addition, the forced evaporative cooling due to the combined effect of the detuning of the first excitation laser and the two-step photoionization plays a role in cooling the remaining cold atoms and results in the dependence of the power factor on the detuning of the first excitation laser.

Femtosecond laser-induced resonance-enhanced multiphoton-ionization photoelectron spectroscopy (REMPI-PS) is faced with two drawbacks of low spectral resolution and poor selective excitation due to the broad spectral bandwidth. We propose a scheme to obtain a high-resolution selective excitation of (2+1) REMPI-PS by combining π and cosinusoidal phase modulation. Our theoretical results indicate that the (2+1) REMPI-PS signals related to neighboring excited states can be differentiated from their indistinguishable photoelectron spectra by the π phase modulation, and then their selective excitation can be realized by supplementally adding the cosinusoidal phase modulation. Furthermore, the physical mechanism of the high-resolution selective excitation of (2+1) REMPI-PS is explained by considering the two-photon power spectrum.