Comparison on corrosion resistance and surface film of pure Mg and Mg−14Li alloy

To study different corrosion resistances and surface film types of hexagonal close-packed(HCP)pure Mg and body-centered cubic(BCC)Mg−14wt.%Li alloy in 0.1 mol/L NaCl,a series of experiments were conducted,including hydrogen evolution,mass loss,in-situ electrochemical testing combined with Raman spectroscopy and microstructural observation.The results indicate that the corrosion resistance of pure Mg is superior to that of Mg−14Li,and the protective function of the surface films on both magnesium systems is elevated within 16 h of immersion in 0.1 mol/L NaCl.An articulated,thick,and needle-like surface film containing Li2CO3 on Mg−14Li,different from the typically thin,flaky Mg(OH)2 film on pure Mg,is confirmed via scanning electron microscopy(SEM).However,both surface films can be broken down at a high anodic over-potential.Thus,different corrosion resistances of the two Mg systems are ascribed to various protective films forming on their surfaces.

All-Solid-State Thin-Film Lithium-Sulfur Batteries

Lithium-sulfur(Li-S)system coupled with thin-film solid electrolyte as a novel high-energy micro-battery has enormous potential for complementing embedded energy harvesters to enable the autonomy of the Internet of Things microdevice.However,the volatility in high vacuum and intrinsic sluggish kinetics of S hinder researchers from empirically integrating it into allsolid-state thin-film batteries,leading to inexperience in fabricating all-solid-state thin-film Li-S batteries(TFLSBs).Herein,for the first time,TFLSBs have been successfully constructed by stacking vertical graphene nanosheets-Li2S(VGsLi2S)composite thin-film cathode,lithium-phosphorous-oxynitride(LiPON)thin-film solid electrolyte,and Li metal anode.Fundamentally eliminating Lipolysulfide shuttle effect and maintaining a stable VGs-Li2S/LiPON interface upon prolonged cycles have been well identified by employing the solid-state Li-S system with an“unlimited Li”reservoir,which exhibits excellent longterm cycling stability with a capacity retention of 81%for 3,000 cycles,and an exceptional high temperature tolerance up to 60℃.More impressively,VGs-Li2S-based TFLSBs with evaporated-Li thin-film anode also demonstrate outstanding cycling performance over 500 cycles with a high Coulombic efficiency of 99.71%.Collectively,this study presents a new development strategy for secure and high-performance rechargeable all-solid-state thin-film batteries.

Highly-rough surface carbon nanofibers film as an effective interlayer for lithium–sulfur batteries

Lithium–sulfur(Li–S)battery with a new configuration is demonstrated by inserting a flexible nitrogen-doping carbon nanofiber(N-CNFs)interlayer between the sulfur cathode and the separator.The N-CNFs film with high surface roughness and surface area is fabricated by electrospinning and a subsequent calcination process.The N-CNFs film interlayer not only effectively traps the shuttling migration of polysulfides but also gives the whole battery reliable electronic conductivity,which can effectively enhance the electrochemical performance of Li–S batteries.Finally,Li–S batteries with long cycling stability of 785 mAh/g after 200 cycles and good rate capability of 573 mAh/g at 5 C are achieved.

水热反应pH值对镁锂合金表面制备Al/Li-LDHs薄膜的影响

采用水热合成法在Mg-5Li-1Al(LA51)镁合金表面上制备Al/Li-LDH膜层。通过X射线衍射仪(XRD)、电化学阻抗测试(EIS)、极化曲线等表征手段和测试方法探究了水热反应pH对Al/Li-LDH膜层形貌及性能的影响。实验结果表明:提高水热反应pH使Al/Li-LDH膜层的尺寸增大,耐蚀性先增强然后减弱;当水热反应pH为11.5时,Al/Li-LDH膜层致密性最好,电荷转移电阻R ct最大,腐蚀电流密度J corr最小,腐蚀速率最小(0.1 g/m^(2)·a),耐蚀性最强。

Quantum Spin Exchange Interactions to Accelerate the Redox Kinetics in Li–S Batteries

Spin-engineering with electrocatalysts have been exploited to suppress the“shuttle effect”in Li–S batteries.Spin selec-tion,spin-dependent electron mobility and spin potentials in activation barriers can be optimized as quantum spin exchange interactions lead-ing to a significant reduction of the electronic repulsions in the orbitals of catalysts.Herein,we anchor the MgPc molecules on fluorinated carbon nanotubes(MgPc@FCNT),which exhibits the single active Mg sites with axial displacement.According to the density functional theory calculations,the electronic spin polarization in MgPc@FCNT not only increases the adsorption energy toward LiPSs intermediates but also facilitates the tunneling process of electron in Li–S batter-ies.As a result,the MgPc@FCNT provides an initial capacity of 6.1 mAh cm^(-2) even when the high sulfur loading is 4.5 mg cm^(-2),and still maintains 5.1 mAh cm^(-2) after 100 cycles.This work provides a new perspective to extend the main group single-atom catalysts enabling high-performance Li–S batteries.

Mechanochemical strategy assisted morphology recombination of COFs for promoted kinetics and LiPS transformation in Li-S batteries

A covalent organic frameworks(COFs)material with regular pores and stable structure can be used as the host of lithium-sulfur batteries to improve battery kinetics and polysulfides conversion.Herein,we designed and synthesized two kinds of rod-liked bulk COFs by adjusting different pore sizes(COF-BTD and COF-TFB),unfortunately,the active sites masking and sluggish kinetics have not met our expectations.Generally,the available layered COFs prepared from mechanochemical can expose abundant active sites and favorable kinetics than bulk COFs.Thus,simple mechanical ball milling is applied to activate the above COFs(M-COFs group).It is worth noting that layered R-COF-BTD is directly synthesized from rod-liked precursors by simple morphological reconstruction.A series of characterization methods are used to systematically explore the advantages of the group of M-COFs@S electrodes in the cycling process,including the effects of specific morphology on the kinetics and transformation of polysulfides.Our research provides a feasible plan for the development and selection of the host material of lithium-sulfur batteries.

First-principles study on the alkali chalcogenide secondary compounds in Cu(In,Ga)Se_2 and Cu_2ZnSn(S,Se)_4 thin film solar cells

The beneficial effect of the alkali metals such as Na and K on the Cu（In.Ga）Se2 （CIGS） and Cu2ZnSn（S,Se）4 （CZTSSe） solar cells has been extensively investigated in the past two decades, however, in most of the studies the alkali metals were treated as dopants. Several recent studies have showed that the alkali metals may not only act as dopants but also form secondary phases in the absorber layer or on the surfaces of the films. Using the first-principles calculations, we screened out the most probable secondary phases of Na and K in CIGS and CZTSSe, and studied their electronic structures and optical properties. We found that all these alkali chalcogenide compounds have larger band gaps and lower VBM levels than CIGS and CZTSSe, because the existence of strong p-d coupling in CIS and CZTS pushes the valence band maximum （VBM） level up and reduces the band-gaps, while there is no such p-d coupling in these alkali chalcogenides. This band alignment repels the photo-generated holes from the secondary phases and prevents the electron-hole recombination. Moreover, the study on the optical properties of the secondary phases showed that the absorption coefficients of these alkali chalcogenides are much lower than those of CIGS and CZTSSe in the energy range of 0-3.4eV, which means that the alkali chalcogenides may not influence the absorption of solar light. Since the alkali metal dopants can passivate the grain boundaries and increase the hole carrier concentration, and meanwhile their related secondary phases have innocuous effect on the optical absorption and band alignment, we can understand why the alkali metal dopants can improve the CIGS and CZTSSe solar cell performance.

Effect of substrate temperature and oxygen plasma treatment on the properties of magnetron-sputtered CdS for solar cell applications

Cadmium sulfide(CdS)is an n-type semiconductor with excellent electrical conductivity that is widely used as an electron transport material(ETM)in solar cells.At present,numerous methods for preparing CdS thin films have emerged,among which magnetron sputtering(MS)is one of the most commonly used vacuum techniques.For this type of technique,the substrate temperature is one of the key deposition parameters that affects the interfacial properties between the target film and substrate,determining the specific growth habits of the films.Herein,the effect of substrate temperature on the microstructure and electrical properties of magnetron-sputtered CdS(MS-CdS)films was studied and applied for the first time in hydrothermally deposited antimony selenosulfide(Sb_(2)(S,Se)_(3))solar cells.Adjusting the substrate temperature not only results in the design of the flat and dense film with enhanced crystallinity but also leads to the formation of an energy level arrangement with a Sb_(2)(S,Se)_(3)layer that is more favorable for electron transfer.In addition,we developed an oxygen plasma treatment for CdS,reducing the parasitic absorption of the device and resulting in an increase in the short-circuit current density of the solar cell.This study demonstrates the feasibility of MS-CdS in the fabrication of hydrothermal Sb_(2)(S,Se)_(3)solar cells and provides interface optimization strategies to improve device performance.

The fabrication of ideal diamond disk(IDD)by casting diamond film on silicon wafer

With the relentless densification of interconnected circuitry dictated by Moore’ s Law,the CMP manufacture of such delicate wafers requires the significant reduction of polishing pressure of integrated circuits,not only globally,but also locally on every tip of the pad asperities.Conventional diamond disks used for dressing the polyurethane pads cannot produce asperities to achieve such uniformity.A new design of diamond disk was fabricated by casting diamond film on a silicon wafer that contains patterned etching pits. This silicon mold was subsequently removed by dissolution in a hydroxide solution.The diamond film followed the profile of the etching pits on silicon to form pyramids of identical in size and shape.The variation of their tip heights was in microns of single digit that was about one order of magnitude smaller than conventional diamond disks for CMP production.Moreover,the diamond film contained no metal that might contaminate the circuits on polished wafer during a CMP operation.The continuous diamond film could resist any corrosive attack by slurry of acid or base.Consequently,in-situ dressing during CMP is possible that may improve wafer uniformity and production throughput.This ideal diamond disk(IDD) is designed for the future manufacture of advanced semiconductor chips with node sizes of 32 nm or smaller.

Polymer-free electrospun separator film comprising silica nanofibers and alumina nanoparticles for Li-ion full cell

A separator film for high-performance Li-ion batteries was prepared by electrospinning. The film had a hybrid morphology of silica nanofibers(SNFs) and alumina nanoparticles(ANPs), with a smooth surface, polymer-free composition, high porosity(79%), high electrolyte uptake(876%), and excellent thermal stability. Contact angle measurements demonstrated the better immersion capability of the SNF-ANP separator film for commercial liquid electrolytes than a commercial CELGARD 2500 separator film. Moreover,compared to the commercial CELGARD 2500 separator, the ionic conductivity of the SNF-ANP separator film was nearly three times higher, the bulk resistance was lower at elevated temperature(120 ℃), the interfacial resistance with lithium metal was lower, and the electrochemical window was wider. Full cells were fabricated to determine the cell performance at room temperature. The specific capacity of the full cell with the SNF-ANP separator film was 165 mAh g-1;the cell was stable for 100 charge/discharge cycles and exhibited a capacity retention of 99.9%. Notably, the electrospun SNF-ANP separator film can be safely used in Li-ion or Li-S rechargeable batteries.

Multi-dimensional hybrid flexible films promote uniform lithium deposition and mitigate volume change as lithium metal anodes

Lithium metal is the ultimate anode material for next-generation high-energy batteries.Yet,the practical application of lithium metal anodes is limited by the formation of Li dendrites and large volume changes.Herein,an effective multi-dimensional hybrid flexible film(MD-HFF)composed of iodine ion(0 dimension),CNTs(1 dimension)and graphene(2 dimensions)is designed for regulating Li deposition and mitigating volume changes.The multi-dimensional components serve separate roles:(1)iodine ion enhances the conductivity of the electrode and provides lithiophilic sites,(2)CNTs strengthen interlaminar conductance and mechanical strength,acting as a spring in the layered structure to alleviate volume changes during Li plating and stripping and(3)graphene provides mechanical flexibility and electrical conductivity.The resulting MD-HFF material supports stable Li plating/stripping and high Coulombic efficiency(99%)over 230 cycles at 1 mA cm^(-2) with a deposition capacity of 1 mAh cm^(-2).Theoretical calculations indicate that LiI contributes to the lateral growth of Li on the MD-HFF surface,thereby inhibiting the formation of Li dendrites.When paired with a typical NCM811 cathode,the assembled MD-HFF‖NCM811 cell exhibit improved capability and stable cycling performance.This research serves to guide material design in achieving Li anode materials that do not suffer from dendrite formation and volume changes.

Thin Film Evolution Equation for a Strained Anisotropic Solid Film on a Deformable Isotropic Substrate

We consider a continuum model for the evolution of an epitaxially-strained dislocation-free anisotropic thin solid film on isotropic deformable substrate in the absence of vapor deposition. By using a thin film approximation we derived a nonlinear evolution equation. We examined the nonlinear evolution equation and found that there is a critical film thickness below which every film thickness is stable and a critical wave number above which every film thickness is stable.

Nanocrystalline CuO Thin Films for H₂S Monitoring: Microstructural and Optoelectronic Characterization

Nanocrystalline copper oxide (CuO) thin films were deposited onto glass substrates by a spin coating technique using an aqueous solution of copper acetate. These films were characterized for their structural, mor-phological, optoelectronic properties by means of X-ray diffraction (XRD) scanning electron microscopy (SEM), UVspectroscopy and four probe method. The CuO films are oriented along (1 1 1) plane with the monoclinic crystal structure. These films were utilized in H2S sensors. The dependence of the H2S response on the operating temperature, H2S concentration of CuO film (annealed at 700。C) was investigated. The CuO film showed selectivity for H2S. The maximum H2S response of 25.2 % for the CuO film at gas concentra-tion of 100 ppm at operating temperature 200oC was achieved.

Translation of Film Titles with the Application of Peter Newmark＇s Translation Theory

This paper, based on the Chinese audience＇s aesthetic and cultural anticipation and the application of Peter Newmark＇s translation theory on translating film rifles, discusses the features and translation of film title from English to Chinese. The four main translation methods--literal translation, transliteration, free translation, semantic translation and/or communicative translation and the different translation strategies of film titles used in Hong Kong and Taiwan are introduced in detail with sufficient examples.

Globalization of China’s film industry through “telling China’s stories”

As is known to all,the globalization of China’s film industry plays as one important means in enhancing China’s national image and international voice.During the process of exporting externally,there exist some problems in its content production and marketing system.However,due to the"Belt and Road",the present film industry has ushered in new opportunities.In the essay,according to the author,only with strategies of ecological marketing in global market,China’s film industry could strengthen China’s cultural confidence through telling China’s stories,as so to shape China’s national image in the world.

Structural and Thermomechanical Study of Plastic Films Made from Cassava-Starch Reinforced with Kaolin and Metakaolin

The structural and thermomechanical properties of starch-based plastic films reinforced with kaolin and metakaolin have been studied by various techniques (X-ray diffraction, IR-TF spectroscopy, scanning electron microscopy, tensile tests, and thermal resistance). The results obtained showed that kaolin, an inert material, prevents the starch from losing its granular structure and to solubilize during the heating, generating plastic films of low Young’s modulus (7 MPa). On the other hand, metakaolin, an amorphous and dehydroxylated material obtained after heating of kaolin at 700°C for 1 hour, substantially improves the thermomechanical properties of the plastic films. The Young’s modulus increases from 19 MPa to 25 MPa while the thermal resistance increases from 90°C to 120°C. This was attributed to good dispersion of the metakaolin in the polymer matrix after the loss of the granular structure of the starch during heating.

Nickel Antimony Sulphide Thin Films for Solar Cell Application: Study of Optical Constants

Chemical bath deposition technique has been used to deposit Ni-doped Sb2S3 thin films onto glass substrate. Doping was carried out by adding 1, 3 and 5 wt% of Ni. Bath temperature was kept as 10℃ and films were annealed at 250℃ under vacuum. Polycrystalline nature of films with an orthorhombic phase was analyzed by X-ray diffraction technique. Scanning electron microscopy was used for morphological study which shows that grains are spherical. Optical measurements using transmittance data indicated that films have a direct band gap of 1.00 - 2.60 eV with an absorption coefficient of ~104 cm-1 in visible range. The average value of electrical conductivity was calculated as 1.66, 1.11 and 1.06 (Ω·cm)-1 for as-deposited films and 1.90, 2.08 and 1.15 (Ω·cm)-1 for annealed films while refractive indices were found as 2.18 - 3.38 and 1.91 - 3.74 respectively. The obtained films can be used for solar cell applications due to their good absorbing properties like higher absorption coefficient and refractive index values.

Numerical Analysis on the Effect of n-Si on Cu(In, Ga)Se2 Based Thin-Films for High-Performance Solar Cells by 1D-SCAPS

We report the performances of a chalcopyrite Cu(In, Ga)Se2 CIGS-based thin-film solar cell with a newly employed high conductive n-Si layer. The data analysis was performed with the help of the 1D-Solar Cell Capacitance Simulator (1D-SCAPS) software program. The new device structure is based on the CIGS layer as the absorber layer, n-Si as the high conductive layer, i-In2S3, and i-ZnO as the buffer and window layers, respectively. The optimum CIGS bandgap was determined first and used to simulate and analyze the cell performance throughout the experiment. This analysis revealed that the absorber layer’s optimum bandgap value has to be 1.4 eV to achieve maximum efficiency of 22.57%. Subsequently, output solar cell parameters were analyzed as a function of CIGS layer thickness, defect density, and the operating temperature with an optimized n-Si layer. The newly modeled device has a p-CIGS/n-Si/In2S3/Al-ZnO structure. The main objective was to improve the overall cell performance while optimizing the thickness of absorber layers, defect density, bandgap, and operating temperature with the newly employed optimized n-Si layer. The increase of absorber layer thickness from 0.2 - 2 µm showed an upward trend in the cell’s performance, while the increase of defect density and operating temperature showed a downward trend in solar cell performance. This study illustrates that the proposed cell structure shows higher cell performances and can be fabricated on the lab-scale and industrial levels.

Selling Chinese Films Abroad

THE story of Wudang swordsman Li Mubai is one that resonated with moviegoers across the globe. The thrilling martial arts sequences, sumptuous costumes and sweeping musical score of Ang Lee＇s four-time Academy Award-winning Crouching Tiger, Hidden Dragon （2000） ensured its position as one of the greatest non-Hollywood films of the new millennium and the highest-grossing foreign language film in Hollywood history.

Liu Yi’s Adventure in Wonderland(Cantonese Opera Film)

粤港澳大湾区具有同根同源的湾区文化基因。其中,风靡海内外的粤剧,不仅是大湾区共同的文化瑰宝,更是联结粤港澳大湾区人民情感和共同文化记忆的'乡音'。2018年上映的粤剧电影《柳毅奇缘》由国家一级编剧、著名影视导演邓原和广东省电影家协会会员、优秀青年导演潘钧联合执导,国家一级演员、中国戏剧梅花奖、文华表演奖获得者丁凡、曾小敏领衔主演。《柳毅奇缘》把粤剧和电影碰撞在一起,用电影的手段展示粤剧这种优秀传统文化.