Ultrafine ordered L1_(2)-Pt-Co-Mn ternary intermetallic nanoparticles as high-performance oxygen-reduction electrocatalysts for practical fuel cells

The long-range periodically ordered atomic structures in intermetallic nanoparticles(INPs)can significantly enhance both the electrocatalytic activity and electrochemical stability toward the oxygen reduction reaction(ORR)compared to the disordered atomic structures in ordinary solid-solution alloy NPs.Accordingly,through a facile and scalable synthetic method,a series of carbon-supported ultrafine Pt_3Co_(x)Mn_(1-x)ternary INPs are prepared in this work,which possess the"skin-like"ultrathin Pt shells,the ordered L1_(2) atomic structure,and the high-even dispersion on supports(L1_(2)-Pt_3Co_(x)Mn_(1-x)/~SPt INPs/C).Electrochemical results present that the composition-optimized L1_(2)-Pt_3Co_(0.7)Mn_(0.3)/~SPt INPs/C exhibits the highest electrocata lytic activity among the series,which are also much better than those of the pristine ultrafine Pt/C.Besides,it also has a greatly enhanced electrochemical stability.In addition,the effects of annealing temperature and time are further investigated.More importantly,such superior ORR electrocatalytic performance of L1_(2)-Pt_3Co_(0.7)Mn_(0.3)/~SPt INPs/C are also well demonstrated in practical fuel cells.Physicochemical characterization analyses further reveal the major origins of the greatly enhanced ORR electrocata lytic performance:the Pt-Co-Mn alloy-induced geometric and ligand effects as well as the extremely high L1_(2) atomic-ordering degree.This work not only successfully develops a highly active and stable ordered ternary intermetallic ORR electrocatalyst,but also elucidates the corresponding"structure-function"relationship,which can be further applied in designing other intermetallic(electro)catalysts.

Expression,Purification and Activity Detection of VP1 of A-type FMDV

[Objective] The research aimed to induce the expression of FMDV structural protein VP1 in E.coli and purify the protein,then detect the activity.[Method] The fragment coding VP1 was amplified by PCR and doubly digested with BamH Ⅰ and XhoⅠ,then cloned into expression vector pGEX-4T-1 and pPROExHTb respectively to get recombinant plasmid pGEX-4T-1-VP1 and pPROExHTb-VP1.The recombinant plasmid pGEX-4T-1-VP1 and pPROExHTb-VP1 was transformed into E.coli BL21(DE3)and induced by IPTG,fusion protein was identifie...

OXIDATIVE COUPLING OF METHANE OVER Sr_2TiO_4 WITH K_2NiF_4 STRUCTURE^1

Some K_2NiF_4-type oxides(A_2BO_4) exhibited good catalytic activity for oxidative coupling of methane to form ethane and ethylene. The C_2 selectivity was well correlated with A-site ion when B-site was Ti^(4+) ion.

A New Luminescent Cd(Ⅱ) Coordination Polymer Constructed by Mixed 1,4-Naphthalenedicarboxylate and N-donor Chelating Ligand

In this work, we synthesized a new two-dimensional Cd（Ⅱ） coordination polymer, [Cd（1,4-NDC）（L）]（1）, by using mixed 1,4-naphthalenedicarboxylic acid（1,4-H2NDC） and typical chelating N-donor ligands 2-（2-chloro-6-fluorophenyl）-1H-imidazo[4,5-f][1,10]phenanthroline ligand（L）. Compound 1 crystallizes in monoclinic, space group P21/n with a = 12.936（5）, b = 15.245（5）, c = 13.499（5） ？, β = 105.456（5）o, V = 2565.9（16） A^3, Z = 4, C（31）H（16）CdClFN4O4, Mr = 675.33, Dc = 1.748 g/cm^3, F（000） = 1344, μ（MoKa） = 1.011 mm^-1, R = 0.0350 and wR = 0.0926. In 1, each 1,4-NDC anion bridges three adjacent Cd（Ⅱ） atoms to give a two-dimensional layer structure. The L ligands are attached on both sides of the layer in chelating coordination modes. In addition, the N–H···O hydrogen bond between L and 1,4-NDC further stabilizes the layer structure of 1. Moreover, the solid state luminescent property of 1 was also investigated at room temperature.

Numerical simulation of a triple-junction thin-film solar cell based on μc-Si_(1-x)Ge_x :H

In this paper, a-Si：H/a-SiGe：H/μc-SiGe：H triple-junction solar cell structure is proposed. By the analyses of mi- croelectronic and photonic structures （AMPS-1D） and our TRJ-F/TRJ-M/TRJ-B tunneling-recombination junction （TRJ） model, the most preferably combined bandgap for this structure is found to be 1.85 eV/1.50 eV/1.0 eV. Using more realistic material properties, optimized thickness combination is investigated. Along this direction, a-Si：H/a-SiGe：H/μc-SiGe：H triple cell with an initial efficiency of 12.09% （Voc = 2.03 V, FF = 0.69, Jsc = 8.63 mA/cm^2, area = 1 cm^2） is achieved in our laboratory.

Syntheses and Crystal Structures of Two New Complexes Generated from 2-（（Pyridin-3-ylmethyl）thio）-5-（6-quinolinyl）-1,3,4-oxadiazole and Ag~Ⅰ Salts

Two new Ag~Ⅰ-complexes have been synthesized based on the semi-rigid ligand 2-（（pyridin-3-ylmethyl）thio）-5-（6-quinolinyl）-1,3,4-oxadiazole（L）,obtained by the condensation reaction of 5-（6-quinolinyl）-1,3,4-oxadiazole-2-thiol and 3-chloromethyl pyridine hydrochloride. Crystallization of L with Ag OTf and Ag PF_6 in a CH_2Cl_2/MeO H mixed solvent system at room temperature affords a novel supramolecular [Ag_2L_2（CF_3SO_3）_2]（I） and a coordination polymer [Ag L（PF_6）]_n（Ⅱ）,respectively. Two complexes were characterized by TGA,X-ray powder and single-crystal diffraction.

A New Organo-Directed Titanium Phosphate Phase Containing Zigzag Chains of Corner-Sharing TiO_6 Octahedra

A new organo-directed titanium phosphate, [NH3CH2CH2NH3]·[TiO(HPO4)2], was synthesized by the solvothermal method and its structure was determined by single crystal X-ray diffraction. The structure consists of 1-D zigzag chains built up from trans-corner-sharing titanium oxo octahedra running along the b axis, with fused Ti2P three-membered rings being attached to the ( Ti ( O ( Ti ( O ( backbone.

1-D P- and S-wave velocity models for the collision zone between the northern Tianshan mountain and the Junggar basin based on local earthquake data

We have developed crustal minimum I-D P- and S-wave velocity models of the collision zone between the northern Tianshan mountain and the Junggar basin （86°E-89°E, 43°N-44.5°N）. These two models were created through inversion of 1 370 P- and 1 396 S-wave travel times from 173 well-constrained local earthquakes recorded by the Uriimqi sparse local seismic network and temporary seismic arrays. In contrast to previous models, our results indicate relatively low velocity at both shallow （〈10 km） and deep （30-45 km） depths. The shallow zone is interpreted to be the result of thick surficial sedimentary deposits, whereas the deeper anomaly is interpreted to result from ductile shearing and lower crustal fow. Additionally, we detected several transition layers under the lower crust, which may imply structural complexity of the uppermost mantle in this region. The improved models reduce the RMS residual of earthquake locations by 41.7% from 1.2 to 0.5 seconds. The more accurately located hypocenters appear to correlate with prominent local over-thrusts, which underlie an anticlinal fold belt and several blind faults. Positive station corrections are observed near the Junggar basin, which likely reflects low wave velocity; negative corrections near the Tianshan mountain and Bogda mountain suggest high wave velocity.

Synthesis,Structure and Photoluminescence of a New Pb(Ⅱ)Coordination Polymer[Pb(1,4-chdc)(L)]n·nH2O Based on a Flexible 1,4-Cyclohexanedicarboxylic Acid

A new Pb（Ⅱ） coordination polymer, [Pb（1,4-chdc）（L）]_n·nH_2O（1）, was synthesized under hydrothermal condition（1,4-H2 chdc = 1,4-cyclohexanedicarboxylic acid and L = 2-（3-fluorophenyl）-1H-imidazo[4,5-f][1,10]phenanthroline）. Its crystal structure was determined by singlecrystal X-ray diffraction. Compound 1 crystallizes in triclinic, space group P1 with a = 9.1182（8）, b = 11.3249（10）, c = 12.7326（12） A, α = 77.897（2）, β = 81.644（2）, γ = 84.491（2）°, V = 1269.0（2） A^3, Z = 2, C_（27）H_（24）FN_4O_5Pb, M_r = 710.69, D_c = 1.860 g/cm^3, F（000） = 690, μ（MoKa） = 6.701 mm^（-1）, R = 0.0349 and wR = 0.0746. In 1, each 1,4-chdc anion bridges two neighboring Pb（Ⅱ） atoms in a bidentate chelating coordination mode to give a chain structure. The L ligands are attached on one side of the chain through chelating the Pb（Ⅱ） atoms, and are stacked with those of an adjacent chain through π-π interactions, yielding a layer structure. The O-H···O and N-H···O hydrogen bonding interactions further stabilize the supramolecular layer structure of 1. Moreover, solid state luminescent property of 1 was also studied.

Microstructure and magnetic properties of granularFePt/(FePt)_(27)Ti_(73) films for ultrahigh-density recording media

FePt granular films were prepared by direct current facing-target magnetron sputtering system onto glass substrates and subsequently in-situ annealed in vacuum. Vibrating sample magnetometer, X-ray diffraction and scanning probe microscope were applied to study the magnetic properties, microstructures, morphologies and domain structures of the samples. （FePt）27Ti73 bilayer films were fabricated at various conditions to investigate the effect of Ti on FePt grains. The results show that without Ti matrix layer, FePt films deposited onto the glass substrates are fcc disordered; with addition of Ti matrix layer, FePt/Ti films form a ternary （FePt）27Ti73 alloy possessing fcc and L10 （111） mixed texture. FePt/（FePt）27Ti73 films with perfectly ordered L10（111） structure and unique magnetic properties can be obtained at Ti thickness of 35nm and substrate temperature of 250℃. The maximum coercivity is more than 240kA/m and the squareness ratio is more than 0.9. The obtained results suggest that the granular FePt/（FePt）27Ti73 films can be applicable to ultrahigh-density magnetic recording media.

Synthesis,Crystal Structure and Properties of a Zinc(Ⅱ) Complex Based on 5-(1H-Tetrazol-5-yl)isophthalic Acid Ligand

A novel polymeric zinc（II） complex {[Zn2（TIA）（H2O）3]·（NO3）}n（1, H3TIA = 5-（1H-tetrazol-5-yl）isophthalic acid） has been synthesized in mixed solvents under solvothermal conditions and characterized by elemental analysis, IR spectroscopy and X-ray single-crystal diffraction. Complex 1 crystallizes in orthorhombic, space group Cmcm with a = 10.4210（6）, b =23.3526（14）, c = 6.9214（4）A, V = 1684.37（17）A^3, Z = 4, C9H4N5O（10）Zn2, Mr = 472.91, Dc = 1.865g/cm^3, F（000） = 932, λ（MoK α） = 2.909 mm^-1, R = 0.0423 and wR = 0.1287. The complex has good thermal stability and excellent photoluminescent property.

Syntheses,Crystal Structures and Photoluminescent Properties of Two New 1-D d^10 Metal Complexes Based on Tetrazole 1-Acetato Ligand

Two new tetrazole 1-acetato complexes, [Ag（1-tza）（phen）]∞ （1） and [Cd（1- tza）2（2,2＇-bipy）]∞ （2） （1-Htza = tetrazole 1-acetato, phen = 1,10-phenanthroline, 2,2＇-bipy = 2,2＇-bipyridine）, have been synthesized by solvothermal synthesis and structurally characterized by elemental analyses, IR spectra and single-crystal X-ray diffraction. Complex 1 shows a 1-D chained structure, while the structure of 2 contains two 1-D chains, which is the first 1-tza-based complex containing three different coordination modes of the 1-tza ligand. The aromatic stacking effects play an important role in the formation of supramolecular frameworks of these two complexes. Photoluminescent studies show that the two complexes exhibit efficient luminescence. In addition, optical diffuse reflectance spectra and thermogravimetric analyses of 1 and 2 have also been investigated.

The heterodimeric structure of heterogeneous nuclear ribonucleoprotein C1/C2 dictates 1,25-dihydroxyvitamin D-directed transcriptional events in osteoblasts

Heterogeneous nuclear ribonucleoprotein （hnRNP） C plays a key role in RNA processing but also exerts a dominant negative effect on responses to 1,25-dihydroxyvitamin D （1,25（OH）2D） by functioning as a vitamin D response element-binding protein （VDRE-BP）. hnRNPC acts a tetramer of hnRNPC1 （huC1） and hnRNPC2 （huC2）, and organization of these subunits is critical to in vivo nucleic acid-binding. Overexpression of either huC1 or huC2 in human osteoblasts is sufficient to confer VDRE-BP suppression of 1,25（OH）2D-mediated transcription. However, huC1 or huC2 alone did not suppress 1,25（OH）2D-induced transcription in mouse osteoblastic cells. By contrast, overexpression of huC1 and huC2 in combination or transfection with a bone-specific polycistronic vector using a ＂self-cleaving＂ 2A peptide to co-express huC1/C2 suppressed 1,25D-mediated induction of osteoblast target gene expression. Structural diversity of hnRNPC between human/NWPs and mouse/rat/rabbit/dog was investigated by analysis of sequence variations within the hnRNP CLZ domain. The predicted loss of distal helical function in hnRNPC from lower species provides an explanation for the altered interaction between huC1/C2 and their mouse counterparts. These data provide new evidence of a role for hnRNPC1/C2 in 1,25（OH）2D-driven gene expression, and further suggest that species-specific tetramerization is a crucial determinant of its actions as a regulator of VDR-directed transactivation.

Edge Structure of Reynolds Stress and Poloidal Flow on the HL-1M Tokamak

The measurement on radial profile of electrostatic Reynolds stress, plasma poloidal rotations, radial and poloidal electric field have been performed in the plasma boundary region of the HL-IM Tokamak using a multi-array of Mach/Langmuir probes. In the experiments of Lower Hybrid Current Drive (LHCD), Supersonic Molecular Beam injection (SMBI), Multi-shot Pellet Injection (MPI) and Neutral Beam injection (NBI), the correlation between the Reynolds stress and poloidal flow in the edge plasma is presented. The results indicate that a sheared poloidal flow can be generated in Tokamak plasma due to radially varying Reynolds stress.

Crystal Structure,Thermal Behavior and Luminescence of a New Dimeric Manganese(Ⅱ) Complex Constructed with 3-Carboxy-1-carboxymethyl-2-oxidopyridinium

A new dimeric Mn（Ⅱ） complex,namely,[Mn（L）（PIP）]_2·H_2O（1）,was synthesized under hydrothermal condition（H_2L = 3-carboxy-1-carboxymethyl-2-oxidopyridinium and PIP = 2-（pyridin-3-yl）-1H-imidazo[4,5-f][1,10]phenanthroline）.It crystallizes in triclinic,space group P1 with a = 9.2037（13）,b = 9.6794（13）,c = 14.649（3） A,α = 94.858（3）,β = 94.928（3）,γ = 114.468（2）o,V = 1172.9（3） A^3,Z = 1,C_（52）H_（34）Mn_2N_（12）O_（11）,Mr = 1112.79,Dc = 1.575 g/cm^3,F（000） = 568,μ（Mo Ka） = 0.618 mm^-1,R = 0.0432 and w R = 0.1151.In 1,two L anions bridge two Mn（Ⅱ） atoms to give a dimeric [Mn（L）（PIP）] unit with the Mn···Mn distance of 3.009（2） A.The two PIP ligands are located on both sides of the dimer,which provides suitable π-π stacking interactions between PIP ligands.By these π-π stacking interactions,adjacent dimers are extended into a two-dimensional supramolecular layer.Further,the strong N–H···O hydrogen bond stabilizes the supramolecular layer structure of 1.Moreover,the thermal behavior and luminescent property of 1 have been studied.

GGA+U study of the electronic energy bands and state density of the wurtzite In_(1-x)Ga_xN

The electronic band structures, densities of states （DOSs）, and projected densities of states （PDOSs） of the wurtzite In1-xGaxN with x=0, 0.0625, 0.125 are studied using the generalized-gradient approximation （GGA） and GGA＋U in density functional theory. Our calculations suggest that in the case of wurtzite InN it is important to apply an on-site Hubbard correction to both the d states of indium and the p states of nitrogen in order to recover the correct energy level symmetry and obtain a reliable description of the InN band structure. The method is used to study the electronic properties of the wurtzite In1-xGaxN. The conduction band minimum （CBM） energy increases, while the valence band maximum （VBM） energy decreases with the increase of the gallium concentration. The effect leads to broadening the band gap （BG） and the valence band width （VBW）. Furthermore, the compressive strain in the crystal can cause the BG and the VBW to increase with the increase of gallium concentrations.

Denoising Letter Images from Scanned Invoices Using Stacked Autoencoders

Invoice document digitization is crucial for efficient management in industries.The scanned invoice image is often noisy due to various reasons.This affects the OCR(optical character recognition)detection accuracy.In this paper,letter data obtained from images of invoices are denoised using a modified autoencoder based deep learning method.A stacked denoising autoencoder(SDAE)is implemented with two hidden layers each in encoder network and decoder network.In order to capture the most salient features of training samples,a undercomplete autoencoder is designed with non-linear encoder and decoder function.This autoencoder is regularized for denoising application using a combined loss function which considers both mean square error and binary cross entropy.A dataset consisting of 59,119 letter images,which contains both English alphabets(upper and lower case)and numbers(0 to 9)is prepared from many scanned invoices images and windows true type(.ttf)files,are used for training the neural network.Performance is analyzed in terms of Signal to Noise Ratio(SNR),Peak Signal to Noise Ratio(PSNR),Structural Similarity Index(SSIM)and Universal Image Quality Index(UQI)and compared with other filtering techniques like Nonlocal Means filter,Anisotropic diffusion filter,Gaussian filters and Mean filters.Denoising performance of proposed SDAE is compared with existing SDAE with single loss function in terms of SNR and PSNR values.Results show the superior performance of proposed SDAE method.

STRUCTURE OF 1-BROMOMETHYL-7, 7-DIMETHYLBICYCLO[2.2.1]HEPT-2-YL ACRYLATE AND THE PROPERTIES OF ITS POLYMER

In this paper, the structure of 1-bromomethyl-7,7-dimethyl btcyclo[2.2.1]hept-2-yl acrylate has been studied by X-ray diffraction, and the relation between the molecular structure and the properties of polymerization and its polymer have been discussed.

Preparation, Characterization and Crystal Structure Determination of (C_6H_(14)N)_5(V_5O_(15))

A 1D chain-like organic/inorganic composite material with polyoxovanadates serving as building blocks has been synthesized by the reaction of cyclohexylamine with vana- dium pentoxide, and characterized by IR, UV spectra and TG-DTA technique. The title compound (C30H70N5O15V5, Mr = 995.61) crystallizes in orthorhombic, space group P212121 with a = 6.0093(12), b = 26.780(5), c = 27.979(6) ? V = 4502.6(16) 3, Z = 4, Dc = 1.461 g/cm3, F(000) = 2060, = 1.063 mm-1, R = 0.0651 and wR = 0.1084 for 3426 observed reflections (I > 2(I)). Single-crystal X-ray structural analysis indicates that the title compound consists of five proto- nated cyclohexylamine molecules and a polyoxovanadate anion of V5O155-. In addition, the results of IR spectra and single-crystal X-ray diffraction exhibit that there exists comparatively stronger interaction between the organic groups and polyoxovanadate anion in solid state. Adjacent structure units are bridged through corner-sharing oxygen atoms of VO4 tetrahedra to construct a novel one-dimensional zigzag infinite linear chain arrangement. The curves of TG- DTA elucidate that the process of weight loss of the title compound is divided into two stages, and also reveal that the framework of polyoxovanadate anion decomposes at 473.0 ℃.

Hydrothermal Synthesis,Crystal Structure and Thermal Properties of a Novel Samarium Complex with 1D Nano-chain Structure

1 Introduction The design and construction of metal-organic polymers has been a field of rapid growth in materials chemistry because of their intriguing topologies and potential applications as functional materials. In this regard, every effort has been devoted to the deliberate design and control of self-assembly infinite coordination networks via selecting the chemistry structures of ligands, Multidentate carboxylate ligands are widely adopted for construction of coordination frameworks due to their rich coordination modes.