Synthesis and antibacterial activity of new layered perovskite compounds,Ag_xNa_(2-x)La_2Ti_3O_(10)

Three kinds of new layered perovskite compounds with Ruddlesden-Popper （R-P） phase, AgrNa2-xLa2Ti3O10 （x = 0.2, 0.3 and 0.5）, were synthesized by an ion-exchange reaction of Na2La2Ti3O10 with AgNO3 solution. The structures of the compounds were characterized by EDX and XRD, and their antibacterial activity and light-resistance property were evaluated. The results indicated that the molecular formula of AgxNa2-xLa2Ti3O10 （x = 0.2, 0.3 and 0.5） was confirmed, and that the crystalline structure of Na2La2Ti3O10 was not obviously affected by exchange of silver ion. The minimum inhibitory concentrations （MICs） of Ag0.3Na1.7La2Ti3O10 against Escherichia coli （E. coli）, Staphylococcus aureus （S. aureus） were 180 μg/mL and 240 μg/mL, respectively, while its discoloration was not observed after 24 h light ageing test.

Structure and antibacterial activity of new layered perovskite compounds

New layered perovskite compounds, AgxNa2-xLa2Ti3O10 (x=0.2, 0.3 and 0.5) were synthesized by an ion-exchange reaction of Na2La2Ti3O10 with AgNO3 solution and characterized by energy dispersive X-ray analysis(EDX), X-ray diffractometry(XRD), scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy(XPS). The ion-exchange processes were optimized, and the antibacterial activity, light permanency and water-resistance were evaluated. Surprisedly, no significant changes in crystal structure of Na2La2Ti3O10 are found by the exchange of silver ions. The Ag0.3Na1.7La2Ti3O10 particles conglomerate obviously with irregular shape and size. Ag0.3Na1.7La2Ti3O10, possessing the minimum inhibitory concentrations(MICs) against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) of 180 mg/L and 240 mg/L, has high antibacterial activity, good light permanency and water-resistance. The ionic state silver in AgxNa2-xLa2Ti3O10 is the antibacterial active component.

Quantum Size Effect of the Magnetism of an Electron in a Metal Layer of the Layered Compounds M/I/M/I…

The energies and the magnetization of an electron in a piece of metal in the structure of Metal/Insulator/Metal/Insulator… (M/I/M/I…), in a magnetic field, at high temperature, and in range of quantum size thickness of the piece of metal layer have been obtained. The results show that when the thickness of the metal layer becomes smaller, the orbital magnetism of the charged particles which collide with the wall of the metal layer is to vary from diamagnetism to paramagnetism. The smaller the thickness of the metal layer becomes, the more particles will collide with the boundary of the metal layer, and then the paramagnetism becomes stronger. Finally, when the thickness of the metal layer becomes very small (<100 nm), all of the orbital diamagnetism will reverse to paramagnetism, and then the paramagnetization will be almost a maximum constant.

Vertical Evolution of Boundary Layer Volatile Organic Compounds in Summer over the North China Plain and the Differences with Winter

The vertical observation of volatile organic compounds(VOCs)is an important means to clarify the mechanisms of ozone formation.To explore the vertical evolution of VOCs in summer,a field campaign using a tethered balloon during summer photochemical pollution was conducted in Shijiazhuang from 8 June to 3 July 2019.A total of 192 samples were collected,23 vertical profiles were obtained,and the concentrations of 87 VOCs were measured.The range of the total VOC concentration was 41-48 ppbv below 600 m.It then slightly increased above 600 m,and rose to 58±52 ppbv at 1000 m.The proportion of alkanes increased with height,while the proportions of alkenes,halohydrocarbons and acetylene decreased.The proportion of aromatics remained almost unchanged.A comparison with the results of a winter field campaign during 8-16 January 2019 showed that the concentrations of all VOCs in winter except for halohydrocarbons were more than twice those in summer.Alkanes accounted for the same proportion in winter and summer.Alkenes,aromatics,and acetylene accounted for higher proportions in winter,while halohydrocarbons accounted for a higher proportion in summer.There were five VOC sources in the vertical direction.The proportions of gasoline vehicular emissions+industrial sources and coal burning were higher in winter.The proportions of biogenic sources+long-range transport,solvent usage,and diesel vehicular emissions were higher in summer.From the surface to 1000 m,the proportion of gasoline vehicular emissions+industrial sources gradually increased.

Preparation and Characterization of Layered Compound Zirconium Bis(monohydrogenphosphate) Intercalated with Rare Earth Complex

Layered compound zirconium bis(monohydrogenphosphate)(alpha-ZrP) intercalated with rare earth complex Eu(DBM)(3)phen was prepared. The pre-intercalation of p-methoxyaniline into alpha-ZrP makes the interlayer separation large enough to exchange PMA with europium complex, thus, the luminescent assembly was prepared. This was confirmed by X-ray diffraction, UV-visible spectra and elemental analysis. The fluorescence spectra and lifetime of the assembly were also presented.

STUDIES OF FAR-INFRARED SPECTRA AND SOLID-SOLID PHASE TRANSITION IN [n-C_n H_(2n+1) NH_3]_2 CuX_4 LAYER COMPOUNDS WITH n=7-12,16

Far-infraraed spoctra of the title compounds (adr.CnCuX) have been studied. Empirical assignments of the main badns have been made. The solid- solid phase transition at Tp=38℃ in CaCuCL compound has been investigated by the far-infrared spectra with variation of temperatures. It is found that the solid-solid phase transition of this compound waw accompanied by the distortion disorder of the MCL52- octahedra.

CMC d-p π Bond in Solid State(Ⅱ) Band Structure and Metallic Properties in Incommensurate Misfit Layer Compounds(MS)_xTS_2(M=Sn, Pb and La; T=V,Nb,Ta and Cr)

In this paper, we present Continuous Multiple Center(CMC) d-p πbond in TS_2 slabs on the basis of Extended Huckle calculation for incommensurate misfit compounds (MS)_xTS_2(where M=Pb, Sn and La; T=V,Nb,Ta, Cr), and put forwards the trigonal prismatic coordination CMC d-p π conductive model. According to this model the conductivity of (MS)_xTS_2 series and the similarity between (MS)_xTS_2 and Na_xTS_2 series compounds in metallic behaviors can be explained successfully. Some relations between metallic behaviors and CMC d-p π bond (or band) are found.

Synthesis and Crystal Structure of a Novel Compound:[Nd_3(OH)_7(O_2CC_6H_4SO_3)(H_2O)]_n·nH_2O with a Pillar-layered Structure

A novel Nd（Ⅲ） compound,[Nd3（OH）7（O2CC6H4SO3）（H2O）]n·nH2O 1,has been synthesized by the hydrothermal reaction of Nd2O3 and 3-sulfobenzoic acid monosodium salt. It was characterized by IR spectroscopy,elemental analysis,thermogravimetric analysis and single-crystal X-ray diffraction. It crystallizes in monoclinic,space group P21/c with a = 13.024（3）,b = 10.961（2）,c = 12.792（3） ,β = 91.271（3）°,V = 1825.6（7） 3,Z = 4,Mr = 787.97,Dc = 2.867 g/cm3,μ = 8.584 mm-1,F（000） = 1460,S = 1.035,R = 0.0442 and wR = 0.1166 （I 〉 2σ（I））. In this compound,the cross-linkage of Nd atoms by bridging hydroxy groups results in a Nd-O inorganic 〈200〉 layer,and such layers are linked by the 3-O3S-C6H4-CO2 dianions into a pillar-layered structure. The lattice water molecules are located in the cavity.

Direct Process to Prepare Crystallized Freestanding Membranes of Hydroxyapatite Using Sacrificial Layer of Barium-Compounds

Freestanding membrane (FSM) of hydroxyapatite (HA) is a thin sheet of pure HA without any supporting substrates. Our original preparation process of FSM of HA had three steps: The first was the deposition of HA layer on sacrificial layer of solvent-soluble materials, the second was separation of FSM of HA by means of dissolution of sacrificial layer, and the third was post-annealing to crystallize FSM of HA. To date, the post-annealing process was a serious bottleneck of productivity owing to its too long time. In this short report, we proposed a novel sacrificial layer, heatproof and water-soluble Ba-compound, which makes the direct deposition of crystallized HA possible due to its heatproof property because the problem on the original process was that the previous sacrificial layers have no heatproof property and HA layer should be deposited as amorphous. We can deposit the Ba-compound sacrificial layer only in 1 hour followed with the direct deposition of crystallized HA layer, substituting the 20 hours of post-annealing. The FSM of HA was separated successfully from the substrate by means of dissolution of Ba-compound with water. Our novel process can shrink the process time by 19 hours.

In Situ Synthesis of Titanium Nickel Intermetallic Compounds Layer and TiN Coating By Laser Cladding

Laser cladding,together with laser nitriding was used to synthesize a titanium nickel intermetallic compound layer on the nickel substrate and a TiN coating on the cladding layer. During the laser cladding, Ti and Ni powders were blown into the melting pool by a six-hole coaxial nozzle powder injection system. Exothermic reactions between Ti and Ni took place in the melting pool, and a cladding layer of titanium nickel intermetallic compounds was produced. Laser nitriding in a nitrogen-rich atmosphere followed the production of the cladding layer, and formed a golden yellow TiN layer over it. An optical and a scanning electron microscope were used to investigate the microstructures and measure the thicknesses of the cladding layer and the TiN layer. Phase identification was carried out by XRD. For the nitriding sample, the microhardness profile of the clad layer was tested. The optimal process parameters of the in situ synthesis of titanium nickel intermetallic compounds were obtained.

Growth kinetics for intermetallic compound layer between molten In-Sn alloy and CuZr-based bulk metallic glass

The growth kinetics of intermetallic compound layer between molten In-Sn alloy and Cu40Zr44Al8Ag8 bulk metallic glass substrate was examined by solid state isothermal aging at the temperature range between 333 and 393 K.The aged samples were characterized by scanning electron microscopy and energy dispersive spectrometry.It is found that the intermetallic compound layer is composed of Zr,Cu and Sn.The layer growth of the intermetallic compound is mainly controlled by a diffusion mechanism over the temperature range and the value of the time exponent is approximately 0.5.The apparent activation energy for the growth of total intermetallic compound layers is 98.35 kJ /mol calculated by the Arrhenius equation.

Preparation,Characterization and Application of ZnAlLa-Hydrotalcite-Like Compounds

The preparation of ZnAlLa-hydrotalcite-like compounds [ZnAlLa-HTLcs] wasstudied. ZnAlLa-HTLcs were synthesized by a method of variable pH with the raw materials ofZn(NO_3)_2, Al(NO_3)_3, La(NO_3)_3, and NaOH. The eS'ccts of some factors (i.e. pH values, the moleratio of Al^(3+) to La^(3+), temperature and the period of hydrothermal treatment) on thepreparation of HTLcs were discussed systematically. XRD, TG-DTA, FT-IR spectroscopy, and ICP wereperformed to characterize ZnAlLa-HTLcs samples, and the thermal stability of HTLcs was alsodiscussed. It was shown that unique ZnAlLa-HTLcs with high crystallinity can be prepared, under theconditions of pH = 5.5-6.5, n(Zn^(2+))/n(Al^(3+) + La^(3+))=2 and the atomic ratio of La^(3+) toAl^(3+) ranging from 0.07 to 2, hydrothermal treatment at 120 ℃ for 5 h. When the calcination ofthe HTLcs is performed at temperatures above 200 ℃, ZnO phase is detected with Al_2O_3 and La_2O_3spreading on its top. The complex metal oxides derived from ZnAlLa-HTLcs at 500 ℃ have highercatalytic activity and selectivity than those from ZnAl-HTLcs for the esterification of acetic acidwith n-butanol under the same reaction conditions.

Recent advance on VOCs oxidation over layered double hydroxides derived mixed metal oxides

Catalytic oxidation is regarded as one of the most promising strategies for volatile organic compounds(VOCs)purification.Mixed metal oxides(MMOs),after topological transformation using layered double hydroxides(LDHs)as precursors,are extensively used as catalysts for VOCs oxidation due to their uniformity advantage.This review summarizes the developments in the LDH-derived VOCs heterogeneous catalytic oxidation over the last 10 years.Particularly,it addresses the VOCs abatement performance over MMO,noble metal/MMO,core-shell structured MMO,and integral MMO film catalysts originating from LDHs.Moreover,it highlights the water vapor effect and oxidation mechanism.This review indicates that LDH-based catalysts are a category of important VOCs oxidation materials.

Corrosion resistance of Mg-Al-LDH steam coating on AZ80 Mg alloy:Effects of citric acid pretreatment and intermetallic compounds

In this study,the effects of intermetallic compounds(Mg_(17)Al_(12)and Al_(8)Mn_(5))on the Mg-Al layered double hydroxide(LDH)formation mechanism and corrosion behavior of an in-situ LDH/Mg(OH)_(2)steam coatings on AZ80 Mg alloy were investigated.Citric acid(CA)was used to activate the alloy surface during the pretreatment process.The alloy was first pretreated with CA and then subjected to a hydrothermal process using ultrapure water to produce Mg-Al-LDH/Mg(OH)_(2)steam coating.The effect of different time of acid pretreatment on the activation of the intermetallic compounds was investigated.The microstructure and elemental composition of the obtained coatings were analyzed using FE-SEM,EDS,XRD and FT-IR.The corrosion resistance of the coated samples was evaluated using different techniques,i.e.,potentiodynamic polarization(PDP),electrochemical impedance spectrum(EIS)and hydrogen evolution test.The results indicated that the CA pretreatment significantly influenced the activity of the alloy surface by exposing the intermetallic compounds.The surface area fraction of Mg_(17)Al_(12)and Al_(8)Mn_(5)phases on the surface of the alloy was significantly higher after the CA pretreatment,and thus promoted the growth of the subsequent Mg-Al-LDH coatings.The CA pretreatment for 30 s resulted in a denser and thicker LDH coating.Increase in the CA pretreatment time significantly led to the improvement in corrosion resistance of the coated AZ80 alloy.The corrosion current density of the coated alloy was lower by three orders of magnitude as compared to the uncoated alloy.

Retraction:Intercalation of Amines into Layered Calcium Phosphate and Their New Behavior for Copper Retention from Ethanolic Solution

The following article has been retracted due to the investigation of complaints received against it. The Editorial Board found that substantial portions of the text came from other published papers. Unethical behavior such as self-plagiarism and misuse of published figures and data without copyright consent will be treated very seriously. The scientific community takes a very strong view on this matter, and the OJSTA treats all unethical behavior such as plagiarism seriously. This paper published in Vol.2 No. 1,1-7, 2013, has been removed from this site.

In Situ Synthesis of Nanocrystalline Intermetallic Compound Layer during Surface Mechanical Attrition Treatment of Zirconium

The surface mechanical attrition treatment (SMAT) technique was developed to synthesize a nanocrystalline (NC) layer on the surface of metallic materials for upgrading their overall properties and performance. In this paper, by means of SMAT to a pure zirconium plate at the room temperature, repetitive multidirectional peening of steel shots (composition (wt%): 1C, l.SCr, base Fe) severely deformed the surface layer. A NC surface layer consisting of the intermetallic compound FeCr was fabricated on the surface of the zirconium. The microstructure characterization of the surface layer was performed by using X-ray diffraction analysis, optical microscopy, scanning and transmission electron microscopy observations. The NC surface layer was about 25 urn thick and consisted of the intermetallic compound FeCr with an average grain size of 25±10 nm. The deformation-induced fast diffusion of Fe and Cr from the steel shots into Zr occurred during SMAT, leading to the formation of intermetallic compound. In addition, the NC surface layer exhibited an ultrahigh nanohardness of 10.2 GPa.

Low contact resistivity between Ni/Au and p-GaN through thin heavily Mg-doped p-GaN and p-InGaN compound contact layer

Thin heavily Mg-doped InGaN and GaN compound contact layer is used to form Ni/Au Ohmic contact to p-GaN. The growth conditions of the compound contact layer and its effect on the performance of Ni/Au Ohmic contact to p-GaN are investigated. It is confirmed that the specific contact resistivity can be lowered nearly two orders by optimizing the growth conditions of compound contact layer. When the flow rate ratio between Mg and Ga gas sources of p＋＋-InGaN layer is 10.6% and the thickness of p＋＋-InGaN layer is 3 nm, the lowest specific contact resistivity of 3.98× 10-5 Ω cm2 is achieved. In addition, the experimental results indicate that the specific contact resistivity can be further lowered to 1.07 × 10-7Ω.cm2 by optimizing the alloying annealing temperature to 520 ℃.

Compound buried layer SOI high voltage device with a step buried oxide

A silicon-on-insulator （SOI） high performance lateral double-diffusion metal oxide semiconductor （LDMOS） on a compound buried layer （CBL） with a step buried oxide （SBO CBL SOI） is proposed. The step buried oxide locates holes in the top interface of the upper buried oxide （UBO） layer. Furthermore, holes with high density are collected in the interface between the polysilicon layer and the lower buried oxide （LBO） layer. Consequently, the electric fields in both the thin LBO and the thick UBO are enhanced by these holes, leading to an improved breakdown voltage. The breakdown voltage of the SBO CBL SOI LDMOS increases to 847 V from the 477 V of a conventional SOI with the same thicknesses of SOI layer and the buried oxide layer. Moreover, SBO CBL SOI can also reduce the self-heating effect.

Layered structure of Ni-Al multi-layered metal-intermetallic composites fabricated by in-situ reactions

Systematical experiments were done at five temperature levels: （500 ℃,） （630 ℃,） （900 ℃,） （1 000 ℃） and （1 100 ℃） to illuminate the layer structure of the multi-layered metal-intermetallic composites of Ni-Al system that were fabricated by a previously reported simple and cost-effective method. The analysis of back scattering photos and XRD examination of specimens reveal that the look like single compound layer is composed of several different components. The primary phase produced during reaction is Ni2Al3 and there exists a like two-phase field between NiAl3 and Ni2Al3. The high temperature phases like NiAl and Ni3Al are also found at low temperature. The results indicate that the key driving force of in-situ reaction is not temperature, but the atom concentration.

Synthesis and Characterization of Layered Co_2(OH)_3(CH_3COO)·H_2O

Layered hydroxide metal acetate Co2（OH）3（CH3COO）·H2O with an interlayer spacing of 1.282 nm has been synthesized by a novel method which is employed in ethanol-aqueous mixed solvents media. Experiment results show that the purity of the product by the modified method is higher compared with that by the previous methods. A complete characterization of the as-prepared samples was performed by means of X-ray powder diffraction, IR spectroscopy, scanning electron microscope, as well as magnetic measurement. The facile and effective approach for the preparation of this compound in this study is very interesting and important because it has wide application in the field of anionic exchange reaction for the synthesis of hybrid organic-inorganic compounds.