Some Topological Values of Supramolecular Chain of Different Complexes of N-Salicylidene-L-Valine

L-valine is a glycogen-type amino acid regarded among the necessary mammalian amino acids.This is an amino acid that is essential for protein synthesis.N-salicylidene-L-valine is gaining a lot of attention because of its unique structure and increased catalytic and cytotoxic activity.We explore the chain of supramolecular dialkyltin N-salicylidene-L-valine complexes 2,3,and 4 to learn more about this structure and its features regarding topological indices.We computed the first and second Randi′c index,harmonic index,sum-connectivity index,atom-bond-connectivity index,geometric arithmetic index and reduced reciprocal Randi′c index of Supramolecular Chain of Different Complexes of N-Salicylidene-L-Valine.Furthermore,we present an analysis of such structures using specific examples,as well as a comparison of topological indices.

Technology of black coloring for stainless steel by electrochemical method

The technology of black coloring for stainless steel by electrochemical method was studied. The optimum bath compositions and operating conditions were obtained as follows: 4050g/L K2Cr2O7 , 1520g/L MnSO4, 1520g/L （NH4）2SO4, 2040g/L H3BO3, 2030 g/L additive A, 2 g/L （NH4）6Mo7O 24 ; time 920 min; temperature 1530℃; potential 3V and current density 12mA/cm 2 . The effects of the compositions of the bath on the quality of black colored film were discussed. The influences of passivation process on the black coloring velocity and performances of black colored film layer were investigated. The results show that the passivation process can improve the corrosion resistance and the stability to bear color-change; （NH4）2SO4 can control the black coloring velocity and prolong black coloring bath life remarkably; and additive A can improve the evenness and compactness of black colored film layer. The results of scanning electron microscopy and energy dispersive spectra show that the microstructure is of cylindrical lump, the filling process can decrease the crackles, and the main elements of black colored film are Fe, Cr, Mn and Ni.

Process of electroless plating Cu-Sn-Zn ternary alloy

Cu-Sn-Zn ternary alloy layer with 10 μm thickness was prepared through electroless plating method. The influences of process conditions including the concentration of metallic salts, reductant and complex agent on Cu-Sn-Zn alloy were studied in details. The stability to bear color changes and corrosion resistance of Cu-Sn-Zn film layer were studied through air-exposure experiment and electrochemical analyses test respectively. The results show that the performances of Cu-Sn-Zn film layer are obviously superior to brass matrix. By use of SEM,EDS and XRD, the morphology, microstructure and chemical composition were investigated. The results show that complex agent can increase the content of Sn and Zn, improve the evenness and compactness and decrease needle holes, therefore the properties of electroless plating layer such as the stability to bear color changes and corrosion resistance are improved remarkably. The probable mechanism of complex agent was discussed.

Process of pulse electrodeposition nanocrystalline chromium from trivalent chromium bath

Nanocrystalline chromium coating was prepared by pulse electrodeposition from trivalent chromium bath containing carboxylate-urea as complexing agent. The effects of electrodeposition parameters such as current density,bath temperature and solution concentration on the thickness and electrodeposition velocity of Cr deposited films were investigated. The crystallographic structures,morphology and chemical composition of Cr deposited films were analyzed by means of XRD,SEM and EDS. The results indicate that the deposited films with thickness up to 11.2 μm possess a smooth and clean appearance,and the grain size is less than 100 nm. The coating is pure chromium and the Cr deposit has face-centered cubic(fcc) structure and exhibits a(210) growth preference. Both the electrodeposition velocity and thickness exist maximum under different concentration complex agents,ureas,acetates,different temperatures and current densities. Compared with direct current electrodeposition,the thicker coating and finer grains can be obtained at lower temperature and current density by pulse electrodeposition. The electrodepostion velocity is about 0.24 μm/min,which is faster than that by direct current electrodeposition. In 1 mol/L H2SO4,3.5% NaCl and 10% NaOH solution,corrosion potential of Cr pulse-deposited film is about 100 mV higher than that of direct current. Corrosion and passivation current densities are lower and the nanocrystalline exhibits better corrosion resistance.

光电材料与应力传感的交叉学科:有机摩擦发光化合物及其传感应用的最新进展

摩擦发光,也称为机械发光,是一种特殊的光学现象,指特定的有机或无机材料在受到外力作用(如挤压、变形、劈裂、振动等)时的发光行为。无机摩擦发光材料在传感领域已经显示出巨大的应用潜力,如应力传感、损伤检测等。然而,有机摩擦发光材料的摩擦发光机理及其应用还需要进一步推动。在本文中,我们总结了有机摩擦发光材料的发展历史和摩擦发光的机理,以及在传感领域中的应用。同时,受到现有无机摩擦发光材料应用的启发,我们对有机摩擦发光材料在应力传感器、运动监测、应力成像分布、裂纹扩展可视化、结构诊断等领域的应用前景进行了展望。

High-loading single cobalt atoms on ultrathin MOF nanosheets for efficient photocatalytic CO_(2) reduction

Based on suitable scaffolds,constructing high-loading single-atom catalysts is a promising strategy to achieve highly efficient catalysis.Herein,using ultrathin metal-organic framework(MOF)nanosheets(2.4±0.5 nm)as the support,single-atom catalysts with high cobalt loading(6.0 wt%)were constructed(denoted as Co-MNSs)by a simple bottom-up synthetic strategy.The catalytic system of Co-MNSs exhibited an outstanding photocatalytic CO_(2)-to-CO evolution rate of 7,041μmol g^(-1)h^(-1)and a selectivity of 86%in aqueous media under visible-light irradiation,which has reached the top level of the reported MOF-based photocatalysts.The control experiments and theoretical calculation revealed that the Co-N_(4)moiety in the MOF nanosheets acted as the active site for the photocatalytic CO_(2)-to-CO conversion.The boosted photocatalytic performance could be ascribed to the high aspect-ratio of layered Co-MNSs providing abundant accessible active sites on their surfaces,which reduced the energy barrier,improved the charge separation efficiency,and also facilitated the adsorption of CO_(2)to form the reactive radicals of*COOH.Our study provides an appealing strategy for constructing high-loading single-atom catalysts and demonstrates the significance of 2D ultrathin MOF nanosheets as the support in boosting CO_(2)photoreduction efficiency.

Assembling Tunable Time-Resolved Fluorescence Layer onto Nano-Gold

The assembling of a coating of time-resolved fluorescent chelator BSPDA （ abbreviated for 4, 7-bis （ sulfhydrylphenyl）-1, 10-phenanthroline-2, 9-dicarboxylic acid） onto a nano-gold layer was demonstrated. First, BSPDA was synthesized by simple procedures, and then an approach was developed to immobilize BSPDA onto the nano-gold layer deposited on a silane modified glass substrate, whereby europium ion （Ⅲ, Eu^3＋ ） was captured and released owing to the interactive process of complexation and dissociation between BSPDA functionalized coating and Eu^3＋ solution. The fluorescence spectra and related lifetimes were determined. Also, the BSPDA functionalized coating＇s specific complexation with Eu^3＋ on the BSPDA assembly layer and the nonspecific adsorption of Eu^3＋ on the nano-gold layer were compared. These results allowed a selective complexation of Eu^3＋ by assembling a BSPDA chelating layer on the nano-gold layer; thus, a tunable time-resolved fluorescent layer was covalently attached, The results of the nanoparticle assembling and probing （or labeling） processes to specific bio-systems were very interesting and had significant implications to time-resolved-fluorescence-based detection on biosensor surfaces such as DNA chip and to arrayed light display devices.

Synthesis and characterization of soluble intrinsic black polyimide with excellent comprehensive properties

Black polyimides(BPIs)have attracted increasing attention owing to their growing demand in optoelectronics.However,commonly used black polyimides doped with black fillers suffer from poor mechanical and electrical properties.To address these issues,a new diamine(2,5-bis(4′-amino-[1,1′-biphenyl]-4-yl)-3,4-bis(4-fluorophenyl)cyclopenta-2,4-dien-1-one,TPCPFPDA)bearing a tetraphenylcyclopentadienone(TPCP)moiety bonded with benzene and fluorine units was synthesized.The diamine was reacted with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride(6FDA)to yield a soluble intrinsic black polyimide(TPCPFPPI).Bonding fluorine(auxochrome group)and benzene units to TPCP can increase the conjugation ofπ-electrons systems and facilitate the movement of electron throughout the bigπbond,respectively.Owing to the structural features,the synthesized TPCPFPPI exhibited complete visible-light absorption with high blackness and opacity.Its cutoff wavelength(λ_(cut))and CIE(Commission Internationale de I′Eclairage)parameter L^(*)were 684 nm and 1.33,respectively.Moreover,TPCPFPPI displayed exceptional electrical,mechanical,and thermal properties as well as excellent solubility.A detailed theoretical calculation was conducted to gain better insight into the electronic properties of the TPCPFPPI.Results showed that the blackness of TPCPFPPI was chiefly attributed to the electron transition from highest occupied molecular orbital(HOMO)to lowest unoccupied molecular orbital(LUMO)in the diamines,where the charges primarily migrated from the aryl groups in the 2-and 5-positions to the cyclopentadienone center.The as-obtained intrinsic BPI(TPCPFPPI),exhibiting both high solubility and outstanding overall properties,has important applications in photo-electronics.

Synthesis and Properties of High Performance Functional Polyimides Containing Rigid Nonplanar Conjugated Fluorene Moieties

A diamine(WuFDA) containing vertical rigid non-planar conjugated fluorene moiety and low polarizability group(C―F)was designed and synthesized through three steps of reactions(halogenated reaction, Suzuki coupling reaction, and reduction reaction).Four kinds of high performance functional polyimides(WuFPI-6 F, WuFPI-BP, WuFPI-BT, and WuFPI-PM) were thus prepared by the condensation polymerization of WuFDA with four commercial dianhydride 6 FDA, BPDA, BTDA, and PMDA, respectively. The polyimides exhibited low dielectric constant, excellent thermal stability, outstanding solubility, good film-forming property, and mechanical properties. The dielectric constants of the polyimides were in the range of 2.28-2.88(f = 10~4 Hz). The 5% weight-loss temperatures(Td 5%)in nitrogen were in the range of 555-584 °C, and the glass transition temperatures(T_g) were in the range of 408-448 °C. The weight loss of WuFPI-BP maintaining at 450 and 500 °C for half an hour was only 0.33% and 1.26%, respectively. All the WuFPIs could be dissolved in almost all organic solvents, even chloroform. The tensile strength and tensile modulus of these films were in the ranges of 78.6-85.7 MPa and 3.1-3.2 GPa, respectively. In addition, the polyimides displayed light color with special fluorescent and resistive switching(ON-OFF) characteristics; the maximum fluorescence emission was observed at 422-424 nm in NMP solution and at 470-548 nm in film state. The memory devices with the configuration of indium tin oxide/WuFPIs/aluminum(ITO/WuFPIs/Al) exhibited distinct volatile memory characteristics of static random access memory(SRAM), with an ON/OFF current ratio of 10~5-10~6. These functional polyimides showed attractive potential applications in the field of high performance flexible polymer photoelectronic devices or polymer memory devices.

Melt Crystallization of Poly(butylene 2,6-naphthalate)

Poly(butylene 2,6-naphthalate)(PBN)is a crystallizable linear polyester containing a rigid naphthalene unit and flexible methylene spacer in the chemical repeat unit.Polymeric materials made of PBN exhibit excellent anti-abrasion and low friction properties,superior chemical resista nee,and outstanding gas barrier characteristics.Many of the properties rely on the presence of crystals and the formatio n of a semicrystalline morphology.To develop specific crystal structures and morphologies during cooling the melt,precise information about the melt-crystallization process is required.This review article summarizes the current knowledge about the temperature-controlled crystal polymorphism of PBN.At rather low supercooling of the melt,with decreasi ng crystal I izatio n temperature,0'-and a-crystals grow directly from the melt and organize in largely different spherulitic superstructures.Formation of a-crystals at high supercooling may also proceed via intermediate formation of a transient monotropic liquid crystalline structure,then yielding a non-spherulitic semicrystalline morphology.Crystallization of PBN is rather fast since its suppression requires cooling the melt at a rate higher than 6000 K-s_1.For this reason,investigation of the two-step crystallization process at low temperatu res requires application of sophisticated experimental tools.These in elude temperatureresolved X-ray scattering techniques using fast detectors and synchrotron-based X-rays and fast scanning chip calorimetry.Fast scanning chip calorimetry allows freezi ng the transie nt liquid-crystalline structure before its con version into a-crystals,by fast cooling to below its glass transition temperature.Subsequent an alysis using polarized-light optical microscopy reveals its texture and X-ray scatteri ng con firms the smectic arrangement of the mesogens.The combination of a large variety of experimental techniques allows obtaining a complete picture about crystallization of PBN in the entire range of melt-supercoolings down to the glass transition,including quantitative data about the crystallization kinetics,semicrystalline morphologies at the micrometer length scale,as well as nanoscale X-ray structure information.

无模板法合成具有增强催化活性的分级纳米孔结构MIL-101(Cr)

MIL-101(Cr)是最重要的金属有机框架(MOFs)材料之一,稳定的框架结构和超高的比表面积使其在众多科学领域得到了广泛研究和应用.但是MIL-101(Cr)的合成条件比较苛刻,且稳定性较强,因此,有关于其分级结构的研究报道仍比较少.本文提出了一种简单制备分级纳米孔结构MIL-101(Cr)的方法,即以乙酸作为调节剂,采用水热合成的方法,一步得到具有微孔-介孔-大孔分级结构的MIL-101(Cr)材料.实验结果表明,该分级结构的MIL-101(Cr)与无分级结构的MIL-101(Cr)相比,其大分子染料吸附能力和催化能力均有显著提高.而且分级结构MIL-101(Cr)负载了磷钨酸催化剂之后,表现出了与均相催化剂(纯磷钨酸)相当的催化能力.进一步研究发现,使用其他短碳链的一元羧酸作为调节剂,如丙酸、丁酸等,也可获得类似分级纳米结构MIL-101(Cr).

Nutritious mushroom protein crisp–healthy alternative to starchy snack

Global salty snacks category had reached USD 137 billion in sales in 2018.Due to growing health concerns and awareness,consumers are looking for healthy snack choices by avoiding ingredients such as fat,sugar,cholesterol,and sodium and selecting baked and salt free multigrain chips.A sizable number of consumers are concerned about snack nutrition and look for quality ingredients and minimally processed foods called as“Good Health Snack(GHS)”.In this work,we present the development of method of producing and testing mushrooms protein crisps(MPC),a healthy alternative to conventional starchy snacks that are rich in protein,nutraceutical compounds,minerals,vitamin,dietary fiber,and immunity inducing beta-glucans.The methods of producing MPC with different seasoning and hydrolyzed protein,calorie,nutritional and chemical composition,consumer response,shelf life after packing and market analysis are described.These systematic studies will help to market potential of this product which is a healthy alternative to other calorie rich snacks sold in the market benefiting the consumers.