One-step green method to prepare progressive burning gun propellant through gradient denitration strategy

Gradiently denitrated gun propellant(GDGP)prepared by a“gradient denitration”strategy is obviously superior in progressive burning performance to the traditional deterred gun propellant.Currently,the preparation of GDGP employed a tedious two-step method involving organic solvents,which hinders the large-scale preparation of GDGP.In this paper,GDGP was successfully prepared via a novelty and environmentally friendly one-step method.The obtained samples were characterized by FT-IR,Raman,SEM and XPS.The results showed that the content of nitrate groups gradiently increased from the surface to the core in the surface layer of GDGP and the surface layer of GDGP exhibited a higher compaction than that of raw gun propellant,with a well-preserved nitrocellulose structure.The denitration process enabled the propellant surface with regressive energy density and good progressive burning performance,as confirmed by oxygen bomb and closed bomb test.At the same time,the effects of different solvents on the component loss of propellant were compared.The result showed that water caused the least component loss.Finally,the stability of GDGP was confirmed by methyl-violet test.This work not only provided environmentally friendly,simple and economic preparation of GDGP,but also confirmed the stability of GDGP prepared by this method.

Synthesis of the CuInSe_2 thin film for solar cells using the electrodeposition technique and Taguchi method

The Taguchi method was used to obtain the optimum electrodeposition parameters for the synthesis of the CuInSe2 thin film for solar cells. The parameters consist of annealing temperature, current density, CuCl2 concentration, FeCl3 concentration, H2SeO3 concentration, TEA amount, pH value, and deposition time. The experiments were carried out according to an L18（2^13^7） table An X-ray diffractometer （XRD） and a scanning electron microscope （SEM） were respectively used to analyze the phases and observe the microstructure and the grain size of the CuInSe2 film before and after annealing treatment. The results showed that the CuInSe2 phase was deposited with a preferred plane （112） parallel to the substrate surface. The optimum parameters are as follows： current density, 7 mA/cm^2; CuCl2 concentration, 10 mM; FeCl3 concentration, 50 mM; H2SeO3 concentration, 15 mM; TEA amount, 0 mL; pH value, 1.65; deposition time, 10 min; and annealing temperature, 500℃.

Noether＇s theorem and one-step corrections method for holonomic system

In this paper, a new computational method for improving the accuracy of numerically computed solutions is introduced. The computational method is based on the one-step method and conserved quantities of holonomic systems are considered as kinematical constraints in this method.

Constraint Stabilization and One-Step Correction Method for Dynamical Systems

A computational method of constraint stabilization and correction is introduced. The method is based on the Baumgart＇s one-step method. Constraint conditions are addressed to stabilize and correct the solution. Two examples are given to illustrate the results of the method.

One-step Eco-friendly Fabrication of Antibacterial Polyester Via On-line Amination Reaction by Melt Coextrusion

The work is dedicated to develop a one-step eco-friendly method to prepare antibacterial polyethylene terephthalate(PET).We report a one-step eco-friendly method to manufacture antibacterial PET via on-line amination reaction by melt coextrusion.Beside evenly mixing of poly(hexamethylene guanidine)(PHMG)and PET in the melt coextrusion procedure,the amination reaction also occurred between PHMG and PET under high temperature(230-270℃).The antibacterial ability of composite PET showed obvious PHMG concentration dependence,and antibacterial activity reached more than 99%when PHMG content was 2.5 wt%.Moreover,LIVE/DEAD fluorescence test further confirmed that the composite PET could kill bacteria quickly and efiectively(within 30 min);while negligible cytotoxicity was observed to HSF and HUVEC cells.Onestep eco-friendly fabrication of composite antibacterial PET was accomplished by on-line melt coextrusion.The composite antibacterial PET has potential use in multiple fields to combat with pathogenic including textiles,packaging materials,decoration materials and biomedical devices,etc.

Engineering of Self-Supported Electrocatalysts on a Three-Dimensional Nickel Foam Platform for Efficient Water Electrolysis

Economical water electrolysis requires highly active non-noble electrocatalysts to overcome the sluggish kinetics of the two half-cell reactions,oxygen evolution reaction,and hydrogen evolution reaction.Although intensive efforts have been committed to achieve a hydrogen economy,the expensive noble metal-based catalysts remain under consideration.Therefore,the engineering of self-supported electrocatalysts prepared using a direct growth strategy on three-dimensional(3D)nickel foam(NF)as a conductive substrate has garnered significant interest.This is due to the large active surface area and 3D porous network offered by these electrocatalysts,which can enhance the synergistic eff ect between the catalyst and the substrate,as well as improve electrocatalytic performance.Hydrothermal-assisted growth,microwave heating,electrodeposition,and other physical methods(i.e.,chemical vapor deposition and plasma treatment)have been applied to NF to fabricate competitive electrocatalysts with low overpotential and high stability.In this review,recent advancements in the development of self-supported electrocatalysts on 3D NF are described.Finally,we provide future perspectives of self-supported electrode platforms in electrochemical water splitting.

三维柱阵列型纳米多孔硫化亚锡负极的电化学合成与储锂性能研究

本研究在铜箔基底上通过无模板恒流电沉积技术成功制备出三维柱阵列型纳米多孔铜镍集流体。采用恒压电沉积方式在该集流体表层沉积SnS纳米颗粒,形成了具有三维柱状结构的纳米多孔硫化亚锡电极。利用恒流充放电测试与XRD、SEM、EDS技术,综合评估了该负极的电化学特性、微观结构、化学元素分布及其物相成分。结果表明,所制备的纳米柱表面存在孔隙,阵列间隙均匀。在0.1 mA/cm^(2)电流密度下,该电极首次放/充电过程中分别提供了0.77/0.48 mAh/cm^(2)的面积比容量,首次库仑效率为62%。经过50周循环后,电极可逆比容量仍达0.30 mAh/cm^(2),容量保持率为62.5%。

青海盐湖水氯镁石制备氢氧化镁的进展

青海柴达木盆地盐湖提钾后产生的废卤水经日晒蒸发形成巨量的水氯镁石,对盐湖生态环境造成严重影响。利用水氯镁石制备氢氧化镁是盐湖固废减量化、无害化、资源化利用的有效途径。文章介绍了青海盐湖水氯镁石的成因、典型组成及储量规模,综述了利用盐湖水氯镁石制备氢氧化镁的典型工艺。对直接沉淀法、水热法、声化学合成法、微乳液法、电沉积法制备氢氧化镁的技术原理、工艺流程及研究现状进行了介绍,并对其技术特点进行分析比较。介绍了电沉积法制备高纯氢氧化镁的研究进展、优势及尚需解决的问题。

AZ31镁合金基Cu-MOF-SA超疏水膜的制备及其耐腐蚀性能研究

腐蚀是影响镁及其合金大规模应用的关键技术难题之一,因可有效隔离金属基底与腐蚀介质的直接接触,从而降低腐蚀速率,制备超疏水表面成为提高镁合金耐蚀性的有效途径。通过一步电沉积方法,在AZ31镁合金基底上成功制备了铜-金属有机骨架-硬脂酸(Cu-MOF-SA)超疏水膜,并对超疏水膜的耐腐蚀性、化学稳定性和耐热性进行了综合研究。结果表明,表面的水接触角可达158°,超疏水膜覆盖的试样在3.5%NaCl溶液中表现出良好的耐腐蚀性能,相比AZ31镁合金基底,其腐蚀电位正移了0.24 V,腐蚀电流密度降低了1个数量级。在pH值为1~14的溶液中浸润24 h后,超疏水膜的水接触角仍可达135°以上,浸泡在pH=1的溶液24 h的超疏水膜的腐蚀电位比AZ31镁合金基底高0.21 V。在20~90℃空气中保温24 h后,超疏水膜的水接触角仍保持在154°以上,80℃下保温24 h后其腐蚀电位比AZ31镁合金基底的高0.22 V,腐蚀电流密度比AZ31镁合金基底的小1个数量级。结果表明,本研究制备的Cu-MOF-SA疏水膜具有良好的超疏水性和耐腐蚀性。

Synthesis of Codon-optimized Human Interleukin-18 Gene by Combination of Chemical and Enzymatic Method

According to the amino acid sequence and codon preference of E. coli, the human interleukin-18（IL-18） gene was optimized to avoid the rare codons. The total length of the synthesized gene is 571 bp; 18 oligonucleotides, DNA fragments were designed and synthesized by the phosphoramidite four-step chemical method. The whole DNA sequence was synthesized by a one-step total gene synthesis method, and then inserted in pUC18 vector. Five positive clones identified by blue-white colony screening were sent to Shanghai Sangon Biological Engineering Technology and Service Co., Ltd. for sequencing. The sequencing result shows that one clone contained the complete correct gene in all the five positive clones.

One-Step Multiplex PCR for Simultaneous Detection and Identification of Eight Medically Important <i>Candida</i>Species

Recently, the incidence of Candida infections has substantially increased. Conventional identification methods for Candida species are technically difficult to conduct and cannot accurately distinguish each species. The purpose of the present study was to design primers to identify and detect simultaneously eight medically important Candida species using one-step multiplex PCR. PCR primers were designed based on partial sequences of intergenic spacer (IGS) and internal transcribed spacer (ITS) genes of eight medically important Candida species. These primers were able to distinguish each Candida species and did not display cross-reactivity with representative Candida species other than the eight Candida species. Moreover, our developed one-step multiplex PCR method is accurate, specific, cost-effective, time-saving, and worked without requiring DNA extraction.

Cup-drawing formation of steel sheet with nickel coating by finite element method

The finite element method(FEM) simulation of deep-drawing of steel sheet with nickel coating based on the solid element and dynamic explicit method was reported. Penalty function method was used to treat the contact algorithm. The friction between the punch and coating sheet was based on a Coulomb formulation. The combination of coating and substrate was defined as tied with failure contact. The results of the simulation illustrate that the steel sheet and the nickel coating do not delaminate at the interface. The stress field of the nickel coating is more complicated than that of the steel substrate. Furthermore,it is found that the punch-nose radius is the most unsubstantial part for the intensity of the entire deep-drawing part and the thinnest part,it is a dangerous zone for the break. At this zone,the thickness thinning of the steel sheet and the nickel coating are up to 4.8% and 6.7%,respectively. Meanwhile,it is found that the curve of the variable blankholder force(VBHF) designed can improve the formability of sheet.

电沉积法制备碱性电解水镍基析氧电极的研究进展

在“碳达峰、碳中和”的目标下,绿氢成为极具前景的清洁能源。碱性电解水制取绿氢技术商业化程度最高,但由于析氧反应(OER)动力学过程缓慢且需要较高的过电位,成为制约电解水电极效率的主要瓶颈。商业电解槽中广泛使用的镍网或泡沫镍电极的OER性能仍有很大提升空间,在其上复合镍基催化功能层,开发新型高活性的析氧电极有利于提高电极效率,降低制氢成本。电沉积技术具有工艺简单、条件温和、利于放大生产自支撑电极的优势,成为工业化生产OER电极的理想工艺之一。本文综述了近年来利用电沉积技术制备的镍基析氧电极并用于碱性电解水的研究进展。采用电沉积技术在镍网或泡沫镍基底上制备镍(氢)氧化物、双金属及多元金属以及非金属掺杂的镍基催化剂作为催化功能层,通过增强催化功能层的电导率及金属间的协同作用、增加活性位点数量、减小扩散路径以及改变表面原子构型等方式提高镍基自支撑电极的OER性能。最后,展望了镍基自支撑电极在电解水领域的应用,同时指出了电沉积法制备电极材料存在的挑战。

电沉积法从硫氰酸盐浸金液回收金的试验研究

针对硫氰酸盐浸金液金回收效率低且成本高等问题,利用电沉积法从硫氰酸铵浸金液中回收金。采用单因素法研究了阳极材料、阴极材料、极间距、槽电压、溶液pH值和温度对金沉积率的影响,结果表明:以石墨棒作阳极、自制电极作阴极,在极间距为10 mm、槽电压为4 V、溶液pH=12和温度为35℃的条件下,电解2 h,金沉积率达到98.95%。采用响应面法研究了槽电压、溶液pH值与溶液温度之间的交互作用及其对金沉积率的影响,结果表明:各因素对金沉积率的影响程度依次为槽电压>溶液pH值>溶液温度,并建立了电沉积金响应面回归模型。在槽电压为4.10 V、溶液pH=12.40和温度为39.58℃的最佳条件下,模型预测值为99.06%,试验平均值为99.04%,二者结果非常接近,证明该模型能够对金沉积率进行准确的分析预测。本研究进一步完善了硫氰酸盐提金工艺理论体系。

CoV-LDH及其磷化物的制备和赝电容储能研究

磷化处理是一种提高电极材料活性位点的有效策略,被广泛用来增强赝电容材料的电化学储能性能。分别采用水热法和电沉积法合成了微球状和针状形貌结构的钴钒层状双金属氢氧化物(CoV-LDH),经过磷化后得到了赝电容储能性能较好的钴钒磷化物(CoV-P)电极材料。相对于水热法和电沉积法制备的CoV与CoV/NF,磷化后的CoV-P和CoV-P/NF比电容分别提高了61.5%和87.7%。在1 A·g^(-1)的电流密度下,CoV-P/NF的放电比电容达到了1871 F·g^(-1)。当电流密度增加5倍时,具有65%的容量保留率。经动力学分析表明,CoV-P/NF的比电容贡献以赝电容扩散控制过程占主导作用。以活性炭(AC)为负极组装的CoV-P//AC非对称超级电容器,当功率密度为511 W·kg^(-1)时,提供了37 W·h·kg^(-1)的能量密度,且在能量密度为12 W·h·kg^(-1)时,达到了2491 W·kg^(-1)的功率密度,表现出了良好的储能性能。

Pd/GO/ITO复合电极的制备及对2,4-DCP的降解研究

2,4-DCP在环境中的积累已成为当今的一个严重问题,并且难以通过传统的处理方法处理。采用恒电流电沉积法制备了新型Pd/GO/ITO复合电极,并通过扫描电镜、X-射线衍射、X-射线光电子能谱对电极的表面形态、晶体结构及表面元素价态进行了观察与分析。最后通过研究Pd/GO/ITO电极对2,4-DCP的电解率,验证了新型复合电极对有机化合物降解的有效性。

基于差重法的碳化硅电沉积涂层耐蚀性研究

为研究内燃机中纳米流体电沉积涂层的耐蚀性,采用差重法对涂层进行耐蚀性分析。首先,采用两步法制备出稳定的纳米流体;然后,以所得流体为电解液制备电沉积涂层;最后,利用差重法对涂层耐蚀性进行对比分析,得到腐蚀环境下的质量损失曲线。实验结果表明,纳米流体电沉积涂层的沉积条件对涂层耐蚀性具有重要影响。

镀镍层内应力及其测量方法

镀镍是电镀工业中应用最广泛的镀种之一,镀层的内应力是影响镀层质量的重要因素。综述了镀镍层内应力产生的原因,介绍了镀镍层内应力的测量方法,并对各种影响镀镍层内应力的因素进行了分析。

镀铜研究中的电化学方法

综述了镀铜研究中常用的电化学方法,包括恒电位技术、线性电势扫描伏安法、恒电流技术和交流阻抗技术,展望了电化学方法在镀铜研究中运用的前景。

电沉积Ni-S合金阴极析氢反应

用电沉积法制备各种硫含量的Ni S合金镀层电极。用恒电流极化法研究各电极在 80℃的 5mol/LNaOH溶液中作为析氢反应阴极的催化性能 ,并用XRD及SEM研究Ni S合金镀层的组织结构。实验结果表明 ,硫含量为 2 9.4% (原子百分比 )的Ni S合金电极具有优良的催化性能 ,在 15 0mA/cm2 的电流密度下 ,析氢反应过电位最低 ,比Fe低约 35 0mV。这与其组织结构有关。