硅源对纳米级ZSM-5分子筛结构及其对甲醇转化制丙烯与丁烯反应催化性能的影响

采用低温水热晶化法,以四丙基氢氧化铵为模板剂,分别使用98%粗孔固体硅胶和30%硅溶胶为硅源,制备不同硅铝物质的量比的纳米级ZSM-5分子筛,研究硅源对其物化结构及甲醇转化制丙烯与丁烯催化性能的影响。结果表明,硅源种类影响ZSM-5分子筛的结构及铝分布,进而影响其酸性和催化性能。固体硅胶为硅源,有利于形成弱酸性位点;硅溶胶为硅源,有利于形成强酸性位点。在相同硅铝物质的量比时,以固体硅胶为硅源的ZSM-5分子筛的总酸量小于以硅溶胶为硅源的样品。无论使用何种硅源,对ZSM-5分子筛的晶型结构影响不大,且ZSM-5分子筛颗粒形貌均呈现为由小晶粒堆积成(500~1 000)nm的类球形颗粒。以硅溶胶为硅源制备的样品颗粒尺寸大于以固体硅胶为硅源制备的样品。硅铝物质的量比为400时,两种硅源合成分子筛的丙烯与丁烯的选择性相近,但以硅溶胶为硅源的ZSM-5分子筛的寿命更长。     

CL-20/DNT共晶炸药的制备及其性能研究

以丙酮为溶剂,通过蒸发结晶法制得六硝基六氮杂异伍兹烷(CL-20)/二硝基甲苯(DNT)共晶炸药。利用扫描电镜(SEM)、X射线衍射(XRD)和热重/差示量热法(TGA/DSC)研究了共晶炸药的形貌、结构和热分解特性,测试了CL-20/DNT共晶炸药的机械感度和5s爆发点温度,并计算了其爆轰性能。结果表明,共晶炸药的微观形貌不同于原料CL-20,呈条状晶体;衍射峰明显不同于CL-20/DNT物理混合物的衍射峰,表明有新物相生成。在DSC曲线上,CL-20/DNT共晶几乎没有DNT的熔化吸热峰,而CL-20/DNT物理混合物中有明显的熔化峰,且二者的放热峰峰形和峰位不同;与原料CL-20相比,共晶炸药的分解峰温提前了21℃,放热量(ΔH)和最大热流量(Qmax)分别增加了39%和104%。与CL-20/DNT物理混合物相比,共晶炸药的5s爆发点温度和表观活化能分别增加3.9℃和65.7kJ/mol,撞击感度降低88.9%,摩擦感度降低40%,说明共晶炸药热稳定性增强。CL-20/DNT共晶炸药的理论爆速达到8 340m/s。     

10Ni5CrMoV钢错位同步双面双弧焊接接头抗低温脆断性能

文中采用系列温度冲击试验、动态撕裂（Dynamic Tear, DT）试验和落锤试验研究了10Ni5CrMoV钢错位同步双面双弧焊接接头的抗低温脆断性能.结果表明,10Ni5CrMoV钢双面双弧焊接接头抗脆性转变能力满足服役要求.双面双弧焊接接头的熔合线位置的冲击吸收功满足10Ni5CrMoV钢焊接接头A_kv（-50℃）≥47 J的技术指标要求,且余量较大;-1℃时焊接接头动态撕裂能最低值为1 150 J,高于配套焊接材料0℃时DT功大于644 J的要求;落锤试验确定10Ni5CrMoV钢焊缝金属无塑性转变温度（Nil-Ductility Temperature）为-80℃,焊缝的弹性断裂转变温度Fracture Transtiton of Elastic（FTE）为-47℃,全塑性断裂转变温度Farcture Transition Temperature（FTP）为-14℃.     

37Mn5钢管内壁鼓包缺陷分析

37Mn5钢管热轧矫直后在内管壁出现鼓包缺陷,为了查找鼓包产生原因,采用显微镜和扫描电子显微镜等设备对鼓包的形貌、微观组织、化学成分及鼓包区域的形貌等内容进行了分析。结果表明:钢管化学成分和组织正常,钢管基体和鼓包区域含有较多相同的夹杂物,夹杂物均含有Ca、O、Fe、Na、K、Mg 等元素,这些元素组成含有多种氧化物和结晶器保护渣的大尺寸复合型夹杂物。进而得知钢管的鼓包缺陷产生原因:由于钢管内存在大量此类复合夹杂物在穿管过程中和钢管基体间的接触层面脱离并逐渐萌生裂纹,裂纹在比较大的周向压力作用下向内壁凸起并形成鼓包。     

5ESS-2000型程控交换机的计费原理及应用

介绍了5ESS-2000型程控交换机计费的基本原理及其应用。     

KTC5型综采工作面网络通讯控制装置

KTC5型综采工作面网络通讯控制装置主要用于煤矿井下综采工作面运输机、转载机、破碎机及乳化液泵的控制和沿线通讯。它采用微控芯片和先进的语音技术进行单一频率报警，可实现沿线的断线监测和故障判断，该装置成本不高，性能可靠，沿线管理功能和通话功能强大。     

JHX-5型回柱及调度两用绞车的性能试验方案研究

新型JHX-5型回柱及调度两用绞车是采用少齿差行星传动取代现有的蜗杆-蜗轮传动,该绞车具有结构紧凑、重量轻、传动效率高、加工工艺简单、成本低等特点。通过理论分析并设计制造了样机,拟定了实验方案来测定该新型绞车的拉力、绳速、传动效率等重要参数,对今后的进一步改进和推广应用具有较大的意义。     

冷冲高硬度材料模具的失效分析与选材

用WC-Co型硬质合金和高合金钢以不同的匹配方式制作冷冲模具,对高硬度材料2Cr13不锈钢进行冲裁,发现以高合金钢制作的模具寿命远高于硬质合金制作的模具。其失效方式及所占比例表明,硬质合金主要以掉渣和崩刃为主,而高合金钢以正常磨损为主。分析可知,由于剧烈磨损而引起WC-Co型硬质合金Co的缺失,破坏了WC骨架,最终导致模具局部韧性不足而掉渣;而高合金钢韧性相对较好,延长了使用寿命,但同时由于热加工工艺的不适当导致碳化物不均或硬度不稳定而未充分发挥材料的潜能,对提高高合金钢的使用寿命给出了改进方案。     

High-Qf value and temperature stable Zn2+-Mn4+ cooperated modified cordierite-based microwave and millimeter-wave dielectric ceramics

Cordierite-based dielectric ceramics with a lower dielectric constant would have significant application potential as dielectric resonator and filter materials for future ultra-low-latency 5G/6G millimeter-wave and terahertz communication. In this article, the phase structure, microstructure and microwave dielectric properties of Mg₂Al_4–2x(Mn_0.5Zn_0.5)_2xSi₅O₁₈ (0 ≤ x ≤ 0.3) ceramics are studied by crystal structure refinement, scanning electron microscope (SEM), the theory of complex chemical bonds and infrared reflectance spectrum. Meanwhile, complex double-ions coordinated substitution and two-phase complex methods were used to improve its Q×f value and adjust its temperature coefficient. The Q×f values of Mg₂Al_4–2x(Mn_0.5Zn_0.5)_2xSi₅O₁₈ single-phase ceramics are increased from 45,000 GHz@14.7 GHz (x = 0) to 150,500 GHz@14.5 GHz (x = 0.15) by replacing Al³⁺ with Zn²⁺-Mn⁴⁺. The positive frequency temperature coefficient additive TiO₂ is used to prepare the temperature stable Mg₂Al_3.7(Mn_0.5Zn_0.5)_0.3Si₅O₁₈-ywt%TiO₂ composite ceramic. The composite ceramic of Mg₂Al_3.7(Mn_0.5Zn_0.5)_0.3Si₅O₁₈-ywt%TiO₂ (8.7 wt% ≤ y ≤ 10.6 wt%) presents the near-zero frequency temperature coefficient at 1225 °C sintering temperature: ε_r = 5.68, Q×f = 58,040 GHz, τ_f = ?3.1 ppm/°C (y = 8.7 wt%) and ε_r = 5.82, Q×f = 47,020 GHz, τ_f = +2.4 ppm/°C (y = 10.6 wt%). These findings demonstrate promising application prospects for 5 G and future microwave and millimeter-wave wireless communication technologies.     

Transparent and anti-fogging AlPO4-5 films constructed by oblique oriented nano-flake crystals

In the present work, transparent and anti-fogging AlPO₄-5 films were prepared on glass substrates using a novel developed process. The process entails a simple in-situ sol–gel followed by vapor phase transport. The in-situ sol–gel process was implemented by coating the precursor sols for the synthesis of AlPO₄-5 on the glass substrates successively using the spin-coating method. The films and powders scribed from the films were characterized by X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), atomic force microscope (AFM), X-ray photoelectron spectroscopy and transmission electron microscope (TEM). The unique films were composed of oblique oriented nano-flake AlPO₄-5 crystals with the thickness of about 20 nm. The formation of nano-flake crystals can be ascribed to the high concentration of the precursors, resulting in the formation of a supersaturation system. The obtained films showed high antifogging performance due to the superhydrophilicity with a water contact angle of lower than 1.0°. The silicone oil contact angle was also low about 8.2°. In addition, heteroatom-substituted AlPO₄-5 films showing different colors can be obtained easily by simply adding transition metal ions in the phosphate acid solution during the preparation that can extend the application of the method for different coating demand.