焦炭塔自动顶盖机与底盖机故障类型及故障频率分析

通过调研,搜集了两家大型石化公司12家企业的43台法兰密封型顶盖机、22台法兰密封型底盖机、7台平板式阀门底盖机的180起故障,并进行了统计分析,比较和分析了法兰密封型自动顶盖机和底盖机的故障情况,以及法兰密封技术和阀门密封技术的优缺点,提出了建议措施:建议有关企业加强顶/底盖机设备的维护保养能力,提高维保人员的素质,加强监测,有效降低故障频率;在关键设备的设计、制造、采购和安装全过程,实施严格的质量保证措施,做到全面质量管理,确保产品生产的全过程质量处于受控状态;加强技术人员和操作人员在顶/底盖机设备结构、运行原理、操作技能方面的培训,正确处理生产中出现的问题;建议在顶盖机锁环部位设置开关位回讯信号,接入DCS系统联锁,将此信号与四通阀进行联锁,同时加机械确认装置,确保锁环到位,防止出现类似事故;加强平板闸阀结构的自动顶/底盖机的研发,加快国产化速度,加强设备可靠性、安全性分析。     

N‐Doped Graphene‐SnO2 Sandwich Paper for High‐Performance Lithium‐Ion Batteries

A new facile route to fabricate N‐doped graphene‐SnO₂ sandwich papers is developed. The 7,7,8,8‐tetracyanoquinodimethane anion (TCNQ^?) plays a key role for the formation of such structures as it acts as both the nitrogen source and complexing agent. If used in lithium‐ion batteries (LIBs), the material exhibits a large capacity, high rate capability, and excellent cycling stability. The superior electrochemical performance of this novel material is the result from its unique features: excellent electronic conductivity related to the sandwich structure, short transportation length for both lithium ions and electrons, and elastomeric space to accommodate volume changes upon Li insertion/extraction.     

超宽带信道建模中基于压缩感知的解卷积算法

针对频域测量方式下的超宽带(UWB)信道测量数据后处理,该文提出了用具有高斯滚降特性过渡带的类高斯窗,提取符合中国UWB频谱规范的信道测量数据,并将类高斯窗对应的时域脉冲作为先验信息,使用基于压缩感知(CS)的算法对时域信道测量信号解卷积,使得解卷积后的信道冲激响应具有高分辨率特性。利用频域加窗补零,以及改变解卷积算法中参数化波形字典原子的步长,可以得到不同分辨率的解卷积结果。采用匹配追踪(Matching Pursuit,MP)算法作为CS的重构算法。针对一间办公室的视距(LOS)与非视距(NLOS)信道测量数据处理结果表明,基于压缩感知的解卷积算法可以用较少的观测值获得和CLEAN算法相近的解卷积性能。     

Effect of Ag and Ti3SiC2 on Tribological Properties of TiAl Matrix Self-lubricating Composites at Room and Increased Temperatures

Dry sliding tribological properties of TiAl matrix self-lubricating composites (TMSC) containing Ag, Ti₃SiC₂, Ag and Ti₃SiC₂ were investigated from 25 to 800 °C under ball-on-disk test conditions against Si₃N₄ counterface under the same conditions of 10 N-0.234 m/s. The results indicated that the tribological properties were strongly dependent on the lubricant additives. TMSC with the addition of Ag and Ti₃SiC₂ (TAT) exhibited the lower friction coefficients (0.32–0.43) and less wear rates (1.23–4.13 × 10^?4 mm³ N^?1m^?1) in the wide temperature range of 25–800 °C. The excellent tribological properties of TAT over the wide temperature range were attributed to the synergetic effect of Ag and Ti₃SiC₂ lubricants, silver diffusion forming a rich-silver smooth tribo-film on the frictional surface of TAT at low and moderate temperatures from 25 to 400 °C, while Ti₃SiC₂ oxidation reaction forming rich-oxide tribo-film on the worn surface of TAT at higher temperatures of 600 and 800 °C.     

基于MSP430的HART协议流量计设计

叙述了基于MSP430单片机的HART协议流量计设计,介绍了该流量计的结构及其软硬件设计。详细介绍了采用HT20C15及AD421构成的HART协议通信线路设计。     

Lysine-fortified wheat flour improves the nutritional and immunological status of wheat-eating families in northern China

The purpose of this study was to determine the impact of the fortification of wheat flour with lysine on selected health indicators among farm families obtaining 58% to 67% of their dietary protein from wheat. A man, a woman, and a child aged 5 to 12 years were studied from each of 88 families in a village near Huixian City, Henan Province, China. Half of the families received wheat flour fortified with 3 g of lysine per kilogram for three months, and the other half received wheat flour without fortification. The results showed a significantly greater gain in the height and weight of children receiving lysine-fortified wheat flour. Hemoglobin values were not affected. The mean prealbumin values of adult men and women were higher in those receiving lysine. The numbers of CD3 T cells increased significantly in women and children, as did the complement fraction C3 and IgG in men, IgA in women, and IgG, IgA, IgM, and C3 in children. These results indicate that lysine fortification of wheat flour can significantly improve some indicators of the nutritional status and immune function of family members consuming a wheat-based diet.     

Enhancement of gas sensing properties of CdS nanowire/ZnO nanosphere composite materials at room temperature by visible-light activation

CdS nanowire/ZnO nanosphere materials (CdS/ZnO) with hierarchical structure were synthesized by a three-step solvothermal process. XRD, FESEM and TEM analysis confirmed the growth of ZnO nanospheres on the surface of CdS nanowires (NWs). The transient photovoltage (TPV) measurements revealed that the interface between CdS and ZnO can inhibit the recombination of photogenerated excess carriers and prolong the lifetime of excess carriers in CdS/ZnO materials. Moreover, the CdS/ZnO materials exhibit a dramatic improvement in optoelectronic performance and visible-light-irradiation gas sensing activity, which gave 1 order of magnitude larger than that of CdS NWs in response to formaldehyde. The enhancement of sensing properties is attributed to the interfacial transport of excess carriers.     

Thick lead-free ferroelectric films with high Curie temperatures through nanocomposite-induced strain

Ferroelectric materials are used in applications ranging from energy harvesting to high-power electronic transducers. However, industry-standard ferroelectric materials contain lead, which is toxic and environmentally unfriendly. The preferred alternative, BaTiO(3), is non-toxic and has excellent ferroelectric properties, but its Curie temperature of ～130 °C is too low to be practical. Strain has been used to enhance the Curie temperature of BaTiO(3) (ref. 4) and SrTiO(3) (ref. 5) films, but only for thicknesses of tens of nanometres, which is not thick enough for many device applications. Here, we increase the Curie temperature of micrometre-thick films of BaTiO(3) to at least 330 °C, and the tetragonal-to-cubic structural transition temperature to beyond 800 °C, by interspersing stiff, self-assembled vertical columns of Sm(2)O(3) throughout the film thickness. The columns, which are 10 nm in diameter, strain the BaTiO(3) matrix by 2.35%, forcing it to maintain its tetragonal structure and resulting in the highest BaTiO(3) transition temperatures so far.     

Aqueous-phase synthesis of Ag-TiO2-reduced graphene oxide and Pt-TiO2-reduced graphene oxide hybrid nanostructures and their catalytic properties

We demonstrate an aqueous solution method for the synthesis of a Ag-TiO₂-reduced graphene oxide (rGO) hybrid nanostructure (NS) in which the Ag and TiO₂ particles are well dispersed on the rGO sheet. The Ag-TiO₂-rGO NS was then used as a template to synthesize Pt-TiO₂-rGO NS. The resulting hybrid NSs were characterized by transmission electron microscopy (TEM), high-resolution TEM (HRTEM), energy-dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, UV-vis spectroscopy, Raman spectroscopy, inductively coupled plasma mass spectrometry (ICP-MS), and catalytic studies. It was found that TiO₂-rGO, Ag-TiO₂-rGO and Pt-TiO₂-rGO NSs all show catalytic activity for the reduction of p-nitrophenol to p-aminophenol by NaBH₄, and that Pt-TiO₂-rGO NS exhibits the highest catalytic activity as well as excellent stability and easy recyclability.