载荷对D2车轮钢滑动磨损表层微观组织和性能影响

目的 研究滑动磨损条件下,载荷变化对D2车轮钢表层微观组织和磨损性能的影响。方法 利用MRH-30(环块)滑动摩擦磨损试验机进行滑动磨损试验。使用金相显微镜(OM)、场发射扫描电镜 (SEM)、X射线衍射仪(XRD)和场发射透射电镜(TEM)等设备,分析滑动磨损后表层微观组织、表面磨损形貌和硬度变化。结果 不同载荷条件下,随着磨损时间的增加,轮轨试样磨损量逐渐增加。200 N载荷条件下,(环状)车轮试样的磨损量大于100 N车轮试样磨损量,但200 N钢轨(块状)试样的磨损量却低于100 N钢轨试样。滑动磨损后,在不同载荷条件下,车轮试样表面主要形成长条状白层和不连续的月牙状白层。在200 N载荷条件下,由于车轮试样的磨损量较高,其白层厚度和表面白层硬度都小于100 N载荷条件下的车轮试样。在200 N载荷条件下,车轮试样表面更易形成不连续的月牙状白层。由于轮轨试样表面存在微凸体,高载荷会加速车轮试样表面局部微凸体发生严重塑性变形,导致月牙状白层的形成。在白层内片状渗碳体发生明显溶解和铁素体晶粒显著细化。结论 车轮表面白层对磨损性能有明显影响。滑动磨损过程中,高载荷条件下,月牙状白层和周边微观组织界面易形成裂纹,裂纹会逐渐沿着界面向内部扩展,导致不连续月牙状白层发生剥落,降低车轮试样表面的硬度,加速车轮试样磨损。另一方面,高载荷会加速无白层区域塑性变形,导致其形成棘轮失效,从而加速磨损。     

Quantitative Proteomic Analysis of Escherichia coli Heat-Labile Toxin B Subunit (LTB) with Enterovirus 71 (EV71) Subunit VP1

The nontoxic heat-labile toxin (LT) B subunit (LTB) was used as mucosal adjuvant experimentally. However, the mechanism of LTB adjuvant was still unclear. The LTB and enterovirus 71 (EV71) VP1 subunit (EVP1) were constructed in pET32 and expressed in E. coli BL21, respectively. The immunogenicity of purified EVP1 and the adjuvanticity of LTB were evaluated via intranasal immunization EVP1 plus LTB in Balb/c mice. In order to elucidate the proteome change triggered by the adjuvant of LTB, the proteomic profiles of LTB, EVP1, and LTB plus EVP1 were quantitatively analyzed by iTRAQ-LC-MS/MS (isobaric tags for relative and absolute quantitation; liquid chromatography-tandem mass spectrometry) in murine macrophage RAW264.7. The proteomic data were analyzed by bioinformatics and validated by western blot analysis. The predicted protein interactions were confirmed using LTB pull-down and the LTB processing pathway was validated by confocal microscopy. The results showed that LTB significantly boosted EVP1 specific systematic and mucosal antibodies. A total of 3666 differential proteins were identified in the three groups. Pathway enrichment of proteomic data predicted that LTB upregulated the specific and dominant MAPK (mitogen-activated protein kinase) signaling pathway and the protein processing in endoplasmic reticulum (PPER) pathway, whereas LTB or EVP1 did not significantly upregulate these two signaling pathways. Confocal microscopy and LTB pull-down assays confirmed that the LTB adjuvant was endocytosed and processed through endocytosis (ENS)-lysosomal-endoplasmic reticulum (ER) system.     

基于FANUC Oi-mate数控车床零件加工中G71与G73指令应用对比

本文对FANUC Oi-mate数控车床在手工编程中用到的粗车指令G71与G73进行了应用上的对比分析,叙述了G71、G73在走刀路线上的不同,并举例说明G71和G73指令的不同使用方法及需要注意的事项。     

Criminal Lines,Indian Colours,and the Creation of a Black Legend: The Photographs of ‘Los Bandidos de la Halancha’, Bolivia

The author’s discovery of a set of inscribed photographs of the ‘Bandits of La Jalancha’, made in La Paz, Bolivia in 1871 and now in the collections of Harvard’s Peabody Museum of Archaeology and Ethnology, has made possible the identification of the photographed gang’s leader ‘Salvador Chico’ with the Afro-Aymara anti-hero known in contemporary folklore as El Zambo Salvito. On their photographic journeys out of Bolivia, Salvador and his men were transformed into anonymous ‘Indian bandits’ and became generic illustrations of ethnic Aymara types in the service of racialised evolutionary science. Back in La Paz, however, the photographs were forgotten but the legend of the infamous son of an African slave from Chicaloma, a coca-producing hacienda in the region of Yungas, grew in the public imagination. Whereas nineteenth-century racial discourse only recognised his indigeneity, twentieth- and twenty-first-century folklore and illustrations have instead emphasised his blackness. In tracing the split legacies of Salvador of Chicaloma, through exported photographs and the formation of local legends, this work reveals how identity was constructed, evacuated, and made anew. This fluidity of representation was made possible, in part, by the relative archival invisibility of afrodescendientes in Andean South America, whose lives and histories remain largely uninscribed.     

基于71M6542F的高精度智能电表的设计

介绍一种以美信片上系统71M6542F为核心的单相智能电能表的设计,给出了该电表的关键硬件电路和软件流程。该系统采用了单芯片集成系统的设计方法,打破了智能电表由计量芯片加控制芯片的常规设计思路。应用表明,该电表计量精度高、抗干扰能力强、市场前景好。     

Intermediate goods and the location of productive activity

This paper assesses the impact of the production and use of an intermediate good upon the location of productive activity in an economy consisting of two asymmetrically sized regions. The Nash equilibria of locations of an upstream and two downstream firms are completely defined in the the space of parameters transport cost and intensity of vertical linkages. While the relationship between transport cost and agglomeration is usually regarded as a decreasing one, the inclusion of an intermediate good can make it nonmonotonic.Received: September 2003/Accepted:01 March 2004The author wishes to thank the Editor of The Annals of Regional Science and three anonymous referees for helpful comments. The usual disclaimer applies.     

基于71M6543G的三相智能电表实现

针对我国智能电网的发展趋势和需求,介绍一种以71M6543G为核心的三相智能电表的设计方案。详细介绍了智能电表关键硬件部分以及软件部分的实现。设计采用MAXIM公司生产的第四代多相电表片上系统(SoC)71M6543G,实际使用表明,该电表设计抗干扰能力强,精度高,符合当前市场对智能电表的实际需求。     

Annealing-free multi-thermal techniques comprising aging,cycling and seeding to enhance performance of thick P3HT:PCBM photovoltaic cells via developing hairy crystals

Distinct multi-thermal treatments comprising cycling, aging, and seeding were introduced to prepare very thick bulk heterojunction (BHJ) active layers (ca. 800 nm) of poly(3-hexylthiophene) (P3HT):phenyl-C71-butyric acid methyl ester (PC71BM) photovoltaic cells. To this end, various P3HT₄₈₈₀₀-based rod-coil block copolymers having the coily blocks of polystyrene (PS), poly(methyl methacrylate) (PMMA), and poly(ethylene glycol) (PEG) were synthesized. The grazing incidence X-ray scattering, field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) analyses proved that the dielectric coily blocks, which were excluded from the P3HT crystalline structure, accumulated on the crystals surface without decreasing the crystal quality and formed hairy crystals. The multi-thermal techniques facilitated stacking of the growth planes in π-π direction for the P3HT crystals, thereby, this dimension was improved from 5 to 27 nm for conventionally prepared BHJs to 53–265 nm for multi-thermally developed ones. The hydrophobic coily blocks were capable of neutralizing the influence of the PCBM molecules presence in the growth environment, which resulted in the larger P3HT crystals in a similar condition. By switching the conventional spin coating approach to the cycling, aging, and seeding methods, the P3HT crystals and the PCBM clusters were gradually coarsened and the respective d-spacings decreased. This trend enhanced the hole mobility (=8.8×10⁻⁵ cm²/Vs), electron mobility (=2.5×10⁻³ cm²/Vs), short circuit current density (J_sc=12.02 mA/cm²), fill factor (FF=69%), and power conversion efficiency (PCE=4.39%) up to the maximum values for seeding approach. Moreover, the higher percentages of face-on orientation were detected in the BHJs with lower d-spacings in the hexyl side chain direction. Hairy P3HT₄₈₈₀₀-b-PS crystals developed by seeding method possessed the highest face-on orientation (~5.5%).     

基于TDK71M6513 的智能仪表设计

介绍了一种低成本、稳定可靠的智能仪表的硬件设计与软件设计。系统采用TDK71M6513 为计量与管理核心,具有高精度测量、分时电能计量、液晶显示、数据储存、负荷曲线、事件记录、负荷控制等功能。并具有RS485 数据通信接口,遵循自动抄表协议以完成抄表功能。详细阐述了系统组成模块、工作原理,通信电路设计以及软件结构。最后列出实验测试数据。系统已在实践中得到应用,达到设计标准。