在我上期的文章《Windows XP Service Pack2发布倒计时：强制安全防护》和《初识WindOWS防火墙》里，讨论了windows XP SP2——尤其是该Service Pack版本默认启用Windows防火墙(以前叫ICF)。现在微软把SP2的发布时间延迟到今年8月，我...在我上期的文章《Windows XP Service Pack2发布倒计时：强制安全防护》和《初识WindOWS防火墙》里，讨论了windows XP SP2——尤其是该Service Pack版本默认启用Windows防火墙(以前叫ICF)。现在微软把SP2的发布时间延迟到今年8月，我就有更多的时间给大家作Windows防火墙特征的概述。展开更多
To improve the compactness and properties of C/C-SiC-ZrC composites produced by precursor infiltration and pyrolysis(PIP)method,the low-temperature reactive melt infiltration(RMI)process was used to seal the composite...To improve the compactness and properties of C/C-SiC-ZrC composites produced by precursor infiltration and pyrolysis(PIP)method,the low-temperature reactive melt infiltration(RMI)process was used to seal the composites using Zr_(2)Cu as the filler.The microstructure,mechanical properties,and ablation properties of the Zr_(2)Cu packed composites were analyzed.Results show that during Zr_(2)Cu impregnation,the melt efficiently fills the large pores of the composites and is converted to ZrCu due to a partial reaction of zirconium with carbon.This results in an increase in composite density from 1.91 g/cm^(3)to 2.24 g/cm^(3)and a reduction in open porosity by 27.35%.Additionally,the flexural strength of Zr_(2)Cu packed C/C-SiC-ZrC composites is improved from 122.78±8.09 MPa to 135.53±5.40 MPa.After plasma ablation for 20 s,the modified composites demonstrate superior ablative resistance compared to PIP C/C-SiC-ZrC,with mass ablation and linear ablation rates of 2.77×10^(−3)g/s and 2.60×10^(−3)mm/s,respectively.The“selftranspiration”effect of the low-melting point copper-containing phase absorbs the heat of the plasma flame,further reducing the ablation temperature and promoting the formation of refined ZrO_(2)particles within the SiO_(2)melting layer.This provides more stable erosion protection for Zr_(2)Cu packed C/C-SiC-ZrC composites.展开更多
8月中旬,微软宣布投入巨资研发的Windows XP Service Pack2完成,并将免费提供给用户。微软的这一举措,在市场上引起了强烈的反响。相当数量的用户表示了欢迎,但一些自身做了应用开发的企业表示会谨慎对待,因为SP2和其系统出现了不兼容...8月中旬,微软宣布投入巨资研发的Windows XP Service Pack2完成,并将免费提供给用户。微软的这一举措,在市场上引起了强烈的反响。相当数量的用户表示了欢迎,但一些自身做了应用开发的企业表示会谨慎对待,因为SP2和其系统出现了不兼容问题。对于这样的用户,微软正视了问题的存在,强调要做好整体规划并做详尽测试后再安装SP2,微软会提供相应的技术支持和帮助。9月15日,SP2的简体中文版也正式发布了。无论是从网上,还是光盘,还是电话技术支持,中国用户想要得到SP2,都是免费的。继9月13日本栏目推出windows XP2中文版专题报道《要不要立即升级SP2》之后,本期继续关注这方面的话题。栏目热线:jiez@ccu.com.展开更多
Electrochemical reduction of CO_(2) to fuels and chemicals is a viable strategy for CO_(2) utilization and renewable energy storage.Developing free-standing electrodes from robust and scalable electrocatalysts becomes...Electrochemical reduction of CO_(2) to fuels and chemicals is a viable strategy for CO_(2) utilization and renewable energy storage.Developing free-standing electrodes from robust and scalable electrocatalysts becomes highly desirable.Here,dense SnO_(2) nanoparticles are uniformly grown on three-dimensional(3D)fiber network of carbon cloth(CC)by a facile dip-coating and calcination method.Importantly,Zn modification strategy is employed to restrain the growth of long-range order of SnO_(2) lattices and to produce rich grain boundaries.The hybrid architecture can act as a flexible electrode for CO_(2)-to-formate conversion,which delivers a high partial current of 18.8 m A cm-2 with a formate selectivity of 80%at a moderate cathodic potential of-0.947 V vs.RHE.The electrode exhibits remarkable stability over a 16 h continuous operation.The superior performance is attributed to the synergistic effect of ultrafine SnO_(2) nanoparticles with abundant active sites and 3D fiber network of the electrode for efficient mass transport and electron transfer.The sizeable electrodes hold promise for industrial applications.展开更多
In this study, the two kinds of Fe-Al coatings were fabricated by pack aluminizing on low-carbon steel at different temperatures. The corrosion behavior of the Fe-Al coatings in artificial seawater was investigated by...In this study, the two kinds of Fe-Al coatings were fabricated by pack aluminizing on low-carbon steel at different temperatures. The corrosion behavior of the Fe-Al coatings in artificial seawater was investigated by the electrochemical and weight loss techniques. Results show that the thickness of coating layer increases with increasing aluminizing temperature. The coatings exhibit high micro-hardness and good metallurgical bonding with the substrate. In comparison with the steel substrate, the corrosion current density Ico^r of the Fe-AI coatings is always lower than that of substrate, about 1/38 or 1/33 after 2 h immersion, and 1/3 or 1/6 for 720 h immersion. As can be seen from the weight loss curve, the Fe-AI coatings show less loss than that of the substrate within 30-day immersion. The corrosion products formed on the surface of the coatings include oxides of Al, Mg, Fe and Ca, and pitting defect has also been found. The Fe-Al coating with higher content of Fe2Al5 has better corrosion resistance.展开更多
Densification of mono-sized sphere packings using two-dimensional （2D） vibration was experimentally studied. The effects of vibration mode, amplitude and frequency, feeding method, and container size on packing dens...Densification of mono-sized sphere packings using two-dimensional （2D） vibration was experimentally studied. The effects of vibration mode, amplitude and frequency, feeding method, and container size on packing density were systematically analyzed. Useful results were obtained.展开更多
文摘在我上期的文章《Windows XP Service Pack2发布倒计时：强制安全防护》和《初识WindOWS防火墙》里，讨论了windows XP SP2——尤其是该Service Pack版本默认启用Windows防火墙(以前叫ICF)。现在微软把SP2的发布时间延迟到今年8月，我就有更多的时间给大家作Windows防火墙特征的概述。
基金Open Fund of Zhijian Laboratory,Rocket Force University of Engineering(2024-ZJSYS-KF02-09)National Natural Science Foundation of China(51902028,52272034)+1 种基金Key Research and Development Program of Shaanxi(2023JBGS-15)Fundamental Research Funds for the Central Universities(Changan University,300102313202,300102312406)。
文摘To improve the compactness and properties of C/C-SiC-ZrC composites produced by precursor infiltration and pyrolysis(PIP)method,the low-temperature reactive melt infiltration(RMI)process was used to seal the composites using Zr_(2)Cu as the filler.The microstructure,mechanical properties,and ablation properties of the Zr_(2)Cu packed composites were analyzed.Results show that during Zr_(2)Cu impregnation,the melt efficiently fills the large pores of the composites and is converted to ZrCu due to a partial reaction of zirconium with carbon.This results in an increase in composite density from 1.91 g/cm^(3)to 2.24 g/cm^(3)and a reduction in open porosity by 27.35%.Additionally,the flexural strength of Zr_(2)Cu packed C/C-SiC-ZrC composites is improved from 122.78±8.09 MPa to 135.53±5.40 MPa.After plasma ablation for 20 s,the modified composites demonstrate superior ablative resistance compared to PIP C/C-SiC-ZrC,with mass ablation and linear ablation rates of 2.77×10^(−3)g/s and 2.60×10^(−3)mm/s,respectively.The“selftranspiration”effect of the low-melting point copper-containing phase absorbs the heat of the plasma flame,further reducing the ablation temperature and promoting the formation of refined ZrO_(2)particles within the SiO_(2)melting layer.This provides more stable erosion protection for Zr_(2)Cu packed C/C-SiC-ZrC composites.
文摘8月中旬,微软宣布投入巨资研发的Windows XP Service Pack2完成,并将免费提供给用户。微软的这一举措,在市场上引起了强烈的反响。相当数量的用户表示了欢迎,但一些自身做了应用开发的企业表示会谨慎对待,因为SP2和其系统出现了不兼容问题。对于这样的用户,微软正视了问题的存在,强调要做好整体规划并做详尽测试后再安装SP2,微软会提供相应的技术支持和帮助。9月15日,SP2的简体中文版也正式发布了。无论是从网上,还是光盘,还是电话技术支持,中国用户想要得到SP2,都是免费的。继9月13日本栏目推出windows XP2中文版专题报道《要不要立即升级SP2》之后,本期继续关注这方面的话题。栏目热线:jiez@ccu.com.
基金supported by the National Natural Science Foundation of China(51902204,22003041,21975163)Bureau of Industry and Information Technology of Shenzhen(201901171518)Shenzhen Science and Technology Program(KQTD20190929173914967)。
文摘Electrochemical reduction of CO_(2) to fuels and chemicals is a viable strategy for CO_(2) utilization and renewable energy storage.Developing free-standing electrodes from robust and scalable electrocatalysts becomes highly desirable.Here,dense SnO_(2) nanoparticles are uniformly grown on three-dimensional(3D)fiber network of carbon cloth(CC)by a facile dip-coating and calcination method.Importantly,Zn modification strategy is employed to restrain the growth of long-range order of SnO_(2) lattices and to produce rich grain boundaries.The hybrid architecture can act as a flexible electrode for CO_(2)-to-formate conversion,which delivers a high partial current of 18.8 m A cm-2 with a formate selectivity of 80%at a moderate cathodic potential of-0.947 V vs.RHE.The electrode exhibits remarkable stability over a 16 h continuous operation.The superior performance is attributed to the synergistic effect of ultrafine SnO_(2) nanoparticles with abundant active sites and 3D fiber network of the electrode for efficient mass transport and electron transfer.The sizeable electrodes hold promise for industrial applications.
基金supported by the Foundation of Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology (No. ASMA 201403)Cooperative Innovation Fund of Jiangsu Province (No. BY 2014004-09)
文摘In this study, the two kinds of Fe-Al coatings were fabricated by pack aluminizing on low-carbon steel at different temperatures. The corrosion behavior of the Fe-Al coatings in artificial seawater was investigated by the electrochemical and weight loss techniques. Results show that the thickness of coating layer increases with increasing aluminizing temperature. The coatings exhibit high micro-hardness and good metallurgical bonding with the substrate. In comparison with the steel substrate, the corrosion current density Ico^r of the Fe-AI coatings is always lower than that of substrate, about 1/38 or 1/33 after 2 h immersion, and 1/3 or 1/6 for 720 h immersion. As can be seen from the weight loss curve, the Fe-AI coatings show less loss than that of the substrate within 30-day immersion. The corrosion products formed on the surface of the coatings include oxides of Al, Mg, Fe and Ca, and pitting defect has also been found. The Fe-Al coating with higher content of Fe2Al5 has better corrosion resistance.
基金supported by National Natural Science Foundation of China(No.50974040)Personnel Department of Liaoning Province(No.2009921053)
文摘Densification of mono-sized sphere packings using two-dimensional （2D） vibration was experimentally studied. The effects of vibration mode, amplitude and frequency, feeding method, and container size on packing density were systematically analyzed. Useful results were obtained.
