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1.
根据对我国境内31个省市区6000家企业法人单位进行的调查,给出了2014年下半年各企业电子商务在在线销售和在线采购两方面的使用情况,分析了企业在互联网营销推广方面的使用情况.  相似文献   
2.
The rolling process is determined by the interaction of a number of different movements,during which the relative movement occurs between the vibrating roll system and the rolled piece,and the roll system’s vibration interacts with the strip’s deformation and rigid movement.So many parameters being involved leads to a complex mechanism of this coupling effect.Through testing and analyzing the vibration signals of the mill in the rolling process,the rolling mill’s coupled model is established with comprehensive consideration of the coupling interaction between the mill’s vertical vibration,its torsional vibration and the working roll’s horizontal vibration,and vibration characteristics of different forms of rolling mill’s vibration are analyzed under the coupling effect.With comprehensive attention to the relationship between the roll system,the moving strip and the rolling parameters’dynamic properties,and also from the strip thickness control point of view,further research is done on the coupling mechanism between the roll system’s movement and the moving strip’s characteristics in the rolling process.As a result,the law of inertial coupling and the stiffness coupling effect caused by different forms of the roll system’s vibration is determined and the existence of nonlinear characteristics caused by the elastic deformation of moving strip is also found.Furthermore,a multi-parameter coupling-dynamic model is established which takes the tandem strip mill as its research object by making a detailed kinematics analysis of the roll system and using the principle of virtual work.The coupling-dynamic model proposes the instruction to describe the roll system’s movement,and analyzes its dynamic response and working stability,and provides a theoretical basis for the realization of the strip thickness’dynamic control.  相似文献   
3.
初始等轴组织Ti-55531合金在相变点以上经过0.01、0.1、1 s~(-1)不同应变速率的等温压缩变形,随后进行750℃×5 min/AC热处理。采用扫描电子显微镜和透射电子显微镜研究了后续热处理时变形α相和基体β相的静态再结晶机理。结果表明,随着应变速率的升高,残留等轴α相的含量增加。变形合金中拉长α相在经过热处理后有球化现象,同时在强度相对较高的拉长α相端部的基体β相中,位错储能较高,有助于β相再结晶形核和空冷过程中局部高密度次生α相析出。  相似文献   
4.
使用有限元软件平台ABAQUS对NbTi/Cu多芯复合超导线集束拉拔过程进行数值模拟,研究了拉拔模具参数对芯丝畸变程度的影响。通过引入畸变因子进行量化分析,获得了集束拉拔过程中芯丝畸变极小值所对应的参数区间。结果表明:工作锥半角为6°~8°,定径带长度4.5~5.5 mm,道次加工率为20%~25%时,NbTi/Cu多芯复合超导线芯丝畸变存在极小值。  相似文献   
5.
Rapid synthesis of silver nanowires(Ag NWs) with high quality and a broad processing window is challenging because of the low selectivity of the formation of multiply twinned particles at the nucleation stage for subsequent Ag NWs growth.Herein we report a systematic study of the water-involved heterogeneous nucleation of Ag NWs with high rate(less than 20 min) in a simple and scalable preparation method.Using glycerol as a reducing agent and a solvent with a high boiling point,the reaction is rapidly heated to 210 ℃ in air to synthesize Ag NWs with a very high yield in gram level.It is noted that the addition of a small dose of water plays a key role for obtaining highly pure Ag NWs in high yield,and the optimal water/glycerol ratio is0.25%.After investigating a series of forming factors including reaction temperature and dose of catalysts,the formation kinetics and mechanism of the Ag NWs are proposed.Compared to other preparation methods,our strategy is simple and reproducible.These Ag NWs show a strong Raman enhancement effect for organic molecules on their surface.  相似文献   
6.
关键词:金红石矿;深度还原;配碳比;KOH;K2CO3  相似文献   
7.
关键词: CO2; 高炉煤气; 乙酸浸出; 钙基吸附剂; 精炼渣  相似文献   
8.
In this paper,we investigate the matched filter based spectrum sensing in a more reasonable cognitive radio(CR) scenario when the primary user(PU) has more than one transmit power levels,as regulated in most standards,i.e.,IEEE 802.11 Series,GSM,LTE,LTE-A,etc.This new multiple primary transmit power(MPTP) scenario is specialized by two different targets:detecting the presence of PU and identifying the power level.Compared to the traditional binary sensing where only the presence of PU is checked,SU may attain more information about the primary network(making CR more "intelligent") and design the subsequent optimization strategy.The key technology is the multiple hypothesis testing as opposed to the traditional binary hypothesis testing.We discuss two situations under whether the channel phase is known or not,and we derive the closed form solutions for decision regions and several performance metrics,from which some interesting phenomenons are observed and the related discussions are presented.Numerical examples are provided to corroborate the proposed studies.  相似文献   
9.
为实现将协议栈移植于资源有限的嵌入式系统,论文讨论了LwIP各模块的工作机制,详细设计了LwIP的移植过程,最后设计了一个微型的嵌入式Web服务器,测试LwIP的通行功能,测试结果证明移植成功.  相似文献   
10.
In order to control the impacts of blown sand in salty desert, in this article, the amphoteric emulsion, for the first time, was applied as an ecological sand‐fixing material. This study started from the synthesis of the poly{vinyl acetate‐dibutyl maleate‐acrylamide‐co‐3‐[N‐(2‐methacroyloylethyl)‐N, N‐dimethylammonio]‐propane sulfonate} [P(VAc‐DBM‐AM‐DMAPS)] copolymer emulsion. Then, the structures, composition, thermal property of the emulsion were characterized by 1H‐NMR, FTIR, and DSC, respectively. The basic properties of the emulsion and salt tolerance of the latex films were measured by using viscometer, dynamic light scattering, and laser Doppler electrophoresis also. And the sand‐fixing properties of the emulsion were evaluated. Finally, the influence of the emulsion on the growth of soil microbe and plants were discussed for understanding its ecological effect. The experimental results showed that the emulsion has been successfully synthesized and could be as an ecological sand‐fixing material. The related reason is that, first, the emulsion could significantly improve the compressive strength and water retaining; second, the emulsion had good thermal aging, freeze‐thaw stabilities and salt tolerance to withstand the changes in temperature and NaCl concentration of salty desert; third, the influence of the emulsion on the growth of plants and microbe of sand also showed a dependable ecological effect. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43715.  相似文献   
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