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101.
针对常规分立双积分AD只能处理单端信号的问题,给出了一种输入和基准电压均支持差分信号的分立差分双积分AD;在热电阻测量中,把热电阻和基准电阻串联同一回路,以基准电阻压降作为基准,对热电阻的压降进行测量,并从软硬件两个方面对常见的误差因素进行对消处理;实验表明,该电路用于PT100测温时,跳字不超过0.1℃,精度可以达到±0.1℃,且对运放型号无特殊要求,是一种低成本、高精度的温度测量方案. 相似文献
102.
In double-pulse laser-induced breakdown spectroscopy(DP-LIBS), the collinear femtosecond double-pulse laser configuration is experimentally investigated with different initial sample temperatures using a Ti:sapphire laser. The glass sample is ablated to produce the plasma spectroscopy. During the experiment, the detected spectral lines include two Na(I) lines(589.0 nm and 589.6 nm) and one Ca(I) line at the wavelength of 585.7 nm. The emission lines are measured at room temperature(22 ℃) and three higher initial sample temperatures(T_s?=?100 ℃, 200 ℃, and 250 ℃). The inter-pulse delay time ranges from-250 ps to 250 ps.The inter-pulse delay time and the sample temperature strongly influence the spectral intensity,and the spectral intensity can be significantly enhanced by increasing the sample temperature and selecting the optimized inter-pulse time. For the same inter-pulse time of 0 ps(single-pulse LIBS), the enhancement ratio is approximately 2.5 at T_s?=?200 ℃ compared with that obtained at T_s?=?22 ℃. For the same inter-pulse time of 150 ps, the enhancement ratio can be up to 4 at T_s?=?200 ℃ compared with that obtained at T_s?=?22 ℃. The combined enhancement effects of the different initial sample temperatures and the double-pulse configuration in femtosecond LIBS are much stronger than that of the different initial sample temperatures or the double-pulse configuration only. 相似文献
103.
104.
在基于短时能量和短时过零率的双门限语音端点检测算法基础上,改进其有效语音的判断条件,采用MATLAB工具分析了改进算法的有效性。提出了基于改进算法的语音端点检测电路的设计,该设计减少了实现语音端点检测电路对硬件资源的需求。ModelSim仿真验证表明,改进后的算法有较好的实时性,在采集完一帧语音数据后第4拍给出语音有效信号。最后给出该语音检测电路的FPGA验证平台。 相似文献
105.
106.
Mathieu Balcaen Lien Vermeir Arnout Declerck Paul Van Der Meeren 《Particulate Science and Technology》2013,31(5):565-570
ABSTRACTDuring the preparation of W/O/W-type double emulsions, a part of the internal water phase is often released to the external water phase. Thus, it is important that the enclosed water volume fraction can be determined in a simple and straightforward manner after preparation. In this work, a method is developed to determine the enclosed water volume fraction of W/O/W-type double emulsions using analytical photocentrifugation after which the results are compared to the enclosed water volume fraction as determined using pulsed field gradient Nuclear Magnetic Resonance (NMR). From the results, it can be concluded that analytical photocentrifugation is indeed a simple and straightforward method to determine the enclosed water volume fraction of double emulsions. 相似文献
107.
108.
利用ANSYS/LS-DYNA仿真软件研究了药型罩曲率半径对双层药型罩EFP战斗部成形及侵彻特性的影响规律。数值计算结果表明,当药型罩曲率半径的相对值在0.67~0.93时,弧锥结合型双层药型罩EFP战斗部可成形具有良好外形的侵彻体;此时,成形侵彻体的最大侵彻深度约为1倍装药口径。试验结果表明,双层药型罩EFP战斗部成形侵彻体能够有效击穿2层2 cm厚45#钢靶,成形侵彻体对钢靶侵彻的开口形状近似呈现圆形,是具有相同装药结构EFP战斗部成形侵彻体侵彻深度的2倍左右。研究结果可以为双层药型罩EFP战斗部结构优化设计提供参考。 相似文献
109.
Eiji Kamio Tomoki Yasui Yu Iida Jian Ping Gong Hideto Matsuyama 《Advanced materials (Deerfield Beach, Fla.)》2017,29(47)
Highly robust ion gels, termed double‐network (DN) ion gels, composed of inorganic/organic interpenetrating networks and a large amount of ionic liquids (ILs), are fabricated. The DN ion gels with an 80 wt% IL content show extraordinarily high mechanical strength: more than 28 MPa of compressive fracture stress. In the DN ion gel preparation, a brittle inorganic network of physically bonded silica nanoparticles and a ductile organic network of polydimethylacrylamide (PDMAAm) are formed in the IL. Because of the different reaction mechanisms of the inorganic/organic networks, the DN ion gels can be formed by an easy and free‐shapeable one‐pot synthesis. They can be prepared in a controllable manner by manipulating the formation order of the inorganic and organic networks via not only multistep but also single‐step processes. When silica particles form a network prior to the PDMAAm network formation, DN ion gels can be prepared. The brittle silica particle network in the DN ion gel, serving as sacrificial bonds, easily ruptures under loading to dissipate energy, while the ductile PDMAAm network maintains the shape of the material by the rubber elasticity. Given the reversible physical bonding between the silica particles, the DN ion gels exhibit a significant degree of self‐recovery by annealing. 相似文献
110.
Dong Xie Wangjia Tang Yadong Wang Xinhui Xia Yu Zhong Ding Zhou Donghuang Wang Xiuli Wang Jiangping Tu 《Nano Research》2016,9(6):1618-1629
Scrupulous design and fabrication of advanced electrode materials are vital for developing high-performance sodium ion batteries. Herein, we report a facile one-step hydrothermal strategy for construction of a C-MoSe2/rGO composite with both high porosity and large surface area. Double modification of MoSe2 nanosheets is realized in this composite by introducing a reduced graphene oxide (rGO) skeleton and outer carbon protective layer. The MoSe2 nanosheets are well wrapped by a carbon layer and also strongly anchored on the interconnected rGO network. As an anode in sodium ion batteries, the designed C-MoSe2/rGO composite delivers noticeably enhanced sodium ion storage, with a high specific capacity of 445 mAh·g-1 at 200 mA·g-1 after 350 cycles, and 228 mAh·g-1 even at 4 A·g-1; these values are much better than those of C-MoSe2 nanosheets (258 mAh·g-1 at 200 mA·g-1 and 75 mAh·g-1 at 4 A·g-1). Additionally, the sodium ion storage mechanism is investigated well using ex situ X-ray diffraction and transmission electron microscopy methods. Our proposed electrode design protocol and sodium storage mechanism may pave the way for the fabrication of other high-performance metal diselenide anodes for electrochemical energy storage.
相似文献