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1. chinaXiv:201707.00135 [pdf]

Simultaneous fusion, imaging and encryption of multiple objects using a single-pixel detector

Shi Dongfeng; Huang Jian, Wang Yingjian, Yuan Kee, Xie Chenbo, Liu Dong and Zhu Wenyue
分类: 物理学 >> 电磁学、光学、声学、传热、经典力学和流体动力学

A novel technique for the simultaneous fusion, imaging and encryption of multiple objects using a single-pixel detector is proposed. Here, encoded multiplexing speckles are employed to illuminate multiple objects simultaneously. The mixed light reflected from the objects is detected by a single-pixel detector. An iterative reconstruction method is used to restore the fused image by summing the multiplexed speckles and detected intensities. Next, clear images of the objects are recovered by decoding the fused image. We experimentally obtain fused and multiple clear images by utilizing a single-pixel detector to collect the direct and indirect reflected light. Technically, by utilizing the speckles with per-pixel exposure control, multiple objects’ information is multiplexed into the detected intensities and then demultiplexed computationally under the single-pixel imaging and compressed sensing schemes. An encryption experiment is performed by setting the multiplexed speckles’ encoding as keys. We find that the encryption performance in a scattering medium is better than that in a clear medium.

提交时间: 2017年07月13日 点击量:20, 下载量:13

2. chinaXiv:201707.00056 [pdf]

Killing Vectors in Spacetime of the De Sitter Invariant Special Relativity

Yan, Mu-Lin
分类: 物理学 >> 基本粒子与场物理学

In this paper, we use the Killing vector method to formulate the de Sitter/Anti-de Sitter invariant special relativity (dS/AdS-SR). Through solving the Einstein equation with $\Lambda\neq 0$, the basic inertial metric for dS/AdS-SR is determined to be the Beltrami metric $B_{\mu\nu}(x)$. The corresponding Killing equations are system of ten simultaneous partial differential equations of first order. Their most general solutions were obtained, and all the ten independent Killing vectors were found out. These results confirm that the Beltrami metric has maximal spacetime symmetry. The ten Killing-Noether charges are obtained. They are energy, momenta, Lorentz boost and angular momentum in SR-theory with $\Lambda\neq 0$. Consequently, dS/AdS-SR is consistently established for the vacuum with $\Lambda\neq 0$ via Killing vector method rather than the unpopular classical domain theory.

提交时间: 2017年07月08日 点击量:255, 下载量:80

3. chinaXiv:201705.00860 [pdf]

基于Pulser-sustainer 放电的高重复频率长脉冲TE CO2 激光器持续运转特性

卢远添; 黄文武; 钟艳红; 刁伟伦; 柯长军; 吴谨
分类: 物理学 >> 电磁学、光学、声学、传热、经典力学和流体动力学

摘要:研究了一台长脉冲紫外预电离 TE CO2 激光器的长时间持续运转特性。激光器增益体积为 1.17L、采用摘要:研究了一台长脉冲紫外预电离 TE CO2 激光器的长时间持续运转特性。激光器增益体积为 1.17L、采用Pulser/sustainer 放电激励。在工作气体气压 30kPa、不采用固体催化剂的条件下,采用三种放电脉冲宽度(14.2us, 20.0us 和 24.5us) 和不同的注入能量,激光器分别连续不中断运转 30 分钟。详细记录了单脉冲放电时激光器的典型放电电压/电流波形和相应激光脉冲波形以及高重复频率工作时激光平均功率的实时变化曲线。数据显示,这种长脉冲 TE CO2激光器在不同放电脉冲宽度、不同注入能量、不同脉冲重复频率下均成功稳定运转 30 分钟,激光平均功率下降均小于 15%;同时,这种激光器在高重复频率运转时具备较好的“抗起弧”能力,偶尔的起弧放电不会雪崩发展至中断激光输出。研究结果表明,这种长脉冲 TE CO2激光器在高重复频率下具备良好持续运转能力。

提交时间: 2017年05月18日 点击量:1247, 下载量:274

4. chinaXiv:201705.00086 [pdf]

Tandem catalytic conversion of 1-butene and ethene to propene over combined mesoporous W-FDU-12 and MgO catalysts

Xu, W [Xu, Wei][ 1,2 ]; Lin, C [Lin, Chao][ 1 ]; Liu, H [Liu, Huan][ 1 ]; Yu, HB [Yu, Hongbo][ 1 ]; Tao, K [Tao, Kai][ 1 ]; Zhou, SH [Zhou, Shenghu][ 1 ]
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等

Tungsten substituted mesoporous FDU-12 (W-FDU-12) catalysts were synthesized by a one-pot hydrothermal process using F127 as the structure directing agent. The studies of TEM, SAXS and BET illustrated that the highly ordered mesoporous structure of FDU-12 was maintained in the doped W-FDU-12 samples. XPS studies revealed that a high concentration of W5+ species appeared in doped W-FDU-12 catalysts whereas supported WO3/FDU-12 and WO3/SiO2 catalysts only contained W6+ species. Tandem catalytic conversion of 1-butene and ethene to propene through isomerization of 1-butene to 2-butene and consecutive cross metathesis of 2-butene and ethene in a fixed-bed reactor at different temperatures and atmospheric pressure was used to evaluate the catalytic performance of the W-FDU-12 catalyst, combined with MgO. The catalytic results showed that the doped W-FDU-12 illustrated a superior catalytic performance relative to the supported WO3/FDU-12 and WO3/SiO2 catalysts. The higher metathesis activity of W-FDU-12 catalysts can be ascribed to the good dispersion of W species and the incorporation of W species into the framework of FDU-12, forming a substantial amount of W5+, which was beneficial for the cross metathesis of 2-butene and ethene to propene.

提交时间: 2017年05月08日 点击量:725, 下载量:78

5. chinaXiv:201705.00166 [pdf]

High thermoelectric performance in two-dimensional graphyne sheets predicted by first-principles calculations

Tan, XJ [Tan, Xiaojian][ 1 ]; Shao, HZ [Shao, Hezhu][ 1 ]; Hu, TQ [Hu, Tianqi][ 1 ]; Liu, GQ [Liu, Guoqiang][ 1 ]; Jiang, J [Jiang, Jun][ 1 ]; Jiang, HC [Jiang, Haochuan][ 1 ]
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等

The thermoelectric properties of two-dimensional graphyne sheets are investigated by using first- principles calculations and the Boltzmann transport equation method. The electronic structure indicates a semiconducting phase for graphyne, compared with the metallic phase of graphene. Consequently, the obtained Seebeck coefficient and the power factor of graphyne are much higher than those of graphene. The calculated phonon mean free path for graphene is 866 nm, which is in good agreement with the experimental value of 775 nm. Meanwhile the phonon mean free path of graphyne is only 60 nm, leading to two order lower thermal conductivity than graphene. We show that the low thermal conductivity of graphyne is due to its mixed sp/sp2 bonding. Our calculations show that the optimized ZT values of graphyne sheets can reach 5.3 at intermediate temperature by appropriate doping.

提交时间: 2017年05月08日 点击量:661, 下载量:114

6. chinaXiv:201705.00065 [pdf]

Structural effect on the resistive switching behavior of triphenylamine-based poly[azomethine]s

Zhang, WB [Zhang, Wenbin][ 1,2 ]; Wang, C [Wang, Cheng][ 3 ]; Liu, G [Liu, Gang][ 1 ]; Wang, J [Wang, Jun][ 2 ]; Chen, Y [Chen, Yu][ 3 ]; Li, RW [Li, Run-Wei][ 1 ]
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等

Linear and hyperbranched poly(azomethine)s (PAMs)-based on tri- phenylamine moieties are synthesized and used as the functioning layers in the Ta/PAM/Pt resistive switching memory devices. Com- parably, the hyperbranched PAM with isotropic architecture and semi-crystalline nature shows enhanced memory behaviors with more uniform distribution of the HRS and LRS resistances.

提交时间: 2017年05月08日 点击量:641, 下载量:98

7. chinaXiv:201705.00159 [pdf]

Fabrication of stretchable, flexible conductive thermoplastic polyurethane/graphene composites via foaming

Chen, YJ [Chen, Yuejuan][ 1 ]; Li, Y [Li, Yang][ 1 ]; Xu, DH [Xu, Donghua][ 2 ]; Zhai, WT [Zhai, Wentao][ 1 ]
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等

Stretchable and flexible conductive polymers have aroused great interest recently because of their applications in the fields of novel electronics, such as smart textiles, artificial electronic skin, flexible electronic displays, etc. In this work, stretchable and flexible conductive thermoplastic polyurethane (TPU)/graphene composite foams have been developed by water vapour induced phase separation. The as-prepared TPU/graphene composite foams exhibited a lower modulus, larger elongation at break, and lower hysteresis during a cycle tensile test than a TPU/graphene composite did. It is expected that the improved elasticity of the TPU/graphene composite foams was caused by the deformation of cells, which partially offset the deformation of the TPU matrix. In addition, the cell walls divided the whole composites into many small parts, which could further restrain plastic deformation of hard segment domains under deformation.

提交时间: 2017年05月08日 点击量:657, 下载量:107

8. chinaXiv:201705.00095 [pdf]

Research progress on bio-based thermosetting resins

Ma, SQ [Ma, Songqi][ 1 ]; Li, TT [Li, Tingting][ 1,2 ]; Liu, XQ [Liu, Xiaoqing][ 1 ]; Zhu, J [Zhu, Jin][ 1 ]
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等

Compared with the rapid progress on bio-based thermoplastics, research on bio-based thermosetting resins should have attracted much more attention, considering that they will have a bright future. In this paper, the current research progress on bio-based thermosetting resins is reviewed. We pay special attention to the synthesis and investigation of properties of epoxies and unsaturated polyesters derived from renewable plant oil, cardanol, rosin acid, lignin, glycerol, gallic acid, furan, isosorbide, itaconic acid, etc. This mini review gives an overall perspective for bio-based thermosets. © 2015 Society of Chemical Industry

提交时间: 2017年05月08日 点击量:452, 下载量:115

9. chinaXiv:201705.00123 [pdf]

Fabricating binary anti-corrosion structures containing superhydrophobic surfaces and sturdy barrier layers for Al alloys

Wu, YH [Wu, Yinghao][ 1,2 ]; Zhao, WJ [Zhao, Wenjie][ 1 ]; Wang, WR [Wang, Wurong][ 2 ]; Sui, WJ [Sui, Wenjie][ 1 ]
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等

Aluminum alloys with novel binary anti-corrosion structures on the surface showing superhydrophobic properties were fabricated via chemical etching, anodic oxidation and chemical modification. Surface morphologies and chemical elements of the as-prepared films were investigated by Fourier transform infrared spectrometer, scanning electron microscopy and confocal laser scanning microscope. Surface wettability was investigated by the contact angle meter. Manipulation of surface morphology by anodic oxidation current density and the influence of surface chemical modification on the wettability were investigated. The anti-corrosion properties of the as-prepared films were characterized using an electrochemistry workstation. The results showed that surface water contact angle could reach 156 after chemical modification when the current density of anodic oxidation was 5 A dm 2. The corrosion potential (Ecorr) was positively increased from 1189 mV for bare Al alloys to 304 mV for the samples anodized at 5 A dm 2. The synergetic effect between the protective properties of air trapped in a low adhesion superhydrophobic surface and good barrier properties of the barrier layer of anodic oxidation film was remarkably enhanced the corrosion resistance of aluminum alloys. Influences of the anodic oxidation current density and the self-assembled films on the anti-corrosion performance were discussed in detail.

提交时间: 2017年05月08日 点击量:613, 下载量:67

10. chinaXiv:201705.00163 [pdf]

Highly flexible and transparent film heaters based on polyimide films embedded with silver nanowires

Huang, QJ [Huang, Qijin][ 1 ]; Shen, WF [Shen, Wenfeng][ 1 ]; Fang, XZ [Fang, Xingzhong][ 1 ]; Chen, GF [Chen, Guofei][ 1 ]; Guo, JC [Guo, Junchao][ 1 ]; Xu, W [Xu, Wei][ 1 ]; Tan, RQ [Tan, Ruiqin][ 2 ]; Song, WJ [Song, Weijie][ 1 ]
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等

Highly flexible and transparent film heaters (TFHs) with superior mechanical and thermal stability were fabricated by embedding silver nanowires (AgNWs) into transparent polyimide (PI) films using a solution coating method. The fabricated AgNW/PI hybrid TFHs exhibited higher heating temperatures ($96 C) with lower input voltage ($6 V), shorter response time (T < 40 s), and lower power consumption (160.6 C cm2 W 1) than ITO/FTO heaters, as well as stability after repeated use. The AgNW/PI hybrid TFHs also showed excellent resistance to bending. After undergoing outer bending for a 1000 times, the change of sheet resistance was less than 18%. The effective embedment of the AgNW network in the surface of the transparent PI film not only decreased the surface roughness (Rrms < 1 nm) but also enhanced the resistance against oxidation and moisture. Potential applications of the AgNW/PI TFHs in window defogging and thermochromics are demonstrated.

提交时间: 2017年05月08日 点击量:645, 下载量:109

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