Pereformance and cooperative thresholds analysis for cooperative MIMO system

In this paper,the bit error rate(BER) performance of cooperative multiple input multiple output(MIMO) system is analyzed and two thresholds for decode-and-forward(DF) cooperative network are proposed.While the two thresholds are satisfied,the cooperative network may achieve a notable improvement of BER performance compared with the non-cooperative network.The analysis and simulation results show that the average BER of cooperation with the two thresholds is much lower than traditional cooperation,and the average BER of cooperation with only threshold one is almost the same as the former scheme and it is much easier to implement.

Robust Audio Blind Watermarking Algorithm Based on Haar Transform

To solve the problem of low capacity of audio watermarking information and poor robustness of impact resistance,a digital audio watermark algorithm based on wavelet transform is presented in this paper. In this algorithm,the fine and approximate components are obtained when the Haar wavelet base is used to convert each frame of the audio signal to its discrete transform. Then the HAS algorithm is applied to the fine component embedded with watermark to realize encryption process. The original audio carrier signal is not needed in extraction,as long as the signal is embedded after the frame is divided. The first two sections of each frame are implemented in Haar transform respectively to get the fine and approximate component. The watermark images are obtained from the former two fine components of the energy watermark sequence after calculating,comparing and extracting. The simulation results show that there is a certain transparency for the algorithm,a good robustness against the resampling and low pass filtering attack.

Active/passive Q-switching operation of 2 μm Tm,Ho:YAP laser with an acousto-optical Q-switch/MoS_2 saturable absorber mirror

The active/passive Q-switching operation of a 2 μm a-cut Tm,Ho:YAP laser was experimentally demonstrated with an acousto-optical Q–switch∕MoS_2 saturable absorber mirror. The active Q-switch laser was operated for the first time, to the best of our knowledge, with an average output power of 12.3 W and a maximum pulse energy of 10.3 mJ. The passive Q-switch laser was also the first acquired with an average output power of 3.3 W and per pulse energy of 23.31 μJ, and the beam quality factors of M_x^2 = 1.06 and M_y^2 = 1.06 were measured at the average output power of 2 W.

Chlorine gas sensors using hybrid organic semiconductors of PANI/ZnPcCl_(16)

PANI/ZnPcCl_（16）（polyaniline doped with sulfosalicylic acid/hexadecachloro zinc phthalocyanine） powders were vacuum co-deposited onto Si substrates,where Pt interdigitated electrodes were made by micromachining.The PANI/ZnPcCl_（16） films were characterized and analyzed by SEM,and the influencing factors on its intrinsic performance were analyzed and sensitivities of the sensors were investigated by exposure to chlorine（Cl_2） gas.The results showed that powders prepared with a stoichiometric ratio of（ZnPcCl_（16））_（0.6）（PANI）_（0.4） had a preferential sensitivity to Cl_2 gas, superior to those prepared otherwise;the optimal vacuum co-deposition conditions for the films are a substrate temperature of 160℃,an evaporation temperature of 425℃and a film thickness of 75 nm;elevating the operation temperature （above 100℃） or increasing the gas concentration（over 100 ppm） would improve the response characteristics,but there should be upper levels for each.Finally,the gas sensing mechanism of PANI/ZnPcCl_（16） films was also discussed.

A method to restrain the charging effect on an insulating substrate in high energy electron beam lithography

Pattern distortions caused by the charging effect should be reduced while using the electron beam lithography process on an insulating substrate. We have developed a novel process by using the SX AR-PC 5000/90.1solution as a spin-coated conductive layer, to help to fabricate nanoscale patterns of poly-methyl-methacrylate polymer resist on glass for phased array device application. This method can restrain the influence of the charging effect on the insulating substrate effectively. Experimental results show that the novel process can solve the problems of the distortion of resist patterns and electron beam main field stitching error, thus ensuring the accuracy of the stitching and overlay of the electron beam lithography system. The main characteristic of the novel process is that it is compatible to the multi-layer semiconductor process inside a clean room, and is a green process, quite simple, fast, and low cost. It can also provide a broad scope in the device development on insulating the substrate,such as high density biochips, flexible electronics and liquid crystal display screens.