摘要：The full-duplex(FD) based wireless communication devices,which are capable of concurrently transmitting and receiving signals with a single frequency band,suffer from a severe self-interference(SI) due to the large power difference between the devices' own transmission and the useful signal comes from the remote transmitters. To enable the practical FD devices to be implementable,the SI power must be sufficiently suppressed to the level of background noise power,making the received signal-to-interference-plus-noise ratio(SINR) satisfy the decoding requirement. In this paper,the design and implementation of the duplexer for facilitating SI cancellation in FD based wireless communications are investigated,with a new type of duplexer(i.e. an improved directional coupler) designed for improving the spatial suppression of the SI power. Furthermore,the practical circuit boards are designed and verified for the proposed prototype,showing that the spatial suppression capability may be up to 36 d B(i.e. much higher than that attainable in the commonly designed ferrite circulator) by using the proposed design.

摘要：Cardiovascular diseases are the leading cause of morbidity and mortality throughout the world underlining the importance of efficient treatments including disease modeling and drug discovery by cardiac tissue ***,the predictive power of these applications is currently limited by the immature state of the ***,we developed gelatin hydrogels chemically crosslinked by genipin,a biocompatible crosslinker,as cell culture *** rat cardiomyocytes appear synchronous beatingwithin 2 days after seeding on ***,we applied the electrical stimulation as a conditioning treatment to promote the maturation of cardiomyocytes cultured on the *** results show that electrical stimulation improves the organization of sarcomeres,establishment of gap junctions,calcium-handling capacity and propagation of pacing signals,thereby,increase the beating velocity of cardiomyocytes and responsiveness to external *** above system can be applied in promoting physiological function maturation of engineered cardiac tissues,exhibiting promising applications in cardiac tissue engineering and drug screening.

摘要：To evaluate the efficiencies of different sampling methods for a rare and clustered population, we investigated the sampling effects for the two species Tamarix chinensis (Salt cedar) and Elaeagnus angustifolia (Russian olive) in western Inner Mongolia with two-stage sequential sampling, which is a new sampling method, traditional simple random sampling and two-stage sampling. Based on two-stage sequential sampling and two-stage sampling, each population was partitioned into four primary sampling units, and then two of them were randomly selected. Sampling designs were simulated based on the conditions of five secondary sampling unit areas, two criterion values, five initial secondary sampling units and two sequential secondary sampling units in 1000 repetitions. To evaluate the performance of the sampling designs for each method, the variance and relative error of the density estimates were used. The relative sampling efficiencies of the three sampling methods were compared using the same final sampling sizes. We analyzed the sampling efficiency generated by two-stage sequential sampling and found that it yielded smaller variances than those of simple random sampling and two-stage sampling in all sampling designs, and that two-stage sampling was more efficient than simple random sampling. Density estimates from the two-stage sequential sampling were very close to the true values. We also determined the optimum secondary sampling unit areas for the two species in the two-stage sequential sampling. It was best for Tamarix chinensis and Elaeagnus angustifolia when the secondary sampling unit areas were 200 and 100 m2 , respectively.

摘要：生物材料支架的精确设计和制造是骨组织工程系统研究的基础。生物材料支架应该同时满足大孔隙率和与骨组织匹配的力学性能要求。这两个目标相互制约,大的孔隙率会降低其力学性能。利用拓扑优化的方法,在体积分数的约束下,寻求刚度最大的最优材料分布微结构。建立算法,得到了不同体积分数的2D和3D最优微结构,并提取3D拓扑优化的结果,然后将其转化为STL格式的CAD模型文件。微结构在三维方向整列成支架结构,通过选区激光熔化方法制造30%(体积分数)的Ti支架样品。从SEM图像看出,支架样品的结构和孔径与CAD模型基本一致,500μm微结构单元的平均孔径为231μm。复杂形状金属生物材料支架的精确制造证实了选区激光熔化技术在金属生物医学材料制造中的可行性。

摘要：For the surgical treatment of cardiovascular disease(CVD),there is a clear and unmet need in developing small-diameter(diameter<6 mm)vascular *** our previous work,sulfated silk fibroin(SF)was successfully fabricated as a potential candidate for preparing vascular grafts due to the great cytocompatibility and ***,vascular graft with single layer is difficult to adapt to the complex internal *** this work,polycaprolactone(PCL)and sulfated SF were used to fabricate bilayer vascular graft(BLVG)to mimic the structure of natural blood *** enhance the biological activity of BLVG,nicorandil(NIC),an FDA-approved drug with multi-bioactivity,was loaded in the BLVG to fabricate NIC-loaded *** morphology,chemical composition and mechanical properties of NIC-loaded BLVG were *** results showed that the bilayer structure of NIC-loaded BLVG endowed the graft with a biphasic drug release *** in vitro studies indicated that NIC-loaded BLVG could significantly increase the proliferation,migration and antioxidation capability of endothelial cells(ECs).Moreover,we found that the potential biological mechanism was the activation of PI3K/AKT/eNOS signaling ***,the results effectively demonstrated that NIC-loaded BLVG had a promising in vitro performance as a functional small-diameter vascular graft.

摘要：为探讨薄壁高筋筒形件整体内高压成形的可行性,采用力学分析和数值模拟相结合的方法,研究了一端约束、一段自由约束特征的薄板(加强筋)失稳的力学条件。基于"板条梁"理论给出了筋板失稳欧拉力的数学表达式。结合数值模拟分析了筋板高度和内径对失稳的影响。结果表明:对于1Cr18Ni9Ti薄壁高筋筒形件胀形量为20%时其临界高厚比和径厚比分别为14和30。随着高厚比增大,成形性降低,随着径厚比增大,成形性提高。绘制了内高压成形窗口图,为薄壁高筋筒形件内高压成形规律的深入研究和内高压成形工艺设计奠定了理论基础。

摘要：A novel 1×2 polymer electro-optic(EO)switch based on seven vertical-turning serial-coupled microrings is proposed for dropping crosstalk and obtaining flat boxlike *** device structure,theory and formulation are presented,and the microring resonance order and coupling gaps are *** switching voltage of the device for obtaining crosstalk lower than 30 dB under through state is decided to be about 1.86 *** the operation voltages of 0 V(drop state)and 1.86 V(through state),the switching performance is characterized,and the output spectrum is *** calculation results show that the crosstalk at through state and that at drop state are 30.2 dB and 53.2 dB,respectively,while the insertion losses are 0.86 dB and 3.18 dB,*** to the seven serial-coupled microrings resonance structure,the proposed switch reveals the favorable boxlike spectrum compared with the simple device with only one microring,and thus the crosstalk under drop state is improved from 26.8 dB to 53.2 *** to the low crosstalk,this device can be used in optical networks-on-chip for signal switching and routing.

摘要：利用光学显微镜、扫描电镜、透射电镜、X射线衍射、硬度和拉伸实验研究Sn添加对钨极氩弧焊接Mg-6Al-0.3Mn(质量分数,%)(AM60)合金板材的显微组织和力学性能的影响。结果表明:向AM60镁合金中添加1%(质量分数)的Sn后,即Mg-6Al-1Sn-0.3Mn(ATM610),其焊缝的硬度和接头效率均提高。ATM610镁合金焊缝抗拉强度达到母材的96.8%,且断裂位置也由热影响区转移至熔合区。焊接性能的改善主要源于合金中Mg2Sn有效阻碍热影响区晶粒的长大而形成的细小显微组织。在AM60镁合金中添加1%的Sn可改善其力学性能。

摘要：In this paper,we introduce a novel approach to automatically regulate receptive fields in deep image parsing *** previous work which placed much importance on obtaining better receptive fields using manually selected dilated convolutional kernels,our approach uses two affine transformation layers in the network’s backbone and operates on feature *** maps are inflated or shrunk by the new layer,thereby changing the receptive fields in the following *** use of end-to-end training,the whole framework is data-driven,without laborious manual *** proposed method is generic across datasets and different *** have conducted extensive experiments on both general image parsing tasks,and face parsing tasks as concrete examples,to demonstrate the method’s superior ability to regulate over manual designs.

摘要：The general performance characteristics of an irreversible quantum refrigeration cycle using many non-interacting spin-1/2 systems as the working substance and consisting of two adiabatic and two isomagnetic field processes are investigated, based on the quantum master equation and semi-group approach. Expressions for several important performance parameters such as the coefficient of performance, cooling rate and power input are derived. By using numerical solutions, the cooling rate of the refrigeration cycle subject to the finite cycle duration is optimized. The maximum cooling rate and the corresponding parameters are calculated numerically. The optimal region of the coefficient of performance and the optimal ranges of the temperatures of the working substance and the times spent on the two isomagnetic field processes are determined. Moreover, the optimal performance of the cycle in the high-temperature limit is also analysed in detail. The results obtained here are further generalized, so that they may be directly used to describe the performance of the quantum refrigeration cycle using spin-J systems as the working substance.