Evolution of the gain extinction ratio in dual-pump phase sensitive amplification

We have experimentally achieved a gain extinction ratio (GER) of 30 dB at 21.75 dBm pump power in a dual-pump phase sensitive amplifier based on highly nonlinear fiber, which is more efficient than what we predict with the conventional three-wave model. We point out that high-order sidebands play a key role. Then we scrutinize the trajectories of the output signal vector in the complex plane with increasing nonlinear phase shift and understand the roll-over behavior of GER versus pump power curve. We found that the phase "flip" of the output signal occurs around the largest GER. Adjusting design parameters, we show how to improve GER.     

Beryllium-7 activity concentration in maize during the growth period

Beryllium-7 (⁷Be) activity in maize was measured in Yangling County, Shaanxi Province, on the Loess Plateau Region of China in 2007. The ⁷Be mass activity concentration in maize leaf samples was significantly greater than in maize stem, maize root and maize grain samples. The ⁷Be activity in maize leaves accounted for 78% of the total maize ⁷Be activity. The ⁷Be mass activity concentration in maize varied from 25.4 to 122.4 Bq kg⁻¹ and areal activity concentration held by maize from 1.2 to 111.5 Bq m⁻² during the growth period. The percentage of ⁷Be areal activity concentration held by maize relative to the ⁷Be areal activity concentration measured in reference soils ranged from 0.4 to 24.2% with a mean of 13.7%.     

有限液体负载下压电平板声板波理论分析

主要推导平板声板波受有限液体负载后能量衰减与波速改变情形, 以部分波传理论分析该受液体负载的压电平板波传行为, 并以一128$^{\circ}Y$向切角的铌酸锂芯片为例,分析前20个声板波受水与甘油负载下 的能量衰减,并固定某一平板板波, 针对不同甘油厚度负载下, 计算其相速度与衰减变化,该理论分析对于液体负载下的平板板波传感器应用具有极大的参 考价值.     

Flexible Broad‐Range Pressure Sensors Enabled by Deformation‐Induced Conductive Channels in 3D Graphene Foam@Polydimethylsiloxane Composite for Precise Vibrational Signal Detection

Here we report the design and fabrication of high‐performance pressure sensors based on three‐ dimensional (3D) graphene foam filled polydimethylsiloxane (GF@PDMS) composite with a broad sensing range spaning from 0.05 kPa to 130 kPa. The interpretation of device functioning mechanism can be classified into low and high pressure sensing regions. In the low pressure region (<15 kPa), the pressure loading leads to the temporal connection of micro‐cracks in GF scaffold and forming conductive channels. In the high pressure region (15 kPa to 130 kPa), the pressure induced deformation of GF results in the better connections among micro‐cracks and the shortening of conductive pathway to further decrease the electrical resistance. The GF@PDMS sensors exhibited accuracy, sensibility and reproducibility to detect pressure signals with remarkable stability for over 16000 loading‐unloading cycles, indicating its great potential for practical applications. Moreover, the GF@PDMS sensors also showed high performances in the detection of dynamic pressures, such as subtle mechanical vibration signals, as well as physiology vibrational signals generated by human throats. We expect this technology could be integrated into different sensing systems for the applications in wearable smart electronics and human‐machine communications.     

Effects of heat treatment and SOC on fire behaviors of lithium-ion batteries pack

Journal of Thermal Analysis and Calorimetry - Numerous lithium-ion battery fire accidents raise comprehensive safety concerns in modern society. In this paper, an experimental study was conducted...     

三倍频能量测量误差分析

从理论上分析了影响三倍能谱能量测量绝对精度和相对精度的若干因素，并且通过简单的模拟实验，验证了入射角平板取样分光比的影响，提出了三倍频能量测量中消除杂散光影响的一些特殊的技术措施。     

Synthesis of Fucosylated Chondroitin Sulfate Nonasaccharide as a Novel Anticoagulant Targeting Intrinsic Factor Xase Complex

Fucosylated chondroitin sulfate (FuCS) is a structurally distinct glycosaminoglycan, and its oligosaccharides exhibit excellent anticoagulant activity with lower risks of adverse effects and bleeding. Herein we report a facile approach to the synthesis of FuCS hexa‐ and nonasaccharides on the basis of the enzymatic degradation of chondroitin over 12 linear steps. As compared with a clinical low‐molecular‐weight heparin drug (enoxaparin), the nonasaccharide synthesized in this study displayed similar APTT activity and selective intrinsic factor Xase complex inhibitory activity ((12.9±0.83) nm ) by binding to factor IXa with high affinity, thus offering promise for the development of new anticoagulant agents targeting the intrinsic coagulation pathway.     

A Novel Synthetic Route to Furan-Lignans

Three naturally occurring furan–lignans and two analogs have been synthesized by a short and efficient route starting from the corresponding aryl acid. The selective reductive removal of allylic hydroxy by palladium oxide in a mixed solvent of THF–CHCl₃ was employed as the key step.