Development of a Highly Selective,Sensitive, and Fast Response Upconversion Luminescent Platform for Hydrogen Sulfide Detection

Hydrogen sulfide (H₂S) has been recognized as one of most important gaseous signaling molecules mediated by a variety of physiological and pathological processes. Yet, its functions remain largely elusive due to the lack of potent monitoring methods. Hereby this issue is addressed with a powerful new platform—dye‐assembled upconversion nanoparticles (UCNPs). A series of chromophores with different absorption bands and fast responses towards H₂S is combined with UCNPs and results in a library of H₂S sensors with responsive emission signals ranging from the visible to the near‐infrared (NIR) region. These nanoprobes demonstrate highly selective and rapid responses to H₂S in vitro and in cells. Furthermore, H₂S levels in blood can be detected using the developed nanoprobes. Hence the reported H₂S sensing platform can serve as a powerful diagnostic tool to research H₂S functions and to investigate H₂S‐related diseases.     

基于熔融拉锥过耦合器的光纤光栅解调系统

提出了一种基于光纤熔融拉锥过耦合器进行解调的方法,实验制作了一个特殊的熔融拉锥过耦合器,对其输出的两路光功率进行了测试,并论证了用该耦合器进行解调的原理.利用该过耦合器组成的检测系统对光纤光栅传感器进行解调,得到了较好的响应.该解调方法成本低,结构简单,解调范围大,线性范围可达10 nm以上.     

Nanoparticles of the Lead-free Solder Alloy Sn-3.0Ag-0.5Cu with Large Melting Temperature Depression

Due to the toxicity of lead (Pb), Pb-containing solder alloys are being phased out from the electronics industry. This has lead to the development and implementation of lead-free solders. Being an environmentally compatible material, the lead-free Sn-3.0Ag-0.5Cu (wt.%) solder alloy is considered to be one of the most promising alternatives to replace the traditionally used Sn-Pb solders. This alloy composition possesses, however, some weaknesses, mainly as a result of its higher melting temperature compared with the Sn-Pb solders. A possible way to decrease the melting temperature of a solder alloy is to decrease the alloy particle size down to the nanometer range. The melting temperature of Sn-3.0Ag-0.5Cu lead-free solder alloy, both as bulk and nanoparticles, was investigated. The nanoparticles were manufactured using the self-developed consumable-electrode direct current arc (CDCA) technique. The melting temperature of the nanoparticles, with an average size of 30 nm, was found to be 213.9°C, which is approximately 10°C lower than that of the bulk alloy. The developed CDCA technique is therefore a promising method to manufacture nanometer-sized solder alloy particles with lower melting temperature compared with the bulk alloy.     

全固体腔内倍频Nd:YAG/SrWO4/KTP拉曼激光器

报道了以KTP晶体作为倍频介质,以Nd:YAG晶体作为激活介质,以SrWO4晶体作为拉曼介质的折叠腔型主动调Q腔内倍频拉曼激光器的输出特性,给出了输出黄光平均功率、脉冲能最、脉冲宽度随激光二极管(LD)抽运功率及脉冲重复率的变化关系.在输入抽运功率为12.6 W,脉冲重复率为20 kHz时,获得了1.4 W的590 nm激光输出,从LD到黄光的转换效率为11.1%.在输入抽运功率为12.6 W,脉冲重复率为10 kHz时,单脉冲能量为122 μJ,脉冲宽度为4.0 ns.相应的脉冲峰值功率为30.5 kW.     

A Universal VLSI Architecture for Reed–Solomon Error-and-Erasure Decoders

This paper presents a universal architecture for Reed-Solomon (RS) error-and-erasure decoder. In comparison with other reconfigurable RS decoders, our universal approach based on Montgomery multiplication algorithm can support not only arbitrary block length but various finite-field degree within different irreducible polynomials. Moreover, the decoder design also features the constant multipliers in the universal syndrome calculator and Chien search block, as well as an on-the-fly inversion table for calculating error or errata values. After implemented with 0.18-mum 1P6M technology, the proposed universal RS decoder correcting up to 16 errors can be measured to reach a maximum 1.28 Gb/s data rate at 160 MHz. The total gates count is around 46.4 K with 1.21 mm² silicon area, and the average core power consumption is 68.1 mW.     

全自动电脑横机控制系统的设计

介绍了一种全自动电脑横机控制系统的新型分层体系设计.在该体系中,花型准备系统是基于Windows的开放式编程系统,通过编译自动生成编织指令数据文件,提供了独有的可扩充布纹库.下位NC硬件控制系统无需操作系统支持,便可完成对整个编织过程的实时监控,故障诊断,修改编织参数及测试执行部件等功能.新型的分层体系实现了上、下位机的功能独立,并保持了良好的人机交互界面和便捷的操作性,真正实现了全自动和智能化设计.     

降温水循环泵恒压供水变频改造

本文介绍了降温水循环泵恒压供水变频改造的特点及变频控制系统与DCS控制应用于降温水循环泵变频调速控制的基本情况。     

Texture analysis and classification with tree-structured wavelettransform

A multiresolution approach based on a modified wavelet transform called the tree-structured wavelet transform or wavelet packets is proposed. The development of this transform is motivated by the observation that a large class of natural textures can be modeled as quasi-periodic signals whose dominant frequencies are located in the middle frequency channels. With the transform, it is possible to zoom into any desired frequency channels for further decomposition. In contrast, the conventional pyramid-structured wavelet transform performs further decomposition in low-frequency channels. A progressive texture classification algorithm which is not only computationally attractive but also has excellent performance is developed. The performance of the present method is compared with that of several other methods.     

Signal and interference statistics of a CDMA system with feedbackpower control

Power control is essential in the use of direct-sequence code-division multiple-access (CDMA) techniques over fading radio channels. The paper investigates a feedback power control approach that allows power commands to be updated at a higher rate than the rate of multipath fading. The signal and interference statistics as received at the base stations after power control are obtained for a simulated CDMA system which includes multiple base stations with diversity receivers and a large number of power-controlled users continuously moving at various speeds. The authors show that often-used analyses based on perfect average power control lead to optimistic capacity results (by about 25%) because interference is underestimated by as much as 1 dB     

Slot-fed higher order mode Fabry-Perot filters

Low-loss bandpass filters consisting of Fabry-Perot resonators excited by waveguide-fed slots coupling to higher-order resonator modes are demonstrated. For close reflector spacings, the waveguide couples efficiently through the slots to the TEM₄₀₀ and TEM₃₀₀ modes. The characteristics of both rectangular and circular waveguide feeds with various slot lengths and widths are presented. At X-band the filters have unloaded Q values which range from 1000 to 7000 with insertion losses less than 1 dB. The filters which have the rectangular waveguide feeds are mechanically tunable over a 20% bandwidth