The electronic nose in Lilliput

Electronic noses today are handy enough systems for detecting gaseous chemicals used in industrial cleaning or fabrication processes. Available from a half-dozen manufacturers, the instruments are desktop or laptop in size, depending on their features. The gases, called volatile organic compounds (VOCs), are toxic, carcinogenic and quick to evaporate in combination, a danger to their environs. Here, the authors describe how a miniature experimental system based on a CMOS chip is being readied to detect a range of gaseous compounds     

空心布拉格光纤及其在传感应用中的研究进展

基于一维光子带隙(PBG)效应导波机制的空心布拉格光纤(HC-BFs)具有灵活方便的带隙调控能力和优良的宽带低损耗传输特性,作为一类独特的光子带隙型空心光纤,在光波传输、色散管理与控制、光纤型器件和传感检测等领域表现出巨大的应用潜力.从光纤波导结构设计与导波模式传输特性、包层材料构成与光纤制备工艺,以及基于气态或液态被测物质填充中空纤芯的痕量气体检测和生化传感中的应用等方面对HC-BF研究的发展历程和新进展进行了综合评述.     

Tunnel Diode Oscillator in an Open Structure

This paper describes a theoretical and experimental evaluation of the oscillation conditions of a microwave tunnel diode integrally mounted at the feed point of a semicircular loop antenna. The oscillation conditions are based on a quasi-linear equivalent circuit where the diode load impedance is the complex radiation impedance of the semicircular loop antenna. The results of a radiation impedance calculation based on a Fourier transform method are presented. Diode fabrication techniques are described and experimental results are reported to be consistent with the theory.     

Increasing the efficiency of photoelectric cells by nanostructuring their surface

A method of fabrication of nanostructured objects, which increases the efficiency of the photo-electric system used in the conversion of energy of electromagnetic radiation into electric energy is suggested. The method is based on the formation of metal nanodots on the basis of the surface layer of porous silicon, which concentrates the energy of electromagnetic radiation due to localized plasmon modes.     

Interpretation of the visible photoluminescence of inequisized silicon nanoparticles suspended in ethanol

Silicon nanoparticles obtained by laser-assisted dissociation of molecules of gaseous silane have been immersed in ethanol. If a cell filled with such a medium is exposed to radiation from an argon laser, the luminescent trace of the laser beam propagating through the cell is observed in the visible region of the spectrum. A model based on the Lorentz classical harmonic oscillator and a multiphoton scheme of interaction between laser radiation and a nearly resonant medium is used to derive a model of luminescence in a medium with suspended nanoparticles. The reported experimental data are discussed and compared with the predictions of the suggested model.     

A new low-loss wide-angle Y-branch configuration for opticaldielectric slab waveguides

A new Y-branch configuration for dielectric slab waveguides is proposed, based on the natural refraction of optical field at the dielectric interfaces and analysed by BPM. It has been shown that the radiation loss of the structure is very small with relatively wide branching angle and fairly insensitive to the fabrication errors     

基于电容读出的非制冷红外探测器

介绍了一种基于标准硅工艺的电容读出式微悬臂梁非制冷红外探测器的设计、制作以及集成读出电路的设计。该探测器用于探测室温下物体的红外辐射,其响应波长为8～12 μm 。由于氮化硅和铝的热膨胀系数相差很大,用这两种材料的薄膜做成的双材料微悬臂梁在红外辐射下会发生弯曲,微悬臂梁和衬底形成一个可变电容,通过检测电容的变化来反映微悬臂梁的弯曲,从而可以探测红外辐射的情况。采用和探测器集成的CMOS读出电路对探测器信号进行读取,微悬臂梁的电容灵敏度可达2.5 fF/K,温度分辨率为0.1 K。     

The influence of chlorine on the optical properties of monoclinic lead phthalocyanine thin films

The optical transmittance and absorption of thin films of monoclinic lead phthalocyanine have been studied as a function of exposure to chlorine and air. The effect of chlorine on the refractive index and dielectric constant of freshly prepared films was estimated from reflectivity data in the photon energy range 2.1–2.6 eV. Responsivity and recovery from gaseous exposure were studied with regard to the applicability of lead phthalocyanine to the fabrication of an optical chlorine sensor.     

Laser patterning of metal oxide superconductor films by reactivesolid-state transformation

A planar submicrometer-resolution patterning method has been developed for fabrication of thin-film Ba₂YCu₃O _x devices without photoresist, water, or solvent exposure. The method is based on a rapid transformation from the superconductive to a dielectric phase. The phase change is induced by controlled changes in the oxygen stoichiometry which are induced thermally by local-area laser irradiation of the thin film in a gaseous ambient. Both extended-area pattern projection and scanned-beam direct writing have been demonstrated with a spatial resolution in the submicrometer range and are presently limited by the grain size of available films. Negligible thickness loss is observed in patterning. The method circumvents lithographic techniques which tend to degrade the electronic quality of Ba₂YCu₃O_x superconductors     

基片集成波导缝隙稀疏阵天线的设计

提出并分析了两类基于基片集成波导(Substrate Integrated Waveguide,SIW)的缝隙稀疏阵列天线.减少缝隙单元的数目,对于(基片集成)波导缝隙阵列天线具有重要的意义,可以简化设计、展宽带宽、降低加工工艺要求等.阵列天线稀疏化明显降低了缝隙单元间的互耦,使得低副瓣天线的设计更容易.全波仿真结果有效验证了设计的正确性和有效性.     

Improvement of microstrip patch antenna radiation patterns

Microstrip patch antennas typically have radiation patterns containing unwanted sidelobes or local minima caused by surface waves, especially when fabricated on high dielectric-constant substrates. The paper shows that removal of the substrate beneath the patch can greatly improve the pattern. A variation of this technique, compatible with monolithic fabrication, is applied to fabrication of a patch on GaAs and shows similar pattern improvement     

A cylindrical Fresnel zone antenna

A cylindrical Fresnel zone antenna as a candidate for a base station in wireless indoor LAN systems is described. An arbitrary angle-tilted fan beam in azimuth can be achieved by moving the position of the strip dipole feed at the cylinder center. A simple theory based on the diffraction integral is developed which predicts the antenna radiation characteristics. The antenna fabrication and measurement are carried out at 9 GHz with good agreement between calculated and measured results     

Detection of Therapeutic Levels of Ionizing Radiation Using Plasmonic Nanosensor Gels

Radiotherapy is a highly complex and efficient treatment modality for ablation of malignant tumors. Despite several technological advances, determination of the dose delivered to the tumor remains a challenge due to limitations of complex fabrication, cumbersome operation, and high costs associated with current dosimeters. This study describes fundamental studies and development of a novel gel‐based colorimetric nanosensor for detecting therapeutic levels of X‐rays (1–10 Gy) administered in clinical radiotherapy. Following exposure to X‐rays, gold salts in the gel are converted to nanoparticles within the matrix, resulting in the formation of a maroon‐colored plasmonic gel. Differences in color intensity of the gel following irradiation are used as a quantitative indicator of the radiation dose employed. The gel‐based nanosensor is able to detect doses as low as 0.5 Gy, and demonstrates a linear detection range of 0–3 Gy, which indicates its application in the fractionated radiotherapy regime. The gel is also able to successfully report therapeutic levels of radiation doses administered to anthropomorphic tissue phantoms. The range of detection, ease of fabrication, simplicity of colorimetric detection, and relatively lower costs indicate that this technology can be potentially translated to different radiotherapy applications in the clinic.     

采用扫描谐振腔进行腔内振铃红外吸收光谱研究

提出了一种新型的连续激光振铃吸收光谱方法，采用由高反射率腔镜组成的谐振腔作气体吸收池，通过压电晶体对谐振腔以4Hz频率进行扫描调制，对连续波激发光源在一定光谱范围内以0．001Hz的低重复频率进行同步光谱扫描，让振铃腔与激光频率形成共振．通过探测腔模的透射峰光强，获得光谱信息．采用该技术在0．5mbar的极低气压下，探测到CO2在6537cm^-1和6577cm^-1附近的弱吸收谱线(10^-27.10^26cm^-1／(molecute．cm^-2)，其检测灵敏度远高于常规红外吸收光谱方法，为气态原子、分子和离子的微量探测提供了高灵敏度的光谱分析方法。     

Topological variation on sub-20 nm double-gate inversion and Junctionless-FinFET based 6T-SRAM circuits and its SEU radiation performance

Introduction of new conduction mechanism called junctionless in MOSFETs takes us to another direction in device fabrication. Moving from inversion to junctionless devices in nanoscale regime proves a good alternative for low-power applications and overcomes the barrier of lightly doped channels. 6T-SRAM circuits, the first to arrive in the market long ago, still occupy its area in modern-day ICs too. In this work, four topologies of 6T-SRAM namely Flex-V_th, Flex-PG, PG-SN, and FinFETs are generated based on inversion type independent double-gate as well as common double-gate devices. For the first time, the same four topologies are also generated using junctionless devices. In nanoscale range, the reliability of circuits is given paramount importance since they are easily affected by radiation. This 6T-SRAM's radiation sensitivity is studied and from our simulation results, the common double-gate based 6T-SRAM shows good performance over the independent double-gate based 6T-SRAM in both inversion and junctionless type.     

量子线红外光子探测器的研究进展

基于半导体量子线子能带间跃迁的量子线红外光子探测器（QRIP）由于其独特的电子性质,具有工作温度较高、信噪比较高、暗电流较低、光谱范围较宽以及垂直入射光响应等特点．对于新型红外探测器的研发而言,QRIP是颇具潜力的候选者之一．通过对近年来部分相关文献的分析介绍,总结和评述了QRIP制备工艺、物理性质、仿真方法等方面的研究进展．     

直热式远红外辐射加热器的研究

介绍了直热式远红外辐射加热器的制备工艺。测试出这种加热器具有很高的红外辐射效率，且寿命长、表面绝缘性好、用途广，是一种很有魅力的新型红外辐射源。     

激光等离子体辐射诱导气体漂移

本文采用黑体辐射模型描述了激光等离子体辐射场诱导气体原子漂移的基本原理,导出了漂移速度的计算公式。对于某些难以获得强单色光源的频段,用激光等离子体辐射场诱导气体原子漂移具有特别重要的意义。     

New Configuration of Solid‐State Neutron Detector Made Possible with Solution‐Based Semiconductor Processing

The unique benefit of solution‐based fabrication of solid‐state p‐n junctions is demonstrated for radiation detection. In particular, an in situ inorganic semiconductor synthesis and film deposition facilitates a novel neutron detector configuration consisting of a host inorganic semiconductor matrix impregnated with a guest neutron sensitizing material. Spectroscopic investigations of the structural order of the top detector active layer indicate that it consists of interpenetrating networks of the host semiconductor nanocrystals and sensitizing guest material that self‐assemble during film formation. The host semiconductor network exhibits a good charge transport as evidenced by steady‐state photoconductivity measurements. The detectors developed indicate high sensitivity to ionizing radiation and a demonstrated ability to detecting thermal neutrons.     

Simulation results on submillimeter wave detection by Josephson fluxonic diode and a method to address its focal plane array

Application of radiation to a reverse-biased Josephson fluxonic diode (JFD) creates vortex-antivortex pairs. Pairs are created at each peak of sinusoidal radiation and move under the application of the bias current, exhibiting a voltage which depends on the frequency of incoming radiation. Simulation results for frequencies ranging from 50 to 700 GHz have been obtained. A simple and practical addressing scheme is proposed for a matrix of JFD pixels. Ease of fabrication, inherent gain, simultaneous determination of amplitude and frequency of radiation, large output current, and simple addressability in focal plane arrays are among the advantages of JFD as a direct submillimeter wave detector.