Terahertz and Millimetre Wave Imaging with a Broadband Josephson Detector Working above 77 K

A high-T_c superconducting (HTS) broadband Josephson detector has been developed and applied to millimetre wave (mm-wave) and terahertz (THz) imaging. The detector is based on a YBa₂Cu₃O_7-x (YBCO) step-edge Josephson junction, which is coupled to a thin-film log-periodic antenna, designed for operation at 200–600 GHz, and a hemispheric silicon lens. The junction parameters have been optimised to achieve a high I_cR_n value so that the detector responds well to the specified frequencies at liquid nitrogen temperature (77 K). Images at ∼200 GHz and ∼600 GHz were acquired with the same detector; each demonstrated their unique properties. The results demonstrate the potential of achieving a cheaper, compact and portable multi-spectral imager based on a HTS detector.     

Investigations on the structural and optical properties of Li,N and (Li,N) co-doped ZnO thin films prepared by sol–gel technique

Pure and doped zinc oxide thin films have been deposited on sapphire substrates by using the sol–gel method and spin coating technique. The X-ray diffraction pattern showed that the deposited films exhibit hexagonal zinc oxide structure. Room temperature photoluminescence measurements show the presence of two emission bands. The predominant near band edge ultraviolet emission is at 3.28 eV and a suppressed broad band of deep level emission in the range of 2.1–2.5 eV. The incorporation of nitrogen is indicative of p-type behavior as observed from X-ray photoelectron spectrum of nitrogen in the doped samples. The p-type conduction of Li, N:ZnO may be attributed to the formation of a LiZn–N complex acceptor.     

Switching On and Off Macrophages by a “Bridge-Burning” Coating Improves Bone-Implant Integration under Osteoporosis

Osteoporosis poses substantial challenges for biomaterials implantation. New approaches to improve bone-implant integration should resolve the fundamental dilemma of inflammation—proper inflammation is required at early stages but should be suppressed later for better healing, especially under osteoporosis. However, precisely switching on and off inflammation around implants in vivo remains unachieved. To address this challenge, a “bridge-burning” coating material that comprises a macrophage-activating glycan covalently crosslinked by a macrophage-eliminating bisphosphonate to titanium implant surface is designed. Upon implantation, the glycan instructs host macrophages to release pro-osteogenic cytokines (“switch-on”), promoting bone cell differentiation. Later, increasingly mature bone cells secrete alkaline phosphatase to cleave the glycan-bisphosphonate complexes from the implant, which in turn selectively kill the proinflammatory macrophages (“switch-off”) that have completed their contribution—hence in the manner of “burning bridges”—to promote healing. In vivo examination in an osteoporotic rat model demonstrates that this coating significantly enhances bone-implant integration (88.4% higher contact ratio) through modulating local inflammatory niches. In summary, a bioresponsive, endogenously triggered, smart coating material is developed to sequentially harness and abolish the power of inflammation to improve osseointegration under osteoporosis, which represents a new strategy for designing immunomodulatory biomaterials for tissue regeneration.     

Special Issue on: Towards a “Smart Society” Through Digital and Wireless Communication Technology

Wireless Personal Communications -     

Investigations about the effect of annealing temperatures in the presence of oxygen flow on optical and electronic properties of titanium nano-layers by using Kramers–Kronig and DFT methods

Nano-layers of titanium were deposited on glass substrates by resistive evaporation at room temperature. Thickness of the layers was measured 66.8 nm, by a quartz crystal method. Deposition conditions such as deposition rate, vacuum pressure, incidence of angle and substrate temperature were the same for all layers. After producing pure Ti layers a post-annealing method was used in the presence of a uniform oxygen flow of 6 cm³/s and different 100 °C, 200 °C and 300 °C annealing temperatures. Optical reflectance and transmittance of the layers were measured in the wave length of 200–4100 nm by a spectrophotometer. Kramers–Kronig relations were used to calculate the optical constants. The influence of annealing temperature and oxygen flow on optical properties is investigated. Also to make the obtained optical results clearer, a full-potential linearized augmented plane wave (FP-LAPW) method within the generalized gradient approximation (GGA) has been used. Comparison results confirm that in higher annealing temperatures the obtained structure is more similar to anatase crystalline one. According to AFM images, by increasing annealing temperature in the presence of oxygen flow, configuration of layers change and due to high annealing temperature and surface diffusion effect, void fraction increases. With increase in annealing temperature to 300 °C, anatase phase structure (A(004)) gets clearer and sharper also other phase structures are about to grow.     

New IC package,assembly technique by means of a “blind” alignment “flip-chip” method and assembling facilities

俄罗斯专家Vladimir V.Novikov提出了一种封装新技术,欲寻求技术和投资合作。有意者请与Vladimir V.Novikov本人或本刊编辑部联系。     

Analog image recognition arrays design by using co-fabricated MOSFET and MESFETs on a 0.25?μm SOS process

This paper presents an analog image recognition system with a novel MESFET device fabricated on a fully depleted (FD) CMOS process. An analog image recognition system with a power consumption of 2.4?mW/cell and a settling time of 6.5???s was designed, fabricated and characterized. A CNN is employed to realize a core cell of the proposed image recognition system. While a CNN benefits from its regular structure, it faces challenges due to its power consumption, speed, and size in their CMOS implementations. SOS MESFETs can deal with the challenges associated with CMOS-based CNNs. Advantages of SOS MESFETs associated with nonlinear signal processing include lower power consumption and higher operating speeds compared to similar geometry MOSFETs carrying the same current. SOS MESFET-based analog image recognition systems were fabricated and the transient response is characterized in both simulation using a TOM3 SPICE model extracted from SOS MESFETs and in experiment using image testing lab equipment. Settling times of 3.5 and 6.5???s for one-by-four and one-by-eight arrays, respectively, were achieved with line recognition template. The corresponding power consumption for the two arrays was 9.6 and 19.2?mW, respectively.     

Design and Simulation of a Broadband Bandpass Filter Based on Complementary Split Ring Resonator Circular “CSRRs”

Wireless Personal Communications - The aim of this article was to design CSRRs (complementary split ring resonator) miniaturized metamaterial cells. These cells should then be associated with...     

Comment on “Novel lossless and lossy grounded inductor simulators consisting of a canonical number of components”

A recently published paper (Singh, Analog Integr Circuit Signal Process, 62:327–332, 2010) dealing with the relationship between the Barkhausen condition for oscillation and the well known Nyquist stability criterion for systems with feedback is highly appreciated. However, it seems to be necessary to place some comments on it. The circuit examples presented in the cited paper as well as the conclusions will be critically reviewed. Apparently, there is still no sufficient oscillation condition. Therefore, the necessity to complete the existing oscillation criterion with a sufficient condition is emphasized.     

Reply to Comments on “Cut-off Characteristics of a Cylindrical Magnetron”

A new circuit for generation of triangle/square waveform is described. The circuit uses a linear pulse amplifier, a clipper and a differentiating network, consisting of a capacitance and a FET behaving as a voltage-controlled resistor. The circuit covers a wide frequency range and the variation of frequency with the control voltage is fairly linear.