There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

[Crohn's disease].

Recently, Kovalenko and co-workers and Li and co-workers developed CsPbX3 (X = Cl, Br, I) inorganic perovskite quantum dots (IPQDs), which exhibited ultrahigh photoluminescence (PL) quantum yields (QYs), low-threshold lasing, and multicolor electroluminescence. However, the usual synthesis needs high temperature, inert gas protection, and localized injection operation, which are severely against applications. Moreover, the so unexpectedly high QYs are very confusing. Here, for the first time, the IPQDs' room-temperature (RT) synthesis, superior PL, underlying origins and potentials in lighting and displays are reported. The synthesis is designed according to supersaturated recrystallization (SR), which is operated at RT, within few seconds, free from inert gas and injection operation. Although formed at RT, IPQDs' PLs have QYs of 80%, 95%, 70%, and FWHMs of 35, 20, and 18 nm for red, green, and blue emissions. As to the origins, the observed 40 meV exciton binding energy, halogen self-passivation effect, and CsPbX3@X quantum-well band alignment are proposed to guarantee the excitons generation and high-rate radiative recombination at RT. Moreover, such superior optical merits endow them with promising potentials in lighting and displays, which are primarily demonstrated by the white light-emitting diodes with tunable color temperature and wide color gamut.

CsPbX3 Quantum Dots for Lighting and Displays: Room-Temperature Synthesis, Photoluminescence Superiorities, Underlying Origins and White Light-Emitting Diodes

Light-Emitting Diodes. (Monographs in Electrical and Electronic Engineering.) By A. A. Bergh and P. J. Dean. Pp. viii+591. (Clarendon: Oxford; Oxford University: London, 1976.) £22.

/pdf/light-emitting-diodes-ubzde6g9qc.pdf

Light-emitting diodes

A novel wideband hybrid dielectric resonator antenna structure comprises a rectangular dielectric resonator (DR) and a coplanar waveguide (CPW) inductive slot is proposed. In this configuration, the CPW inductive slot simultaneously acts as an effective radiator and the feeding structure of the DR. Dual res- onances of the two radiators are merged to extend the antenna's bandwidth. A parametric study is performed to optimize the an- tenna performance and a prototype for 5-GHz WLAN application has been built and tested. Index Terms—Dielectric resonator antennas (DRAs), slot an- tennas, wideband antennas.

A Compact Wideband Hybrid

With the emerging trend in miniaturization of complete optical sensor on a silicon platform for gas sensing applications, this paper presents a promising candidate towards monolithic gas sensor with features of 1) a CMOS compatible Aluminum Nitride (AlN)-based pyroelectric infrared detector (PID); 2) customized micropower high-precision CMOS integrated readout circuits. In the PID design, the sensitivity and device integrity are improved with optimized sensing area and modified layer structure. In the readout circuits, to amplify the pico-amperes current from detector, a tunable resistive transimpedance amplifier (TIA) with robust pseudo-resistor in series is proposed to achieve reduced variations against process-voltage-temperature (PVT). A micropower incremental analog-to-digital converter (ADC) is designed to digitize the voltage output from TIA. In addition, to compensate the drifts induced by local temperature change around the detector, an accurate BJT-based temperature sensor is integrated in the circuits as well. Fabricated in an 8-inch wafer, the AlN-based PID with sensing area of 0.29 mm2 achieves the detectivity of 6.04× 106 cm√ Hz/W. The readout circuits are implemented in a 40nm-CMOS process, consuming total power of 24.5 μW under 1.2-V supply. Simulation results show that the TIA gain variation is 11-bit resolution over 1 kHz bandwidth, and the temperature error over -20 °C − 80 °C is ±0.65 °C (3σ) without any calibration.

Design of Pyroelectric Infrared Detector And Micropower CMOS Integrated Circuitry Towards a Monolithic Gas Sensor

Owing to the unique feature that the signal and reference waves of self-interference digital holography (SIDH) contain the same spatial information from the same point of object, compared with conventional digital holography, the SIDH has the special spatial coherence properties. We present a statistical optics approach to analyzing the formation of cross-correlation image in SIDH. Our study reveals that the spatial coherence of illumination light can greatly influence the imaging characteristics of SIDH, and the impact extent of the spatial coherence depends substantially on the recording distance of hologram. The theoretical conclusions are supported well by numerical simulation and optical experiments.

Impact of the spatial coherence on self-interference digital holography*

This paper presents a time-domain continuous-time sigma delta modulator (CT-DSM) based neuro-recording interface circuit. This circuit consists of a current-reuse fully differential OTA, a voltage-controlled oscillator (VCO), a counter-based quantizer and a capacitive DAC feedback circuit with Data Weighted Averaging (DWA) logic. A current-reuse G m cell is adopted to suppress the input-referred noise with high energy efficiency. The VCO converts the input signal amplitude into phase for integration as well as quantization by the counter-based quantizer. The DAC feedback circuit ensures a linear operation of Gm-VCO within the input range. The prototype circuit is designed and implemented in a commercial 40-nm CMOS process. the proposed circuit consumes 19.5 $\mu$ W under 1.2-V supply voltage. With the maximum tolerable input swing of 100-mV pp , the proposed circuit achieves an SNDR of 59 dB over a bandwidth of 10 kHz. The proposed design is suitable for application such as the neuro-recording circuit in the closed-loop neural stimulation system.

A 100-mV pp Input Range 10-kHz BW VCO-based CT-DSM Neuro-Recording IC in 40-nm CMOS

Prototypical models and their material incarnations are cornerstones to the understanding of quantum magnetism. Here we show theoretically that the recently synthesized magnetic compound Na$_2$BaCo(PO$_4$)$_2$ (NBCP) is a rare, nearly ideal material realization of the $S=1/2$ triangular-lattice antiferromagnet with significant easy-axis spin exchange anisotropy. By combining the automatic parameter searching and tensor-network simulations, we establish a microscopic model description of this material with realistic model parameters, which can not only fit well the experimental thermodynamic data but also reproduce the measured magnetization curves without further adjustment of parameters. According to the established model, the NBCP hosts a spin supersolid state that breaks both the lattice translation symmetry and the spin rotational symmetry. Such a state is a spin analogue of the long-sought supersolid state, thought to exist in solid Helium and optical lattice systems, and share similar traits. The NBCP therefore represents an ideal material-based platform to explore the physics of supersolidity as well as its quantum and thermal melting. 

/pdf/spin-supersolidity-in-nearly-ideal-easy-axis-triangular-2tf1f1xe.pdf

Yuan Gao

Papers

A Compact Wideband Hybrid

Design of Pyroelectric Infrared Detector And Micropower CMOS Integrated Circuitry Towards a Monolithic Gas Sensor

Impact of the spatial coherence on self-interference digital holography*

A 100-mV pp Input Range 10-kHz BW VCO-based CT-DSM Neuro-Recording IC in 40-nm CMOS

Spin supersolidity in nearly ideal easy-axis triangular quantum antiferromagnet Na2BaCo(PO4)2