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

This paper presents the characterization procedures of a CMOS electrochemical oxygen sensor and its readout circuits in application specific integrated circuit (ASIC) format. As the sensor needs to be tested inside deionized water, a master controller Printed Circuit Board (PCB) is designed to provide power and control signals to test the ASIC. The transimpedance (TIA) amplifier gain, voltage amplifier gain, sensor array sensitivity and 8-bit Digital-to-Analog Converter (DAC) trimming voltage are configured through the master controller. The oxygen sensor ASIC is mounted on another PCB with chip-on-board (COB) packaging. Biocompatible hydrogel Nafion is coated to cover the entire sensor electrodes for oxygen transportation. The measured sensor sensitivity is 0.78 mV/mmHg and a transient output voltage change of 50 mV is observed when the deionized water is changed from air saturation to nitrogen saturation.

Characterization of CMOS electrochemical oxygen sensor for biomedicai applications

A new time-domain impedance sensor readout circuit based on 0.18-µm CMOS technology is presented. A current DAC is used to charge the device under test (DUT) to increase the node voltage of the DUT. Using a time-domain comparator and a counter, a time period between the start of charge till the moment that the node voltage reaches a reference level is recorded and digitally converted. The resistance and capacitance components of the impedance can be quantized by using the time period data. The fabricated prototype consumes only 9.84 to 73.2 nJ of energy and requires merely 3 ms per measurement, where both are >103 times' reductions as compared to the state-of-the-arts. Moreover, to the best of the authors' knowledge, this proposed readout chip is the first of its kind that is able to deduce each resistance and capacitance component of the impedance. The chip takes up 0.048-mm2 of area.

A 9.84–73.2 nJ, 0.048 mm 2 time-domain impedance sensor that provides values of resistance and capacitance

This paper presents a mathematic method and a cost-efficient circuit to measure the value of each component of the bio-impedance model at electrode-electrolyte interface. The proposed current excited triple-time-voltage oversampling (TTVO) method deduces the component values by solving triple simultaneous electric equation (TSEE) at different time nodes during a current excitation, which are the voltage functions of time. The proposed triple simultaneous electric equations (TSEEs) allows random selections of the time nodes, hence numerous solutions can be obtained during a single current excitation. Following that, the oversampling approach is engaged by averaging all solutions of multiple TSEEs acquired after a single current excitation, which increases the practical measurement accuracy through the improvement of the signal-to-noise ratio (SNR). In addition, a print circuit board (PCB) that consists a switched current exciter and an analog-to-digital converter (ADC) is designed for signal acquisition. This presents a great cost reduction when compared against other instrument-based measurement data reported [1]. Through testing, the measured values of this work is proven to be in superb agreements on the true component values of the electrode-electrolyte interface model. This work is most suited and also useful for biological and biomedical applications, to perform tasks such as stimulations, recordings, impedance characterizations, etc.

A current-excited triple-time-voltage oversampling method for bio-impedance model for cost-efficient circuit system

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/lpor.201770063

Flexible Manipulation of the Polarization Conversions in a Structured Vector Field in Free Space (Laser Photonics Rev. 11(6)/2017)

We theoretically propose and experimentally generate the nondiffracting Bessel–Poincare beams whose Stokes vortices radially accelerate during propagation. To this end, we design the Bessel beams whose intensity is specified to be uniformly distributed along the longitudinal direction. By superposing two such Bessel beams having different helical phases and mutually orthogonal polarizations, the synthesized vector beam is endowed with the polarization singularity that can rotate about the optical axis, while the total intensities maintain their profiles. Radially self-accelerating Stokes vortices in the resulting beam can be manipulated by adjusting the predefined parameters in the constituent beams.

Yuan Gao

Papers

Characterization of CMOS electrochemical oxygen sensor for biomedicai applications

A 9.84–73.2 nJ, 0.048 mm 2 time-domain impedance sensor that provides values of resistance and capacitance

A current-excited triple-time-voltage oversampling method for bio-impedance model for cost-efficient circuit system

Flexible Manipulation of the Polarization Conversions in a Structured Vector Field in Free Space (Laser Photonics Rev. 11(6)/2017)

Radially self-accelerating Stokes vortices in nondiffracting Bessel-Poincaré beams.