Bioinspired MXene-Based Piezoresistive Sensor with Two-stage Enhancement for Motion Capture (Adv. Funct. Mater. 18/2023)

Structured piezoresistive membranes are compelling building blocks for wearable bioelectronics. However, the poor structural compressibility of conventional microstructures leads to rapid saturation of detection range and low sensitivity of piezoresistive devices, limiting their commercial applications. Herein, a bioinspired MXene-based piezoresistive device is reported, which can effectively boost the sensitivity while broadening the response range by architecting intermittent villus-like microstructures. Benefitting from the two-stage amplification effect of this intermittent architecture, the developed MXene-based piezoresistive bioelectronics exhibit a high sensitivity of 461 kPa⁻¹ and a broad pressure detection range of up to 311 kPa, which are about 20 and 5 times higher than that of the homogeneous microstructures, respectively. Cooperating with the deep-learning algorithm, the designed bioelectronics can effectively capture complex human movements and precisely identify human motion with a high recognition accuracy of 99%. Evidently, this intermittent architecture of biomimetic strategy may pave a promising avenue to overcome the limitation of rapid saturation and low sensitivity in piezoresistive bioelectronics, and provide a general way to promote its large-scale applications.     

Rapidly Modulated Wide-Spectrum Infrared Source Made of Super Aligned Carbon Nanotube Film for Greenhouse Gas Monitoring

Non-dispersive infrared (NDIR) gas monitoring has advantages of environment stability, convenient operation and maintenance, wide detection range, and multi-gas-detection capability. However, the conventional IR sources for NDIR gas monitoring, such as miniature lamps, microelectromechanical system (MEMS) light sources, and light-emitting diodes (LEDs), can only work at narrow modulation frequency and spectral range, or require complicated design and fabrication, because of the constraint of materials and work principle. These issues cause low data acquisition rate, poor anti-interference ability and limited gas compatibility to NDIR. Here, the super-aligned carbon nanotube (SACNT) film is developed as an IR source in NDIR gas monitoring system. It has a wide spectral range (0.2–334 µm), a facile fabrication method, and can work up to a high frequency ≈150 kHz. A mechanical-chopper-free and wide-concentration-range monitoring equipment for CO₂ and CH₄ greenhouse gases is demonstrated with SACNT film IR source. The concentration ranges for CO₂ and CH₄ investigated in this paper are 0.0195–20.10% (v/v) and 0.10–17.11% (v/v), respectively. It can be easily applied to monitor other kinds of gases as well.     

The Research on Surface Technology and Structures for Camouflage Net

This paper is about how to improve camouflage net protecting effect from radar detection, by introducing the layer-composite technology of radar-absorbing materials and optimizing radar-absorbing structure. In the layer-composite technology, materials choices and parameters setting, especially the relation between the content of Phosphor and radar absorption on the Ni-P electroless plating technology, are mentioned. Moreover, four superficial structures, are compared. A conclusion is got that jungle-two structure can do the best to attenuate 5.7 dB over the whole frequency ranges. In addition, according to the theory of the interaction of electromagnetic wave, the study applies physical optics to the RCS computation for optimizing technological parameters and structure by the computing software.     

六自由度运动系统运动范围的初等分析法

本文从运动学的观点出发,利用初等数学有关知识,对协同式六自由度运动平台的运动范围进行了分析,以运动平台升降、倾斜方向为例,给出了运动平台运动范围的求解方法。此种算法简单、实用,为初学者熟悉协同式六自由度运动平台的运动范围求解提供了一种简单易学的方法。     

漏电与短路保护范围交叉

论述了剩余电流动作保护器与短路保护电器保护范围交叉的概念,必要性和判断方法,为使两种保护具有足够的交叉范围,还提出了在设计中应注意的问题。     

Presence and Persistence of White Phosphorus On Military Training Ranges

The use of obscurants is a common practice by militaries worldwide. One of the most effective of these is white phosphorus (WP). WP is the elemental form of phosphorus that does not occur in nature and is highly toxic. The use of WP rounds on training ranges has led to a number of die‐offs of grazing land animals and dabbling waterfowl, the first recorded in 1930. In the 1980s, thousands of waterfowl were dying annually at an impact range in Alaska, leading to the first large‐scale investigation of WP as a lethal range contaminant. Tests were conducted at an upland impact range in New York to determine the quantity and persistence of WP in a typical environment. At all sites cited in this paper, WP was persistent for months to years following the detonation of WP munitions. At the Eagle River Flats range in AK, WP was identified from rounds fired in the 1950s, persisting over 45 years in a non‐saturated environment. In New York, dispersal of gram quantities of WP occurred at detonation, and high concentrations of WP were found in the detonation craters a year after firing. Caution needs to be exercised when using white phosphorus munitions on ranges.     

利用CSTR生物制氢系统厌氧发酵的研究现状

生物制氢技术在开发能源方面具有重要的现实地位,连续流搅拌槽式反应系统（CSTR）采用机械搅拌,传质效率高,可有效提高产氢效率,同时此设备技术要求较为简单,能大幅降低生物制氢的成本,易于实现氢气的工业化生产.本文阐述了连续流搅拌槽式反应器（CSTR）生物制氢系统的研究进展,着重剖析了CSTR生物制氢系统的影响因素、底物范围和相关的技术研究,并对其发展和实际应用进行了简要论述.     

Ranges of Expedient Use of Extrahigh-Voltage-Class AC and DC Transmission Lines in the United Energy System of Russia

Generalized characteristics of 500 – 2000-km transmission lines are used to define the ranges of expedient use of ac and dc transmission for the Unified Energy System of Russia with allowance for the reliability factor and today's cost parameters.     

Trace metal stabilisation in a shooting range soil: mobility and phytotoxicity

Due to impact and abrasion of projectiles firing berms of shooting ranges frequently exhibit increased levels of bullet-borne contaminants. Stabilisation of backstop soils may be a promising pre- and post-use treatment to minimise leaching and bioavailability. This study focused on mobility and phytotoxicity of antimony, copper, and lead in stabilised berm material compared to an untreated control. Ferric (goethite, deferrisation sludge) and phosphatic amendments (diammonium phosphate, calcium dihydrogen phosphate) were used. Batch and column experiments demonstrated effective stabilisation of the contaminants by ferric amendments. Sequential extractions showed an increase of contaminant fractions associated with iron (hydr)oxides. Stabilisation was accompanied by a detoxification of seepage water compared to the control soil as shown by Duckweed growth inhibition. Contrasting the ferric additives, phosphatic amendments effectively stabilised lead but mobilised copper and antimony possibly due to a competitive displacement process. Thereby, benefits of lead stabilisation were completely overridden; this was underlined by increased phytotoxicity relative to the untreated soil. Overall, understanding stabilised soil as a multicomponent system is a prerequisite for the choice of appropriate amendments. This requires the synopsis of results from complementary test methods and a screening for a wide range of substances.     

基于空间仿射对应点列的双曲抛物面三维构建及分析

利用计算机3D 软件构建基于空间仿射对应点列的双曲抛物面。对双曲抛 物面进行不同方向的投射,可以准确得到双曲抛物面不同方位和角度的投影图。从这些投影 图中,可以更直观、清楚的了解双曲抛物面的投影特点。使用多个不同位置的平面对双曲抛 物面进行截切,并通过分析、观察截交线的变化趋势,得出几点规律性的结论。