Three-Dimensional Self-assembled Hairball-Like VS4 as High-Capacity Anodes for Sodium-Ion Batteries

Sodium-ion batteries(SIBs)are considered to be attractive candidates for large-scale energy storage systems because of their rich earth abundance and consistent performance.However,there are still challenges in developing desirable anode materials that can accommodate rapid and stable insertion/extraction of Na+and can exhibit excellent electrochemical performance.Herein,the self-assembled hairball-like VS4 as anodes of SIBs exhibits high discharge capacity(660 and 589 mAh g−1 at 1 and 3 A g−1,respectively)and excellent rate property(about 100%retention at 10 and 20 A g−1 after 1000 cycles)at room temperature.Moreover,the VS4 can also exhibit 591 mAh g−1 at 1 A g−1 after 600 cycles at 0°C.An unlike traditional mechanism of VS4 for Na+storage was proposed according to the dates of ex situ characterization,cyclic voltammetry,and electrochemical kinetic analysis.The capacities of the final stabilization stage are provided by the reactions of reversible transformation between Na2S and S,which were considered the reaction mechanisms of Na–S batteries.This work can provide a basis for the synthesis and application of sulfur-rich compounds in fields of batteries,semiconductor devices,and catalysts.     

一种权系数两级自调整的融合定位精度提高方法

在分布式传感器网络节点定位技术中,使用数据融合方法以提高探测系统的检测与定位精度正成为研究的热点。提出了一种应用于分布式传感器网络中的数据融合定位算法,通过对各个传感器节点的定位信息的加权求和来进行数据融合,用来提高探测系统目标定位的精度。该算法采用两级自适应调整得到最优加权因子,首先利用线性最小均方差（LMSE）算法得到权系数的初始值,然后利用训练节点和递归最小二乘（RLS）算法自适应地调整达到最优。对静态和运动目标的定位数据融合算法进行了仿真,仿真结果表明：相比单节点定位,提出的融合算法的定位精度有约1—2个数量级的提高。     

Triangular photovoltaic modules for polar-axis trackers

It is argued that solar cell modules having an equilateral triangular shape would have several practical advantages over the rectangular modules which are commonly produced. Chief among these advantages would be the possibility of using such modules on polar-axis trackers, since the latter could generate almost as much annual power as the mechanically far more complex 2-axis trackers currently in use in various parts of the world.     

The impact of carrier gas on room-temperature trace nitrogen dioxide sensing of ZnO nanowire-integrated film under UV illumination

Chemiresistive gas sensors have been extensively explored for hazardous gas detection. Currently, an overwheming majority of previous attention was focused on the parameter improvement of sensor performance while the impact of carrier gas species on the performance was severely ignored. Aiming to a deep insight into this issue, in this work we prepared zinc oxide (ZnO) nanowire-network sensor and explored its UV-activated sensing performance toward trace nitrogen dioxide gas (NO₂) at room temperature (25 °C) under two carrier gases, i.e., dry nitrogen (N₂) and air. Within N₂, the sensor exhibited a reversible response of 157 toward 50 ppb NO₂ and a sensitivity of 7.8/ppb, which was not only among the best showcases of the existing work, but much larger than those within air (11 and 0.091/ppb, respectively). Moreover, decent selectivity and long-term stability were demonstrated. Far more UV irradiation-induced electrons which reacted with adsorbed NO₂ molecules on ZnO surface as well as smaller baseline resistance under N₂ than those under air jointly led to the superior response and sensitivity. After long-time UV exposure prior to gas-sensing tests within both carrier gas cases, the remaining oxygen ions (O₂⁻) were weakly bonded on ZnO surface, contributing to the reversible behaviors at room temperature. The interconversion between physisorbed O₂ molecules and ionic O₂⁻ on ZnO surface was proposed to rationalize the sensing phenomena especially when no continuous oxygen was supplied under N₂ atmosphere, which enriched the current transduction mechanisms.     

Excellent photoelectrochemical hydrogen evolution performance of FeSe2 nanorod/ZnSe 0D/1D heterostructure as efficiency carriers migrate channel

In the photoelectrochemistry reaction, the electrode is most important. As a common electrode material, the metal oxide has a large band gap and high internal resistance, which is disadvantageous for photocatalytic hydrogen production. Metal selenide generally has a narrow band gap and low internal resistance, which is a promising new type of photocatalyst. A FeSe₂/ZnSe heterojunction photocatalyst is constructed by loading ZnSe nanoparticles on FeSe₂ nanorods. In this heterostructure, ZnSe is uniformly supported on the surface of FeSe₂ to form a 0D/1D structure. Experiments have confirmed that the photoelectrochemical activity and photocatalytic H₂ production rate of this heterojunction photocatalyst is greatly improved, and its optimum performance is three times of ZnSe in photoelectrochemical activity and 2.3 times in photocatalytic H₂ production rate. Further analysis reveals that the internal resistance of the composite photocatalyst is greatly reduced due to the compositing of FeSe₂, and the carrier separation efficiency is also improved. In this FeSe₂/ZnSe heterojunction, the conduction band of ZnSe is more negative than that of FeSe₂, and the photogenerated electrons generated on the conduction band of ZnSe can be transferred to that of FeSe₂, thereby prolonging the carrier lifetime and improving photoelectrochemical activity. This work confirms that FeSe₂/ZnSe is a very effective heterostructure, which avoids the addition of precious metals and rare earth metals and shows great application prospects.     

Effect of birefringence on the bandwidth of noise-like pulse in an erbium-doped fiber laser

We report on the generation of superbroad spectrum bunched noise-like pulses from a passively mode-locked erbium-doped fiber laser, in which the cavity is made of purely anomalous dispersion fibers. The maximum 3 dB spectral bandwidth of the pulse is about 98 nm. We show numerically that the superbroad spectrum of the pulse is caused by the fiber birefringence.     

Triphenylamine-cored star-shape compounds as non-fullerene acceptor for high-efficiency organic solar cells: Tuning the optoelectronic properties by S/Se-annulated perylene diimide

Three novel star-shaped S/Se-annulated perylene diimide (PDI) small molecule acceptors with triphenylamine as the core, namely TPA-PDI, TPA-PDI-S and TPA-PDI-Se, were designed and synthesized. Using the wideband-gap polymer PDBT-T1 as the donor and Se-annulated perylene diimide (TPA-PDI-Se) as the acceptor, power conversion efficiencies (PCE) of up to 6.10% was achieved, which is 38% higher than the reference of TPA-PDI without heteroatom annulation. Impressively, the S/Se-annulated perylene diimides as acceptors showed high open-circuit voltage (V_OC) of 1.00 V. The high efficiency for TPA-PDI-Se can be attributed to complementary absorption spectra with the donor material, relatively high-lying LUMO level, balanced carrier transport and favorable morphologies. To the best of our knowledge, this PCE of 6.10% is among the highest values based on star-shaped non-fullerene acceptors so far.