Charge collection narrowing mechanism in electronic-grade-diamond photodetectors

Recently,an extreme narrowband spectral response of only 8 nm in electronic-grade diamond-based photodetectors has been observed by Zheng Wei and his colleagues from Sun Yat-sen University for the first time.A charge collection narrowing mechanism assisted by free exciton radiative recombination is proposed,which well reveals the characteristic spectral response of diamond.

One Novel Hydraulic Actuating System for the Lower-Body Exoskeleton

The hydraulic exoskeleton is one research hotspot in the field of robotics,which can take heavy load due to the high power density of the hydraulic system.However,the traditional hydraulic system is normally centralized,inefficient,and bulky during application,which limits its development in the exoskeleton.For improving the robot's performance,its hydraulic actuating system should be optimized further.In this paper a novel hydraulic actuating system(HAS)based on electric-hydrostatic actuator is proposed,which is applied to hip and knee joints.Each HAS integrates an electric servo motor,a high-speed micro pump,a specific tank,and other components into a module.The specific parameters are obtained through relevant simulation according to human motion data and load requirements.The dynamic models of the HAS are built,and validated by the system identification.Experiments of trajectory tracking and human-exoskeleton interaction are carried out,which demonstrate the proposed HAS has the ability to be applied to the exoskeleton.Compared with the previous prototype,the total weight of the HAS in the robot is reduced by about 40%,and the power density is increased by almost 1.6 times.

Investigation on microstructures and mechanical properties of Mg-6Zn-0.5Ce-xMn(x=0 and 1)wrought magnesium alloys

The microstructure evolution and mechanical properties of Mg–6Zn–0.5Ce–xMn(x=0 and 1 wt.%)wrought magnesium alloys were researched,and the morphologies and role of Mn element in the experimental alloys were analyzed.The research shows that all of Mn elements form theα-Mn pure phases,which do not participate in the formation of other phases,such as theτ-phases.The mechanical properties of Mn-containing alloys in as-extruded and aged states are superior to Mn-free alloys.During the hot extrusion process,the dispersed fineα-Mn particle phase hinders the migration of grain boundaries and inhibits dynamic recrystallization,which mainly takes effect of grain refining and dispersion hardening.During the aging treatments,the dispersed fineα-Mn particle phase not only hinders the growth of the solution-treated grains,but also becomes the nucleation cores ofβ1 rod-like precipitate phase,which is conducive to increasing the nucleation rate of the precipitate phase.For the aged alloy,the Mn addition mainly takes effect of grain refining and promoting aging strengthening.

Electrocatalytic and photocatalytic performance of noble metal doped monolayer MoS2 in the hydrogen evolution reaction: A first principles study

To maximize the catalytic performance of MoS_(2) in the hydrogen evolution reaction,we investigate the electrocatalytic and photocatalytic performance of monolayer MoS_(2) doped with noble metal(Ag,Au,Cu,Pd,and Pt)using first principles calculation combined with the climbing image nudged elastic band method.We find the band gap of the monolayer MoS_(2) is reduced significantly by the noble metal doping,which is unfavorable to improving its photocatalytic performance.The optical absorption coefficient shows that the doping does not increase the ability of the monolayer MoS_(2) to absorb visible light.The monolayer MoS_(2) doped with the noble metal is not a potential photocatalyst for the hydrogen evolution reaction because the band edge position of the conduction band minimum is lower than-4.44 eV,the reduction potential of H^(+)/H_(2).Fortunately,the band gap reduction increases the electron transport performance of the monolayer MoS_(2),and the activation energy of water splitting is greatly reduced by the noble metal doping,especially the Pt doping.On the whole,noble metal doping can enhance the electrocatalytic performance of the monolayer MoS_(2).

A cerium-doped NASICON chemically coupled poly(vinylidene fluoride-hexafluoropropylene)-based polymer electrolyte for high-rate and high-voltage quasi-solid-state lithium metal batteries

The isolated inorganic particles within composite polymer electrolytes(CPEs) are not correlated to the Li^(+)transfer network,resulting in the polymer dominating the low ionic conductivity of CPEs.Therefore,we developed novel quasi-solid-state CPEs of a Ce-doped Na super ion conductors(NASICON)Na_(1.3+x)Al_(0.3)Ce_(x)Ti_(1.7-x)(PO_(4))_(3)(NCATP) chemically coupled poly(vinylidene fluoride-hexafluoropropylene)(PVDF-HFP)/Li-bis(trifluoromethanes-ulfonyl)imide(LiTFSI) matrix.A strong interaction between Ce^(3+)from NCATP and TFSI-anion from the polymer matrix contributes to the fast Li+transportation at the interface.The PVDF-HFP/NCATP CPEs exhibit an ionic conductivity of 2.16 × 0^(-3) S cm^(-1) and a Li^(+) transference number of 0.88.A symmetric Li/Li cell with NCATP-integrated CPEs at 0.1 mA cm^(-2) presents outstanding cycling stability over 2000 h at 25℃.The quasi-solid-state Li metal batteries of Li/CPEs/LiFePO_(4) at 2 C after 400 cycles and Li/CPEs/LiCoO_(2) at 0.2 C after 120 cycles deliver capacities of 100 and 152 mAh g^(-1) at 25℃,respectively.

Carbon materials:The burgeoning promise in electronics

Current electronic technology based on silicon is approaching its physical and scientific limits. Carbon-based devices have numer- ous advantages for next generation electronics (e.g., fast speed, low power consumption and simple process), that when combined with the unique nature of the versatile allotropes of carbon elements, are creating an electronics revolution. Carbon electronics are greatly advancing with new preparations and sophisticated designs. In this perspective, representatives with various dimensions, e.g., carbon nanotubes, graphene, bulk diamond, and their extraordinary performance, are reviewed. The associated state-of-the-art devices and composite hybrid all-carbon structures are also emphasized to reveal their potential in the electronics field. Advances in commercial production have improved the cost effi-ciency, material quality, and device design, accelerating the promise of carbon materials.

Comparative adsorption of heavy metal ions in wastewater on monolayer molybdenum disulfide

To maximize the potential of monolayer molybdenum disulfide(MoS2)sheet in the disposal of heavy metal ions in wastewater,we compared the adsorption of several common heavy metal ions(including Cr^(3+),Ni^(2+),Cu^(2+),Zn^(2+),Cd^(2+),Hg^(2+),and Pb^(2+))in wastewater on the monolayer MoS2 sheet through first-principles calculation.Our simulation results show that the monolayer MoS2 sheet is a potential heavy metal adsorption material because of the attractive interaction between them.The most negative adsorption energy determines that the TMo site is the most stable adsorption site for the heavy metal ions.The attractive interaction is considered as chemical adsorption,and it is closely related to charge transfer.The orbital hybridization between S p and heavy metal ions p and d states electrons contributes to the adsorption,except the orbital hybridization between S p and Pb p states electrons contributes to the Pb^(2+) adsorption.All the results show that the monolayer MoS2 sheet is most suitable for removing Ni^(2+) and Cr^(3+) ions from wastewater,followed by Cu^(2+) and Pb^(2+).For the ions Cd^(2+),Zn^(2+),and Hg^(2+),its adsorption strength remains to be improved.

A laser-engraved wearable gait recognition sensor system for exoskeleton robots

As a reinforcement technology that improves load-bearing ability and prevents injuries,assisted exoskeleton robots have extensive applications in freight transport and health care.The perception of gait information by such robots is vital for their control.This information is the basis for motion planning in assistive and collaborative functions.Here,a wearable gait recognition sensor system for exoskeleton robots is presented.Pressure sensor arrays based on laser-induced graphene are developed with flexibility and reliability.Multiple sensor units are integrated into an insole to detect real-time pressure at key plantar positions.In addition,the circuit hardware and the algorithm are designed to reinforce the sensor system with the capability of gait recognition.The experimental results show that the accuracy of gait recognition by the proposed system is 99.85%,and the effectiveness of the system is further verified through testing on an exoskeleton robot.

Cost-effective natural graphite reengineering technology for lithium ion batteries

Graphite tailings produced by natural graphite is usually regarded as garbage to be buried underground,which would result in a certain waste of resources.Here,in order to explore the utilization of natural graphite tailings(NGT),a liquid-polyacrylonitrile(LPAN)is used to modify the NGT fragments and aggregate them together to form secondary graphite particles with low surface area and high tap density.Moreover,the modified NGT show much better electrochemical performances than those of original one.When tested in full cells coupled with NMC532 cathode,the material achieves a high rate capability and cycle stability at the cutoff voltage of 4.25 V as well as 4.45 V,which maintains 84.32%capacity retention after 500 cycles at 1 C rate(4.25 V),higher than that of the pristine one(73.65%).The enhanced performances can be attributed to the use of LPAN to create a unique carbon layer upon graphite tailings to reconstruct surface and repair defects,and also to granulate an isotropic structure of secondary graphite particles,which can help to weaken the anisotropy of Li^(+)diffusion pathway and form a uniform,complete and stable solid-electrolyte-interface(SEI)on the surface of primary NGT fragments to promote a fast Li+diffusion and suppress lithium metal dendrites upon charge and discharge.

Latest developments in room-temperature semiconductor neutron detectors: Prospects and challenges

Semiconductor-based neutron-detectors are characterized by small size, high energy-resolution, good spatial resolution, and stable response(at the depletion voltage). Consequently, these neutron-detectors are important for the fields of nuclear proliferation prevention, oil exploration, monitoring neutron-scattering experiments, cancer treatments, and space radiation effect research. However, there are some well-known problems for conventional silicon-based neutron detectors: low neutron-detection efficiency and limited resistance to radiation. Therefore, critical improvements are needed to enable sufficiently effective and practical neutron detection. To address these problems, direct-conversion neutron detectors as well as wide bandgap semiconductor-based detectors have been developed and studied intensely during the past years. Significant progress with respect to detection efficiency, radiation resistance, and room temperature operation was achieved. This paper reviews the latest research highlights, remaining challenges, and emerging technologies of direct-conversion neutron detectors as well as wide-bandgap semiconductor neutron detectors. This compact review serves as a reference for researchers interested in the design and development of improved neutron detectors in the future.

Low operating voltage memtransistors based on ion bombarded p-type GeSe nanosheets for artificial synapse applications

Two-dimensional(2D)layered materials have many potential applications in memristors owing to their unique atomic structures and electronic properties.Memristors can overcome the in-memory bottleneck for use in brain-like neuromorphic computing.However,exploiting additional lateral memtransistors based on 2D layered materials remains challenging.There are few studies on p-type semiconductors that have not been theoretically analyzed.In this study,a lateral memtransistor based on p-type GeSe nanosheets is investigated.A threeterminal GeSe memtransistor that modulated the interfacial barrier height was fabricated using low-energy ion irradiation;the memtransistor exhibited a low operating voltage.The memtransistor successfully mimics biological synapse,including neuroplasticity functions,such as short-term plasticity,long-term plasticity,paired-pulse facilitation,and spike-timing-dependent plasticity.The mechanism of interfacial modulation was verified by experimental results and theoretical calculations.The results show that it is feasible to modulate the interface of 2D GeSe nanosheets using low-energy ion irradiation to realize a lateral memtransistor.This may provide promising opportunities for artificial neuromorphic system applications based on 2D layered materials.

Modulating the electronic spin state by constructing dual-metal atomic pairs for activating the dynamic site of oxygen reduction reaction

In this study,dual-metal atomic pairs of manganese(Mn)-iron(Fe)binuclear sites(BNSs)with two conjoint MnN4 and FeN4 moieties(MnFeN8)anchored onto a graphite-like structure(GLS)(Mn-Fe BNSs/GLS)were constructed.The binuclear MnFeN8 structure was verified experimentally and theoretically.Magnetic measurements and Gaussian calculations reveal that this unique Mn-Fe BNSs exhibit strong short-range electronic interaction between Mn and Fe sites,which decouples two paired d electrons in Fe sites,thereby transforming Fe sites from an intermediate to a high spin state.The optimal electronic configuration of Fe sites and their binuclear structure facilitate an oxygen reduction reaction(ORR)thermodynamically and dynamically,respectively,endowing Mn-Fe BNSs with improved ORR performance.

调节Co_(3)O_(4)的价电子结构提高硝酸根还原制氨的催化活性

通过硝酸根电化学还原反应将NO_(3)^(-)转化为NH_(3)是一种有前景的制氨和“绿氢”储存方案.Co_(3)O_(4)对于硝酸根还原析氨反应表现出较高的析氨法拉第效率和稳定性,有望成为理想的催化剂.然而,在Co_(3)O_(4)上发生硝酸根还原反应仍需较高的过电位,从而阻碍了能量转换效率的提升.本文中,我们合成了Cu掺杂Co_(3)O_(4)多孔空心纳米球用作硝酸根还原析氨催化剂.Cu掺杂在保障析氨法拉第效率和稳定性的前提下大幅降低了反应所需的过电位,有效提高了析氨速率.实验和理论分析均表明,Cu掺杂使Co_(3)O_(4)的最高占据态能量上移,缩小了Co_(3)O_(4)的最高占据态与NO_(3)^(-)的最低未占据分子轨道之间的能垒,从而降低了电子从Co_(3)O_(4)向NO_(3)^(-)跃迁所需的过电位,赋予了Cu掺杂Co_(3)O_(4)多孔空心纳米球优异的硝酸根还原析氨电催化活性和耐久性.本研究为纳米材料的电化学性能调控研究提供了新的理论视角.

High Efficiency Formamidinium-Cesium Perovskite-Based Radio-Photovoltaic Cells

Radio-photovoltaic cell is a micro nuclear battery for devices operating in extreme environments,which converts the decay energy of a radioisotope into electric energy by using a phosphor and a photovoltaic converter.Many phosphors with high light yield and good environmental stability have been developed,but the performance of radio-photovoltaic cells remains far behind expectations in terms of power density and power conversion efficiency,because of the poor photoelectric conversion efficiency of traditional photovoltaic converters under low-light conditions.This paper reports an radio-photovoltaic cell based on an intrinsically stable formamidinium-cesium perovskite photovoltaic converter exhibiting a wide light wavelength response from 300 to 800 nm,high open-circuit voltage(V_(oc)),and remarkable efficiency at low-light intensity.When a He ions accelerator is adopted as a mimickedαradioisotope source with an equivalent activity of 0.83 mCi cm^(-2),the formamidinium-cesium perovskite radio-photovoltaic cell achieves a V_(oc)of 0.498 V,a short-circuit current(J_(sc))of 423.94 nA cm^(-2),and a remarkable power conversion efficiency of 0.886%,which is 6.6 times that of the Si reference radio-photovoltaic cell,as well as the highest among all radio-photovoltaic cells reported so far.This work provides a theoretical basis for enhancing the performance of radio-photovoltaic cells.

温和光热疗法在肿瘤治疗中的研究进展

癌症是目前世界上发病率和死亡率最高的疾病之一.光热疗法(photothermal therapy,PTT)是一种无创的癌症治疗新策略,即把具有较高光热转化效率的材料(photothermal agent,PTA)注入人体内部,利用靶向性聚集在肿瘤组织附近,再在近红外(near-infrared,NIR)等外部光源的照射下,将光能转化为热能来杀死癌细胞.然而,光热治疗所需要达到的高温可能对正常组织损伤较大,因此,相对低温的温和光热疗法(mild photothermal therapy,MPTT)备受关注.温和光热疗法本身的抗肿瘤作用有限,通常需与其他疗法联合以构建协同治疗体系,达到治疗肿瘤的目的.近期,本团队合成了一种二维锗量子点光热转换材料,突破了既往无法得到二维材料以及传统材料光热转换效率低的重大难题.本文从温和光热疗法常用光热转换剂的类型及特点、主要障碍及其解决策略、抗肿瘤作用机制、与其他疗法联合的效果等方面对温和光热疗法在肿瘤治疗中的研究现状进行系统性总结,并对未来的发展方向进行展望和讨论,旨在为肿瘤治疗提供一种新思路和新方法.

Erianin,a novel dibenzyl compound in Dendrobium extract,inhibits lung cancer cell growth and migration via calcium/calmodulin-dependent ferroptosis

Ferroptosis,a novel form of programmed cell death,is characterized by iron-dependent lipid peroxidation and has been shown to be involved in multiple diseases,including cancer.Stimulating ferroptosis in cancer cells may be a potential strategy for cancer therapy.Therefore,ferroptosis-inducing drugs are attracting more attention for cancer treatment.Here,we showed that erianin,a natural product isolated from Dendrobium chrysotoxum Lindl,exerted its anticancer activity by inducing cell death and inhibiting cell migration in lung cancer cells.Subsequently,we demonstrated for the first time that erianin induced ferroptotic cell death in lung cancer cells,which was accompanied by ROS accumulation,lipid peroxidation,and GSH depletion.The ferroptosis inhibitors Fer-1 and Lip-1 but not Z-VAD-FMK,CQ,or necrostatin-1 rescued erianin-induced cell death,indicating that ferroptosis contributed to erianin-induced cell death.Furthermore,we demonstrated that Ca^(2+)/CaM signaling was a critical mediator of erianin-induced ferroptosis and that blockade of this signaling significantly rescued cell death induced by erianin treatment by suppressing ferroptosis.Taken together,our data suggest that the natural product erianin exerts its anticancer effects by inducing Ca^(2+)/CaMdependent ferroptosis and inhibiting cell migration,and erianin will hopefully serve as a prospective compound for lung cancer treatment.

Status and development of high-power laser facilities at the NLHPLP

In this paper, we review the status of the multifunctional experimental platform at the National Laboratory of High Power Laser and Physics(NLHPLP). The platform, including the SG-II laser facility, SG-II 9th beam, SG-II upgrade(SG-II UP) facility, and SG-II 5 PW facility, is operational and available for interested scientists studying inertial confinement fusion(ICF) and a broad range of high-energy-density physics. These facilities can provide important experimental capabilities by combining different pulse widths of nanosecond, picosecond, and femtosecond scales. In addition, the SG-II UP facility, consisting of a single petawatt system and an eight-beam nanosecond system, is introduced including several laser technologies that have been developed to ensure the performance of the facility. Recent developments of the SG-II 5 PW facility are also presented.

Accurate reconstruction of soft X-ray energy spectrum in detector response matrix

In this paper, we report the design of a Monte Carlo simulation for the energy spectrum measurement system based on the ladderabsorption method. Herein, the detector response matrix can be calculated using the detector responses to several monochromatic X-ray beams. A novel soft X-ray spectrum unfolding method based on the two-step reverse iteration(TSRI) algorithm is applied to acquire the primary spectrum. This paper provides examples of the use of TSRI, and the unfolded energy spectra for the soft Xray beams show excellent agreement with the references. The unfolded energy spectra obtained using the TSRI exhibit better accuracy than those obtained from the commonly used unfolding code GRAVEL.

Organic–inorganic hybrid perovskite scintillators for mixed field radiation detection

Sensitive and fast detection of neutrons and gamma rays is vital for homeland security,high-energy physics,and proton therapy.Fast-neutron detectors rely on light organic scintillators,andγ-ray detectors use heavy inorganic scintillators and semiconductors.Efficient mixed-field detection using a single material is highly challenging due to their contradictory requirements.Here we report hybrid perovskites(C_(8)H_(12)N)_(2)Pb(Br_(0.95)Cl_(0.05))_(4)that combine light organic cations and heavy inorganic skeletons at a molecular level to achieve unprecedented performance for mixed-field radiation detection.High neutron absorption due to a high density of hydrogen,strong radiative recombination within the highly confined[PbX_(6)]^(4-)layer,and sub-nanometer distance between absorption sites and radiative centers,enable a light yield of 41000 photons/MeV,detection pulse width of 2.97 ns and extraordinary linearity response toward both fast neutrons andγ-rays,outperforming commonly used fast-neutron scintillators.Neutron energy spectrum,time-of-flight based fast-neutron/γ-ray discrimination and neutron yield monitoring were all successfully achieved using(C_(8)H_(12)N)_(2)Pb(Br_(0.95)Cl_(0.05))_(4)detectors.We further demonstrate the monitoring of reaction kinetics and total power of a nuclear fusion reaction.We envision that molecular hybridized scintillators open a new avenue for mixed-field radiation detection and imaging.

Deep reinforcement with spectrum series learning control for a mode-locked fiber laser

A spectrum series learning-based model is presented for mode-locked fiber laser state searching and switching.The mode-locked operation search policy is obtained by our proposed algorithm that combines deep reinforcement learning and long short-term memory networks.Numerical simulations show that the dynamic features of the laser cavity can be obtained from spectrum series.Compared with the traditional evolutionary search algorithm that only uses the current state,this model greatly improves the efficiency of the mode-locked search.The switch of the mode-locked state is realized by a predictive neural network that controls the pump power.In the experiments,the proposed algorithm uses an average of only 690 ms to obtain a stable mode-locked state,which is one order of magnitude less than that of the traditional method.The maximum number of search steps in the algorithm is 47 in the 16°C–30°C temperature environment.The pump power prediction error is less than 2 mW,which ensures precise laser locking on multiple operating states.This proposed technique paves the way for a variety of optical systems that require fast and robust control.