Taming of trinitromethyl-oxadiazole to access high density and high oxygen balance via a dual modulation strategy

Energetic compounds bearing the trinitromethyl group are garnering broad attraction as potential candidates for a new generation of high energy dense oxidizers.In this work,an effective dual modulation strategy involving both molecular isomerization and crystal morphology control was employed to design and optimize trinitromethyl-oxadiazole with improved comprehensive performance.Utilizing this dual strategy,3,5-bis(trinitromethyl)-1,2,4-oxadiazole(3)was synthesized,resulting in the formation of two distinct crystal morphologies(needle and sheet)corresponding to two crystal forms(3-a and3-b).Encouragingly,while maintaining ultra-high oxygen balance(21.73%),3 achieves impressive densities(1.97-1.98 g/cm^(3)).To our knowledge,the density of 1.98 g/cm^(3)for 3-a sets a new record among that of nitrogen-rich monocyclic compounds.Notably,practical crystal morphology prediction was creatively introduced to guide the experimental crystallization conditions of 3,increasing the impact sensitivity and friction sensitivity from 1 J to 80 N(3-a)to 10 J and 240 N(3-b),respectively.Additionally,the crystal structural analyses and theoretical calculations were conducted to elucidate the reasons of differences between 3-a and 3-b in density and stability.This work provides an efficient strategy to enhance performance of trinitromethyl derivatives,broadening the path and expanding the toolbox for energetic materials.

Electro-optical dual modulation on resistive switching behavior in BaTiO3/BiFeO3/TiO2 heterojunction

The novel BaTiO3/BiFeO3/TiO2 multilayer heterojunction is prepared on a fluorine-doped tinoxide(FTO) substrate by the sol–gel method. The results indicate that the Pt/Ba TiO3/BiFeO3/TiO2/FTO heterojunction exhibits stable bipolar resistive switching characteristic, good retention performance, and reversal characteristic. Under different pulse voltages and light fields, four stable resistance states can also be realized. The analysis shows that the main conduction mechanism of the resistive switching characteristic of the heterojunction is space charge limited current(SCLC) effect. After the comprehensive analysis of the band diagram and the P–E ferroelectric property of the multilayer heterojunction, we can deduce that the SCLC is formed by the effect of the oxygen vacancy which is controlled by ferroelectric polarizationmodulated change of interfacial barrier. And the effective photo-generated carrier also plays a regulatory role in resistance state(RS), which is formed by the double ferroelectric layer Ba TiO3/BiFeO3 under different light fields. This research is of potential application values for developing the multi-state non-volatile resistance random access memory(RRAM) devices based on ferroelectric materials.

Design of a Novel Dual Flux Modulation Machine with Consequent-Pole Spoke-Array Permanent Magnets in Both Stator and Rotor

In this paper,a novel dual flux modulation(DFM)machine with consequent-pole spoke-array permanent magnets(PMs)in both stator and rotor is proposed to achieve a larger torque density than regular flux modulation machines.The stator has two portions of PMs,one is set next to the stator slot with circumferential magnetization,and the other is inserted between the stator yoke and flux bridge with radial magnetization.The rotor has consequent-pole spoke-array PMs and alternative flux bridges.The proposed DFMPM machine can be regarded as the combination of the flux switching PM(FSPM)machine and vernier PM(VPM)machine.First,the structure and operational principle are introduced.Then,the proposed 12-stator-slot/10-rotor-tooth dual flux modulation permanent magnet(DFMPM)machine is compared with the FSPM machine and VPM machine in terms of flux lines distribution,back-electromotive force(EMF),cogging torque and average torque.Finally,the four proposed DFMPM machines are optimized for maximum average torque and minimum ripple torque considering the effects of split ratio,slot opening ratio,PM depth,PM angle and iron angle.

Dual Adaptive Turbo Coded Modulation for Integrated Multimedia Service Transmission

This paper proposes a cross-layer dual adaptive coded modulation architecture using turbo codes for mobile multimedia communication, which adapts to both the varying channel characteristics and the QoS of various multimedia services simultancously to increase the average system throughput substantially. A pragmatic channeladaptive turbo coded modulation schcme, which comes within 2.5 dB of the Shannon limit, is optimally designed, and then a QoS-adaptive scheme is superimposed to build the dual adaptive architecture. Simulation results show that the novel dual adaption reduces the gap from the fading channel capacity to 2 dB when assuming different services occur in equal probability and the service duration follows exponential distribution.

Transmission Characteristic Simulation of High Frequency Acousto-Optic Modulators

The way by which one can make sure the operating mode of the modulation is by observing the Comsol results of the designed model of proposed acousto-optic modulator (AOM). These results include the pressure distribution, sound pressure distribution, stress distribution at piezoelectric, far-field analysis that describes the diffracted light orders, and electric potential versus light frequency. Throughout the simulating process of modulator operating using Comsol, it begins when the RF is power by a voltage of 100 V, the light is then split into first ordered diffraction, which implies that the modulator is in the operating mode. The use of semiconductor materials is due to its smaller gap that easily transfers the energy that leads to generating first order diffraction when they provided a voltage power. It mentioned that zero order diffraction indicates the modulator does not run;other orders are appearing with increasing the frequency of light leading to decrease of the efficiency of the modulator performance.

Mid-infrared lightly Er^(3+)-doped CaF_(2)laser under acousto–optical modulation

A 1.7-at.%Er:CaF_(2)crystal was synthesized by temperature gradient method.The Er:CaF_(2)crystal was applied in acousto-optically Q-switched laser at mid-infrared region for the first time.Using a Te O_(2)-based crystal as Q-switcher,we obtained a laser diode(LD)end-pumped Er:CaF_(2)laser with the highest single pulse energy up to 0.49 mJ and maximum peak power of 0.56 kW under 6.34-W absorbed pump power.The implication of these results is that the low-doped Er:CaF_(2)crystal exhibits promising optical properties in solid-state lasers.

New Topologies of High Torque Density Machine Based on Magnetic Field Modulation Principle

With the increasing demand for high torque density in motors,more and more new topologies emerge.Furthermore,the magnetic field modulation principle is widely concerned and has evolved into an effective analysis method for studying the new motor topology.This paper introduces the principle of magnetic field modulation.And the research on high torque density in recent years is reviewed from the perspective of magnetic field modulation,including permanent magnet vernier machine(PMVM),flux reverse machine(FRM),flux switching machine(FSM),dual permanent magnet(DPM)machine,and DC biased machine.The principle of magnetic field modulation makes it possible to propose higher torque density topologies in the future.

Acousto-optic Devices: Theory and Applications

The basics and applications of acousto-optic devices are described.The applications include acousto-optic spectrum analyzer,acousto-optic deflector,acousto-optic processors and acousto-optic digital matrix computer.

A channel- and QoS-adaptive turbo coded modulation architecture for mobile multimedia communication

This paper proposed a cross-layer dual adaptive coded modulation architecture using turbo codes for mobile muhimedia communication, which simultaneously adapted to both the varying channel characteristics and the quality of service （QoS） of various mobile multimedia services to increase the average system throughput substantially. A pragmatic channel-adaptive turbo coded modulation scheme, which comes within 2.5dB of the Shannon limit, was optimally designed, and then a QoS-adaptive scheme was superimposed to build the dual adaptive architecture. Simulation results show that the novel dual adaption reduces the difference with the fading channel capacity to 2dB when assuming different services occur in equal probability and the service duration follows the exponential distribution.

A Lightweight Network with Dual Encoder and Cross Feature Fusion for Cement Pavement Crack Detection

Automatic crack detection of cement pavement chiefly benefits from the rapid development of deep learning,with convolutional neural networks(CNN)playing an important role in this field.However,as the performance of crack detection in cement pavement improves,the depth and width of the network structure are significantly increased,which necessitates more computing power and storage space.This limitation hampers the practical implementation of crack detection models on various platforms,particularly portable devices like small mobile devices.To solve these problems,we propose a dual-encoder-based network architecture that focuses on extracting more comprehensive fracture feature information and combines cross-fusion modules and coordinated attention mechanisms formore efficient feature fusion.Firstly,we use small channel convolution to construct shallow feature extractionmodule(SFEM)to extract low-level feature information of cracks in cement pavement images,in order to obtainmore information about cracks in the shallowfeatures of images.In addition,we construct large kernel atrous convolution(LKAC)to enhance crack information,which incorporates coordination attention mechanism for non-crack information filtering,and large kernel atrous convolution with different cores,using different receptive fields to extract more detailed edge and context information.Finally,the three-stage feature map outputs from the shallow feature extraction module is cross-fused with the two-stage feature map outputs from the large kernel atrous convolution module,and the shallow feature and detailed edge feature are fully fused to obtain the final crack prediction map.We evaluate our method on three public crack datasets:DeepCrack,CFD,and Crack500.Experimental results on theDeepCrack dataset demonstrate the effectiveness of our proposed method compared to state-of-the-art crack detection methods,which achieves Precision(P)87.2%,Recall(R)87.7%,and F-score(F1)87.4%.Thanks to our lightweight crack detectionmodel,the parameter count of the model in real-world detection scenarios has been significantly reduced to less than 2M.This advancement also facilitates technical support for portable scene detection.

Dual‑domain Joint Dense Multiple Small Ship Target Detection Algorithm for Spaceborne SAR Images

Ship detection via spaceborne synthetic aperture radar(SAR)has become a research hotspot.However,existing small ship detection methods based on the radar signal domain and SAR image features cannot obtain highly accurate results because of the obvious coherent speckle noise at sea and strong reflection interference from near‑shore objects.To resolve the above problems,this study proposes a dual‑domain joint dense multiple small ship target detection method for spaceborne SAR image that simultaneously detects objects in the image and frequency domains.This method uses an attention mechanism module and algorithm structure adjustments to improve the small ship target feature mining ability.In the frequency‑based image generation,extreme signal strength values are detected in the azimuth and range directions,with the results of the two complementing each other to realize dual‑domain joint small ship target detection.The comprehensive qualitative and quantitative evaluation results show that the proposed method can attain a final precision rate of 92.25%and achieve accurate results for SAR ship detection in open‑sea,coastal,and port area ships.The test results for the self‑built SAR small‑ship dataset demonstrate the effectiveness and universality of the method.

A Dual Arm Complementary Hybrid Modulation Strategy Combining NL-SPWM for MMC Applications

In the medium voltage direct current(MVDC)transmission system,a small number of MMC sub modules will reduce the power quality.In this paper,based on the research background of Photovoltaic Medium VoltageDirect Current(PV-MVDC)system,aHybrid Modulation Strategy based on theDecoupledDouble SynchronousReference Frame(DDSRF)control strategy is proposed.The dual armcomplementary hybrid modulation combining nearest-level-SPWM(NL-SPWM)can keep the number of SMs in the ON state constant.Then,the corresponding voltage sharing control algorithm of sub module(SM)is introduced.Through theoretical calculation,the modulation strategy can be found to stabilize the DC voltage and reduce the harmonic content.A32-level MMC systemhas been developed to verity that the proposed hybrid modulation strategy and its SM voltage sharing algorithm have the advantages of restraining circulating current and maintaining capacitor voltage balance.

基于强化双树复小波包变换的风电机组偏航轴承损伤识别

针对风电机组偏航轴承损伤识别问题,提出了基于强化双树复小波包变换的损伤识别方法。首先,通过双树复小波包变换与线性峭度结合对不同分解层数下的分量计算平均线性峭度值,确定最优分解层数;其次,对最优分解所得小波系数及尺度系数进行幅值调制,进而增强不同信号成分的能量;然后,采用散布熵指标确定各分量最佳调制系数并通过双树复小波包逆变换得到修正信号;最后,对修正信号作归一化平方包络谱分析提取故障特征频率。结果表明:所提方法能够实现复杂工况下偏航轴承损伤类型的准确识别,具有一定工程参考价值。

强t-提升模与强t-dual Rickart模

引入强t-提升模与强t-dual Rickart模的概念,讨论两者的基本性质和关系.证明富足补模M为强t-提升模当且仅当~2（M）为M的直和项且~2（M）为强提升模,并得到强dual Rickart模的一个新刻画.

基于机器视觉的金属零件表面缺陷检测研究

目前制造业中,金属零件的缺陷问题会导致重大经济损失,主要问题在于零件缺陷小且缺陷位置出现随机,传统人工检测难以区分微小缺陷位置与非缺陷位置,且人力成本高,经济效益低下。针对这一问题,研究提出一种基于机器视觉的金属零件表面缺陷检测方法,通过机器视觉检测代替人力劳动,同时采用交互式空间位置注意力模块,解决了金属零件表面的缺陷不明显难以检测的问题,采用对偶局部-全局Transformer模块,解决了缺陷区域与周围正常区域难以区分的问题,提高了金属零件表面微小缺陷的检测性能,从而提高企业经济效益。

Dual pairs of tilting pairs

A module pair （C, T） over an Artin algebra A is called a tilting pair if both C and T are selforthogonal modules and the conditions T e ada C and C ∈ add T hold. The duality on a tilting pair is investigated to discuss the condition under which the dual of a tilting pair is also a tilting pair. A necessary and sufficient condition of （D（7）, D（C） ） being an n-tilting pair over an Artin algebra for an n-tilting pair （ C, 7） is given. And, a necessary and sufficient condition of （ T^＊, C^＊ ） being an ntilting pair over a selfinjective Artin algebra for an n-tilting pair （C, 7） is also given.

Acousto-optic modulator-based bi-frequency interferometer for quantum technology

We demonstrate a high-performance acousto-optic modulator-based bi-frequency interferometer,which can realize either beating or beating free interference for a single-photon level quantum state.Visibility and optical efficiency of the interferometer are(99.5±0.2)%and(95±1)%,respectively.The phase of the interferometer is actively stabilized by using a dithering phase-locking scheme,where the phase dithering is realized by directly driving the acousto-optic modulators with a specially designed electronic signal.We further demonstrate applications of the interferometer in quantum technology,including bi-frequency coherent combination,frequency tuning,and optical switching.These results show the interferometer is a versatile device for multiple quantum technologies.

Electronic structure and geometric construction modulation of carbon-based single/dual atom catalysts for electrocatalysis

Both carbon-based single atom catalysts(SACs)and dual atom catalysts(DACs)have garnered significant attention in the field of electrochemical reactions because of the impressive attributes,including exceptional catalytic activity,selectivity,and cost-effectiveness.The ability to modulate the electronic structure and geometric construction of active sites within SACs/DACs is paramount for unleashing their complete potential,which in turn can ultimately dictate catalytic behavior with unprecedented precision.In this review,the recent major developments of the regulation strategies for modulating electronic structure and geometric construction of carbon-based SACs/DACs are summarized.For the SACs,the recently reported modulation methods are categorized into four strategies,including adjusting the density of single atoms,defect engineering,confinement effect and strain engineering.And for the DACs,the five methods contain bonded dual-atom adjustment,non-bonded and bridged dual-atom adjustment,metal and nonmetal dual-atom adjustment,bilayer dual-atom adjustment and homogeneous dual-atom adjustment.The recently developed synthetic strategies are comprehensively summarized,especially their electronic structure and geometric configuration are discussed in detail,the different catalytic applications of electrochemical reactions,and their unique catalytic mechanism are highlighted.Finally,the challenges and prospects of SACs/DACs for tailoring their electronic structures and geometric arrangements are further discussed.

Acousto-optical modulation of thin film lithium niobate waveguide devices

Due to its strong piezoelectric effect and photo-elastic property, lithium niobate is widely used for acousto-optical applications. However, conventional bulk lithium niobate waveguide devices exhibit a large footprint and limited light–sound interaction resulting from the weak guiding of light. Here, we report the first acousto-optical modulators with surface acoustic wave generation, phononic cavity, and low-loss photonic waveguide devices monolithically integrated on a 500 nm thick film of lithium niobate on an insulator. Modulation efficiency was optimized by properly arranging the propagation directions of surface acoustic waves and optical guided modes.The effective photo-elastic coefficient extracted by comparing the first and third harmonic modulation signals from an on-chip Mach–Zehnder interferometer indicates the excellent acousto-optical properties of lithium niobate are preserved in the thin film implementation. Such material property finding is of crucial importance in designing various types of acousto-optical devices. Much stronger amplitude modulation was achieved in a high Q(>300,000) optical resonator due to the higher optical sensitivity. Our results pave the path for developing novel acousto-optical devices using thin film lithium niobate.

Quasi-dual模和V-环的一个新的推广(英文)

定义了quasi-dual模,讨论了它的性质和等价条件,并且通过quasi-dual模,详细讨论了V-环的一个新的推广结构,得到了以下等价条件:1R/Soc(RR)是右V-环;2每一个R的本质真右理想是极大右理想的交;3存在一个奇异半单右R-模是quasi-dual的.