A Cloud-Fog Enabled and Privacy-Preserving IoT Data Market Platform Based on Blockchain

The dynamic landscape of the Internet of Things(IoT)is set to revolutionize the pace of interaction among entities,ushering in a proliferation of applications characterized by heightened quality and diversity.Among the pivotal applications within the realm of IoT,as a significant example,the Smart Grid(SG)evolves into intricate networks of energy deployment marked by data integration.This evolution concurrently entails data interchange with other IoT entities.However,there are also several challenges including data-sharing overheads and the intricate establishment of trusted centers in the IoT ecosystem.In this paper,we introduce a hierarchical secure data-sharing platform empowered by cloud-fog integration.Furthermore,we propose a novel non-interactive zero-knowledge proof-based group authentication and key agreement protocol that supports one-to-many sharing sets of IoT data,especially SG data.The security formal verification tool shows that the proposed scheme can achieve mutual authentication and secure data sharing while protecting the privacy of data providers.Compared with previous IoT data sharing schemes,the proposed scheme has advantages in both computational and transmission efficiency,and has more superiority with the increasing volume of shared data or increasing number of participants.

Research and Application of Recycled Concrete Technology in Prefabricated Buildings

The utilization of waste concrete as a raw material for recycled concrete in the domain of prefabricated components is garnering greater interest.This paper delineates and examines the concept,categorization,methodologies of preparation,applicable sectors,and evaluative metrics of recycled concrete technology,highlighting its prospective benefits.Nonetheless,for the successful integration of recycled concrete technology into prefabricated component applications,it is imperative to systematically enhance its physical,mechanical,and attributes,as well as its environmental efficacy.Moreover,to foster the continued advancement of recycled concrete technology,innovative initiatives,standardization,educational programs,demonstration projects,and collaborative efforts are crucial to promote broader adoption and realize improved outcomes within the realm of prefabricated components.In conclusion,recycled concrete technology is poised to play a pivotal role in prefabricated construction,offering robust support for propelling the construction industry towards a sustainable future.

A review of control loop monitoring and diagnosis:Prospects of controller maintenance in big data era

Owing to wide applications of automatic control systems in the process industries, the impacts of controller performance on industrial processes are becoming increasingly significant. Consequently, controller maintenance is critical to guarantee routine operations of industrial processes. The workflow of controller maintenance generally involves the following steps: monitor operating controller performance and detect performance degradation, diagnose probable root causes of control system malfunctions, and take specific actions to resolve associated problems. In this article, a comprehensive overview of the mainstream of control loop monitoring and diagnosis is provided, and some existing problems are also analyzed and discussed. From the viewpoint of synthesizing abundant information in the context of big data, some prospective ideas and promising methods are outlined to potentially solve problems in industrial applications.

Data Analytics and Machine Learning for Smart Process Manufacturing: Recent Advances and Perspectives in the Big Data Era

Safe, ef cient, and sustainable operations and control are primary objectives in industrial manufacturing processes. State-of-the-art technologies heavily rely on human intervention, thereby showing apparent limitations in practice. The burgeoning era of big data is in uencing the process industries tremendously, providing unprecedented opportunities to achieve smart manufacturing. This kind of manufacturing requires machines to not only be capable of relieving humans from intensive physical work, but also be effective in taking on intellectual labor and even producing innovations on their own. To attain this goal, data analytics and machine learning are indispensable. In this paper, we review recent advances in data analytics and machine learning applied to the monitoring, control, and optimization of industrial processes, paying particular attention to the interpretability and functionality of machine learning mod- els. By analyzing the gap between practical requirements and the current research status, promising future research directions are identi ed.

管式旋流气液分离器流场特性与分离性能研究

管式旋流气液分离器因具有分离效率高、结构紧凑等优点而受到广泛关注,但能否适应入口气含率大范围变化是制约其实用性的关键。本工作考察了能够适应气含率大范围变化的管式旋流气液分离器,采用计算流体力学(CFD),结合空气-水介质体系下的实验测试,对其流场特性和分离性能进行研究。CFD数值模拟结果显示,入口气含率在10%~90%范围内变化时,气相分离效率均大于80%且变化幅值小于9.9%,液相分离效率均大于97%且变化幅值小于2.2%。实验测试结果显示,入口气含率在9.4%~89.2%范围内变化时,随入口气含率增加,气相出口的含液率逐渐减小而液相出口的气含率逐渐增加,气相出口的含液率均小于4%,除液体流量为12 m^(3)/h的工况外,其他工况下液相出口气含率始终小于10%。对比不同液体流量下的气相分离效率和液相分离效率,液体流量为8 m^(3)/h时分离性能最佳。CFD数值模拟结果与实验测试结果略有差异,但整体变化趋势一致,可作为结构放大设计的有效手段。研究结果表明,管式旋流气液分离器整体采用“强旋流+弱旋流+重力”的作用形式,具有较高的分离效率和良好的抗工况波动性能。

Porous nanocomposites with enhanced intrinsic piezoresistive sensitivity for bioinspired multimodal tactile sensors

In this work,we propose porous fluororubber/thermoplastic urethane nanocomposites(PFTNs)and explore their intrinsic piezoresistive sensitivity to pressure.Our experiments reveal that the intrinsic sensitivity of the PFTN-based sensor to pressure up to 10 kPa increases up to 900%compared to the porous thermoplastic urethane nanocomposite(PTN)counterpart and up to 275%compared to the porous fluororubber nanocomposite(PFN)counterpart.For pressures exceeding 10 kPa,the resistance-pressure relationship of PFTN follows a logarithmic function,and the sensitivity is 221%and 125%higher than that of PTN and PFN,respectively.With the excellent intrinsic sensitivity of the thick PFTN film,a single sensing unit with integrated electrode design can imitate human skin for touch detection,pressure perception and traction sensation.The sensing range of our multimodal tactile sensor reaches~150 Pa,and it exhibits a linear fit over 97%for both normal pressure and shear force.We also demonstrate that an electronic skin,made of an array of sensing units,is capable of accurately recognizing complex tactile interactions including pinch,spread,and tweak motions.

轴向旋流式微气泡发生器的结构设计与数值模拟

设计了一种旋流式微气泡发生器,由环形注气机构和新型气泡破碎机构两部分组成,前者采用中心圆环＋微孔板结构,后者由静止起旋元件和文丘里管组成,采用ANSYS FLUENT软件对新型气泡破碎机构的流道进行数值模拟,并与常规文丘里流道对比.结果表明,新型气泡破碎机构流道内的水流速度、径向速度梯度、湍动能和湍能耗散率均大于常规文丘里流道,常规文丘里流道出口处产生的微气泡直径为新型气泡破碎机构的2倍.采用响应曲面法优化静止起旋元件结构,优化后的叶片出口角度为35？,中心圆柱体直径为12.3 mm,叶片长度为10 mm,优化后的气泡破碎机构产生的微气泡直径为优化前的75%.

Electric-field-controlled superconductor–ferromagnetic insulator transition

Superconductivity beyond electron-phonon mechanism is always twisted with magnetism. Based on a new field-effect transistor with solid ion conductor as the gate dielectric(SIC-FET), we successfully achieve an electric-field-controlled phase transition between superconductor and ferromagnetic insulator in(Li,Fe)OHFeSe. A dome-shaped superconducting phase with optimal T_c of 43K is continuously tuned into a ferromagnetic insulating phase, which exhibits an electric-field-controlled quantum critical behavior. The origin of the ferromagnetism is ascribed to the order of the interstitial Fe ions expelled from the(Li,Fe)OH layers by gating-controlled Li injection. These surprising findings offer a unique platform to study the relationship between superconductivity and ferromagnetism in Fe-based superconductors. This work also demonstrates the superior performance of the SIC-FET in regulating physical properties of layered unconventional superconductors.

Comparison of thermal and light performance in two typical Chinese solar greenhouses in Beijing

Solar greenhouses have been used for producing vegetables in northern China during early spring,late autumn or over-winter.To improve the thermal performance of solar greenhouses,a traditional type and a retrofitted design were comparatively evaluated.In the retrofitted design,three adjustments were incorporated:the material and structure of the walls,south-facing roof angle,and structure of the north-facing back-roof.The results indicated that the thermal and light performance of the retrofitted greenhouse was much better than that of the traditional greenhouse.Specifically,the daily mean temperature,minimum air temperature,and soil temperature inside the greenhouses after retrofit ting were increased by 1.3,2.4,and 1.9℃,respectively,meanwhile,the daily total solar radiation and PAR were increased by 28.2%and 9.2%,respectively.The wall temperature and its daily variation range were reduced with increasing depth and height.The characteristic analysis of heat storage and release indicated that higher locations have longer heat storage,and shorter heat release time in vertical direction,as well as a lower ratio of heat release to storage.In horizontal direction,the western wall has the shortest heat storage time but the highest heat release flux density.Altogether,the heat storage time of the wall is 1.5 h less than that of the soil.The heat storage flux density of the wall is 1.5 times of that of the soil,but the heat release flux is only 61%of the soil’s value.The total wall heat storage is half of that of the soil in the greenhouse;the total wall heat release amount is only a quarter of that of the soil.Therefore,the thermal environment of solar greenhouses can be further improved by improving the thermal insulation properties of the wall.

Frequency comb swept laser with a high-Q microring filter

Frequency comb swept lasers are the enabling technology of circular interferometric imaging.which was proposed to break the bottleneck of data acquisition and proessing in optical coherence tomography(OCT)at video rate.In this paper,we propose and demonstrate a highly coherent frequency comb swept laser by using a high-quality(high-Q)microring comb filter to discretize a Fourier domain mode-locked(FDML)laser.The microring filter has a Q factor of^2×10^6 and a linewidth of^90 MHz.To demonstrate the improvement in performance,a Fabry-Perot comb filter with a Q factor of 6.2×10^4 and a linewidth of 3.1 GHz is also used in the experiment for comparison.Both comb filters have free spectral ranges(FSRs)of^50 GHz for consistence.Stable and clearly discretized temporal waveforms and frequency comb spectra with 50 GHz FSR are observed.Adoption of the high-Q microring filter narrows the instantaneous linewidth of the FDML laser down to 1.5 GHz.The OCT system with the frequency comb swept laser source with a microring filter demonstrates an ultralong imaging range,which has a 6,10,and 15 dB sensitivity roll-off length of^53,~73,and over 100 mm,respectively.

Magnetic-field enhanced high-thermoelectric performance in topological Dirac semimetal Cd3As2 crystal

Thermoelectric materials can be used to convert heat to electric power through the Seebeck effect. We study magneto-thermoelectric figure of merit （ZT） in three-dimensional Dirac semimetal Cd3A 5 2 crystal. It is found that enhancement of power factor and reduction of thermal conductivity can be realized at the same time through magnetic field although magnetoresistivity is greatly increased. ZT can be highly enhanced from 0.17 to 1.1 by more than six times around 350 K under a perpendicular magnetic field of 7 T. The huge enhancement of ZT by magnetic field arises from the linear Dirac band with large Fermi velocity and the large electric thermal conductivity in CdsA 5 2. Our work paves a new way to greatly enhance the thermoelectric performance in the quantum topological materials.

Reconfigurable time-stretched swept laser source with up to 100 MHz sweep rate,100 nm bandwidth,and 100 mm OCT imaging range

The sweep rate,sweep range,and coherence length of swept sources,respectively,determine the acquisition rate,axial resolution,and imaging range of optical coherence tomography(OCT).In this paper,we demonstrate a reconfigurable high-speed and broadband swept laser by time stretching of a flat spectrum femtosecond pulse train with over 100 nm bandwidth and a repetition rate of 100 MHz.By incorporating an optical modulator and utilizing appropriate dispersive modules,the reconfiguration of the swept source is demonstrated with sweep rates of 25 and 2.5 MHz.The 2.5 MHz swept source enables an imaging range of>110 mm with 6 dB sensitivity rolloff in OCT,which is the longest imaging range ever reported for megahertz OCT.

Magnetic field-induced electronic phase transition in the Dirac semimetal state of black phosphorus under pressure

Different instabilities have been confirmed to exist in the three-dimensional(3D) electron gas when it is confined to the lowest Landau level in the extreme quantum limit. The recently discovered 3D topological semimetals offer a good platform to explore these phenomena due to the small sizes of their Fermi pockets, which means the quantum limit can be achieved at relatively low magnetic fields. In this work, we report the high-magnetic-field transport properties of the Dirac semimetal state in pressurized black phosphorus. Under applied hydrostatic pressure, the band structure of black phosphorus goes through an insulator-semimetal transition. In the high pressure topological semimetal phase, anomalous behaviors are observed on both magnetoresistance and Hall resistivity beyond the relatively low quantum limit field, which is demonstrated to indicate the emergence of an exotic electronic state hosting a density wave ordering. Our findings bring the first insight into the electronic interactions in black phosphorus under intense field.

Superconductivity in potassium and ammonia co-intercalated FeSe_(1-x)Te_x

The origin of the ～40 and ～30 K superconducting phases in the metal-intercalated FeSe superconductors is still unclear. We report the synthesis of K_(0.3)(NH_3)_y(FeSe_(1-x)Te_x)_2 and K_(0.6)(NH_3)_y(FeSe_(1-x)Te_x)_2 with x=0-0.6 by using the liquid ammonia method at room temperature. The superconducting transition temperature Tcof the former remains about 43 K for all the nominal Te content less than 0.3, while that of the latter is about 30 K and obviously decreases with Te doping. Superconductivity disappears for x ≥0.4 in both systems. Except for the different chemical pressure induced by substitution of Te for Se in both systems, we also observed distinct external pressure effect on superconductivity for both systems, with much more efficiency of suppressing Tcby external pressure in the former system. These dramatic differences of both chemical and external pressure effects on Tc between the ～30 and ～40 K superconducting phases revealed that the existence of the two superconducting phases can be ascribed to the moderate and negligible coupling between FeSe layers, respectively.

A Survey of Vision and Language Related Multi-Modal Task

With the significant breakthrough in the research of single-modal related deep learning tasks,more and more works begin to focus on multi-modal tasks.Multi-modal tasks usually involve more than one different modalities,and a modality represents a type of behavior or state.Common multi-modal information includes vision,hearing,language,touch,and smell.Vision and language are two of the most common modalities in human daily life,and many typical multi-modal tasks focus on these two modalities,such as visual captioning and visual grounding.In this paper,we conduct in-depth research on typical tasks of vision and language from the perspectives of generation,analysis,and reasoning.First,the analysis and summary with the typical tasks and some pretty classical methods are introduced,which will be generalized from the aspects of different algorithmic concerns,and be further discussed frequently used datasets and metrics.Then,some other variant tasks and cutting-edge tasks are briefly summarized to build a more comprehensive vision and language related multi-modal tasks framework.Finally,we further discuss the development of pre-training related research and make an outlook for future research.We hope this survey can help relevant researchers to understand the latest progress,existing problems,and exploration directions of vision and language multi-modal related tasks,and provide guidance for future research.

Multi-parameter e-skin based on biomimetic mechanoreceptors and stress field sensing

Tactile sensing has been a key challenge in robotic haptics.Inspired by how human skin sense the stress field with layered structure and distributed mechanoreceptors,we herein propose a design for modular multi-parameter perception electronic skin.With the stress field sensing concept,complex tactile signals can be transformed into field information.By analyzing the stress field,the realtime three-dimensional forces can be resolved with 1.8°polar angle resolution and 3.5°azimuthal angle resolution(achieved up to 71 folds of improvement in spatial resolution),we can also detect the hardness of object in contact with the electronic skin.Moreover,we demonstrate random assembly of the sensing arrays and integration of our electronic skin onto differently curved surfaces do not lead to any measurement variation of the stress field.This result reveals that the sensing elements in our electronic skin system can be modularly made and exchanged for specific applications.