Effects of Pr on the structure and magnetic properties of FePt alloys

The effects of Pr on the structure and magnetic properties of PrxFe60.5-xPt39.5 alloys (x = 0, 0.5, 1.0, and 1.5) were investigated. X-ray diffraction data indicated that the phase transition temperature of FePt based alloys from disordered face-centered-cubic to ordered face-centered-tetragonal cubic decreases with the increase in Pr concentration. Pr plays the role of a grain refiner and it can enhance the exchange coupling between soft magnetic phase and hard magnetic phase. The results indicate that the replacement of Fe by Pr can significantly improve the remanence and coercivity of the Fe60.5Pt39.5 alloy. These results can be explained on the basis of phase transformation and microstructure. Both the remanence ratio and coercivity of the FePt based alloy as a function of the Pr content are increased by the optimum addition of 0.5 at.% Pr.

Anomaly detection method based on kinematics model and nonholonomic constraint of vehicle

A method used to detect anomaly and estimate the state of vehicle in driving was proposed.The kinematics model of the vehicle was constructed and nonholonomic constraint conditions were added,which refer to that once the vehicle encounters the faults that could not be controlled,the constraint conditions are violated.Estimation equations of the velocity errors of the vehicle were given out to estimate the velocity errors of side and forward.So the stability of the whole vehicle could be judged by the velocity errors of the vehicle.Conclusions were validated through the vehicle experiment.This method is based on GPS/INS integrated navigation system,and can provide foundation for fault detections in unmanned autonomous vehicles.

Effect of Ho-doping on microstructure and magnetostriction of TbDyFe alloys

Tb0.3Dy0.7HoxFe1.95(x=0.00, 0.05, 0.10, 0.15, 0.20, 0.35, 0.50, 0.65) quaternary alloys were prepared by arc-melting and followed by annealing.The phases present and structure of the alloys were determined using a D8-Advance X-ray diffractometer.The magnetostriction of the alloys was studied by standard strain gauge technique.The dependence of Ho content on the structure, magnetostriction and density of the alloys was investigated in detail.The research results showed that Ho-doping did not change MgCu2-type cubic Laves structure in Tb0.3Dy0.7Fe1.95.When Ho content x≤0.2, rich rare earth phase presented in the alloys increased and magnetostriction of the alloys reduced evidently with increasing x, but for alloys with x>0.2, the content of rich rare earth phase started to reduce and the magnetostriction increased quickly, especially at low magnetic field in the alloy with x=0.65 due to separation of rich rare earth phases on the surface of the alloy.

STUDY ON DYNAMICS, STABILITY AND CONTROL OF MULTI-BODY FLEXIBLE STRUCTURE SYSTEM IN FUNCTIONAL SPACE

The dynamics, stability and control problem of a kind of infinite dimensional system are studied in the functional space with the method of modern mathematics. First, the dynamical control model of the distributed parameter system with multi_body flexible and multi_topological structure was established which has damping, gyroscopic parts and constrained damping. Secondly, the necessary and sufficient condition of controllability and observability, the stability theory and asymptotic property of the system were obtained. These results expand the theory of the field about the dynamics and control of the system with multi_body flexible structure, and have important engineering significance.

Preparation and Magnetostriction of Tb_(0.22)Dy_(0.48)Ho_(0.35)Fe_2 Alloys

Tb0.22Dy0.48Ho0.35Fe2 quaternary alloys are prepared by melting-top casting-annealing process. X-ray diffraction reveals that the alloy is single phase polycrystalline alloy with MgCu2 type cubic Laves phase structure, and (511) preferred orientation occurs in its. The magnetostriction measurements are carried out at room temperature using standard strain gauge technique in magnetic fields up to 400 kA·m-1. The results show that when the magnetic field, H, is 90 kA·m-1, the magnetostriction, λ, of Tb0.22Dy0.48Ho0.35Fe2 quaternary alloys is 260×10-6, and when the H is 210 kA·m-1, the λ is 438×10-6. When the H is 400 kA·m-1, the λ is up to the saturation value, 538×10-6. As compared with TbDyFe ternary alloys, the λ of the quaternary alloy is significantly higher when the H is less than or equal to 210 kA·m-1. When the H is 120 kA·m-1, the λ of the alloy is 333×10-6, 70×10-6 more than the ternary alloy. Research results and mechanism are discussed.

Effects of R-site compositions on the meta-magnetic behavior of Tb_(1-x)Pr_x(Fe_(0.4)Co_(0.6))_(1.88)C_(0.05)(x=0, 0.8, and 1)

We investigate the low-temperature magnetic properties of intermetallic compounds Tb1-xPrx(Fe0.4Co0.6)1.88C0.05(x = 0, 0.8, and 1) by detailed magnetization measurements. Obvious temperature- and field-induced irreversibilities suggest the coexistence of multiple magnetic phases. Sharp magnetization jumps across the antiferromagnetic to ferromagnetic transition are observed only in the Pr-containing samples, indicating that the behavior of the avalanche-like growth of ferromagnetic clusters is mainly related to the light lanthanide Pr ions. In addition, the time relaxation, field sweep rate, and cooling field dependence of magnetization jumps in the sample with x = 1 are consistent with those in the martensitic scenario.

Recent Progress on Electrode Characteristics of Mg and Mg-Based Hydrogen Storage Alloys

Recent development of Mg and Mg-based hydrogen storage alloys used in Ni-MH battery was discussed extensively. The results obtained from recent studies prove that these alloys with nanocrystalline/amorphous structure formed by mechanical alloying (MA) or mechanical grinding (MG) have good electrode characteristics. In general, MA or MG, and elemental substitution alloying are regarded as the effective means to seek new system of Mg-based alloys and nano-composite with improved electrode characteristics. However, until now, the currently known improvement in these electrode characteristics is still far from reach to that required for commercial application.

NONLINEAR CHARACTERIZATION OF CONCURRENT DUAL-BAND RF POWER AMPLIFIERS

In this paper, the synchronous concurrent dual-band RF signal is used to drive the RF Power Amplifier (PA). The nonlinear characterization of a concurrent dual-band RF PA is discussed while two band signals in the dual-band are modulated by CDMA2000 and WCDMA signals. When the two band signals in the dual-band of the PA are modulated with the same signals, it is found that the nonlinearity of the PA can be expressed by any of the two corresponding baseband data. On the other hand, when the two band signals in the dual-band of the PA are modulated with two different signals, the PA nonlinearity cannot be characterized by any of the two corresponding baseband data. In this case, its nonlinearity has to be denoted by a composite signals consisting of the two baseband signals. Consequently, the requirements for the speed of the A/D converter can be largely reduced. The experimental results with CDMA2000 and WCDMA signals demonstrate the speed of the A/D converter required is only 30 M Sample Per Second (SaPS), but it will be at least 70 M SaPS for the conventional method.

Switchable Ferroelectric Diode Effect and Piezoelectric Properties of Bi_(0.9)La_(0.1)FeO_(3) Ceramics

Multiferroic ceramics Bi0.9La0.1FeO3 are synthesized by solid-state reactions and sintered at various temperatures.The rhombohedral structure with the space group R3c is confirmed by means of x-ray diffraction,and their multiferroic properties are investigated.Bi_(0.9)La_(0.1)FeO_(3) ceramics sintered at 880℃ are found to have the lowest leakage current density and the largest saturated polarization among all the samples.A diode-like currentvoltage hysteresis that could be switched by an external voltage is observed in the Bi_(0.9)La_(0.1)FeO_(3) ceramics.A typical “butterfly” shaped strain-versus-voltage curve is shown with a maximum strain of 0.09%o at 7kV.Roomtemperature magnetization exhibits a hysteresis loop,indicating that the modulation of the spin structure of BiFeOa has been suppressed.

Hadoop + Spark Platform Based on Big Data System Design of Agricultural Product Price Analysis and Prediction by HoltWinters

In the market of agricultural products, the price of agricultural products is affected by production cost, market supply and other factors. In order to obtain the market information of agricultural products, the price fluctuation can be analyzed and predicted. A distributed big data software platform based on Hadoop, Hive and Spark is proposed to analyze and forecast agricultural price data. Firstly, Hadoop, Hive and Spark big data frameworks were built to store the data information of agricultural products crawled into MYSQL. Secondly, the information of agricultural products crawled from MYSQL was exported to a text file, uploaded to HDFS, and mapped to spark SQL database. The data was cleaned and improved by Holt-Winters (three times exponential smoothing method) model to predict the price of agricultural products in the future. The data cleaned by spark SQL was imported and predicted by improved Holt-Winters into MYSQL database. The technologies of pringMVC, Ajax and Echarts were used to visualize the data.

Design of a new kind of chemical experiment container with virtual reality fusion

Background At present,the teaching of experiments in primary and secondary schools is affected by cost and security factors.Existing research on virtual experiment platforms has alleviated these problems.However,the lack of real experimental equipment and use of a single channel to understand user intentions weaken these platforms operationally and degrade the naturalness of interactions.Methods To solve these problems,we propose an intelligent experimental container structure and a situational awareness algorithm,both of which are verified and applied to a chemical experiment involving virtual-real fusion.First,the acquired images are denoised in the visual channel using the maximum diffuse reflection chroma to remove overexposure.Second,container situational awareness is realized by segmenting the image liquid level and establishing a relation-fitting model.Then,strategies for constructing complete behaviors and making priority comparisons among behaviors are adopted for information complementarity and independence,respectively.A multichannel intentional understanding model and an inter-active paradigm that integrates vision,hearing,and touch are proposed.Results The experimental results show that the accuracy of the intelligent container situation awareness proposed in this paper reaches 99%,and the accuracy of the proposed intention understanding algorithm reaches 94.7%.The test shows that the intelligent experimental system based on the new interaction paradigm also has better performance and a more realistic sense of operation experience in terms of experimental efficiency.Conclusion The results indicate that the proposed experimental container and algorithm can achieve a natural level of human-computer interaction in a virtual chemical experiment platform,enhance the user′s sense of operation,and achieve high levels of user satisfaction.

Optimal and Effective Resource Management in Edge Computing

Edge computing is a cloud computing extension where physical compu-ters are installed closer to the device to minimize latency.The task of edge data cen-ters is to include a growing abundance of applications with a small capability in comparison to conventional data centers.Under this framework,Federated Learning was suggested to offer distributed data training strategies by the coordination of many mobile devices for the training of a popular Artificial Intelligence(AI)model without actually revealing the underlying data,which is significantly enhanced in terms of privacy.Federated learning(FL)is a recently developed decentralized profound learning methodology,where customers train their localized neural network models independently using private data,and then combine a global model on the core server together.The models on the edge server use very little time since the edge server is highly calculated.But the amount of time it takes to download data from smartphone users on the edge server has a significant impact on the time it takes to complete a single cycle of FL operations.A machine learning strategic planning system that uses FL in conjunction to minimise model training time and total time utilisation,while recognising mobile appliance energy restrictions,is the focus of this study.To further speed up integration and reduce the amount of data,it implements an optimization agent for the establishment of optimal aggregation policy and asylum architecture with several employees’shared learners.The main solutions and lessons learnt along with the prospects are discussed.Experiments show that our method is superior in terms of the effective and elastic use of resources.

The Review of Secret Image Sharing

Secret image sharing(SIS)is a significant research topic of image information hiding,which divides the image into multiple shares and dis-tributes them to multiple parties for management and preservation.In order to reconstruct the original image,a subset with predetermined number of shares is needed.And just because it is not necessary to use all of the shares to make a reconstruction,SIS creates a high fault tolerance which breaks the limitations of traditional image protection methods,but at the same time,it causes a reduce of safety.Recently,new technologies,such as deep learning and blockchain,have been applied into SIS to improve its efficiency and security.This paper gives an overall review of SIS,discusses four important approaches for SIS,and makes a comparison analysis among them from the perspectives of pixel expansion,tamper resistance,etc.At the end,this paper indicates the possible research directions of SIS in the future.

Boundary Slip and Surface Interaction： A Lattice Boltzmann Simulation

影响的因素在 Couette 几何学流动滑动长度借助于包括非理想的液体液体和液体墙相互作用的一个二阶段的 mesoscopic 格子 Boltzmann 模型被分析。影响边界的主要因素滑倒是在液体液体和液体墙粒子之间的相互作用的力量。另外的因素体积压力例如液体粘性，可以也改变 slip 长度。我们发现边界仅仅滑倒发生在某个密度(体积压力) 下面。如果密度足够大， slip 长度将趋于到零。在我们的模拟，墙附近的低密度层不需要被要求先验但是从内在的非理想的 mesoscopic 动力学自然地出现。是低密度层导致边界滑倒。结果可能是有用的在微流动的滑动上理解最近的试验性的观察。

Review of Alloy Membranes/Films for Hydrogen Separation or Purification

Hydrogen separation and purification are two important chemical processes in the extensive application of hydrogen energy. Membrane technology has opened up a potential solution to the problems of separation and purification in an energy effective way. Membranes of adequate hydrogen permeability, good thermal and mechanical stability are the key to successful application of membrane technology in hydrogen separation and purification. In this paper, the relative parameters concerning hydrogen permeability, the development of different types of membranes namely: palladium composite membranes; V-based alloy membranes, specific functionality embraced alloy membranes, metal hydride (MH) thin films and fabrications, were reviewed and discussed. Pd-free membranes are found to be the ideal alternatives. Suitable MH thin films with mono- or multi-layer microstructures produced by novel fabrication techniques, is likely to be the promising candidates due to possessing properties distinct from those of bulk materials in membrane form.

Deformation of Two-Dimensional Nonuniform-Membrane Red Blood Cells Simulated by a Lattice Boltzmann Model

学习与在刚硬和团上不一致的膜在一个 shear 弓使变形的二维的红血房间，膜是进 equilength 片断的 discretized。液体在内并且在红血房间外面被 D2Q9 格子 Boltzmann 模型和在膜上施加从的水动力学力量模仿红血房间内部、外部被一个压力集成方法计算。通过从弯曲的全球偏差一致膜，我们发现当膜在刚硬上是不一致的时，偏差首先随时间增加减少并且暗示红血房间的终端侧面是静态的。到有在膜上不一致的团的一个红血房间，偏差成为更多大，并且集体分发在 shear 流动影响弄平的红血房间的二个方面的侧面。

Multimodal interaction design and application in augmented reality for chemical experiment

Background Augmented reality classrooms have become an interesting research topic in the field of education,but there are some limitations.Firstly,most researchers use cards to operate experiments,and a large number of cards cause difficulty and inconvenience for users.Secondly,most users conduct experiments only in the visual modal,and such single-modal interaction greatly reduces the users'real sense of interaction.In order to solve these problems,we propose the Multimodal Interaction Algorithm based on Augmented Reality(ARGEV),which is based on visual and tactile feedback in Augmented Reality.In addition,we design a Virtual and Real Fusion Interactive Tool Suite(VRFITS)with gesture recognition and intelligent equipment.Methods The ARGVE method fuses gesture,intelligent equipment,and virtual models.We use a gesture recognition model trained by a convolutional neural network to recognize the gestures in AR,and to trigger a vibration feedback after a recognizing a five finger grasp gesture.We establish a coordinate mapping relationship between real hands and the virtual model to achieve the fusion of gestures and the virtual model.Results The average accuracy rate of gesture recognition was 99.04%.We verify and apply VRFITS in the Augmented Reality Chemistry Lab(ARCL),and the overall operation load of ARCL is thus reduced by 29.42%,in comparison to traditional simulation virtual experiments.Conclusions We achieve real-time fusion of the gesture,virtual model,and intelligent equipment in ARCL.Compared with the NOBOOK virtual simulation experiment,ARCL improves the users'real sense of operation and interaction efficiency.