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In this perspective, we outline that a space borne gravitational wave detector network combining LISA and Taiji can be used to measure the Hubble constant with an uncertainty less than 0.5% in ten years, compared with the network of the ground based gravitational wave detectors which can measure the Hubble constant within a 2% uncertainty in the next five years by the standard siren method. Taiji is a Chinese space borne gravitational wave detection mission planned for launch in the early 2030 s. The pilot satellite mission Taiji-1 has been launched in August 2019 to verify the feasibility of Taiji. The results of a few technologies tested on Taiji-1 are presented in this paper. Gravitational wave astronomy has opened the door to test general relativity and the effect of gravity in the Universe. The authors present the capabilities of an overlap between space gravitational wave detectors LISA and Taiji to constrain the Hubble constant to 0.5%, in 10 years, and what can be learned from the satellite pilot Taiji-1 launched in 2019.

The Hall Micro Thrusters (HMTs) use cold gas or accelerated plasma dual mode to provide ultra-precise spacecraft altitude control. They were operated in space for the first time as part of the demonstration payloads on Chinese Academy of Science’s (CASs) Taiji-1 spacecraft since September 2019. Hall Micro Thruster Assemblies (HMTAs) were the actuators in drag-free control, and will compensate the nonconservative force for gravity wave observatories. The HMTAs meet the requirements of operating at 5–100 [Formula: see text] N of thrust with 0.7 [Formula: see text] N resolution and [Formula: see text]0.6 [Formula: see text] N/Hz[Formula: see text] (0.01–1 Hz) noise to deliver the nanometer-level precision control as fast as 30 ms measured by Gravitational Reference Sensor (GRS). A transfer function model in z-domain was fit and used to filter HMTs cathode voltage to predict GRSs thrust noise response. Simulations of a single or dual-frequency disturbance and the corresponding compensation demonstrated that HMTAs could deliver the required thrust profile expected. The capability to meet the requirements of thruster noise in drag-free control is critical for future missions because the acceleration noise on test mass directly relates to the gravity wave signa l. Preliminary in-orbit verification of Taiji-1 has showed HMTAs’ great potential in future, and the data in the experiments are presented in this paper.

Material properties in the process of tribo-emission decides the characteristics of both spectra and intensity of triboluminescence. ZnS:Mn semiconductor material was proved to be a high emission triboluminescent material in many investigations; Ce- and Yb-doped hexacelsian possess the excellent shortwave triboluminescence character due to f-d electronic transition of doping element with position valances ions; the fracto-mecha-luminescence and photoluminescence spectra of phthalic acid, 4-hydroxy coumarin monohydrate, etc. present obviously a broad ultraviolet and violet waveband emissions, showing the disadvantage of these organic crystals as shortwave triboluminescence materials. Triboluminescence test apparatus of drop tower type have the tribo-emission of impact friction effect; the pin-on-disk type apparatus can perform the triboluminescent experiments with sliding friction mechanism; the twin ring tribometer is used to measure the triboluminescence of polymer material friction rings. These units supply a suitable conditions for obtaining triboluminescence with shortwave emission and persistent high intensity.

Routing information release is a kind of promise from the router for network reachability. Illegal routing information may have disastrous effects on the normal work of the network. Open Shortest Path First (OSPF) protocol provides authentication methods to protect the authenticity and integrity of the routing traffic. This paper describes two authentication types of OSPFv2, analyzes the realization mechanism and packet header format of each authentication respectively. Based on GNS3, a typical network topology was designed, and with the aid of it we carried out functional verification and security analysis. The simulation can provide a reference for building an OSPF network. Experimental results show that the configuration of OSPFv2 routing authentication can effectively prevent the router from receiving unauthorized or malicious routing updates, thereby improving network safety.

Expandable polystyrene and expandable polyethylene foams are frequently used in packaging of products. The study on their cushioning properties is important for the design of the transport package. The effect of compression speed and multiple reloading on the cushioning properties of HDEPS, LDEPS and HDEPE was studied in this paper. The results indicate that the cushioning properties of HDEPS and LDEPS are affected obviously by the compression speed, but the change of the cushioning properties for LDEPE was unconspicuous with the compression speed. LDEPE appeared obvious fatigue after twice reloads.

Silicon oxide thin films have many excellent properties such as hardness, optical,dielectric properties,wear-resistance and corrosion-resistance. It has been widely used in optical and microelectronic applications. The preparation methods mainly include phsical vapor deposition and chemical vapor deposition.The paper reviews a few preparation methods of silicon oxide thin films, and compares advantages and disadvantages w ith each other. On the other hand,it point out the tendency of development.

Food Packaging material requires an excellent barrier ability to humidity and oxygen.SiOx barrier thin film deposited on high polymer substrate can compare beauty with aluminum foil in the barrier quality,even more SiOx barrier thin film is obviously allowing microwave permeating directly and it also provide a chance for merchant to vision their production in shelf life.SiOx film as barrier packaging material is becoming a high light.The current status and research progress of new type high barrier thin film packaging material were overviewed and production technology was introduced. The various influencing factors were discussed, including background vacuum, reactive gases, and pretreatment of the substrate surface and properties.

Video signal processing needs high signal-to-noise ratio (SNR) in high-speed time delay and integration charge coupled devices (TDICCD). To solve this problem, this article first analyzes the characteristics of the output video signal of a new type of high-speed TDICCD and its operation principle. Then it studies the correlation double sample (CDS) method of reducing noise. Following that a synthesized processing method is proposed, including correlation double sample, programmable gain control, line calibration and digital offset control, etc. Among the methods, XRD98L59 is a video signal processor for the charge coupled device (CCD). Application of this processor to one kind of high-speed TDICCD with eight output ports achieves perfect video images. The experiment result indicates that the SNR of the images reaches about 50 dB. The video signal processing for high-speed multi-channel TDICCD is implemented, which meets the required project index.

Based on the questionnaire of college students' English learning motivation developed by Gao Yihong, the paper aims to discuss the intensity of students' English learning motivation as well as the most common motivation content, and compare different types of students' English learning motivation. The results show that the intensity of students' English learning motivation are above average, which are in the following descending order: personal development, social responsibility, infor mation media, inherent interest, achievement, going abroad and learning situation. The most c ommon five main motivation contents are related to personal development. Students who have done part-time jobs have distinctive higher inherent interest motivation, going abroad motivation, social responsibility motivation, information media motivation than those of students who have no working experiences, however, the differences of English learning motivation in gender, grade, only child, student status, autoditacte, majors have not been found.

By using college students' learning-related academic emotions questionnaire, learning related academic emotions for Chinese students are explored on its current situation and its related factors. The results show that students' learning emotions consisted of eight ones, and presented mainly in positive ones; there are significant differences on emotions in gender, major and grade; fa mily economic status has significant impacts on students' learning emotions.The implications of the research on education and teaching are discussed finally.

In order to get the higher compression quality of multispectral remote sensing image, which taken the JPEG2000 as the standard, used FPGA and special compression chip ADV212 to realize the remote sensing image compression system is proposed. The system used the specialty compression chip ADV212 which is newly relaesed by Analog Device company. It used to develop fast high-quality compression for the large amount of remote sensing image data. The system realized the image data's input, the compression stream's output, the image preprocessing as well as to control the ADV212 chip's working pattern through FPGA. The experiment result shows that this system which has such characteristics as low power consumption,low cost and easy adjustmen and has a good compressing effect. Meet the requirement of the multispectral remote sensing image's high compression ratio.

Based on the principle of the asymmetric control of the resistance welding machine, this paper adopted embedded system as the controlling core and carried out the simulation experiment to verify this principle. On the basis of the applying circuit of transformer resistance experiments, the transformer primary voltage experiment has been priority carried out. The results indicate that the primary equivalent voltage of asymmetric control is higher than that of segment chopper control.

A calibration method of faint star magnitude of the star scene simulation device is proposed in this paper. In the research of simulation star magnitude, luminometers and CCD devices are the general calibration devices which are used to measure the illumination intensity and calibrate its magnitude. But if the simulation magnitude is only sixth magnitude, its illumination intensity is only 1.0×10 -8 Lux. This illumination intensity level is the lowest illumination intensity that the commercial luminometer can detect. Hence the simulation star magnitude lower than six magnitude cannot be calibrated by luminoters. Likewise CCD devices also need an additive cooler in this case. When the single photon characteristic is presented due to the low luminosity of simulating light sources, the simulation star magnitude can be calibrated by detecting its photon flux of radiation with the method of single photon count. In this paper the detection principle of single photon based on a compact designed PMT detecting of the radiation level of simulation star magnitude is advanced. Especially a spectrum match method is proved theoretically to be an effective means for selecting PMT photosensitive type. In the case of the detection object of the simulation star in visible wavelength，a analysis indicates that the material of tri-alkali cathode materials its best choice after being compared the Signal-to-Noise of photon detector of several PMT photosensitive materials based on the different spectrum match ratio of different object light sources and different cathode materials. An experiment is employed to show the relationship of control voltage of PMT and its dark counter，the relationship of the environment temperature of PMT and its dark counter, which proves its

The key to the auto-focusing technique based on image processing is the selection of focus measure reflecting image definition. Usually the measures derived are on the premise of the images acquired with the same scene. As for the remote-sensing camera working in linear CCD push-broom imaging mode, the premise doesn't exist because the scenes shot are different at any moment, which brings about difficulties to the selection of the focus measure. To evaluate the image definition, the focus measure based on blur estimation for rough adjustment is proposed to estimate the focused position by only two different lens positions, which greatly saves the auto-focusing time. Another evaluation function based on edge sharpness is developed to find best imaging position in the narrow range. Simulations show that the combination of the two measures has the advantages of rapid reaction and high accuracy.

The mass yield and the charge dispersion of secondary fragments produced in high-energetic proton-xenon bombardment are analysed in the frame of our statistical multifragmentation model. The critical mass distribution as well as the charge dispersion, which have led to the discussion of a nuclear liquid-gas phase transition, are easily reproduced within our model. A clear signal of a “phase transition” at T =5 MeV is found and is analysed in terms of various multifragment correlations.

Nuclear fragmentation at excitation energies between ~10 MeV and 2 GeV is simulated by a microcanonical Metropolis sampling method. Contrary to the usual canonical description of compound nucleus decay the total energy, momentum, mass, and charge are strictly conserved quantities. No artificial heat bath is needed. The mass distributions and energy spectra are in good agreement with the data of nuclear fragmentations induced by highly energetic protons.