• Issue 4,2018 Table of Contents
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    • >Special Column: National Young Scholar/Local Science Foundation
    • Research overview of anti-high overload MEMS gyroscope

      2018, 39(4):289-298. DOI: 10.7535/hbkd.2018yx04001

      Abstract (2802) HTML (0) PDF 4.53 M (3449) Comment (0) Favorites

      Abstract:Inertial guidance system plays a very important role in guided artillery. Micro electro mechanical system (MEMS) gyroscope, as the core component of inertial guidance system, has high resistance to overload and restricts the application of inertial guidance system in high overload environment directly. First of all, the high overload environment in the gun chamber is modeled and quantified, and the mechanism of high overload failure of the MEMS gyro structure is summarized. Secondly, based on the previous public research results from different institutes at home and abroad, the anti-high overload MEMS gyroscopes with different monitoring methods, different structural forms, different structural materials and different working principles are introduced from the perspective of anti-overload characteristics of MEMS gyroscopes impact resistance. Finally, the related reports and papers are summarized, and it is pointed out that the anti-high overload MEMS gyroscope should be designed from the aspects of drive-detection mode, reasonable structure of energy-absorbing and energy-dissipating structure, working principle, new structural material and multi-level system buffer methods to improve the anti-high overload ablility.

    • Study of high temperature mechanical performance on Ti6Al4V LBW welding joint

      2018, 39(4):299-305. DOI: 10.7535/hbkd.2018yx04002

      Abstract (1780) HTML (0) PDF 5.46 M (3320) Comment (0) Favorites

      Abstract:To evaluate the effect of temperature on the mechanical properties of Ti6Al4V pulsed laser beam welding (LBW) joint, the mechanical properties are tested by tensile and fatigue tests under different temperature with comparison method, and the microstructure characteristic and fracture morphology are observed by optical microscope (OM) and scanning electron microscope (SEM). The results show that the tensile strength and the fatigue life of the LBW joints and the base metal specimens decline significantly as the temperature rises, the tensile strength of the base metal and the LBW joint under 300 ℃ are reduced by 26.2% and 31.6%, respectively, and the fatigue life of the base metal and the LBW joint under 300 ℃ are reduced by 83.6% and 77.8%, respectively. The microstructure observation after the fatigue fracture shows that the fatigue damage is concentrated in the fusion zone, and with the increase of temperature, the deformation on the surface of all the specimens increases, inducing the reduction of the fatigue life. The research result provides reference for the improvement of the lifetime and application safety of titanium alloys.

    • Research on early fault detecting for wheelset of high-speed train based on metal magnetic memory method

      2018, 39(4):306-313. DOI: 10.7535/hbkd.2018yx04003

      Abstract (1805) HTML (0) PDF 2.16 M (2514) Comment (0) Favorites

      Abstract:The detection of train safety is an important research topic for railway locomotive and vehicle engineering. Wheelsets are key components of high-speed train bogies. The traditional detection method can only diagnose macroscopic structural defects, and it is not suitable for the diagnosis of microscopic defects and status tracking in the operation process. In order to achieve rapid identification of early failures and life prediction of wheelsets, in light of the shortcomings of traditional test methods in early detection and dynamic detection, a new system of dynamic detection is proposed to meet the safety requirements of train operations. This paper also conducts a large number of experimental studies on the relationship between magnetic memory signals and the loading conditions of the material. The results show that in the 50~150 kN load range, the magnetic memory signal of the experimental workpiece changes monotonously, and the change trend is obvious; after fatigue loading, the original values of the magnetic memory signal and the signal characteristics of gradient and kurtosis both have some change, and the kurtosis changes more obviously, which can effectively reflect the fatigue state of the material. The use of metal magnetic memory technology for wheelset early failure detection and dynamic detection has important practical significance in ensuring the safety of the train, and provides reference for its application in non-destructive testing.

    • >Mathematics
    • L(2,1)—labeling of the bracelet graph

      2018, 39(4):314-320. DOI: 10.7535/hbkd.2018yx04004

      Abstract (1836) HTML (0) PDF 897.67 K (1649) Comment (0) Favorites

      Abstract:In order to better study the channel assignment problem, a function from the vertex set to the set of all nonnegative integers is generated, that is the L(2,1)—labeling of a graph. Let the least label be zero, the L(2,1)—labeling number of a graph is the smallest number over the spans of all L(2,1)—labeling of this graph. Aiming at the problem of the L(2,1)—labeling numbers of the bracelet graph, which is a generalized graph from Cartesian products of the path and cycles, the definition of the bracelet graph is given, which is obtained by overlapping the two ends of a similarity ladder. At the same time the definition of the L(2,1)—labeling numbers is given. The L(2,1)—labeling number is completely determined by vertex grouped labeling method according to the difference of the circles' numbers and the vertices' numbers of the circles. The types of graphs are enriched and the labeling number theories are perfected.

    • Spectral distribution problem for Sturm-Liouville with operators the discontinuity conditions at an interior point and boundary

      2018, 39(4):321-330. DOI: 10.7535/hbkd.2018yx04005

      Abstract (1762) HTML (0) PDF 893.53 K (1715) Comment (0) Favorites

      Abstract:In order to enrich the spectral theory of Sturm-Liouvillel (S-L) differential operators, the discontinuous S-L problem with boundary conditions dependent on spectral parameters on closed interval \[0,1\] is studied. Firstly, by using the equivalent characterization of the problem in the direct sum space, the alternating relation between the eigenvalues of the discontinuous S-L problem and the eigenvalues of the continuous S-L problem is given. That is, there is exactly one eigenvalue of the continuous S-L problem in every open subinterval of the eigenvalues of the discontinuous S-L problem, and then the oscillation theory of the discontinuous S-L problem is derived from the oscillation theory of the continuous S-L problem. Through the transformations of Prüfer and Hergloz function, the transformation between the discontinuous S-L problem with boundary conditions dependent spectral parameters and discontinuous S-L problem with constant boundary conditions is established. The obtained converted eigenvalues are equal to those (excluding the finite eigenvalues) before the conversion. Finally, the asymptotic expressions of eigenvalues of discontinuous S-L problems with boundary conditions dependent on spectral parameters are obtained by constructing the eigenfunctions of discontinuous S-L problems with constant boundary conditions. The new research method can be extended to the study of the S-L problem with boundary conditions dependent spectral parameters.

    • >Chemistry and Chemical Industry
    • Electrochemical poperties of new compound based on POMs

      2018, 39(4):331-336. DOI: 10.7535/hbkd.2018yx04006

      Abstract (1895) HTML (0) PDF 1.24 M (1641) Comment (0) Favorites

      Abstract:Polyoxometalates (POMs ) are novel and unique inorganic building blocks, which can activate the terminal oxygen or bridging oxygen by adjusting the synthesis conditions, thus obtaining various compounds. In order to study the electroche-mical properties of POMs, Keggin-phosphomolybdic acid and 1,4-bis ( imidazolyl ) butane (L) are selected to synthesize a new inorganic-organic hybrid compound (H2L)3(PMo12O40)2 based on polyoxometalates by hydrothermal method. The electrocatalysis activity of the compound to nitrite is studied.The compound has been characterized by elemental analyses, IR, TG, X-ray single crystal diffractions and PXRD, and the connection between synthesis conditions(for example pH values) and compound structures is also studied. The electrochemical behavior and electro-catalysis of the target compound are studied. Single-crystal X-ray diffraction analysis reveals that the polyoxometalates and the organic donor are linked to become 3D structure by hydrogen bonds (triclini, P-1). And Fluorescence analysis indicates that the fluorescence of the compound mainly comes from ligand contribution. The compound exhibits remarkable catalytic activity to nitrite ions and may be actually used for the detection of nitrite.

    • Study on the synthesis of amide compound by arylboronic acid-catalyzation

      2018, 39(4):337-342. DOI: 10.7535/hbkd.2018yx04007

      Abstract (1785) HTML (0) PDF 1.12 M (1846) Comment (0) Favorites

      Abstract:Amide bond is a special structure that can exhibit high physiological activity. The most ideal way to form amide is the direct reaction between carboxylic acid and amine, but this reaction has to be under strong heat condition. A method is proposed for direct synthesis of amides by direct condensation of fatty acids and primary amines under milder conditions, namely catalyzed by simple arylboronic acids. The reaction system is established by direct amidation of phenylacetic acid and benzylamine. The type, amount of catalyst, reaction solvent, reaction time, and reaction temperature are optimized. The result shows that with fluorobenzene as solvent and phenylboronic acid as catalyst, organic acids are firstly treated for 1 h at reflux temperature, then the reaction continues for 12 h after adding fatty amines, and under the optimum reaction condition, the yield of the corresponding amide is above 80%. The product is characterized by 1H NMR and 13C NMR. The method is a new simple effective method for preparing amide compounds and the product is easy to purify.

    • Establishment and evaluation of melanoma model

      2018, 39(4):343-348. DOI: 10.7535/hbkd.2018yx04008

      Abstract (1981) HTML (0) PDF 993.18 K (2698) Comment (0) Favorites

      Abstract:In order to screen drug rapidly and effectively in vivo, the approach of the establishment for mouse melanoma model with primary cell from melanin solid tumor tissue of mouse is studied. The primary cell and the cultured B16 cells in vitro are implanted into two groups of C57BL/6 mice by hypodermic, respectively. The appearing time and the growth rate of tumor in two groups of mouse are investigated. The results show that when the inoculation is 0.2 mL for each one (the cell concentration of 5.0×106/mL), the tumor formation rates of the primary tumor cells of mouse melanoma and in vitro cultured B16 cells are 100% and 80%, respectively, and it takes about 3 and 8 days respectively that the tumor sizes become about 4 mm3. The preliminary evaluation of two models are carried out with taxol, showing that the primary B16 cell model is a feasible and effective method for screening and evaluating the antitumor activity of specific compounds in vivo compared with the B16 cell model cultured in vitro, and it has shorter tumor forming time, higher tumor forming rate and less error in the obtained experimental data, which provides a new way for the development and research of related drug evaluation models.

    • >Mechanical, Electronics and Information Science
    • UAV route planning based on improved dynamic weighted A* algorithm

      2018, 39(4):349-355. DOI: 10.7535/hbkd.2018yx04009

      Abstract (2000) HTML (0) PDF 1.54 M (2852) Comment (0) Favorites

      Abstract:With the expansion of high dimensional space in UAV trajectory planning, the flying environment of UAV is very complex, and the external threat of UAV is no longer a simple two-dimensional static threat. The traditional ant colony algorithm and artificial potential field algorithm cannot meet the requirements of real-time and high complex environment. To solve the above problems, a new dynamic programming algorithm based on dynamic weighted A* algorithm is proposed. Firstly, the flight environment of UAV is modeled. By studying the constraints such as the turning radius, the length of track section and the limit of the maximum range, the safe flight of UAV is ensured, thus reducing the crash rate and the threat probability. Secondly, a new navigation mode is designed by studying the track and external threat parameters of the UAV, which can reduce the danger of navigation and reduce the loss. Then, the potential energy of the vertex can be expanded. The dynamic weight of the overall change of location and grid graph is obtained, and the cost function in dynamic environment is obtained, which increases the speed, accuracy and evasion degree of obstacle avoidance search. Finally, the simulation results show that under the same application environment, the proposed algorithm has the best path, the least threat cost and the shortest execution time compared with the ant colony algorithm and artificial potential field algorithm. To sum up, the dynamic weighted A* algorithm can be well applied to UAV trajectory planning, reducing the cost of UAV track, shortening the completion time of the algorithm and improving the search speed and precision of unmanned aerial vehicle trajectory planning in complex environment.

    • Design and implementation of sensor data communication protocol and high concurrent services

      2018, 39(4):356-364. DOI: 10.7535/hbkd.2018yx04010

      Abstract (1981) HTML (0) PDF 2.93 M (1915) Comment (0) Favorites

      Abstract:In order to meet people's needs for limited area monitoring and solve the heterogeneous data representation, transmission and high concurrency issues, the deficiency of traditional Internet platform in sensor data acquisition and transmission is analyzed, and a micro environmental monitoring platform is realized through function module design. As for sensing layer data acquisition work, the communication protocol is designed, the data format is unified to reduce the amount of data transmission and energy consumption, and the communication protocol process is determined. LoRa technology is used to complete the remote transmission of data between the terminal and the gateway. As for the platform network layer, the high concurrency data interface is designed, using the server program to receive and process data. Finally the development and testing of the system is completed. The results show that the designed communication protocol can help unifying heterogeneous data format and reducing the quantity of data transmission and energy consumption. The feasibility, reliability and low latency of the whole transmission plan of the data collected from the terminal equipment to the gateway, through the whole PC to server are verified, as well as the processing performance of the high concurrent data interface. The stable operation of the micro-environment monitoring platform proves it is a set of data collection and transmission solution for the applications of cross-industry Internet.

    • >Material Science
    • Rotating bending fatigue behavior of medium carbon Cr and W nitriding bearing steel

      2018, 39(4):365-371. DOI: 10.7535/hbkd.2018yx04011

      Abstract (1685) HTML (0) PDF 2.40 M (1841) Comment (0) Favorites

      Abstract:Aiming at the problem that the failure mode of bearing steels is mainly fatigue failure, RBF (rotating bending fatigue) test of medium carbon Cr and W nitriding bearing steel and analysis are conducted for the medium carbon Cr and W nitriding bearing steel. The microstructure of the bearing steel after hardening and tempering (880 °C+540 °C), the fatigue fracture after the RBF test and the effect of nitriding are analyzed. The ultimate strength influencing model of non-metallic inclusions and size on medium carbon Cr and W nitriding bearing steel RBF is established. The results of experiments show that the microstructure of the test steel after hardening and tempering is tempered sorbite, the main precipitations are M6C and M23C6 carbides, the mechanical properties are excellent and its fatigue limit is 729 MPa. Fatigue source are divided into surface defect cracking and the internal non-metallic inclusions cracking. Surface defects include the pits after the falling of non-metallic inclusions and the machining marks. Non-metallic inclusions are mainly magnesium aluminates. The bearing steel is kept at a constant temperature of 560 °C for 25 hours in NH3 nitrogen atmosphere, and the nitriding layer thickness is more than 360 μm, showing the nitriding process is suitable. The research has some reference value for the development of the medium carbon Cr and W nitriding bearing steel and the improvement of fatigue performance.

    • >Special Column: New Energy Resources, Energy Conservation and Environmental Protection
    • Array of dendritic TiO2 modified with Sb2S3 and its application in hybrid solar cells

      2018, 39(4):372-378. DOI: 10.7535/hbkd.2018yx04012

      Abstract (1755) HTML (0) PDF 1.63 M (1704) Comment (0) Favorites

      Abstract:In order to provide multiple electron transmission channels and increase the load of narrow gap semiconductor and organic semiconductor, the array of TiO2 dendritic structure assembled by nanotube and nanowire is constructed on FTO glass by hydrothermal method. Narrow gap semiconductor Sb2S3 is fabricated on dendritic TiO2 successfully by chemical bath deposition (CBD) method. By means of SEM, XRD, UV visible absorption spectrum, transient photocurrent, steady-state fluorescence spectrum and J-V curve, the morphology, crystal shape, light absorption and photoelectric properties of the samples are characterized and tested. The effect of deposition time on power conversion efficiency (PCE) is further studied. The results show that sparse TiO2 dendritic structure formed vertical to the FTO substrate might be a benefit for the fast electron transport; the addition of Sb2S3 strengthens the absorption of visible light, improves the photocurrent intensity, increases the intensity of fluorescence quenching and facilitates the generation and transfer of photogenerated carriers; the PCE of hybrid solar cell (HSC) based on dendritic TiO2/Sb2S3/P3HT/PEDOT∶PSS/Au structure reaches 1.10%, and this PCE is 10 times that of the HSC without Sb2S3. The deposition of Sb2S3 on the multistage structure TiO2 is conducive to improving the absorption of visible light, strengthening the transmission capacity of the optical carrier, broadening the spectrum response range and improving the photoelectric performance. It is of great significance to solve the problems of weak absorption intensity and narrow spectrum response range of simple TiO2 electrodes.

Editor in chief:朱立光

Inauguration:

International standard number:ISSN 1008-1542

Unified domestic issue:CN 13-1225/TS

Domestic postal code:

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