Editor in chief：朱立光
International standard number：ISSN 1008-1542
Unified domestic issue：CN 13-1225/TS
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2018, 39(6):477-486. DOI: 10.7535/hbkd.2018yx06001
Abstract:The concept and characteristics of water-lubricated ceramic spindle are introduced. The development trend and industrial application of water-lubricated ceramic spindle at home and abroad are summarized. Finally, the key technologies of water-lubricated ceramic spindle and the problems to be solved urgently are reviewed from four aspects, mainly including. 1) In material tribology, the research on low-cost and high-performance water-based lubrication additives, high-toughness silicon-based ceramics and long-life ceramic coatings should be strengthened. 2) In the modeling and analysis of bearing lubrication, the machining accuracy of ceramic parts, non-Newtonian effect of water-based lubricants, high-speed turbulence effect, temperature-viscosity effect and other factors should be considered to achieve accurate modeling and analysis. 3) In the nonlinear dynamics of high-speed spindle bearing-rotor system, the latest results of reduced-order analysis theory should be used. 4) For the application of surface texture on water-lubricated ceramic spindles, the synergistic effect of surface texture and macrostructure, the design and optimization of surface texture and the low-cost and high-efficiency machining methods of surface texture should be strengthened.
2018, 39(6):487-493. DOI: 10.7535/hbkd.2018yx06002
Abstract:In order to investigate the optical properties of silicon nanocone arrays with different sizes and shapes, the nanocone arrays are fabricated on silicon substrate by submicron dry etching process masked by self-assembled nano-particles. The morphology and optical properties of the nano-cone arrays are characterized. The results show that the nanocone arrays with excellent optical antireflection performance can be obtained when the plasma flow ratio of SF6 and C4F8 is 12 sccm，27 sccm, the power is 750 W and the bias voltage is 25 V. By adjusting the etching time, silicon nanocone structures with similar morpho-logy and different sizes can be obtained. The reflectivity of 200 nm and 400 nm periodic silicon nanocone arrays is 2%~3%, while that of 800 nm periodic silicon nanocone arrays is close to and 10% higher than the reflectivity of silicon substrate, which indicates that the anti-reflectivity of sub-wavelength structure is more remarkable. The result reveals experimentally the dimensional and morphological effect of silicon nanocone array structures on the antireflective properties, which may shed some important insights on further investigation or application in optical devices.
2018, 39(6):494-501. DOI: 10.7535/hbkd.2018yx06003
Abstract:In view of the widely existed two-dimensional friction problems in engineering, an oscillator model which considers the coupling of and direction is established by introducing oblique springs. With the concept of the friction force direction angle being defined to determine the components of the static and kinetic friction force vector, and considering that stick-slip motion may occur when the oscillator is vibrating, a method for analyzing stick-slip motion of a two-dimensional coupled dry friction oscillator is proposed, and complex stick-slip transition boundaries of the two-dimensional coupled dry friction oscillator are given. Based on an exponential-type dynamic friction model, numerical simulation is carried out for stick-slip motion of the two-dimensional coupled dry friction oscillator, with the simulation results and the law of the system solution changing with excitation frequency and phase angle under three different working conditions at x direction and y direction, namely the same excitation frequency and phase angle, the same excitation frequency and different phase angle, and different excitation frequency and phase angle, are provided. Numerical results indicate that transition of stick-slip state may occur in the motion of the two-dimensional coupled dry friction oscillator; in comparison with the first two conditions, when frequencies and phase angle of and direction of the excitation are not equal, trajectory of the mass is a more complicated plane curve, the system can have multiple stick-slip transitions in one cycle at the same time; with the same frequency of and direction, the response of the oscillator has no fractional frequencies and is periodic by altering the frequency and phase angle. The proposed method can provide reference for further study of dynamics and motion stability of a two-dimensional coupled dry friction oscillator.
2018, 39(6):502-510. DOI: 10.7535/hbkd.2018yx06004
Abstract:Carbon fiber reinforced plastic (CFRP) is an advanced inorganic nonmetallic composite material with excellent mechanical properties. It has attracted extensive attention in industrial process and national defense applications, especially in car production and large aircraft manufacturing industry. As one of the most important parameters, electrical conductivity plays a key role for the overall performance of CFRP in researching non-destructive testing, anti-thunder and electromagnetic shielding. The conductive mechanism of CFRP is discussed in depth at first. Then considering the inhomogeneity and anisotropy, the popular CFRP electrical conductivity detection technology is summarized and compared from perspectives of experiment, analytical solution and numerical method. Finally, directions and methods concerning future research on CFRP conductive characteristics are proposed， including more simple and real-time experiment scheme, more precise and effective simulation model and analytical solution.
2018, 39(6):511-517. DOI: 10.7535/hbkd.2018yx06005
Abstract:Toxoplasma gondii as a typical zoonotic disease, because there is no suitable vaccine, its control is important in prevention, so it has been the subject of research by all scholars. in order to study the critical value of controlling its transmission and carry out relevant theoretical analysis, This paper establishes a mathematical model based on the life history and transmission route of Toxoplasma gondii, and analyzes the basic regeneration number that determines whether the disease continues to exist. When the basic reproduction number is less than 1, the disease died out finally. When the basic reproduction number is greater than 1, the model had a unique endemic equilibrium point, and the disease uniformly persisted. In addition, the sufficient conditions for the global asymptotic stability of the disease-free equilibrium and the endemic equilibrium are given by establishing a suitable Lyapunov function. In this paper, a systematic and complete stability study of the established mathematical model can be provided to provide advice for controlling the spread of disease.
2018, 39(6):518-526. DOI: 10.7535/hbkd.2018yx06006
Abstract:In order to effectively solve a class of large-scale unconstrained optimization problems and overcome the shortcomings of other algorithms, such as complex algorithms, large memory and computer programming difficulties, a new search direction is defined, which is based on some traditional three terms PRP conjugate gradient methods as well as combined with the research results of three terms conjugate gradient and some new line searches in recent years. A new line search algorithm is used to construct the algorithm, which proves that it has the properties of automatic full descent and trust region, and proves its global convergence under appropriate conditions. Numerical experiments has showed that the new algorithm is more competitive than the traditional three-term PRP conjugate gradient method in solving a class of large-scale unconstrained optimization problems. The new algorithm with better convergence property provides a more efficient algorithm basis for solving a class of large-scale unconstrained optimization problems.
2018, 39(6):527-531. DOI: 10.7535/hbkd.2018yx06007
Abstract:In order to characterize the additive maps preserving of modulus of symmetric matrices over residue class rings, these maps are firstly proved to be linear in fact, then they are classified and discussed by means of contract transformation, number theory knowledge, determinant operation, and standard prime factorization of integers, to determine the image of the main base, and thus characterize the image of all matrices using the linearity. The relationship between the maps which have different forms but belong to the same class in fact is also discussed. The results show that additive maps preserving determinant on modulus of symmetric matrices over residue class rings are all trival. The research method solves the difficulty caused by the fact that non-zero elements in a general ring are not necessarily invertible, and extends the basic set to the residue class rings. This result can be regarded as a small step toward determinant preserving problem in a ring, which improves the existing results of the linear preserving problem. It has reference value for the study of other preserving problems on the remaining class rings.
2018, 39(6):532-539. DOI: 10.7535/hbkd.2018yx06008
Abstract:In order to improve the stability of Cur-LCL and extend the circulation time of the drug in the body, the existing methods of preparing curcumin liposomes (Cur-Lips) and curcumin long-circulating liposomes (Cur-LCL) are optimized. Cur-Lips are prepared by ethanol injection method, and the Cur-LCL is prepared by inserting DSPE-PEG2000 into Cur-Lips by post-insertion. The results show the appearance is a circular vesicular sphere, and the average encapsulation efficiency is (88.91±0.94)%, which stays unchanged at 4 ℃ for 15 days; the average leakage rate is 2.4%, which has good stability; the average particle size is (118.4±3.2) nm (n=3), showing a single peak distribution, and the average potential is (-12.9±0.32) mV (n=3); the dissolution medium is selected according to the solubility standard, and the physiological solution of 1% Tween 80 is selected as the dissolution medium for the in vitro release experiment. Cur APIs are almost completely released at 12 h while Cur-Lips are almost completely released at 36 h, and the cumulative release rate is 92.67%. Cur-LCL is almost completely released at 72 h, and the cumulative release rate is 91.36%. Cur-LCL has obvious function in slowing the release process, which could prolong the circulation time of the drug in the blood and achieve long-circulation effects.
2018, 39(6):540-545. DOI: 10.7535/hbkd.2018yx06009
Abstract:In order to solve the problems that there are few kinds of cold storage agents suitable for fruit and vegetable preservation, the latent heat of phase change is less than 300 J/g, and there exists the phenomenon of supercooling, the performance of phase change cold storage agents is studied. Firstly, by using the DSC, the aqueous solution formed by proper phase change temperature regulator is selected to get the main energy storage agents with phase transition temperature of -6～-4 ℃ and a higher phase change latent heat. Secondly, through adding different kinds of nucleating agents, the supercooling phenomenon of the main energy storage agents is suppressed. At last, the performance of the better formula of cool storage agent is studied, and two main energy storage agents consisting of temperature regulator with sodium benzoate as main component and aqueous solution, BL-1 and BL-2, are obtained for the first time. The study shows that by adding nucleating agent diatomite, two low cost cool storage agents with phase-transition temperature of -6～-4 ℃ as well as phase change latent heat above 300 J/g and no supercooling phenomenon can be obtained, which are suitable for temperature controlled packaging o fruits, vegetables and other temperature sensitive products whose cold storage temperature is at 0～4 ℃. The developed phase change cold storage agent meets the requirements of food safety and environmental protection, and provides guarantee for the cold storage requirements of related products.
2018, 39(6):546-551. DOI: 10.7535/hbkd.2018yx06010
Abstract:In the process of anaerobic fermentation of Propionibacterium freudenreichii to produce vitamin B12 deoxyadenosylcobalamin (ADO), the intermediate adenosylcobinamide (CBI) and 5,6-dimethylbenzimidazole (DMB) are combined to produce the product ADO. At present, there is lack of detection means for vitamin B12. To solve the problem, taking CBI as the research goal, the metabolic regulation method is used to improve the addition time of DMB, and the effects of different DMB adding time on the growth of bacteria and ADO synthesis are studied. Under the conditions of batch fermentation, the CBI synthesis amount and ADO yield of Propionibacterium are determined, and the growth curve of the bacteria is drawn. It is found that the inhibitory effect of DMB on the growth of the cells is not obvious, but the unit cell yield could be inhibited. The fermentation cycle is 120 h, and the optimal addition time is 90~100 h. Compared with 60 h, the addition of DMB can increase the fermentation unit by 59.08%. The method is simple, rapid, efficient, and has a certain guiding effect on the study of fermentation regulation of vitamin B12.
2018, 39(6):552-558. DOI: 10.7535/hbkd.2018yx06011
Abstract:In order to verify the feasibility of underwater power transmission and study the factors affecting the transmission efficiency, a simple wireless charging circuit is designed based on the principle of electric field coupling. The system structure and basic working principle of electric field coupled radio power transmission are introduced, and its characteristics compared with magnetic field coupling mode are analyzed, as well as the corresponding advantages. The distribution of electric field between plates is simulated by multi-physical field simulation, and a double-sided CPT system of LC is designed, which uses a single-chip microcomputer to form a pulse width modulation control circuit and power amplifier circuit modules to form the transmitting end and the receiving end. The results shows that using electric field coupling principle for wireless charging is feasible, the transmission distance between the plates is a factor affecting the underwater wireless charging efficiency, and the stray capacitance between the two electrodes also affects the power between the plates, so the power loss between the plates is largely due to the plate gap. The LC bilateral CPT system proposed in this paper not only realizes underwater radio power transmission, but also ensures the stability of transmission efficiency at a certain distance and frequency.
2018, 39(6):559-566. DOI: 10.7535/hbkd.2018yx06012
Abstract:In order to conduct the semantic annotation to the heterogeneous, vast and continuous data flow which is captured from micro-environment monitoring platform, inference fresh or implicit knowledge timely according to a new semantic context, and realize real-time monitoring of the micro-environment monitoring platform, the SASML mapping language and the SDRM algorithm are researched and developed, and the S-SASML mapping language and SDS2R algorithm are designed to translate the original sensor data streams into the format of the RDF data streams of the SOSA/SSN. The thread pool techno-logy is used to implement high concurrent processing and improve the real-time performance of our proposed method. The improved mapping language and algorithm can realize the real-time semantic annotation for the continuous, vast data streams on the micro-environmental monitoring platform. The mapping language and algorithm can not only solve the dynamic pickup data flow semantic annotation problem, but also avoid the overload phenomenon caused by high frequency data streams, so that the proposed method has a stable and efficient processing capacity. It basicly meets the demand of micro-environment monitoring platform, and has some application value.
2018, 39(6):567-576. DOI: 10.7535/hbkd.2018yx06013
Abstract:The classical discontinuous Galerkin finite element method has the unstable numerical problem resulting from the inappropriate stability parameter for elasticity problem with interfaces. This problem can be released by the weighted Nitsche discontinuous Galerkin finite element method, but only for constant elements. To solve the above problems, the weights and the stabilization parameters of the weighted Nitsche discontinuous Galerkin finite element method are derived with four-node quadrilateral elements discretization for plane elasticity problems, and a qualitative dependence between the weights and the stabilization parameters is established. The weights and the stabilization parameters are evaluated automatically by setting up and solving generalized eigenvalue problems. This makes the use of high-order elements possible. The convergence and stability of the proposed method are verified through numerical examples. The results show that the weighted Nitsche discontinuous Galerkin finite element method has good stability and high accuracy for both homogeneous and heterogeneous problems in the material partition. In some extent, the method needs less manual work, and has high efficiency, high stability and better accuracy, making it suitable for solution of complicated interface problems.