North University of China is a university based in Taiyuan, Shanxi province, China，which was once called North China Institute of Technology . It was formerly known as Taihang Industrial School,which was founded in September 8, 1941, and renamed Taiyuan Institute of Machinery in 1958. School played an important role in the improvement of the quality of our manpower and weaponry of PLA during the War of Resistance against Japan and the War of Liberation. In 2001, Bo Yibo wrote an inscription "The first school for people's ordnance " at the 60 years' celebration of North China Institute of technology. Wikipedia.
North University of China | Date: 2015-12-11
The present disclosure relates to the technical field of deep hole machining, particularly to a rear-mounted deep hole machining on-line detection and deviating correction device, which provide solution to the difficulty in observing the machining site and correcting the cutter deviation in deep hole machining. The device comprises a cutter bar provided with a plurality of iron blocks mounted uniformly in a circumferential direction, wherein each of the iron blocks is provided with a heating device in the interior thereof and a wear-resistant block mounted on the top thereof, wherein mounted on an end face of the other end of the cutter bar is a pyramid prism, wherein a laser transmitter and a photosensitive sensor are mounted in a height corresponding to the height range of the pyramid prism, wherein the incident beam emitted by the laser transmitter is oriented by a laser orientating block. The advantages of the disclosure lie in that the information of the position the deep hole cutter during deep hole machining process and whether the deep hole is skewed or not can be obtained in time, thereby facilitating a solution to the difficulty in detecting the workpiece deep hole straightness and on-line deviating correction, improving the position accuracy such as straightness of the deep hole and reducing the rejection rate of the workpiece.
Yu D.,North University of China
International Journal of Advanced Manufacturing Technology | Year: 2017
A novel principle for machining of deep holes is proposed. A self-centering positioner (SCP) was invented, and the principle for locating and guiding deep-hole drills using oil films was studied. The SCP is fixed between the drill tip and the drill shank. Four wedge-shaped zones are formed between the SCP and the wall of the machined hole. The rotating SCP draws cutting oil into the converging, wedge-shaped zones, which produces a pressure in each wedge-shaped oil film. The oil films will support, locate, and guide the SCP along with the drill tip and the shank. The oil films act on the SCP in a manner similar to that by which a four-jaw chuck clamps a workpiece, thereby enhancing the stiffness of the drill system and protecting the drill from deviation. The force exerted on the SCP by each oil film is calculated. Experiments showed that hole straightness was improved when using an SCP. The eccentricity ratio and width of the SCP strongly influence the force exerted on the SCP and straightness of the hole. A deep-hole drill with an SCP follows the axis of the hole during the machining process—in contrast to the current method in which the drill is guided by the wall of the hole. This novel principle applies to both symmetric and asymmetric deep-hole drills. It is derived from dynamic lubrication in bearings and serves as a break from the convention that has guided deep-hole machining for many years. © 2017 Springer-Verlag London
Zhang J.,North University of China
PloS one | Year: 2011
Human rabies is one of the major public-health problems in China. The number of human rabies cases has increased dramatically in the last 15 years, partially due to the poor understanding of the transmission dynamics of rabies and the lack of effective control measures of the disease. In this article, in order to explore effective control and prevention measures we propose a deterministic model to study the transmission dynamics of rabies in China. The model consists of susceptible, exposed, infectious, and recovered subpopulations of both dogs and humans and describes the spread of rabies among dogs and from infectious dogs to humans. The model simulations agree with the human rabies data reported by the Chinese Ministry of Health. We estimate that the basic reproduction number [Formula: see text] for the rabies transmission in China and predict that the number of the human rabies is decreasing but may reach another peak around 2030. We also perform some sensitivity analysis of [Formula: see text] in terms of the model parameters and compare the effects of culling and immunization of dogs. Our study demonstrates that (i) reducing dog birth rate and increasing dog immunization coverage rate are the most effective methods for controlling rabies in China; and (ii) large scale culling of susceptible dogs can be replaced by immunization of them.
Sun G.-Q.,North University of China
Nonlinear Dynamics | Year: 2012
One subject of spatial epidemiology is spatial variation in disease risk or incidence. The spread of epidemics can result in strong spatial patterns of such risk or incidence: for example, pathogen dispersal might be highly localized, vectors or reservoirs for pathogens might be spatially restricted, or susceptible hosts might be clumped. Here, spatial pattern of an epidemic model with nonlinear incidence rates is investigated. The conditions for Hopf bifurcation and Turing bifurcation are gained and, in particular, exact Turing domain is found in the two parameters space. Furthermore, numerical results show that force of infection, namely β, plays an important role in the spatial pattern.More specifically, different patterns emerge as β increases. The mathematical analysis and numerical results well extend the finding of pattern formation in the epidemic models and may well explain the field observed in some areas. © Springer Science+Business Media B.V. 2011.
Zhao Z.,North University of China
Journal of Medical Systems | Year: 2014
With the development of wireless networks and medical sensors, wireless body area networks are playing more and more important role in the field of healthcare service. The data transmitted in WBANs is very sensitive since it will be used in clinical diagnoses or measurements. Therefore, security and privacy of communication in WBANs derive increasing attentions from the academia and industry. In this paper, we propose an identity (ID)-based efficient anonymous authentication scheme for WBANs using elliptic curve cryptosystem (ECC). Due to the ID-based concept, there is no certificate is needed in the proposed scheme. Moreover, the proposed scheme not only provides mutual authentication between the client and the application provider but also provides client anonymity. Performance analysis shows that improvements of 50.58 % and 3.87 % in the client side and the application provider side separately. Then the proposed scheme is more suitable for WBANs. © 2014 Springer Science+Business Media New York.
Xue C.-X.,North University of China |
Pan E.,University of Akron
International Journal of Engineering Science | Year: 2013
We consider a functionally graded magneto-electro-elastic rod made of piezoelectric BaTiO3 and piezomagnetic CoFe2O4. The materials properties are assumed to vary exponentially along the rod direction. We derive the one-dimensional wave-motion equation for the functionally graded magneto-electro-elastic rod. Furthermore, for this one-dimensional problem, we demonstrate the phase velocity and frequency spectrum, and discuss the important influence of the gradient factor as well as material coupling on the wave features. We also calculate and compare the effective Young's modulus and effective Poisson's ratio in the BaTiO 3- CoFe2O4 composite rod made of different volume fractions of BaTiO3, showing clearly the important effect of the material coupling on these parameters. © 2012 Elsevier Ltd. All rights reserved.
North University of China | Date: 2012-01-10
A speckle reduction apparatus (300) based on Mie scattering and perturbation drive is disclosed. The speckle reduction apparatus (300) comprises an optical reflective chamber (302) having an incident-light coupling device (301) and an exiting face (303) disposed thereon, and an optical device (308) which faces the incident-light coupling device (301) of the optical reflective chamber (302). The inner walls of the optical reflective chamber (302), except for the wall of light transparent exiting face (303), are mirror surfaces. The optical reflective chamber (302) is fully filled with transparent material (401) having medium particles (402) dispersed therein, which are able to induce Mie scattering of the incident laser. Either or both of the optical reflective chamber (302) and the optical device (308) are provided with a perturbation-sensitive device. The present invention may be implemented with reasonable and compact structure, achieving the following effects: low cost, effective speckle reduction, high laser efficiency, stability, safety, and uniform light intensity.
North University of China | Date: 2011-03-11
The invention discloses a silicon-based monolithic integrated sonar array which includes a cantilevered sensing array structure, a sound-transparent jacket, and a support structure. The cantilevered sensing array structure is fixed on the support structure and in the sound-transparent jacket, wherein the sound-transparent jacket is filled with insulating dielectric oil, and the cantilevered sensing array structure is immersed in the insulating dielectric oil. The sound-transparent jacket is sealed and is treated with water tightness processing. The array can be applied, into devices for underwater ultrasonic imaging, ultrasonic ranging, torpedo navigating, etc.
North University of China | Date: 2016-02-05
A reinforced magnesium matrix composite includes a quasicrystal and alumina mixture particles reinforcement phase and a magnesium alloy matrix, where the weight ratio of the quasicrystal and alumina mixture particles reinforcement phase to the magnesium alloy matrix is (4-8) to 100; the magnesium alloy matrix including by weight 1000 parts of magnesium, 90 parts of aluminum, 10 parts of zinc, 1.5-5 parts of manganese, 0.5-1 part of silicon and 0.1-0.5 part of calcium; the quasicrystal and alumina mixture particles reinforcement phase including by weight 40 parts of magnesium, 50-60 parts of zinc, 5-10 parts of yttrium and 8-20 parts of nanometer alumina particles of which the diameter is 20-30 nm; and the quasicrystal and alumina mixture particles reinforcement phase having a size of 100-200 mesh.
North University of China | Date: 2016-05-19
The present invention relates to a method for preparing an aluminum-copper-iron quasicrystal and silicon carbide mixed reinforced aluminum matrix composite, where the aluminum-copper-iron quasicrystal and silicon carbide mixed reinforced aluminum matrix composite is prepared with an aluminum alloy serving as a matrix and with aluminum-copper-iron quasicrystal and silicon carbide serving as reinforcement agents via smelting in an intermediate-frequency induction melting furnace through the process of intermediate-frequency induction heating, vacuumizing, bottom blowing argon, and casting molding in view of low hardness and low tensile strength of aluminum matrix materials. The prepared aluminum-copper-iron quasicrystal and silicon carbide mixed reinforced aluminum matrix composite has a hardness of 80.3 HB which is improved by 50.64% and tensile strength of 285 Mpa which is improved by 60.42%, and corrosion resistance thereof is improved by 40%.