Search

Hypercrosslinked sorbents which have excellent adsorption capacities for organic compounds were prepared by cross-linking the polypropylene grafted styrene-divinylbenzene fiber according to the Friedel-Crafts reaction. As crosslinking agents, we have used monochloromethylether and bis-chloromethylated derivatives of benzene or biphenyl. We have performed detailed investigations of the preparation and the optimal synthesis conditions of hypercrosslinked sorbents were obtained. Compared with the initial fiber, hypercrosslinked fibers were remarkable materials exhibiting high specific surface area and exceptional adsorption properties for organic compounds. The adsorption capacities on the hypercrosslinked sorbents were related with the size of cross-linking agents, which increased by about 8 to 10 fold.

In order to solve the problem of low accuracy of submunitions dispersed from high rotation cluster munition with time fuse, a new self-adaption method based on dispersing altitude compensation was presented. A trajectory model of cluster munition with high rotation was developed. Then according to the error resulted from initial velocity, shooting angle and dispersing altitude, the impact dispersion of subminution was simulated. With the help of simulation result, a cluster munition self-adaption opening plan was proposed to improve the accuracy of impact points of submunitions based on dispersing altitude compensation. At last, a dispersal altitude compensation formula adapting to cluster munition with high rotation was deduced. [ABSTRACT FROM AUTHOR]

Taking a 155 mm missile-borne grenade as representative and analyzing its special projectile flight dynamic stress variation and its effect on the receiver signal processing, a high dynamic receiver tracking loop strategy was put forward to adapt the special environment. Combined with the loop tracking performance theory and analyzing the tracking performance changes with the noise bandwidth of different signal tracking loop, a theoretical basis was provided for the reasonable selection of noise bandwidth. Simulation results show that, the improved design scheme can not only detect the trajectory, but also improve the detection signal to noise, which enhance the tracking performance of the receiver and the anti-interference ability. [ABSTRACT FROM AUTHOR]

Determination of aiming advance distance and maximum correction distance is important for the correction strategy on one-dimensional trajectory correction projectile. Focusing on the problem that the resistance device of one-dimensional trajectory correction fuze has limit increased-resistance capacity, the aiming advance distance and required maximum correction distance were analyzed using probability and mathematical statistics based on the principle of the maximum number of projectiles that fall into the designated field. Results show that, when parts of the projectiles are corrected, the correction strategy is the best in condition that the aiming advance distance is half of the maximum correction range and 2 times of the standard deviation of range error of uncontrolled projectile. Taking 155 mm shrapnel as an example, the reasonableness of the correction strategy above has been verified using Monte-Carlo simulation. With small aiming advance distance and the maximum range correction, the proposed correction strategy can make the greatest improvement of the range accuracy. Therefore it is perfect for one-dimensional trajectory correction fuze which has limited resistance capacity. [ABSTRACT FROM AUTHOR]

A computational study performed for an artillery projectile using finite volume TVD schemes is described in this paper. First, computed Magnus moment coefficients for the spinning projectile have been compared with the available experimental data of SOCBT at Mach 3 and are found to be generally in good agreement. The results demonstrate that the method can provide an accurate and viable approach for this problem. Then, computational fluid dynamics (CFD) modeling and analysis of the spinning projectile with fixed canard have been conducted to determine the longitudinal aerodynamic coefficients. The analyses provide a detailed understanding of the effects of canard with different circumferential position on longitudinal aerodynamic coefficients at three supersonic speeds and various angles of attack. [ABSTRACT FROM AUTHOR]

To meet the requirement of trajectory correction fuze for missile-borne trajectory calculation with the features of low-cost, compact and high-performance, it is essential to verify the feasibility of utilizing a small micro-controller as trajectory calculator and controller. On the basis of the mathematical model of the projectile's particle trajectory and its numerical solution, the hardware and software MSP430 based were designed and debugged. The accuracy and real- time capability were verified by hardware-in-the-loop simulation. The result shows that the designed trajectory calculator and controller can meet the demand of trajectory correction fuze in accuracy and real-time capability. This research work might lay a preliminary foundation for developing low-cost and compact trajectory calculator and controller for trajectory correction fuze in the future. [ABSTRACT FROM AUTHOR]

Addressing the problem that GPS receiver has no way to work regularly for the high revolution projectiles, the change of GPS singnal's frequency and phase in condition of advanced spinning is calculated and analyzed to provide a basis for designing baseband algorithm of GPS receiver. The mathematical moderation is built up according to the features of spinning projectile's movement and the GPS signal's propagation and the Doppler frequency shift and phase of received signal calculated. The result showed that the signal's maximum Doppler frequency is 300 Hz and the shift phase is 0.6n when the revolution is 200 rounds per second, but the code signals have little change. These can be referenced for the design of GPS signal's capturing and tracking algorithm under advanced spinning. [ABSTRACT FROM AUTHOR]

In order to increase the impact dispersion accuracy of submunitions, a method of self-adaptive cabin opening is put forward. A trajectory model of submunition is built based on the research on the flight dynamics of spin-stabilized shrapnel. The impact dispersion of subminution is simulated by using this model. According to the errors got from the theoretical and practical trajectory results of a certain ejection point of the shrapnel, the effects of the errors on the impact dispersion of submunition are analyzed through simulation comprehensively. With the help of the simulation results, a shrapnel self-adaptive cabin opening method with modified ejection point is proposed to improve the impact dispersion accuracy of submunition. A modified formula for the best cabin opening point of spin-stabilized shrapnel is deduced. The results show that the method used in this paper can be used to increase the impact dispersion of submunitions by 26.3% in horizontal and 53.8% in vertical. [ABSTRACT FROM AUTHOR]

Unilateral linear capillaritis (ULC) is a rare special variation of pigmented purpuric dermatosis (PPD), which is characterized clinically by linear or segmental distribution of pigmented purpuric macules located predominantly on the lower extremities and showing a favorable prognosis. In this case report, we describe two unusual cases of ULC, in one male and one female patient, with unilateral lesions involving the upper extremities that loosely follow the dermatome lines. Biopsy results revealed a common histopathology feature to PPD without heavy band-like infiltration in the upper dermis. On review 20 months after the onset, the eruptions of Patient 1 had spontaneously faded from parts of the affected area. Meanwhile, after a period of 18 months post onset, the eruptions of Patient 2 had became less visible after treatment with PUVA for 2 months, leaving a faded pigmentation.