摘要:

AbstractWe compute the ESR coupling constants and the geometries of ten nitro derivatives of the benzyl radical. We consider the three mononitrobenzyls, the six dinitrobenzyls and 2,4,6‐trinitrobenzyl. The computations are based on the use of the Gaussian 82 Program Package with the STO‐3G basis set. There are no experimental data availa

ISSN:0721-3115    

DOI:10.1002/prep.19890140102

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractThe combustion wave structure and thermal decomposition process of HMX were examined in order to elucidate the burning rate characteristics of HMX. The combustion wave can be divided into three zones: nonreactive solid‐phase, surface reaction, and gas‐phase reaction zones. Measurements with micro‐thermocouples revealed that the heat flux produced in the surface reaction zone is approximately equal to the heat flux transferred back from the gas phase to the burning surface. Accordingly, the reaction process in the suface reaction and the gas phase zones plays a dominant role in the burning rate of HMX. The gas phase reaction zone consists of a two‐stage reaction process: the first stage is the exothermic rapid reaction process between NO2and aldchydes, and the second stage is the exothermic slow reaction process between NO and N2O and remaining fuel species. The luminous flame zone which is determined to be the second stage reaction process approaches rapidly the burning surface as pressure increases. However, the luminous flame reaction appears to be little responsible for the burning rate of HMX.Examinations of the quenched burning surface of HMX samples revealed that the burning surface melts and forms a noncrystallized intermediate material. The surface structure appears to be different from the structure of thermally degraded HMX samples which were obtained by a thermogravnmetric a

ISSN:0721-3115    

DOI:10.1002/prep.19890140103

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractEffect of a moving plate between a shaped charge jet and the target on jet‐penetration has been investigated theoretically. It has been assumed that the plate moves undeformed with uniform velocity, and jet‐penetration in the plate or the target occurs hydrodynamically so that the impact of the jet produces a hole in the plate whose diameter is bigger than that of the jet. The free passage of the jet through this hole is intercepted when the jet touches the wall of the hole due to its transverse motion. The presence of a moving plate between the jet and the target has been found many times more effective than that of a stationary plate in reducing the jet penetration in the target. The effect of angle of attack, velocity of the plate and initial distance between the plate and the target on penetration, produced by the jet going out of the plate, has been investigated for a typical set of arbitrarily selected values of jet and plate paramet

ISSN:0721-3115    

DOI:10.1002/prep.19890140104

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractHAB is a thermally‐ and hydrolytically‐stable solid, easily prepared from available raw materials. It is not highly sensitive to shock, friction, or electrostatic charge, but is sensitive to some types of impact, although not to others. It shows preliminary promise for possible use as a substitute for normal lead styphnate in less‐sensitive bridgewire detonators, and as a substitute for tetracene in percussion detonators, e.g. the M‐42 primer. Easy ignition, and a high burning rate without detonation, suggest application as an igniter. HAB is not sufficiently powerful to dent an aluminum witness block; therefore, it would not be suitable as a replacement for lead azide as an intermediate detonator

ISSN:0721-3115    

DOI:10.1002/prep.19890140105

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractHigh performance shaped charges require a perfect rotational symmetry and homogenity in structure. Therefore the density distribution of the explosive inside the charge has to meet the same specifications in order to obtain the desired geometry of the detonation wave. In this paper we present an analytical model which describes the density inside the charge as a function of the pressure and the friction between the tool surface and the granulate. The density distribution inside a cylindrical body has been calculated. The comparison with experimental data shows a good agreement.

ISSN:0721-3115    

DOI:10.1002/prep.19890140106

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractThermal decomposition of nitrourea salts (K, Na, Ag, Ba) was studied in hydrogen atmosphere, helium atmosphere and vacuum by gas chromatography and mass spectrometry. The evolution of dinitrogen oxide, water, hydrazine, nitrogen dioxide and the formation of cyanate salts during thermodecomposition of nitrourea salts in helium and hydrogen were confirmed. In vacuum the evolved gaseous products changed to dinitrogen oxide, water, nitrogen monoxide, nitrogen gas indicating that interreaction between evolved gaseous products occurred. The same solid products – cyanate salts – are formed showing vacuum having no effects upon the decomposition mechan

ISSN:0721-3115    

DOI:10.1002/prep.19890140107

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractIt is shown that the Mott fragmentation model and the Hirsch formula for the shaped charge jet break‐up time complete one another to yield a unified model. This model is consistant with the microscopic picture of internal flow splitting in the metal, into shear bands undergoing a strain larger than the average and the metal between them which undergoes a strain which is smaller than the average. This splitting reduces the deformation energy dissipated by the metal while elongating. It corresponds to the splitting of the stress versus strain characteristics of the metal into the isothermic and adiabatic curves as measured by Johnson and Cook. The parameter Vplwhich describes the break‐up process according to the Hirsch model, is identified with the expression (dσm/ϱ)1/2where dσmis the difference in yield strength between the isothermic and adiabatic curves where the adiabatic characteristic becomes a maximum. The comparison with available experimental measurements of this prediction shows a very encouraging agreement. The weak dependence of Vplon the strain rate on the one hand and the observed increase of the jet break‐up time in slowly elongating jets on the other hand are also explained using energy considerations. The recent recovery of jet particles by Zernow yields supportive evidence of the proposed theory which may be extended to all semi steady metal plastic flow phenomena. The final break‐up, according to this model is due to the separation between the two sides of shear bands where the slide motion went on during the whole deformati

ISSN:0721-3115    

DOI:10.1002/prep.19890140108

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

ISSN:0721-3115    

DOI:10.1002/prep.19890140109

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

ISSN:0721-3115    

DOI:10.1002/prep.19890140110

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

ISSN:0721-3115    

DOI:10.1002/prep.19890140101

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY