枣滕地区天然焦热爆性及工业用途

天然焦按结构、构造和爆裂特征可分为4类。块状焦、砾状焦、柱状焦、砂状焦。试验结果表明:热爆的主要原因是存在形态各异、大小不等的气孔,孔内的CO_2、CO、CH_4等气体若骤然加热,就会引起膨胀爆裂,若将天然焦制成粉或预热,则可扬长避短,用于各种工业用途。

褐煤热爆特性及影响因素试验研究

为提高我国褐煤的利用效率,选取呼伦贝尔、元宝山、乌兰察布、兴安盟、宝清褐煤为研究对象,以粒度变化率作为衡量热爆性的指标,考察了煤质、初始平均粒径、受热温度、水分对褐煤热爆性的影响,并研究了热爆后碎片的结构特性。试验结果表明:褐煤的变质程度不同,热爆性有较大差别;初始平均粒径越大,受热温度越高,褐煤的热爆性越强;水分是影响褐煤热爆的重要因素,150℃下干燥1 h后样品的热爆性与原煤相比可降低50%以上;褐煤在热爆过程中产生了大量新孔,褐煤的水分和挥发分越高,热爆后碎片的孔隙结构越发达。

永夏煤田天然焦除爆方法实验研究

天然焦的形成,因其特殊的地质环境具有特殊的"热爆性",从而使其热稳定性降低,影响其利用功能。本实验就是尝试找出消除其"热爆性"的方法。根据天然焦的物理化学性质和工艺性能,选择了高温除爆法和破碎除爆法两种实验方法。从其效果看,高温除爆法工艺较复杂,破碎除爆法工艺较简单,各有优缺点。天然焦消除"热爆性"后,作为燃料,可应用于发电、钢铁、铸造以及民用等;作为化工原料,也可以用于气化、活性炭及电石等方面。

Quantum Chemical Studies on Structure and Detonation Performance of Bis（2,2-dinitropropyl ethylene）formal

Based on the full optimized molecular geometric structures via B3LYP/6-311＋G（2d,p） method, a new gem-dinitro energetic plasticizer, bis（2,2-dinitropropyl ethylene）formal was investigated in order to search for high-performance energetic material. IR spectrum, heat of formation, and detonation performances were predicted. The bond dissociation energies and bond orders for the weakest bonds were analyzed to investigate the thermal stability of the title compound. The results show that the four N-NO2 BDEs are nearly equal to the values of 164.38 kJ/mol, which shows that the title compound is a stable compound. The detonation velocity and pressure were evaluated by using Kamlet-Jacobs equations based on the theoretical density and condensed HOF. The crystal structure obtained by molec-ular mechanics belongs to P21 space group, with lattice parameters Z=2, a=13.8017 A, b=13.4072 A, c=5.5635 A.

Comparative Theoretical Studies on Several Energetic Substituted Dioxin-imidazole Derivatives

The molecular structures, infrared spectra, heats of formation （HOFs）, detonation proper- ties, chemical and thermal stabilities of several tetrahydro-[1,4]dioxino[2,3-d：5,6-d＇] diimida- zole derivatives with different substituents were studied using DFT-B3LYP method. The properties of the compounds with different groups such as -NO2, -NH2, -N3, and -ONO2 were further compared. The -NO2 and -ONO2 groups are effective substituents for in- creasing the densities of the compounds, while the substitution of -N3 group can produce the largest HOF. The compound with -NO2 group has the same detonation properties as 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane, while the compound with -ONO2 group has lower detonation properties than those of hexahydro-1,3,5-trinitro-l,3,5-triazine. The na- ture bond orbital analysis reveals that the relatively weak bonds in the molecules are the bonds between substituent groups and the molecular skeletons as well as C-O bonds in the dioxin rings. The electron withdrawing groups （-NO2, -N3, and -ONO2） have induc- rive effects on the linkages between the groups and molecular skeletons. In addition, re- searches show that the electronegativities of the groups are related with the stabilities of the compounds. Considering detonation performance and thermal stability, the 1,5-dinitro-2,6- bis（trinitromethyl）-3a,4a,7a,8a-tetrahydro-[1,4]dioxino-[2,3-d：5,6-d＇] diimidazole satisfies the requirements of high energy density materials.

Theoretical Study on Vibrational Spectra, Detonation Properties and Pyrolysis Mechanism for Cyclic 2-Diazo-4,6-dinitrophenol

Based on the full optimized molecular geometrical structures at the DFT-B3LYP/6- 311＋G^＊＊ level, there exists intramolecular hydrogen bond interaction for cyclic 2-diazo- 4,6-dinitrophenol. The assigned infrared spectrum is obtained and used to compute the thermodynamic properties. The results show that there are four main characteristic regions in the calculated IR spectra of the title compound. The detonation velocities and pressures are also evaluated by using Kamlet-Jacobs equations based on the calculated density and condensed phase heat of formation. Thermal stability and the pyrolysis mechanism of 2- diazo-4,6-dinitrophenol are investigated by calculating the bond dissociation energies at the B3LYP/6-311＋G^＊＊ level.

Design and Selection of High Energy Materials based on 4,8-Dihydrodifurazano[3,4-b,e]pyrazine

In order to search for high energy density materials,various 4,8-dihydrodifurazano[3,4-b,e]pyrazine based energetic materials were designed.Density functional theory was employed to investigate the relationships between the structures and properties.The calculated results indicated that the properties of these designed compounds were influenced by the energetic groups and heterocyclic substituents.The-N3 energetic group was found to be the most effective substituent to improve the heats of formation of the designed compounds while the tetrazole ring/-C(NO_(2))_(3) group contributed much to the values of detonation properties.The analysis of bond orders and bond dissociation energies showed that the addition of-NHNH2,-NHNO_(2),-CH(NO_(2))_(3) and-C(NO_(2))_(3) groups would decrease the bond dissociation energies remarkably.Compounds A8,B8,C8,D8,E8,and F8 were finally screened as the potential candidates for high energy density materials since these compounds possess excellent detonation properties and acceptable thermal stabilities.Additionally,the electronic structures of the screened compounds were calculated.

Study on Heat Dissipater for High-Power Thyristors in Explosion-Proof Shell

A new type water-cooled heat dissipater for multiple high-power thyristors in explosion-proof shell used in coal mine was designed, and then, the numerical computation of the three-dimensional steady-state temperature distributions under different working conditions for cooling core was conducted in order to understand in detail the heat transfer performance. Based on the computation results, the temperature differences and the maximum heat transfer rates were given. These results of the study on the heat dissipater lay a basis for optimising its structure design and guiding its operation.

Blowup mechanism for viscous compressible heat-conductive magnetohydrodynamic flows in three dimensions

We investigate initial-boundary-value problem for three-dimensional magnetohydrodynamic （MHD） system of compressible viscous heat-conductive flows and the three-dimensional full compressible Navier-Stokes equations. We establish a blowup criterion only in terms of the derivative of velocity field, similar to the Beale^Kato-Majda type criterion for compressible viscous barotropic flows by Huang et al. （2011）. The results indicate that the nature of the blowup for compressible MHD models of viscous media is similar to the barotropic compressible Navier-Stokes equations and does not depend on further sophistication of the MHD model, in particular, it is independent of the temperature and magnetic field. It also reveals that the deformation tensor of the velocity field plays a more dominant role than the electromagnetic field and the temperature in regularity theory. Especially, the similar results also hold for compressible viscous heat-conductive Navier-Stokes flows, which extend the results established by Fan et al. （2010）, and I-Iuang and Li （2009）. In addition, the viscous coefficients are only restricted by the physical conditions in this paper.

Responses of zonal wind at -40°N to stratospheric sudden warming events in the stratosphere, mesosphere and lower thermosphere

Based on the data at^40°N at different longitudes during different stratospheric sudden warming(SSW)events,the responses of zonal winds in the stratosphere,mesosphere and lower thermosphere to SSWs are studied in this paper.The variations of zonal wind over Langfang,China(39.4°N,116.7°E)by MF radar and the modern era retrospective-analysis for research and applications(MERRA)wind data during 2010 and 2013 SSW and over Fort Collins,USA(41°N,105°W)by lidar and MERRA wind data during 2009 SSW are compared.Results show that the zonal wind at^40°N indeed respond to the SSWs while different specifics are found in different SSW events or at different locations.The zonal wind has significant anomalies during the SSWs.Over Langfang,before the onset of 2010 and 2013 SSW,the zonal wind reverses from eastward to westward below about 60–70 km and accelerates above this region,while westward wind prevails from 30 to 100 km after the onset of2010 SSW,and westward wind prevails in 30–60 and 85–100 km and eastward wind prevails in 60–85 km after the onset of2013 SSW.Over Fort Collins during 2009 SSW,eastward wind reverses to westward in 20–30 km before the onset while westward wind prevails in 20–30 and 60–97 km and eastward wind prevails in 30–60 and in 97–100 km after the onset.Moreover,simulations by the specified dynamics version of the whole atmosphere community climate model(SD-WACCM)are taken to explain different responding specifics of zonal wind to SSW events.It is found that the modulation of planetary wave(PW)plays the main role.Different phases of PWs would lead to the different zonal wind along with longitudes and the different amplitudes and phases in different SSW events can lead to the different zonal wind responses.

Popcorning-type cracking failure in thermohyperelastic packaging materials in the presence of “wet” and “dry” cavities

Thermal cracking occurs in the plastic packaging materials due to the presence of moisturized micro-cavities in the material.The moisture resident in the micro-cavities gives rise to the internal vapor pressure that drives the thermal expansion of micro-cavities as temperature rises.The plastic packaging materials are considered a class of thermo-hyperelastic materials,thus allowing the micro-cavities to thermally expand to the substantial extent before the cracking failure.The micro-cavities can be moisture-abundant(i.e.,wet) or substantially dry when cracking occurs.Cracking appears to be almost certain in the presence of wet cavities.The possibility of cracking in dry cavities turns to be two-sided:when the initial volume fraction of the micro-cavities is relatively small,cracking cannot occur in the dry cavities regardless of the phase transition temperature;when the initial cavity volume fraction is relatively large,cracking tends to occur in the dry cavities especially when the phase transition temperature is large.Because of the two-sided cracking possibility,the dry-cavity cracking mode presents a scenario that might reveal the mechanism of popcorning-type cracking failure in plastic packaging materials.