The effect of temperature on Payne effect for spherical silica filled rubber combines characteristics of normally filled and pure rubber.

Recyclable and sensitive surface-enhanced Raman scattering (SERS) sensors for the detection of a variety of organic pollutants were fabricated from 3D hierarchical ZnO-Ag hybrids, which were synthesized by an efficient and green approach. The ZnO nanostructure could be controlled by applying a facile organic-chemical-assisted hydrothermal method. The obtained structures were then decorated with different-sized Ag nanoparticles (Ag NPs) on their side surfaces and top ends to construct 3D hierarchical ZnO-Ag nanocomposites for use as multifunctional SERS substrates. The obtained SERS sensor manifested a high sensitivity to rhodamine 6G (R6G) at a low concentration of 1x10(-13) M and a detection limit as low as 5x10(-9) M for the organic herbicide 4-chlorophenol (4-CP). Moreover, because of the good, stable photocatalytic properties of this exotic 3D hierarchical structure, the ZnO-Ag hybrids could self-clean under UV irradiation; this allowed repeatable SERS detection of many organic pollutants over more than three cycles with tolerable intensity attenuation. Finally, the unique repeatable detection of the organic dye R6G and the persistent organic pollutant (POP) 2,4-dichlorophenoxyacetic acid (2,4-D) demonstrates a new route to eliminate the single-use problem of traditional SERS substrates and suggests promising applications of such materials as real-time online sensors for organic pollutant detection.

Instant detection of trace-level nitroaromatic explosives is highly desirable for national security and environmental protection. In this paper, a new strategy for the construction of nitroaromatic-indicator paper was proposed based on a mixture of red emitting cysteamine modified cadmium telluride quantum dots and green emitting thioglycollic acid capped cadmium telluride quantum dots which served as the nitroaromatic sensor and reference probes, respectively. Nitroaromatic-indicator paper showed excellent response to trinitrotoluene and picric acid with visual detection limits of 1.59 and 1.16 ng mm(-2). The screening process was accomplished within half a minute. The visualization of the nitroaromatic-indicating paper was significantly enhanced when the green reference probe was used as the background. Therefore, a rapid, simple, convenient, and high selectivity paper sensor was developed for nitroaromatics.

The 2,2-dinitropropyl acrylate-vinyl acetate( DN PA-VAc) copolymer was synthesized by the free radical polymerization in ethyl acetate using azobisiosbutyronitrile as initiator. The effects of molar ratio of monomers,initiator concentration and time on copolymerization were investigated. The structure and properties of DNPA-VAc copolymer were also characterized by FTIR,1HNMR,DSC and TG measurements. Results show that the copolymer is obtained with the yield of 72% under conditions of DN PA and VAc molar ratio of 3: 1 at 80℃ within 8 hours. The glass transition temperature and thermal decomposition peak temperature of the DNPA-VAc copolymer is 59. 7 ℃and 259. 1 ℃. It is compatible with RDX and HMX,and thermal stable.

A new energetic cocrystal of TNT/TNB was obtained by evaporating ethanol at room temperature over a period of 3 days. It is found that the donor–acceptor π–π interaction, p–π interaction, and C–H···O hydrogen bond interaction are dominant in the formation of the cocrystal. In this work, physicochemical characteristics of cocrystal have also been studied using several methods: Optical Microscopy, Powder X-ray Diffraction, Single Crystal X-ray Diffraction and differential scanning calorimetry. It is shown that TNT and TNB molecules cocrystallize in a monoclinic system with space group P21/c and cell parameters a = 20.4570(8) Å, b = 6.1222(2) Å, c = 15.1635(6) Å, β = 110.091(4)°, and Z = 4. The cocrystal has a crystal density of 1.640 g cm−3 and H50 (50 % explosion characteristics of drop height) of 112.2 cm, which is higher than that of TNT (100 cm), TNB (77.8 cm) and most of the other explosives. The result shows that co-crystallization may help to improve the performance of TNT and TNB.

Co-crystallization is an effective way to improve performance of the high explosive 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (CL-20). A new CL-20/caprolactam (CPL) cocrystal has been prepared by a rapid solvent evaporation method, and the crystal structure investigations show that the cocrystal is formed by strong intermolecular hydrogen bond interaction. The cocrystal can only be prepared with low moisture content of the air, because water in the air has a profound effect on the cocrystal formation, and it can lead to crystal form conversion of CL-20, but not the formation of cocrystal. The CL20/CPL explosive possess very low sensitivity, and may be used as additive in explosives formulation to desensitize other high explosives.

利用4种不同成分的培养基从活性污泥中共分离出39株菌株,通过考察培养条件最终在4种培养基中各筛选得到一株具有较高絮凝活性的菌株,分别命名为A11,B6,C5,D6;同时考察了絮凝剂用量及助凝剂CaCl2的投入量对絮凝效果的影响,结果表明:A11絮凝剂投加量在0.2mL,CaCl2用量在0.8mL;B6絮凝剂投加量在0.2mL,CaCl2用量在1.0mL;C5絮凝剂投加量在0.25mL,CaCl2用量在1.0mL;D6絮凝剂投加量在0.15mL,CaCl2用量在1.0mL;分别具有良好的絮凝效果。

Five novel BTF (benzotrifuroxan) cocrystals, possessing a similar density to RDX (1,3,5-trinitrohexahydro-1,3,5-triazine), have been prepared and reported first. Their single-crystal structures are presented and discussed. Interactions between cocrystal formers are discussed with shifts in the IR spectra providing additional support for the presence of various interactions. Hydrogen-bonding and pi-stacking interactions are found to be the most prominent. Especially, the interactions between electron-poor g-systems of BTF and electron-rich groups of other cocrystal formers such as nitro groups of TNB exist commonly in all five novel cocrystals. This kind of interaction can be a more potential driving force for energetic cocrystals, since explosives with poor active hydrogen bonds are usually hard to form cocrystals with other explosives for the lack of strong intermolecular interactions. Because of the changes in structure, the physicochemical characteristics including density and melting point together with energetic properties of BTF altered after cocrystallization. All of the densities are between both of the cocrystal formers. Cocrystals of BTF with TNT and TNB have impact sensitivities between those of both cocrystal formers, while the remaining three cocrystals (BTF/TNA, BTF/MATNB, and BTF/TNAZ) all are more sensitive than either cocrystal former. It indicates that a cocrystal with TNT or TNB can reduce the shock sensitivity of BTF; especially, the cocrystal BTF/TNB not only has a lower sensitivity than RDX but also equal energetic properties, which potentially improve the viability of BTF in explosive applications. This paper owns an important consideration in the design of future BTF and other explosive cocrystals, and the result provides some feasibility to improve the application of the high explosive BTF.

通过共晶工程法使不同种类的单质炸药在分子层面有序排列,可望解决现有炸药高能与钝感的矛盾,对提高炸药的性能具有重要意义[1-3].苯并三氧化呋咱(BTF)是一种性能优良的炸药,爆轰能量与HMX相当,但感度相对较高,冲击起爆感度和熄爆直径与太安相当[4],使其应用受到一定的限制.通过共晶工程的方法使BTF与安全性能相对较好的单质炸药,如与TNT、TNB等形成共晶,有望在不降低能量的前提下改善其安全性能.

2,2-Dinitropropyl acrylate-styrene(DNPA-St) copolymer was synthesized by free radical polymerization in ethyl acetate by using azobisiosbutyronitrile as initiator.The structure and properties of DNPA-St copolymer were also characterized by FTIR,1H NMR and DSC measurements.The behavior of the copolymerization between 2,2-dinitropropyl acrylate(DNPA) and styrene(St) was studied,the composition of the copolymer was determined using infrared spectrum method,and the reactivity ratios of DNPA and St were measured.Results show that the reactivity ratios of DNPA and St was obtained by using the Fineman-Ross method,rDNPA=0.911 and rSt=0.038,respectively.The polymerization of DNPA with St is a non-ideal copolymerization,and the products are random copolymers.The glass transition temperature and thermal decomposition temperature of the DNPA-St copolymer is 63.3 ℃ and 251.4 ℃.It is compatible with RDX and HMX,and thermal stability.

The nano-SiO2 particles were prepared by sol-gel method and their surface was modified by one-step method in the help of ethanol and silane coupling agent.The basic performance of the powder was characterized by means of XPS,TEM and FI-IR.The results indicated that hydrophobic property of the modified nano-SiO2 paticles enhanced and the surface hydroxyls were reacted with silane coupling agent.

The preparation of monodisperse nano-silica spheres by the sol-gel method are described,and the obtained particle size from 480nm to 500nm.The effects of the amount of emulsifier and ammonia water for the nano-size are studied.Nano-particle size,structure and morphology are characterized by laser particle size analyzer(LS),fourier -infrared spectrometer(FI) and scanning electron microscopy(SEM).The consequence demonstrates:The quantity of ammonia water increases,the particle size and the aggregation degree increase;the amount of emulsifier increases, the range of particle size is relatively narrow,but the particle size increases,and also appeares some aggregation.

A novel method of studying molecular interactions is introduced. It is a method based on the framework of a two-dimensional (2D) infrared (IR) correlation spectroscopy technique with a new data pretreatment strategy. In this method, an additional external perturbation stimulates the system to cause some selective changes in the state, order, and surroundings of system constituents. The overall response of the stimulated system to the applied external perturbation leads to distinctive changes in the measured spectrum, and a series of perturbation-induced dynamic spectra are collected in a systematic manner. Such a set of dynamic spectra are then transformed into a set of 2D correlation spectra by cross-correlation analysis. Temperature was chosen as an external perturbation, and the molecular interaction between 4-aminopyridine (Apy) and methacrylic acid (MAA) was investigated by 2D IR correlation spectroscopy. Synchronous cross peaks exist between the stretching vibration of the C–O group of MAA at 1,298 and 1,202 cm−1 and the C=N group of Apy at 1,531 cm−1, and between the carbonyl group of MAA at 1,705 cm−1 and the amino group of Apy at 3,382 and 3,212 cm−1. The synchronous cross peaks are from orientation of MAA and Apy vibrations generated at the same time; the synchronization of microstructure movements in the molecules indicates that there exists strong interactions between MAA and Apy. According to 2D correlation rules, static electricity and hydrogen-bonding interactions exist between Apy and MAA. Such results were further verified by 1H-NMR spectroscopy. The successful application demonstrates that 2D IR correlation spectroscopy may be a convenient and effective method in the study of molecular interactions.

The preparation of monodispersed nano-SiO2 by sol-gel method used widely in resent years,because of its merits,such as particle size controlled easily,dispersed well in solutions and so on.As its large surface area,nano-SiO2 may reunite.So we can use surface chemical modification method to improve dispersions and applications of nano-silica.Moreover,the preparation of nano-sized SiO2 micropheres using sol-gel method,the surface chemical modification and shear-thickening(STF) effects were reviewed detail.

The Five Second Explosion Point (5 SEP) tests and the SEM detections in this research showed that the HMX crystals and the HMX based explosives treated under different conditions can possess different thermal sensitivities That is to say higher impurity smaller granularity and worse integrity of HMX crystals can make them more thermally sensitive The addition of metal or metal oxide particles, especially nanoparticles to HMX can also enhance its thermal sensitivity Meanwhile, coating of HMX crystals with polymers to form perfect PBX and to keep them undamaged are helpful to decrease their thermal sensitivity Furthermore, the thermal sensitivity of temperature aged HMX changes differently in terms of the integrity of its particles Therefore, it can be concluded that conditions which increase the surface energy of HMX crystals or which make the HMX molecules more active to decompose at lower temperature will increase the thermal sensitivity of HMX Additionally the variation in the thermal sensitivity of HMX treated under different conditions F generally more temperate than that of its mechanical sensitivity

The homogeneous bimetallic catalysts(Fe/Co) particles on a silicon wafer was prepared by spin coating with the mixture of ethanol solution of polyethylene glycol(PEG) and salts of Fe/Co for the synthesis of vertically aligned single-walled carbon nanotubes.The dependence of distribution of catalyst particles on spin-coating speed,PEG content and catalyst concentration was investigated.Consequently,the single walled carbon nanotubes synthesized on the catalysts were characterized by SEM and Raman spectroscopy.The result shows the high rotation rate is favorable to small particle size and the formation of single walled carbon nanotubes,while a relatively high PEG and catalyst content are necessary for the high density of catalyst particles and vertically aligned growth although the higher catalyst content and the larger particle size would result in the multiwalled carbon nanotubes.When the rotation rate was set to be 7 000 r/min,the optimized conditions for the growth of vertically aligned single walled carbon nanotubes were w(PEG)=1.25%,w(Fe)=0.05% and w(Co)=0.05%.

TATB and HNS with different particle sizes Were characterized using particle size analysis, specific surface area analysis and SEM, and the thermal stabilities of different explosives were measured by DTA-TG, 5s, VST and thermostatic TG. The results show that the fine explosive particles with higher specific surface area, have higher surface free energy and heat transfer efficiency, accordingly the thermal decomposition becomes easier, and the thermal stabilities decrease.

单壁碳纳米管的独特性能使其成为一种有着极大应用前景的新兴纳米材料,本文主要介绍了催化剂、裂解温度、载气等因素对化学气相沉积法(CVD)制备单壁碳纳米管的影响和采用化学气相沉积制备定向单壁碳纳米管方面的研究进展情况.

In this article, epoxy foams comprised of diglycidyl ether of bisphenol-A (DGEBA) based epoxy resin E(31) and E(51), polyamide resin, and water were prepared by microwave irradiation method. The structure and properties of epoxy foams were analyzed by FTIR, TGA, SEM, and DMA methods. The density and compressive performance of epoxy foams was also determined. The results indicated that the epoxy foams had excellent compressive performance and the preparation of epoxy foam by microwave irradiation was high efficiency and convenient. The composition has great effect on density, foam structure, dynamical mechanic performance, and thermal degradation behavior of epoxy foams. The epoxy foam with density from 0.08 g cm(-3) to 1.05 g cm(-3) can be obtained by varying ratio of E(51) and E(31) to control the viscosity of mixtures. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 3543-3547, 2009

This paper sums up and expounds various techniques used for wastewater of powder and explosives and conducts detailed analysis and comparisons on the features and applications of each techniuqes,finding out that reducing pollution discharge and clean production is an essential way to reduce powder and explosives water pollution.