过载-振动复合环境下液浮积分陀螺仪动力学分析

采用有限元数值计算方法对液浮积分陀螺仪在过载—振动复合环境中的动力学特性进行研究。对液浮积分陀螺仪浮子组件谐态和模态进行了分析计算，获得了复合载荷下浮子组件质心的附加偏移的数据，从而为分析陀螺仪的附加误差提供了依据。     

Short-term microdamage of a physically nonlinear particulate material under a combination of normal and tangential loads

The structural theory of short-term damage is generalized to the case where the undamaged components of a particulate composite deform nonlinearly under loads that induce a compound stress state. The basis for this generalization is the stochastic elasticity equations for a particulate composite with porous components whose skeletons deform nonlinearly. Damage in a microvolume of the material is assumed to occur in accordance with the Huber-Mises failure criterion. Balance equations for damaged microvolume are derived for the physically nonlinear materials of the components. Together with the macrostress-macrostrain relationship for a particulate composite with porous nonlinear components, they constitute a closed-form system of equations. This system describes the coupled processes of physically nonlinear deformation and microdamage. Algorithms for calculating the microdamage-macrostrain relationship and plotting stress-strain curves are proposed. Such curves are plotted for the case where the composite is subjected to a combination of normal and tangential loads, and microdamages occur in the linearly hardened matrix and do not in the linearly elastic inclusions. The stress-strain curves are examined depending on the volume fraction of inclusions and presence of tangential stresses __________ Translated from Prikladnaya Mekhanika, Vol. 42, No. 12, pp. 48–57, December, 2006.     

双核有机金属化合物的光化学反应探析

有机金属化合物是指分子中至少含有一个金属-碳键（M-C键）的化合物,包括含M-C σ-键、M-Cnπ-键、ηn-M-Cn大π-键的化合物.双核金属-金属碳键的有机化合物的光化学反应包括光诱导金属-金属键的断裂、配体的离解与取代、光化学插入反应、光诱导异构化反应、歧化反应等.     

一种新型黄色荧光类水滑石材料的制备及表征

用适量的Zn(Ⅱ)取代镁铝水滑石中的Mg(Ⅱ),同时将一定量的2-对联苯基-8-羟基喹啉分散到类水滑石层间的亲油性阴离子中,使其与层板表面上的Zn(Ⅱ)配位,用一步法合成、组装得到一类新型黄色荧光类水滑石复合物(Zn-(HQ-4-biPh)-HTlc)。采用荧光光谱、红外光谱、X射线衍射、扫描电子显微镜和热分析等对其进行了表征。研究结果表明,Zn-(HQ-4-biPh)-HTlc在蓝光(481 nm)激发下可发出黄色荧光(554 nm),与其相应的含锌配合物(Zn[2-(p-biph)-8-Q-O]2)相比,不仅可节省配体用量,而且具有更高的发光强度和更好的热稳定性,有望在白光LED等光电领域得到应用。     

木质素及其模型化合物的加氢脱氧反应研究进展

随着化石能源的不断枯竭,以及所产生的环境问题-温室效应及其高硫含量引起的酸雨,迫使人类寻找新型替代能源.在众多可再生能源中,生物质因其碳中性,易获取,作为唯一可转化为液体燃料的可再生资源,正日益受到重视.全球每年生物质产出高达1.7×1011t,其中,含75%的碳水化合物如纤维素、甲壳素和淀粉,20%木质素,其他占     

Copolymerization of N‐tert‐Butylacrylamide with Ethylene Glycol Dimethacrylate

N‐tert‐butylacrylamide (NtBA) was copolymerized with ethylene glycol dimethacrylate (EDMA) in butanone solution over a wide composition and conversion range, using dibenzoyl peroxide (Bz₂O₂) as a free‐radical initiator. The copolymer composition was determined from the nitrogen content. Using only low conversion (≤20%) collected for the copolymerization reactions, monomer reactivity ratios were estimated using the Kelen‐Tüdos graphical method and were found to be r₁=0.26 (NtBA) and r₂=7.05 (EDMA). In order to get a better insight into the mechanism of nanoporous copolymers of NtBA with EDMA preparation by thermal degradation of copolymers of N‐acryl‐N,N′‐di‐tert‐butylurea (A‐DitBuU) with EDMA, nonporous copolymers (model compound), of the same chemical structure and composition, were prepared by performing copolymerization of NtBA with EDMA up to the high conversion of 97–100%. Thermal behavior of nanoporous and nonporous copolymers of NtBA with EDMA was studied.     

Studies on the Particle Morphology of Waterborne Cationic Polyurethane/Polyacrylate Microemulsions

Polyurethane containing tertiary nitrogen atoms was synthesized from polyol, diphenylmethane diisoccyanate (MDI) and N‐methyl diethanolamine. The polymer was converted into cationomers by quarternizing with methacrylic acid (MAA) and then dispersed in water. In this reaction, methyl methacrylate (MMA) was used to decrease viscosity; at the same time, it was the monomer in the later reaction. Finally the cationic polyurethane dispersions were further polymerized with an oil‐soluble initiator, azobisisobutyronitrile (AIBN), water‐soluble initiator, K₂S₂O₈ (KPS) and the mixture of AIBN and KPS. The different emulsion particles with shell‐core structure, “invert” shell‐core structure and “irregular” sandwich structure were obtained; the morphological structures were characterized by TEM observation, FT‐IR and particle size analysis.     

Ab‐Initio study of Helium‐small carbon cage systems

The traditional method for opening the electron shells of noble gas atoms involves a strong electronegative atom or group. However, this approach is limited to only heavy noble‐gas atoms, such as Kr and Xe. In this paper, we performed accurate calculations of He@C₈H₈ and He@C10H16 and showed the possibility of opening the electron shell of a light noble‐gas atom. © 2012 Wiley Periodicals, Inc.     

Anisotropic thermoelectric and superconducting properties of the bulk misfit-layered (SnSe)1.17(TaSe2) compound

We present the thermoelectric and superconducting properties of the bulk misfit-layered (SnSe)_1.17(TaSe₂) compound with the critical temperature (T_c ~ 3.8 K). From XRD and electrical resistivity, the anisotropic properties of the misfit-layered compound by the preferred orientation were observed. The zero-temperature-limit upper critical field H_c2(0) and coherence length ξ are obtained by H_c2(0) = 8.94 T and ξ = 6.1 nm. The electron-phonon coupling constant (λ_e-p = 0.735) and the specific heat jump (ΔC_e/γT_c ~ 1.4) imply that the (SnSe)_1.17(TaSe₂) compound is a weak coupled conventional s-wave superconductor. Density functional theory (DFT) calculation results show that some electronic charge transfers from the SnSe layers into the TaSe₂ layers. In addition, the thermoelectric properties of the bulk misfit-layered (SnSe)_1.17(TaSe₂) compound show significant anisotropic properties.     

Determination of phenolic compounds by MALDI–TOF and essential oil composition by GC–MS during three development stages of Origanum majorana L.

This study aimed to investigate the effect of the maturation process of sweet marjoram (Origanum majorana L.) on essential oil composition, the phenolic profile of ethanolic extract and their antioxidant capacities. The essential oil composition was studied at three stages of maturity by GC–MS. Thirty compounds were detected representing 100% of the total essential oil. p‐Menth‐1‐en‐4‐ol was the major compound (37.15–76.94%) followed by cyclohexanol‐3,3,5 trimethyl (5.41–15.99%) and α‐terpineol (0.94–11.34%). During the maturation process, an accumulation of oxygenated monoterpenes was observed. The phenolic composition was studied using matrix‐assisted laser desorption/ionization time of flight. The analysis showed the presence of short flavonoid monomers at all stages of maturation. The antioxidant capacity of ethanolic extracts and essential oils was evaluated using the DPPH assay, iron chelating power and reducing power assay. The highest phenolic content and antioxidant capacity were found at flowering stage. These findings on essential oil composition, phenolic profile and antioxidant capacity of O. majorana at three different stages of development provide more information on how these secondary metabolites are accumulated.