Ferromagnetic Properties of Bond-Dilution and Random Positive or Negative Uniaxial Anisotropy Blume-Capel Model

We study the ferromagnetic properties of spin-1 system, which is considered in the frame of the bond dilution and random positive or negative anisotropy Blume-Capel model in the effective field theory and a cutting approximation. The investigation of phase diagrams displays some rich properties of the trajectory of tricritical point, reentrant henomena at low temperatures. Under certain both bond concentrations and random negative anisotropy, there are new transition lines of double tricritical points. So special emphasis is placed on the influence of the bond dilution and random anisotropy on phase diagrams. The magnetizations of the system are also discussed. Some results have not been evealed in previous reports.     

A 3D-BPP approach for optimising stowage plans and terminal productivity

This paper addresses the problem of determining stowage plans for containers in a ship, that is the so-called master bay plan problem (MBPP).     

金负载量对低温水煤气变换Au/α-Fe2O3催化剂结构和性能的影响

采用共沉淀法制备了低温水煤气变换Au/α-Fe2O3催化剂。通过正交实验优化催化剂的还原活化条件，考察了金负载量对催化剂性能的影响。采用BET、XRD、UV-VIS、XRF、H2-TPR和O2-TPO等表征手段对催化剂的结构进行分析，并与其催化性能进行关联。结果表明，（1）采用10%-H2/N2还原气将催化剂在150 ℃原位还原9 h，其催化活性最高；（2）金的最佳负载量为8.00%，此时在催化剂制备过程中金的流失量较少，金粒子较小，也有利于抑制催化剂在反应过程中烧结；（3）TPR-TPO结果表明，金的负载量为8.00%时，Au/α-Fe2O3催化剂具有较易被还原、不易被氧化的性质，从而显示出最高催化活性。（4）Au/α-Fe2O3催化剂中的金以单质金（Au0）形式存在；其高活性与Au0-Fe3O4间的协同作用有关。     

钇对2618合金组织及性能的影响

采用X射线，光学显微镜及扫描电镜等手段研究了2618合金中的组织与相结构，并研究了元素钆在2618合金中的存在形式及其对合金力学性能的影响。结果表明，微量钆元素在铝合金中是以化合物形式存在的；钆对合金中的铸态组织及Al9FeNi仃形态没有影响。由于微量钆的加入，降低了铜与镁在2618合金中的固溶量，减少了时效析出相A2CuMg数量，从而降低2618合金的室温强度帮在250℃的高温瞬时强度；但由于微量钆减少了铜与镁在2618合金中的扩散速度，延缓了时效机的粗化，并由于第二相数量的增多，因此提高了2618合金在250℃经100h高温热暴露后的高温瞬时强度。     

SHAPE MEMORY EFFECT OF PU IONOMERS WITH IONIC GROUPS ON HARD-SEGMENTS

SMPU （shape memory polyurethane） non-ionomers and ionomers, synthesized with poly（c-caprolactone） （PCL）, 4, 4＇-diphenylmethane diisocyanate （MDI）, 1,4-butanediol （BDO）, dimethylolpropionic acid （DMPA） were measured with cyclic tensile test and strain recovery test. The relations between the structure and shape memory effect of these two series were studied with respect to the ionic group content and the effect of neutralization. The resulting data indicate that, with the introduction of asymmetrical extender, the stress at 100% elongation is decreased for PU non-ionomer and ionomer series, especially lowered sharply for non-ionomer series; the fixation ratio of ionomer series is not affected obviously by the ionic group content; the total recovery ratio of ionomer series is decreased greatly. After sufficient relaxation time for samples stretched beforehand, the switching temperature is raised slightly, whereas the recovery ratio measured with strain recovery test method is lowered with increased DMPA content. The characterization with FT-IR, DSC, DMA elucidated that, the ordered hard domain of the two series is disrupted with the introduction of DMPA which causes more hard segments to dissolve in soft phase; ionic groups on hard segment enhance the cohesion between hard segments especially at high ionic group content and significantly facilitate the phase separation compared with the corresponding non-ionomer at moderate ionic group content.     

Modification of the resistance of two epoxy resins to accelerated weathering using calcium sulfate as a photostabilizer

Epoxy-timber composites have received increasing attention during the last decades because there are many advantages related to their uses as construction materials in applications such as timber bridges. However, the durability of epoxy-timber composites under outdoor conditions has become a concern for many epoxy resins. This study evaluated the chemical, thermal, and mechanical properties of two cured epoxies, the product of the diglycidyl ether of bisphenol A with 2,4-trimethyl-1,6-hexanediamine (DGEBA-TMDA) and the analogous resin prepared with the hydrogenated diglycidyl ether of bisphenol A (HDGEBA-TMDA), each mixed with 2?wt. % calcium sulfate (CS). We hypothesized that the use of CS, as an inorganic UV absorber, could decrease undesirable effects arising from exposure to UV light, moisture, and extreme temperatures.

An accelerated aging chamber simulated natural weathering for 1, 2, 3, 4, and 6?months. Chemical changes in cured epoxy systems over time in the presence and absence of CS fillers were determined using Fourier transform infrared spectroscopy (FT-IR). Thermal degradation profiles before and after exposure to accelerated weathering were followed by thermogravimetric analysis (TGA). The glass transition temperatures (T_g) before and after accelerated weathering were measured, and the effect of accelerated weathering on the surface morphology of the epoxy systems was investigated by scanning electron microscopy (SEM). In the presence of CS, after 6?months accelerated weathering the tensile strength of DGEBA-TMDA reduced by 23.8?±?2.4%, compared to 46.5?±?5.5% in its absence, while the corresponding values for HDGEBA-TMDA were 21.4?±?2.1% and 28.7?±?1.8%.     

对一个大单轴磁各向异性镍(Ⅱ)配合物中的磁跃迁的直接观察

最近Ruamps和同事发现三角双锥构型的Ni（Ⅱ）配合物[Ni（Me₆tren）Cl]ClO₄（1，Me₆tren=tris（2-（dimethylamino）ethyl）amine）具有大的单轴磁各向异性（J.Am.Chem.Soc.，2013，135：3017-3026）。他们利用HF-EPR研究获得横向零场分裂（ZFS）参数E=1.56（5）cm^-1但未能确定轴向零场分裂参数D。在本工作中，我们利用0~17.5 T和5 K的变磁场远红外光谱（FIRMS）来检测自旋基态S=1中的M_S=±1和M_S=0态之间的磁跃迁。在FIRMS中直接观察到Zeeman分裂态之间的跃迁，得出轴向ZFS参数D=-110.7（3）cm^-1。我们对1的晶体结构进行了Hirshfeld表面分析，揭示了1分子中的阳离子与阴离子之间以及分子之间的相互作用。     

Aging effect on the mechanical properties of hybrid gels

Sol-gel derived unsupported films and thin rods have been obtained from co-hydrolysis of triethoxysilane and methyldiethoxysilane. The materials are flexible, dense and transparent. Films and rods have been aged for different periods of time in air at room temperature. The elastic modulus has been measured by means of tensile or flexural tests. Measurements showed an increase of elastic modulus with aging time and showed different values for films and rods. The observed evolution of mechanical properties has been related to a corresponding structural modification as highlighted mainly by MAS-NMR studies. Analyses pointed out the crucial role of condensation processes and showed that the stiffness increase arises from the formation of relatively few bonds which link and constrain pre-existing mobile network regions.     

Study of reactive ion etching of Si and SiO2 for CFxCl4−x gases

A parametric study of the etching of Si and SiO₂ by reactive ion etching (RIE) was carried out to gain a better understanding of the etching mechanisms. The following fluorocarbons (FCs) were used in order to study the effect of the F-to-Cl atom ratio in the parent molecule to the plasma and the etching properties: CF₄, CF₃Cl, CF₂Cl₂, and CFCl₃ (FC-14, FC-13, FC-12, and FC-11 respectively). The Si etch rate uniformity across the wafer as a function of the temperature of the wafer and the Si load, the optical emission as a function of the temperature of the load, the etch rate of SiO₂ as a function of the sheath voltage, and the mass spectra for each of the FCs were measured. The temperature of the wafer and that of the surrounding Si load strongly influence the etch rate of Si, the uniformity of etching, and the optical emission of F, Cl, and CF₂. The activation energy for the etching reaction of Si during CF₄ RIE was measured. The etch rate of Si depends more strongly on the gas composition than on the sheath voltage; it seems to be dominated by ion-assisted chemical etching. The etching of photoresist shifted from chemical etching to ion-assisted chemical etching as a function of the F-to-Cl ratio and the sheath voltage. The etch rate of SiO₂ depended more strongly on the sheath voltage than on the F-to-Cl ratio.