水泥基腻子面漆二合一内墙涂料的制备

以自制的可再分散乳胶为主要成膜物质,结合水泥水硬性无机粘结剂制备了腻子面漆二合一内墙涂料,重点讨论了可再分散乳胶粉、纤维素醚、粉状憎水剂对涂膜性能的影响。实验结果表明,可再分散乳胶粉及其用量对腻子面漆二合一涂料性能具有重要影响,当其用量为4%~6%时,涂膜具有良好的综合性能;纤维素醚能明显改善涂料的施工性能和保水性能,其最佳用量为0.3%;粉状憎水剂显著提高涂膜的耐水性和耐洗擦性能,其用量为0.3%时可达到很好的效果。产品综合性能达到或超过国标JG/3049—1998N型和GB/T 9756—2001优等品指标值。

外墙“三合一”腻子的开发与应用研究

建筑外墙'三合一'腻子由高性能弹性聚合物乳液及多种功能性助剂精制而成,是一种多功能新型找平材料,它将原有的柔性腻子、抗碱封闭底漆、中间漆三道工序简化成一道程序,能完美匹配真石漆、质感涂料。文章介绍了外墙'三合一'腻子的施工工艺,并将传统外墙腻子与'三合一'腻子进行了优劣对比。

一阶反合一研究

文章讨论一阶反合一问题以及求反合一子完备集的算法．在合一问题中，有多种求解合一问题的方法，其中研究得较为彻底的是用转换规则进行求解的方法．在研究反合一问题的过程中，人们也陆续提出了许多转换规则，这样做的结果是最终给出的是已解出形．该文在已解出形的基础上讨论一种方法，以给出具体解的完备集（反合一子完备集）．通过引入Ｇθ和Ｚ函数，使求解更为方便、直观．

First principles investigation of binary intermetallics in Mg-Al-Ca-Sn alloy:Stability,electronic structures,elastic properties and thermodynamic properties

The structural stability, electronic structures, elastic properties and thermodynamic properties of the main binary phases Mg_（17）Al_（12）, Al_2Ca, Mg_2 Sn and Mg_2 Ca in Mg-Al-Ca-Sn alloy were determined from the first-principles calculation. The calculated lattice parameters are in good agreement with the experimental and literature values. The calculated heats of formation and cohesive energies show that Al_2Ca has the strongest alloying ability and structural stability. The densities of states（DOS）, Mulliken electron occupation number, metallicity and charge density difference of these compounds are given. The elastic constants of Mg_（17）Al_（12）, Al_2Ca, Mg_2 Sn and Mg_2 Ca phases are calculated, and the bulk moduli, shear moduli, elastic moduli and Poisson ratio are derived. The calculations of thermodynamic properties show that the Gibbs free energies of Al_2Ca and Mg_2 Sn are lower than that of Mg_（17）Al_（12）, which indicates that Al_2Ca and Mg_2 Sn are more stable than Mg_（17）Al_（12） phase. Hence, the heat resistance of Mg-Al-based alloys can be improved by adding Ca and Sn additions.

A first-principles study on electronic structure and elastic properties of Al_4Sr, Mg_2Sr and Mg_(23)Sr_6 phases

The electronic structures and mechanical properties of Al4Sr, Mg2Sr and Mg23Sr6 phases were determined by the use of first-principles calculations. The calculated heat of formation and cohesive energy indicate that Al4Sr has the strongest alloying ability as well as the highest structural stability. The elastic parameters were calculated, and then the bulk modulus, shear modulus, elastic modulus and Poisson ratio were derived. The ductility and plasticity were discussed. The results show that Al4Sr and Mg2Sr phases both are ductile, on the contrary, Mg23Sr6 is brittle, and among the three phases, Mg2Sr is a phase with the best plasticity.

Long-Lived Coherence Originating from Electronic-Vibrational Couplings in Light-Harvesting Complexes

We theoretically investigate the evolutions of two-dimensional, third-order, nonlinear photon echo rephasing spectra with population time by using an exact numerical path integral method. It is shown that for the same system, the coherence time and relaxation time of excitonic states are short, however, if the couplings of electronic and intra-pigment vibrational modes are considered, the coherence time and relaxation time of this vibronic states are greatly extended. It means that the couplings between electronic and vibrational modes play important roles in keeping long-lived coherence in light-harvesting complexes. Particularly, by using the method we can fix the transition path of the energy transfer in bio-molecular systems.

丰收·思索——写在全国优秀广播节目评选之后

1988年全国优秀广播节目评选结束了。一百七十件获奖作品,标志着88年广播节目的新水平。我们从中看到,广播在反映现实的广度、深度、真实度和敏锐度上都有了新的拓进。《独居户见闻录》

First-principles calculation of structural and elastic properties of Pd_(3-x)Rh_xV alloys

The structural stability, electronic and elastic properties of Pd3-xRhxV alloys with L12 and D022 structures were investigated theoretically by the first-principles calculations. The results reveal that with the increase of Rh content, the unit cell volume of Pd3-xRhxV alloys with L12 and D022 structures decreases, and the structure of Pd3-xRhxV alloys tends to transform from D022 to L12. The elastic parameters such as elastic constants, bulk modulus, shear modulus, elastic modulus, and Poisson ratio, were calculated and discussed in details. Electronic structures were also computed to reveal the underlying mechanism for the stability and elastic properties.

Syntheses and Crystal Structures of Two Novel Bromocuprate(Ⅰ)Polymers{(PyH)_(3)[Cu_(3)Br_(6)]}_(∞)and{(γ-MePyH)_(2)[Cu_(2)Br_(4)]}_(∞)

Reactions of CuBr with equimolar PyHBr orγMePyHBr afforded two novel one dimensional bromocuprate?polymers{(PyH)_(3)[Cu_(3)Br_(6)]}_(∞)(1)and{(γMePyH)_(2)[Cu_(2)Br_(4)]}_(∞)(2),respectively.Both 1 and 2 were characterized by IR,elemental analysis,and X ray crystallography.Crystal data for 1:monoclinic,space group P2_(1)/n,a=0.93262(12)nm,b=1.3497(2)nm,c=1.9149(2)nm,β=93.465(7)°,V=2.4060(5)nm^(3),Z=4.Crystal data for 2:orthorhombic,space group Pbcm,a=0.8659(4)nm,b=1.5669(6)nm,c=1.2849(5)nm,V=1.7432(2)nm^(3),Z=4.The structure of 1 has a unique helical chain composed of units andμbromide anions while that of 2 shows a linear chain consisted of[Cu_(2)(μBr)_(2)]units bridged by pairs ofμBr atoms.CCDC:1,208412;2,208413.

Ordered mesoporous carbon supported bifunctional PtM(M=Ru,Fe,Mo)electrocatalysts for a fuel cell anode

The deposition onto an ordered mesoporous carbon（OMC）support of well dispersed PtM（M = Ru,Fe,Mo）alloy nanoparticles（NPs）were synthesized by a direct replication method using SBA-15 as the hard template,furfuryl alcohol and trimethylbeneze as the primary carbon sources,and metal acetylacetonate as the alloying metal precursor and secondary carbon source.The physicochemical properties of the PtM-OMC catalysts were characterized by N2 adsorption-desorption,X-ray diffraction,transmission electron microscopy,X-ray absorption near edge structure,and extended X-ray absorption fine structure.The alloy PtM NPs have an average size of 2-3 nm and were well dispersed in the pore channels of the OMC support.The second metal（M）in the PtM NPs was mostly in the reduced state,and formed a typical core（Pt）-shell（M）structure.Cyclic voltammetry measurements showed that these PtM-OMC electrodes had excellent electrocatalytic activities and tolerance to CO poisoning during the methanol oxidation reaction,which surpassed those of typical activated carbon-supported PtRu catalysts.In particular,the PtFe-OMC catalyst,which exhibited the best performance,can be a practical anodic electrocatalyst in direct methanol fuel cells due to its superior stability,excellent CO tolerance,and low production cost.

Threshold Photoelectron-photoion Coincidence Imaging of Dissociation Dynamic of NO＋ at c3∏（v′=0） State

The photodissociation of NO＋ at c3∏（v′=0） state is studied by threshold photoelectron- photoion coincidence imaging method. By some assumptions, the relations between velocity in center of mass （CM） coordinates and most probable center of mass （MPCM） coordinates, time of flight and displacement in the velocity map image of fragment ions are derived using vector addition of velocity and displacement on the condition of perpendicular molecular beam. Using these relations the velocity in CM coordinates, the velocity and angular distri- bution of N＋ fragment ions in MPCM coordinates are obtained and discussed, respectively.

Evolution of Bond-Order-Wave Phase in One-Dimensional Mott Insulators

In this paper, by using the level spectroscopy method and bosonization theory, we discuss the evolution of the bond-order-wave （BOW） phase in a one-dimensional half-filled extended Hubbard model wlth the on-site Coulomb repulsion U as well as the inter-site Coulomb repulsion V and antiferromagnetic exchange J. After clarifying the generic phase diagrams in three limiting cases with one of the parameters being fixed at zero individually, we find that the BOW phase in the U-V phase diagram is initially enlarged as J increases from zero but is eventually suppressed as J increases further in the strong-coupling regime. A three-dimensional phase diagram is suggested where the BOW phase exists in an extended region separated from the spin-density-wave and charge-density-wave phases.

Studies on acute toxicity of three heavy metal ions to Artemia

Studies on acute toxicity of Cu2+,Mn2+and Zn2^to Artemianauplii(36h)and adults were carried out at15±3°C in the natural seawater where salinity is30using single-factor acute toxicity;on this basis,equi-toxicity test was used to evaluate the effect of joint toxicity of Cu2+,Mn2+and Zn2+to Artemia nauplii(36h)in the same conditions.Results show that Artemia has different tolerances for the three heavy metal ions when it is in different growth period,and the interaction of heavy metal ions varied with growth period,adults are more sensitive of the three heavy metals;The48h LC50of these three heavy metal to the Artemia nauplii is4.0,27.19and115.95mg/L,and to the adults is1.31,6.86and34.23mg/L;the order of toxicity of cuprum,manganese and zinc for Artemia nauplii and adults was Cu2^>Mn2+>Zn2+;the safe concentration of the three heavy metal ions(Cu2+,Mn2+and Zn2+)to Artemia nauplii(36h)and adults were0.4,2.72,11.6,0.13,0.69and3.42mg/L.The results of combined toxicity test showed that Cu-Mn,Cu-Zn and Mn-Zn were all antagonistic to the Artemia naupli.

Structural Analysis of ^(23)O Through Single-Neutron Stripping Reaction

We have studied the single-neutron stripping reaction induced by ^23O on carbon target at beam energy of 72 MeV//A with a motive to analyze its ground state structure. The partial stripping cross sections as well as longitudinal momentum distribution of ^22O core have been calculated within the framework of the eikonal approximation approach. Several core-neutron spin coupling configurations, corresponding to J^π= 1/2 ＋ as ground state spin parity of ^23O, along with their suitable admixtures have been considered. The major outcome of the present work is that the s and d admixed configuration with a large contribution of s state seems to explain the longitudinal momentum distribution data more satisfactorily.

Effects of L-arginine on serum nitric oxide, nitric oxide synthase and mucosal Na^+-K^+-ATPase and nitric oxide synthase activity in segmental small-bowel autotransplantation model

AIM:To explore a simple method to create intestinal autotransplantation in rats and growing pigs and to investigate the effect of L-arginine supplementation on serum nitric oxide (NO), nitric oxide synthase (NOS) and intestinal mucosal NOS and Na+-K+-ATPase activity during cold ischemia-reperfusion (IR) in growing pigs. METHODS: In adult Wistar rat models of small bowel autotransplantation, a fine tube was inserted into mesenteric artery via the abdominal aorta. The superior mesenteric artery and vein were occluded. Isolated terminal ileum segment was irrigated with Ringer's solution at 4℃ and preserved in the same solution at 0-4℃ for 60 min. Then, the tube was removed and reperfusion was established. In growing pig models, a terminal ileum segment, 50 cm in length, was isolated and its mesenteric artery was irrigated via a needle with lactated Ringer's solution at 4℃. The method and period of cold preservation and reperfusion were described above. Ten white outbred pigs were randomly divided into control group and experimental group. L-arginine (150 mg/kg) was continuously infused for 15 min before reperfusion and for 30 min after reperfusion in the experimental group. One, 24, 48, and 72 h after reperfusion, peripheral vein blood was respectively collected for NO and NOS determination. At the same time point, intestinal mucosae were also obtained for NOS and Na+-K+-ATPase activity measurement. RESULTS: In adult rat models, 16 of 20 rats sustained the procedure, three died of hemorrhage shock and one of deep anesthesia. In growing pig models, the viability of small bowel graft remained for 72 h after cold IR in eight of 10 pigs. In experimental group, serum NO level at 1 and 24 h after reperfusion increased significantly when compared with control group at the same time point (152.2±61.4μmol/L /s60.8±31.6μmol/L, t=2.802, P=0.02<0.05; 82.2±24.0μmol/L vs 54.0±24.3μmol/L, t=2.490, P=0.04<0.05). Serum NO level increased significantly at 1 h post-reperfusion when compared with the same group before cold IR, 24 and 48 h post-reperfusion (152.2±61.4μmol/L vs 75.6±16.2μmol/L,t=2.820, P=0.02<0.05,82.2±24.0μmol/L,t=2.760, P= 0.03<0.05, 74.2±21.9μmol/L, t=2.822, P= 0.02<0.05). Serum NOS activity at each time point had no significant difference between two groups. In experimental group, intestinal mucosal NOS activity at 1 h post-reperfusion reduced significantly when compared with pre-cold IR (0.79±0.04 U/mg vs 0.46±0.12 U/mg, t = 3.460, P= 0.009<0.01). Mucosal NOS activity at 24, 48, and 72 h post-reperfusion also reduced significantly when compared with pre-cold IR (0.79±0.04 U/mg vs 0.57±0.14 U/mg, t= 2.380, P=0.04 <0.05, 0.61±0.11 U/mg, t= 2.309, P = 0.04<0.05, 0.63±0.12U/mg, t = 2.307, P= 0.04<0.05). In control group, mucosal NOS activity at 1 and 24 h post-reperfusion was significantly lower than that in pre-cold IR (0.72±0.12 U/mg vs 0.60±0.07 U/mg, t= 2.320, P= 0.04<0.05, 0.58±0.18 U/mg, t=2.310, P= 0.04<0.05). When compared to the normal value, Na+-K+-ATPase activity increased significantly at 48 and 72 h post-reperfusion in experimental group (2.48±0.59μmol/mg vs 3.89±1.43μmol/mg, t=3.202, P= 0.04<0.05, 3.96±0.86μmol/mg, t=3.401, P= 0.009 <0.01) and control group (2.48±0.59μmol/mg vs 3.58±0.76 μmol/mg, t=2.489, P= 0.04<0.05, 3.67±0.81μmol/mg, t= 2.542, P= 0.03<0.05). CONCLUSION: This novel technique for intestinal autotransplantation provides a potentially consistent and practical model for experimental studies of graft cold preservation. L-arginine supplementation during cold IR may act as a useful adjunct to preserve the grafted intestine.

Highlights of the major progress in single-atom catalysis in 2015 and 2016

The idea that single metal atoms dispersed on a solid support can act as an efficient heterogeneous catalyst was raised in2011when single Pt atoms on an FeOx surface were reported to be active for CO oxidation and preferential oxidation of CO in H2.The last six years have witnessed tremendous progress in the field of single‐atom catalysis.Here we introduce the major achievements on this topic in2015and2016.Some particular aspects of single‐atom catalysis are discussed in depth,including new approaches in single‐atom catalyst(SAC)synthesis,stable gold SACs for various reactions,the high selectivity of Pt and Pd SACs in hydrogenation,and the superior performance of non‐noble metal SACs in electrochemistry.These accomplishments will encourage more efforts by researchers to achieve the controllable fabrication of SACs and explore their potential applications.

Preparation of gold clusters on metal oxides by deposition-precipitation with microwave drying and their catalytic performance for CO and sulfide oxidation

Gold clusters and small nanoparticles supported on metal oxides could be prepared by deposition‐precipitation followed by microwave irradiation as a drying method and then calcination.The drying method influenced the size of the Au particles.Au(III)was partly reduced during conventional oven drying,resulting in Au aggregates.In contrast,Au(III)was preserved during microwave drying owing to rapid and uniform heating,and the Au diameter was minimized to1.4nm on Al2O3.This method can be applied to several metal oxide supports having different microwave absorption efficiencies,such as MnO2,Al2O3,and TiO2.These catalysts exhibited higher catalytic activities for CO oxidation at low temperature and for selective aerobic oxidation of sulfide than those prepared by conventional methods.

A unified model in the pulsed laser ablation process

In this unified model,we introduce the electron-phonon coupling time(tie) and laser pulse width(tp).For long pulses,it can substitute for the traditional thermal conduction model;while for ultrashort pulses,it can substitute for the standard two-temperature model.As an example of the gold target,we get the dependence of the electron and ion temperature evolvement on the time and position by solving the thermal conduction equation using the finite-difference time-domain(FDTD) method.It is in good agreement with experimental data.We obtain the critical temperature of the onset of ablation using the Saha equation and then obtain the theoretical value of the laser ablation threshold when the laser pulse width ranges from nano-second to femtosecond timescale,which consists well with the experimental data.

One-pot conversion of cyclohexanol to ε-caprolactam using a multifunctional Na_2WO_4-acidic ionic liquid catalytic system

Na2WO4‐acidic ionic liquid was used as a simple, ecofriendly, recyclable and efficient catalytic system for the one‐pot conversion of cyclohexanol to ε‐caprolactam. The effect of the structure of the ionic liquid on the catalytic activity of this system was investigated, and the results revealed that sulfonic acid‐functionalized ionic liquids with HSO4? as an anion gave the best results. The highly efficient performance of this catalyst system was attributed to the phase‐transfer behavior of the cation of the ionic liquid, the improved coordination of the substrate to bisperoxotungstate duringthe oxidation reaction, and the stabilization of the intermediate formed during the Beckmann rearrangement.