汉代男子的“状貌”书写与官吏仕进

“状貌”指某人的面容面貌及身体外形特征,它是汉代传世和出土文献关于男性描述的常见信息,也是政府档案记载官吏身份的基本信息。汉代某些特殊职官对状貌有一定要求,绝大多数情况下状貌并非官吏选任、迁转的影响因素,更非决定因素。但在非常态下,状貌可以左右个别官吏的仕进。强调功劳的仕进制度、谏议制度、重德轻貌的儒家思想等是汉代防范状貌因素干扰、破坏官吏仕进的重要保障。

Discovery of a geomorphological analog to Martian araneiforms in the Qaidam Basin, Tibetan Plateau

Araneiforms are spider-like ground patterns that are widespread in the southern polar regions of Mars.A gas erosion process driven by the seasonal sublimation of CO_(2) ice was proposed as an explanation for their formation,which cannot occur on Earth due to the high climatic temperature.In this study,we propose an alternative mechanism that attrib-utes the araneiform formation to the erosion of upwelling salt water from the subsurface,relying on the identification of the first terrestrial analog found in a playa of the Qaidam Basin on the northern Tibetan Plateau.Morphological analysis indicates that the structures in the Qaidam Basin have fractal features comparable to araneiforms on Mars.A numerical model is developed to investigate the araneiform formation driven by the water-diffusion mechanism.The simulation res-ults indicate that the water-diffusion process,under varying ground conditions,may be responsible for the diverse aranei-form morphologies observed on both Earth and Mars.Our numerical simulations also demonstrate that the orientations of the saltwater diffusion networks are controlled by pre-existing polygonal cracks,which is consistent with observations of araneiforms on Mars and Earth.Our study thus suggests that a saltwater-related origin of the araneiform is possible and has significant implications for water searches on Mars.

Thermodynamic analysis on synthesis of fibrous Ni-Co alloys precursor and Ni/Co ratio control

According to the principles of simultaneous equilibrium and mass equilibrium, a series of thermodynamic equilibrium equations in Ni（II）-Co（II）-C2O4^2--NH3-NH4^＋-H2O system at ambient temperature were deduced. The diagrams of logarithm ion concentrations versus pH values at different solution compositions were drawn. The results show that Ni^2＋ and Co^2＋ can completely precipitate at pH less than 5.0 and the predefined Ni/Co ratios can be well kept in the precursor. The precursor morphology is granular aggregation. However, rod aggregation precursor is obtained in the pH range of 5.0-8.0, and fibre-shape precursor is got at pH value higher than 8.0. The Ni/Co ratios in the above two precursors are not reproduced as that in the feed due to the formhtion of multi-coordinated Ni（NH3）n^2＋ and Co（NH3）n^2＋ （n=1-6）. Modification of precipitation medium is favorable for the precursors to keep the predefined Ni/Co ratios of the feed in the pH range of 2.0-8.6. Meanwhile, the precursors with fibrous morphology can be obtained.

Shape-controlled synthesis of novel precursor for fibrous Ni-Co alloy powders

A novel precursor of nickel-cobalt alloy powders with an appropriate Ni to Co molar ratio was prepared under selectively synthetic conditions. The composition and morphology of the precursor were characterized by X-ray diffractometry （XRD）, scanning electron microscopy （SEM）, Fourier transform infrared spectrometry （FT-IR） and energy dispersive spectrometry （EDS）. The effects of pH value, reaction temperature, metal ion concentrations and surfactant on the morphology and the dispersion of precursor were investigated. The results show that the morphology of precursor depends on ammonia content in the precursor. A fibriform precursor is a complicated ammonia-containing nickel-cobalt oxalate. The uniform shape-controlled fibrous precursor is obtained under the following optimum conditions： ammonia as complex agent as well as pH adjustor, oxalate as coprecipitator, 50-65 °C of reaction temperature, 0.5-0.8 mol/L of total concentration of Ni2＋ and Co2＋, PVP as dispersant, and pH 8.0-8.4.

《春秋左传正义》中的训诂术语“貌”与“状”

“貌”与“状”是两个不同的术语，二者在训释对象、运用形式和使用功能上都有区别。“貌”的训释对象主要是单音节或双音节词，“状”的训释对象可以是词，但主要是语句或语段；“貌”的训释语句比较简洁，附加成分少，“状”的训释语句比较复杂，通常都会构成完整的主谓结构的句子；“貌”的主要使用功能是“揭示状态词的本质”，其中主要是“揭示状态形容词的本质”，“状”的主要使用功能是“揭示描写句的实质”和“揭示行为句的内在原因”。

A highly efficient flower-like cobalt catalyst for electroreduction of carbon dioxide

Electrochemical conversion of CO2 into fuel has been regarded as a promising approach to achieve the global carbon cycle.Herein,we report an efficient cobalt catalyst with a unique flower-like morphology synthesized by a green and facile hydrothermal method,in which n-butylamine is used as the capping agent.The resultant catalyst shows superior electrocatalytic activity toward CO2 electroreduction,which is highly selective for generating formate with a Faraday efficiency of 63.4%.Electrochemical analysis reveals that the oxide on the surface is essential for the electrocatalysis of the CO2 reduction reaction.Cyclic voltammograms further suggest that this catalyst is highly active for the oxidation of reduced product,and can thus be seen as a bifunctional catalyst.

Red-blood-cell-like nitrogen-doped porous carbon as an efficient metal-free catalyst for oxygen reduction reaction

A red-blood-cell-like nitrogen-doped porous carbon catalyst with a high nitrogen content(9.81%)and specific surface area(631.46 m^2/g)was prepared by using melamine cyanuric acid and glucose as sacrificial template and carbon source,respectively.This catalyst has a comparable onset potential and a higher diffusion-limiting current density than the commercial 20 wt%Pt/C catalyst in alkaline electrolyte.The oxygen reduction reaction mechanism catalyzed by this catalyst is mainly through a 4e pathway process.The excellent catalytic activity could origin from the synergistic effect of the in-situ doped nitrogen(up to 9.81%)and three-dimensional(3D)porous network structure with high specific surface area,which is conducive to the exposure of more active sites.It is interesting to note that the catalytic activity of oxygen reduction strongly depends on the proportion of graphic N rather than the total N content.

Shape characterization of sand particles based on digital image processing technology

To characterize the shape of sand particles for concrete,a new method is proposed based on digital image processing(known as the DIP method).By analyzing sand particles projection,the length,width and thickness of sand were measured to characterize particle form.The area and perimeter were measured to characterize particle angularity.The results of the DIP method and Vernier caliper were compared to examine the accuracy of the DIP method.The sample size test was conducted to show the statistical significance of shape results measured by the DIP method.The practicality of the DIP method was verified by instance analysis.The results show that aspect ratios and roundness measured by the DIP method are equal to ones by the Vernier caliper.Results by DIP are dependent on the sand particle number,and at least 350 particles should be measured to represent the overall shape property of sand.The results show that the DIP method is able to distinguish the differences in the shape of sand particles.It achieves the direct measurement of sand particle thickness,and the characterization results of sand aspect ratios and roundness are accurate,statistically significant and practical.Therefore,the DIP method is suitable for sand particle shape characterization.

3D gel printing of VC reinforced high vanadium high-speed steel

Due to their high hardness and high strength,VC reinforced hard materials such as high vanadium high-speed steel(HVHSS)are not suitable for machining to obtain complex shape with low cost.Therefore,3D gel printing(3DGP)was employed to print HVHSS parts,using highly loaded slurry with 60%solid content as printing slurry.After printing parameters optimization,the printing sample had good surface quality,and obvious printing lines were observed.The extruded filament was in-situ cured,thus enough to maintain the designed shape.Uniform sintering shrinkage with a shrinkage rate of about 15%was obtained in the as-sintered sample with relative density of 99%.The surface roughness decreased from 6.5μm to 3.8μm.Fine carbides(<1μm)and dense microstructure were achieved.Besides,the as-sintered sample had comprehensive performance of HRC60 in hardness,3000 MPa in bend strength,and 20−26 J in impact energy.This study proposed one promising method to directly manufacture complex-shaped hard materials without subsequent machining.

Self-assembly of Ophiopogonis polysaccharide-iron(Ⅲ) complex in aqueous solution and solid state

Ophiopogonis polysaccharide-iron(Ⅲ)(OPI)was prepared and characterized in the present study.The optimum condition for preparing OPI was as follows:OP and trisodium citrate were mixed at a weight ratio of 4:1 and reacted in a water bath at 70°C for 3 h within the pH range of 8.0–8.5.Aggregation morphology or structure of OPI in aqueous solution and solid state was studied by scanning electron microscopy,transmission electron microscopy and small-angle X-ray diffraction.In aqueous solution,OPI could self-assemble into micron vesicles with flower-shaped morphology.Results of X-ray diffraction showed OPI with layered structure.A core-shell model was proposed for OPI.