嵌入法解杂形板

提出一种求解杂形板的嵌入法,对杂形板进行了分析,解决了杂形板作用任意荷载时的弯曲问题。该方法在实际工程中具 有一定的指导意义。

半解析梯形有限条法分析化工设备中的杂形板

推导了新型梯形有限条刚度矩阵的计算格式。成功地应用于求解化工设备中常见的六角形板，以及上下底简支梯形板之弯曲变形，其结果与精确解比较，误差分别为０．０５５及０．０４２，完全符合工程要求。对于杂形板，只要具有一根对称轴，采用本法均能取得较为满意的结果。

嵌入法解杂形板

本文提出了一种求解杂形板的嵌入法,以解决杂形板的弯曲问题。

杂形板变曲问题康托罗维兹解法的改进

本文据加权残值法中的伽辽金方程，应用变分法中的康托罗维兹法分析了杂形板的弯曲问题，由于选取梁函数作为试验函数ψｊ（ｙ），使得求解另一族试函数Ｗｊ（ｘ）的准欧拉方程组，简化为单个常微分方程的求解。

卫恒“古今杂形”对沈曾植书法的影响

从沈曾植遗留下来的书学文献与书法作品来看,卫恒的中原书风以及"古今杂形"观对沈曾植的书法创作与书法思想均产生了重要影响。主要体现在:"古今杂形"是沈曾植"杂体书"观念形成的字学基础;"古今杂形"为沈曾植书法思想中的代表性思想-"南北会通"观提供了历史依据;"古今杂形"对沈曾植书风的多变性,尤其晚年的生拙与不稳的风格追求提供了美学支持。

黄牛源Fh/Fg杂合型片形吸虫的鉴定

为弄清黄牛感染的片形吸虫种类,首先对来自河南济源市一肉牛屠宰场黄牛肝脏上的片形吸虫进行形态学观察,然后基于核糖体ITS1、ITS2区域和线粒体nad1、cox1基因序列进行分子鉴定。ITS1和ITS2序列分析结果显示,济源黄牛源片形吸虫分离株JY003和JY004为Fh/Fg杂合型片形吸虫。基于nad1和cox1基因序列,JY003和JY004与大片形吸虫的相似性高于肝片形吸虫,其中nad1序列与大片形吸虫中国云南、日本和韩国分离株的相似性高达100%。在基于nad1和cox1基因的进化树上,分离株均与大片形吸虫参考株处于同一分支。结果表明,首次从河南黄牛体内鉴定出Fh/Fg杂合型片形吸虫,为动物和人的片形吸虫病防控提供重要的基础数据。

简支平行四边形底扁壳大挠度问题的准确解

本文将 S·Levy 在1949年解矩形板大挠度问题的双三角级数解法推广到平行四边形板和扁壳的情形。

可溶性笼形倍半硅氧烷基共轭聚合物作为一种高效的单壁碳纳米管分散剂

利用一种分子内非均质性的星型结构的笼形倍半硅氧烷-聚噻吩杂化共聚物功能化单壁碳纳米管(SWNTs),并通过多种手段充分表征分散SWNTs的性能。结果表明,这种星型杂化共轭聚合物与其线型类似物相比,具有更高效的稳定SWNTs能力。疏水性的笼形倍半硅氧烷核心和聚噻吩链段锚定在疏水的碳纳米管表面,同时水溶性的柔性链段向溶液中伸展并且共轭链段与碳纳米管表面形成的共轭堆叠效应极大地增加聚合物与碳管之间的黏附力,这些非共价作用力赋予SWNTs分散体空间稳定性。SWNTs在水溶液中溶解性的改善也极大地提升了SWNTs复合材料的可加工性,有利于制备柔性透明电活性的薄膜材料。由此,这种笼形倍半硅氧烷-聚噻吩杂化共聚物在柔性光电设备领域具有极高的应用前景。

The effect of the carbon components on the performance of carbonbased transition metal electrocatalysts for the hydrogen evolution reaction

The hydrogen evolution reaction(HER)is a promising way to produce hydrogen,and the use of non-precious metals with an excellent electrochemical performance is vital for this.Carbon-based transition metal catalysts have high activity and stability,which are important in reducing the cost of hydrogen production and promoting the development of the hydrogen production industry.However,there is a lack of discussion regarding the effect of carbon components on the performance of these electrocatalysts.This review of the literature discusses the choice of the carbon components in these catalysts and their impact on catalytic performance,including electronic structure control by heteroatom doping,morphology adjustment,and the influence of self-supporting materials.It not only analyzes the progress in HER,but also provides guidance for synthesizing high-performance carbon-based transition metal catalysts.

Simulation of Revised Puff Trajectory Model in Regional Atmospheric Environmental Risks

[Objective] The aim was to research application of revised puff trajectory model in atmospheric environmental risks simulation.[Method] In the research,theory of puff trajectory model for pollution diffusion in atmosphere in urban areas was analyzed and CALPUFF,a revised puff trajectory model,was applied in prediction on atmospheric environmental risks in Xining City.[Result] The simple puff trajectory model can not be applied for long-distance transport or in complex terrain and airflow field.In contrast,CALPUFF would be applied in urban areas,and complex terrain or underlying surface.With high resolution ratio,it would depict the beginning condition and detailed distribution of pollutants transport and diffusion.For prediction on atmospheric environmental risks in Xining City,northwest wind dominated in Huangshui Valley;north wind dominated in Beichuan Valley;temperature inversion occurred at high altitude.These had a significant effect on the downwind direction in Xining urban district.The simulation results indicated that puffs usually spread along Huangshui Valley and some non-steady phenomena occurred,such as blocking effect by mountains,deformation of puff by airflow field in ridges and influence of valley wind.[Conclusion] The research is of significance for precise prediction on characters,influence and extent of atmospheric environmental risks in cities.

Morphology, photoluminescence and gas sensing of Ce-doped ZnO microspheres

Ce-doped ZnO microspheres were solvothermally prepared, and their microstructure, morphology, photoluminescence, and gas sensing were investigated by X-ray diffractometer, field emission scanning electron microscopy, transmission electron microscopy, fluorescence spectrometer and gas sensing analysis system. The results showed that the Ce-doped ZnO microspheres were composed of numerous nanorods with a diameter of 70 nm and a wurtzite structure. Ce-doping could cause a morphological transition from loose nanorods assembly to a tightly assembly in the microspheres. Compared with pure ZnO, the photoluminescence of the Ce-doped microspheres showed red-shifted UV emission and an enhanced blue emission. Particularly, the Ce-doped ZnO sensors exhibited much higher sensitivity and selectivity to ethanol than that of pure ZnO sensor at 320 °C. The ZnO microspheres doped with 6% Ce (mole fraction) exhibited the highest sensitivity (about 30) with rapid response (2 s) and recovery time (16 s) to 50×10?6 ethanol gas.

Dynamic caustics experimental study on interaction between propagating crack and deformity inclusions in primary structure

The approach combining the dynamic caustics method with high-speed photography technology is used to study the interaction between propagating cracks and three kinds of deformity inclusions（ cylinder inclusion, quadruple inclusion and triangular inclusion） under lowvelocity impact loading. By recording the caustic spots of crack tips at different moments during the crack propagation, the variation regulations of dynamic stress intensity factors（ DSIF） and crack growth velocity with respect to time are obtained. The experimental results showthat the resistance effects to crack growth are varied with different shapes of inclusions in specimens, and the quadruple inclusion＇s effect is more apparent. The distortion degree of caustic spots is affected by the shapes of inclusions as well, and the situation is more serious for cylinder and quadruple inclusions. The overall values of DSIFs of triangular inclusion specimen are greater than the others, and the crack growth velocities, characteristic sizes and DSIFs showprocesses of fluctuations because of the disturbance of reflection waves in specimens. The results provide an experimental basis for the analysis of strength and impact-resistance ability in structures with deformity inclusions.

Raman Studies on Species in Single and Mixed Solutions of Molybdate and Vanadate

Raman spectroscopy was applied to investigate the speciation in both single and mixed solutions of molybdate and vanadate at pH values from 10.0 to 1.0. Evidence was obtained for the difference of existing forms between these two elements. Vanadium mainly exists as （VO3）n^n- while Mo is MoO4^2- in the pH range of 9.0-7.5. This difference is the theoretical basis for many available separation process. The species in the binary system was identified by comparing the Raman spectra with that in the single systems. Molybvanadates are formed below pH=6.5, which may partly be ascribed to the replacement of V atoms by Mo atoms in some V-O-V groups. Vanadium mainly exists as the decavanadate species in the pH range of 6.0-2.0. The predominant species of Mo are heteropolyanions having structural features of heptamolybdate rather than MosO26^4- and Mo36O112^8- which are the predominant Mo species in single solution at pH=2.0-1.0.

Online composite shape recognition based on relevance feedback

This paper describes a novel method of online composite shape recognition interms of the relevance feedback technology to capture a user's intentions incrementally, and adynamic user modeling method to adapt to various users' styles. First, the relevance feedback isadapted to refine the recognition results and reduce the ambiguity incrementally based on theestablishment of a feature-based vector model of a user's sketches. Secondly, a dynamic usermodeling is introduced to model the user's sketching habits based on recording and analyzinghistorical information incrementally. A model-based matching strategy is also employed in the methodto recognize sketches dynamically. Experiments prove that the proposed method is both effective andefficient.

沈曾植与晚清民初书法思想的嬗变与转型

清末民初时期,书法创作风尚和书学思想都出现了一种内在的嬗变与转型,其中尤以沈曾植的创作及其碑帖题跋中所寓书学观念为表征。沈曾植晚年寓居上海期间,专力于诗文创作与金石鉴藏,除承继清代金石学学术传统外,他还系统鉴藏和重估了诸多刻帖、丛帖的学术史价值。故他所倡导的碑帖互证的思想实绾和了碑学和帖学两种观念传统,代表着古代书学传统的一种逻辑完成。而其古今杂形的书体发展观念,拨正了清代金石学视野中唯北碑隶书为尊的书体认识,又蕴含着现代书学思想的历史起点。这样,从清初尚帖之雅正到清代中晚期尊碑之质朴,再到晚清民初主张碑帖融合之会通审美,清代书法思想在以沈曾植为代表的一代学人身上,完成了一种否定之否定的辩证统一过程。

Stem Morphological Structure of Super Hybrid Rice and Its Relationship with Lodging Resistance

The stem morphology and anatomical structure of rice, as well as their relationship with lodging resistance, were studied with six super hybrid rice varieties as the tested materials. The results showed that the rice varieties with stronger lodging resistance were characterized by shorter basal elongated internodes and thicker stem base. The lodging index of hybrid rice was positively correlated with the lengths of the first, second and third basal elongated internodes （P〈0.01） and was negatively correlated with the thickness of basal stem wall and the number and area of small vascular bundles, the area of large vascular bundles and the total area of vascular bundles of the second basal elongated internode （P〈0.05）. The correlations between lodging index and plant height, maximum culm diameter of stem base and minimum culm diameter of stem base were not significant. It indi- cates that the lodging resistance of super hybrid rice can be improved by shorten- ing the length of basal elongated internodes, thickening the wall of stem base and increasing the number and area of vascular bundles of basal elongated internodes.

Formation mechanism and crystal simulation of Na_2O-doped calcium aluminate compounds

Calcium aluminate clinkers doped with Na2O were synthesized using analytically pure reagents CaCO3, Al2O3, SiO2 and Na2CO3. The effects of Na2O-doping on the formation mechanism of calcium aluminate compounds and the crystal property of 12CaO·7Al2O3 (C12A7) cell were studied. The results show that the minerals containing Na2O mainly include 2Na2O·3CaO·5Al2O3 and Na2O·Al2O3, when the Na2O content in clinkers is less than 4.26% (mass fraction). The rest of Na2O is mainly doped in 12CaO·7Al2O3, which results in the decrease of the crystallinity of 12CaO·7Al2O3. The crystallinity of 2Na2O·3CaO·5Al2O3 is also inversely proportional to the Na2O content in clinkers. The formation processes of 2Na2O·3CaO·5Al2O3 and 12CaO·7Al2O3 can be divided into two ways, which are the direct reactions of raw materials and the transformation of CaO·Al2O3, respectively. The simulation shows that the covalency of O-Na bond in Na2O-doped 12CaO·7Al2O3 cell is weaker than those of O-Ca and O-Al bonds. The free energy of the unit cell increases because of Na2O doping, which results in the improvement of chemical activity of 12CaO·7Al2O3. The leaching efficiency of Al2O3 in clinker is improved from 34.81% to 88.17% when the Na2O content in clinkers increases from 0 to 4.26%.

Modeling and Testing of Hydrodynamic Damping Model for a Complex-shaped Remotely-operated Vehicle for Control

In this paper,numerical modeling and model testing of a complex-shaped remotely-operated vehicle（ROV） were shown.The paper emphasized the systematic modeling of hydrodynamic damping using the computational fluid dynamic software ANSYS-CFXTM on the complex-shaped ROV,a practice that is not commonly applied.For initial design and prototype testing during the developmental stage,small-scale testing using a free-decaying experiment was used to verify the theoretical models obtained from ANSYS-CFXTM.Simulation results are shown to coincide with the experimental tests.The proposed method could determine the hydrodynamic damping coefficients of the ROV.

Accuracy assessment of ICESat-2 ATL 08 terrain estimates:A case study in Spain

The Ice,Cloud and Land Elevation Satellite-2(ICESat-2),a new spaceborne light detection and ranging(LiDAR)system,was successfully launched on September 15,2018.The ICESat-2 data increase the types of spaceborne LiDAR data archive and provide new control point data for large-scale topographic mapping and geodetic surveying.However,the accuracy of the ATL 08 terrain estimates has not been fully evaluated on a large scale and in complex terrain conditions.This article aims to quantitatively assess the accuracy of ICESat-2 ATL 08 terrain estimates.Firstly,the ICESat-2 ATL 08 terrain estimates were compared with the high-precision airborne LiDAR digital terrain model(DTM),and impacts of acquisition time,vegetation cover type,terrain slope,and season change on the terrain estimation accuracy were analyzed.We get the following conclusions from the analysis:1)the mean and RMSE of the terrain estimates of day acquisitions are 0.22 m and 0.59 m higher than that of night acquisitions;2)the accuracy of the ATL 08 terrain estimates acquired in vegetated areas is lower than those in non-vegetated areas;3)the accuracy of the ATL 08 terrain estimates is inversely proportional to the slope,and the elevation error increases significantly when the terrain slope is larger than 30°;4)in the non-vegetation covered area,the accuracy of the ATL 08 terrain estimates of summer and winter acquisitions has no obvious discrepancy,but in vegetated area,the accuracy of winter acquisitions is significantly better than that of summer acquisitions.This research provides references for the selection and application of ICESat-2 data.

Prediction of tri-modal microstructure under complex thermomechanical processing history in isothermal local loading forming of titanium alloy

To control the tri-modal microstructure and performance,a prediction model of tri-modal microstructure in the isothermal local loading forming of titanium alloy was developed.The staged isothermal local loading experiment on TA15alloy indicates that there exist four important microstructure evolution phenomena in the development of tri-modal microstructure,i.e.,the generation of lamellarα,content variation of equiaxedα,spatial orientation change of lamellarαand globularization of lamellarα.Considering the laws of these microstructure phenomena,the microstructure model was established to correlate the parameters of tri-modal microstructure and processing conditions.Then,the developed microstructure model was integrated with finite element(FE)model to predict the tri-modal microstructure in the isothermal local loading forming.Its reliability and accuracy were verified by the microstructure observation at different locations of sample.Good agreements between the predicted and experimental results suggest that the developed microstructure model and its combination with FE model are effective in the prediction of tri-modal microstructure in the isothermal local loading forming of TA15alloy.