古诗四条轴的出版

古诗四条轴的出版沈伯文四条轴在年画家族中，历来能与中堂媲美，因为消费者在购买中堂时，总忘不了相伴相随的条轴。这一传统的购买习俗一直被顾客尤其是广大农材消费者所沿袭，故而务轴的销量经久不衰。为繁荣年画市场，各美术出版社相继出版了不少古诗金轴（屏），颇得...

大型抽水蓄能机组轴系的动特性研究

以广州蓄能水电厂１ 号机组的实际结构为例，首先应用Ｒｉｃｃａｔｉ传递矩阵法建立了计算机组自振特性的动力学模型，并分析了机组的自振特性及油膜轴承刚度对它的影响。然后结合Ｒｉｃｃａｔｉ传递矩阵法与Ｗｉｌｓｏｎ－θ法［５］编制了轴系的瞬态响应计算程序，给出了机组在几种典型外载荷作用下的瞬态响应。该模型的建立将加深对水轮机组动特性的认识。

S型发条力矩的理论分析与计算

应用塑性力学理论,分析S型发条无应力状态与冷卷成型状态的曲率,导出计算发条截面弯矩的计算式,为计算S型发条的形态与力矩提供了理论依据。

天台山国清寺建筑概说

国清寺坐落在天台山南麓,北离天台县城3.5公里,是佛教天台宗的根本道场,始建于隋开皇十八年(598),现存建筑基本上为清雍正十一年(1733)重建时的规模.从建筑学角度看,国清寺无疑有它的独特之处.本文试就国清寺建筑的选址和总体的构思、功能要求、建筑布局、空间构图、艺术特色等几个方面进行一些探讨.(见图)

梅兰芳与二十世纪

每一个人都会有自己的坐标图,其一条轴是自身随生命而伸延的年岁,另一条轴是自身对于这个社会所存在的价值。每个人的一生都会分出若干阶段,那即是由“年岁轴”及“价值轴”上各自选出若干个点进行相交,并由这许多的相交点连接为一条由若干短直线所构成的波折曲线。这若干短直线,即是该人一生的若干阶段;

在数学教学中培养学生的创新能力

创新是一个民族不断进步的灵魂。作为以培养学生精确的运算能力、丰富的空间想象能力、严密的逻辑推理能力和应用知识解决实际问题能力为主要任务的数学教学,应该把提高学生的创新能力作为课堂教学过程中的重要任务。本文结合自身教学实践,对在数学教学中如何培养学生的创新能力作了一些探讨。

一本十分珍贵的戏曲图相册

在华东师大图书馆书库的尘封角落里,我忽然发现一本相册,名曰《戏剧服装、脸谱、乐器照相册》,无制作者、原藏者名字,原是解放初由上海旧书店购进,共44页,照片44幅,尺寸约28mm×20mm,有的较小些。经仔细阅读,查找有关文献,方知此乃齐如山1930年主持编制为梅兰芳赴美演出之宣传图轴全部照片,共15类217条轴,每类前有齐氏手书《说明》及英译文,图题、名词皆有英文译名,于1929年1月至1930年7月间制成。 齐如山(1875—1962年)毕生研究戏曲,写有专著40种,编剧32种,杂著23种。

金地海景花园——创造居住新概念

由深圳市金地(集团)股份有限公司开发的金地海景花园一经推出,就以其含金量极高的地理位置,完善的配套设施,卓尔不群的物业管理,成为成功人士向往的高尚住宅区,目前A区已售罄,即将入伙的B区、C区也销售殆尽。 不可再生的黄金地段 选择住宅其实就是选地。

A Novel Roll Compensation Method for Two-Axis Transportable Satellite Antennas

Two-axis transportable satellite antennas(TATSAs) have been widely adopted owing to its simple structure and low cost. However, by searching in a wide range, it will take a very long searching time. Under extreme conditions, it will even fail to work. In this paper, we propose a novel roll compensation(RC) method for the low-cost TATSAs to achieve faster tracking even if when the antenna has no azimuth sensor. By analyzing the influence of roll axis on the system performance, details of the compensation method are derived. Simulation and measurement results indicate that the proposed RC method can effectively reduce the initial searching time for satellite communication. In addition, tracking along with the ellipse path with the RC method provides the highest tracking efficiency.

Cracking process of rock mass models under uniaxial compression

Anisotropic strength and deformability of the rock mass with non-persistent joints are governed by cracking process of the rock bridges. The dependence of cracking process of jointed rock masses on the two important geometrical parameters, joint orientation and joint persistence, was studied systematically by carrying out a series of uniaxial compression tests on gypsum specimens with regularly arranged multiple parallel pre-existing joints. According to crack position, mechanism and temporal sequence, seven types of crack initiations and sixteen types of crack coalescences, were identified. It was observed that both tensile cracks and shear cracks can emanate from the pre-existing joints as well as the matrix. Vertical joints were included and coplanar tensile cracks initiation and coalescence were observed accordingly. For specimen with joint inclination angle ,8=75~, it was found that collinear joints can be linked not only by coplanar shear cracks but also by mixed tensile-shear cracks, and that a pair of them can form a small rotation block. Seven failure modes, including axial cleavage, crushing, crushing and rotation of new blocks, stepped failure, stepped failure and rotation of new blocks, shear failure along a single plane and shear failure along multiple planes, were observed. These modes shift gradually in accordance with the combined variation of joint orientation and joint persistence. It is concluded that cracking process and failure modes are more strongly affected by joint orientation than by joint persistence, especially when joint inclination angle is larger than 45~. Finally, variations of macroscopic mechanical behaviors with the two geometrical parameters, such as patterns of the complete axial stress-axial strain curves, peak strength and elastic modulus, are summarized and their mechanisms are successfully explained according to their different cracking process.

Landslides & Debris Flows Formation from Gravelly Soil Surface Erosion and Particle Losses in Jiangjia Ravine

Gravelly soils are made up of gravel, sand, silt and clay. They are widely used in engineering applications such as rock-fill dams with clay cores, which are the main researches at present. The strength and mechanical properties of the gravelly soils are affected by the content of coarse grain, fine particles, and their adhesive states. These Properties can be verified by laboratory unconsolidated undrained triaxial tests with grain size less than 5 mm and by large scale direct-shear tests with original grain content. Fine particles of the loose gravelly slopes are released under rainfalls, alternated the structures and mechanical properties, even affected the slope stability. There are a series of large scale direct-shear tests with different coarse grain contents to study the influence of fine particles releasing and migration, results showed the strength behavior of the gravelly soils were affected by the coarse grain content （5） and the inflection coarse grain contents. In order to study the erosion features of the gravelly soil slopes on rainfall conditions and the slopes stability alteration, we had carried out one sort of artificial rainfall local and model experiments, the runoff sediment contents were monitored during the experiments. Result showed that the shapes of the slopes surface transformed periodically, runoff sediment contents were divided into five phases according to the experiment phenomena, runoff sediment contents maintained downtrend during the rain time and the downtrend was obviouslyinterpreted by one descend belt no matter the rainfall intensity and the slope angels. Particle size analysis released the deposit on the slope surface lost almost all of the clay, most of the silt and sand after the experiments, this meant the fine particles releasing, migration and accumulation process on condition of rainfall resulted in the instability factor of the slopes even induced landslide or debris flow.

Undrained response of reconstituted clay to cyclic pure principal stress rotation

A series of monotonic and rotational shearing tests are carried out on reconstituted clay using a hollow cylinder apparatus under undrained condition. In the rotational shearing tests, the principal stress axes rotate cyclically with the magnitudes of the principal stresses keeping constant. The anisotropy of the reconstituted clay is analyzed from the monotonic shearing tests. Obvious pore pressure is induced by the principal stress rotation alone even with shear stress q0=5 k Pa. Strain components also accumulate with increasing the number of cycles and increases suddenly at the onset of failure. The deviatoric shear strain of 7.5% can be taken as the failure criterion for clay subjected to the pure cyclic principal stress rotation. The intermediate principal stress parameter b plays a significant role in the development of pore pressure and strain. Specimens are weakened by cyclic rotational shearing as the shear modulus decreases with increasing the number of cycles, and the shear modulus reduces more quickly with larger b. Clear deviation between the directions of the principal plastic strain increment and the principal stress is observed during pure principal stress rotation. Both the coaxial and non-coaxial plastic mechanisms should be taken into consideration to simulate the deformation behavior of clay under pure principal stress rotation. The mechanism of the soil response to the pure principal stress rotation is discussed based on the experimental observations.

Mechanical and damage evolution properties of sandstone under triaxial compression

To study the mechanical and damage evolution properties of sandstone under triaxial compression, we analyzed the stress strain curve characteristics, deformation and strength properties, and failure process and characteristics of sandstone samples under different stress states. The experimental results reveal that peak strength, residual strength, elasticity modulus and deformation modulus increase linearly with confining pressure, and failure models transform from fragile failure under low confining pressure to ductility failure under high confining pressure. Macroscopic failure forms of samples under uniaxial compression were split failure parallel to the axis of samples, while macroscopic failure forms under uniaxial compression were shear failure, the shear failure angle of which decreased linearly with confin- ing pressure. There were significant volume dilatation properties in the loading process of sandstone under different confining pressures, and we analyzed the damage evolution properties of samples based on acoustic emission damage and volumetric dilatation damage, and established damage constitutive model, realizing the real-time Quantitative evaluation of samnles damage state in loading process.

Liquid Axial Mixing in Packed Tower at Elevated Pressure

Liquid phase axial mixing was measured with the tracer technique in a packed column with inner diameter of 0.15m, in which the structured packing, Mellapak 350Y, was installed. Tap water as the liquid phase flowed down through the column and stagnant gas was at elevated pressure ranging from atmospheric to 2.0MPa. The model parameters of Bo and 9 were estimated with the least square method in the time domain. As liquid flow rate was increased, the liquid axial mixing decreased. Under our experimental conditions, the effect of pressure on Bo number on single liquid phase was negligible, and eddy diffusion was believed to be the primary cause of axial mixing in liquid phase.

Micro-and macro-fractures of coarse granite under true-triaxial unloading conditions

We studied the mechanical behavior of rock under different boundary conditions, based on the fractal characteristics of fractures in terms of microscopic and macroscopic investigations. Three rectangular granite specimens of similar dimensions were tested by a triaxial rock testing machine under uniaxial compression （UC）, confined compression （CC） and true-triaxial unloading conditions （RB） under rock burst boundary conditions. The failure processes of these specimens were investigated via examinations of their fracture behavior on a macro-scale by laser profilometers and on a micro-scale by a scanning electron microscopic （SEM） imaging technique. The SEM images, showing the spailing features of RB frag- ments, are compared with the grain dislocations under UC and CC conditions. Based on a variogram method, two fractal parameters, i.e., fractal dimensions （Dr^d） and the scale dependent fractal parameter Kv, were induced to present the surface roughness of scanning profiles in all directions. The fitted ellipses of Dr^d distribution show that RB surface has the smallest eccentricity, followed by the CC surface, while the UC surface had the largest eccentricity. As a result of this assessment, we conclude that rocks are affected by shear traction in an intermediate stress direction, which will cause fractures generated during rock bursts to twist rather than to tilt as shown in the uniaxial compression and the confined compres- sion tests.

感谢冬天(五章)

雪花一群群洁白的小蝴蝶,飞呀、飞呀,一晃,就飞越了几千年。怎么,每一只小蝴蝶竟如此相同?六个翅膀,三条轴,全身都像长满了圣洁的小绒毛。那是生命的触须么?你飘在江南的枝头上,成了一树树梨花;

赤道仪

相信各位对赤道仪都不陌生。赤道仪其实是天文望远的专用座架和观测天体的好助手,就让我详细地讲解它的构造和功能!

Investigation of the Flow in the Impeller Side Clearances of a Centrifugal Pump with Volute Casing

The paper is concerned with the fluid flow in the impeller side clearances of a centrifugal pump with volute cas-ing.The flow conditions in these small axial gaps are of significant importance for a number of effects such as disk friction,leakage losses or hydraulic axial thrust to name but a few.In the investigated single stage pump,the flow pattern in the volute turns out to be asymmetric even at design flow rate.To gain a detailed insight into the flow structure,numerical simulations of the complete pump including the impeller side clearances are accom-plished.Additionally,the hydraulic head and the radial pressure distributions in the impeller side clearances are measured and compared with the numerical results.Two configurations of the impeller,either with or without balancing holes,are examined.Moreover,three different operating points,i.e.:design point,part load or overload conditions are considered.In addition,analytical calculations are accomplished to determine the pressure distri-butions in the impeller side clearances.If accurate boundary conditions are available,the 1D flow models used in this paper can provide reasonable results for the radial static pressure distribution in the impeller side clearances.Furthermore,a counter rotating wake region develops in the rear impeller side clearances in absence of balancing holes which severely affects the inflow and outflow conditions of the cavity in circumferential direction.

Effects of Suction Side Squealer Tip on the Performance of a Low-Speed Axial Compressor

This paper presents the investigation of the effects of suction side squealer tip on the performance of an axial compressor. The experiment is carded out in a single-stage large-scale low-speed compressor. The investigated tip geometries include fiat tip as the baseline and suction side squealer tip. The tip clearance of the baseline is 0.5% of the blade span. The static pressure rise characteristic curves of both the rotor and the stage are measured. The flow field at the exit of the rotor is measured by a 5-hole probe under design and off-design conditions. The static pressure on the endwall of the rotor passage is also obtained. The results show that the pressure rise characteristic curves obtained by measuring the pressure on the end wall are almost unchanged by using the suction side squealer tip. The measuring results of the 5-hole probe show the static pressure and the total pressure in tip region is slightly greater than that of the flat tip at the design condition at the exit of the rotor. It also leads to greater averaged static pressure rise and total pressure. At the near stall condition, the averaged static pressure and total pressure is lower than the baseline which is related to the redistribution of the blade load caused by the suction side squealer tip.