Studying the counting rate capability of a glass multigap resistive plate chamber at an increased operating temperature

It is shown that a multigap resistive plate chamber made of commercial float glass is capable of sustaining high counting rates at an increased operating temperature. Two glass chambers were investigated on the test beamline of the U-70 accelerator at the Institute for High Energy Physics. The required radiation flux density at the detector was produced by means of radioactive sources. The time resolution of 80 ps or better was attained at a rate of ～20 kHz/cm² and an operating temperature of 45°C.     

Stream surface strip element method for simulation of the three-dimensional deformations of plate and strip rolling

A new method—the stream surface strip element method (SSSEM)—for simulating the three-dimensional deformations of plate and strip rolling process is proposed. The rolling deformation zone is divided into a number of stream surface (curved surface) strip elements along metal flow traces, and the stream surface strip elements are mapped into the corresponding plane strip elements for analysis and computation. The longitudinal distributions of the lateral displacement and the altitudinal displacement of metal are constructed respectively to be a quartic curve and a quadratic curve, the transverse distributions of them are expressed as the third-power spline function, and the altitudinal distributions of them are fitted to be a quadratic curve. Based on the flow theory of plastic mechanics, the three-dimensional deformations and stresses of the deformation zone are analyzed and formulated. Compared with the streamline strip element method, the SSSEM considers the uneven distributions of stresses and deformations along altitudinal direction, and realizes an accurate three-dimensional analysis and computation. The simulation examples indicate that the method and the model of this paper are in accord with facts, and provide a new reliable engineering-computation method for the three-dimensional mechanics simulation of plate and strip rolling process.     

A finite strip method for the post-locally-buckled analysis of plate structures

A finite strip method is presented for the post-locally-buckled analysis of prismatic thin walled structures under end compression. Sample problems are analysed and the economy of the method compared with the finite element method is demonstrated.     

Detector with a profile-based cathode and the two-coordinate pad-strip readout system

A detector with a profile-based cathode and a two-coordinate cathode readout system has been experimentally investigated. Cathode pads located in each profile along the anode wire are diagonally interconnected, thus forming strips that cross the detector at some angle with respect to the anode wire. Owing to the availability of the two cathode coordinates and the coordinate associated with the anode wire, it is possible to solve the problem of identifying high-multiplicity events in a single detector.     

A finite strip method for the buckling of plate structures under arbitrary loading

A finite strip method is presented for the stability analysis of prismatic thin walled structures under arbitrary loading. Sample problems are analysed and the economy of the method compared with the finite element method is demonstrated.     

Spline finite strip analysis of the buckling and vibration of composite prismatic plate structures

A spline finite strip capability is described for predicting the buckling stresses and natural frequencies of vibration of prismatic plate structures which may be of composite laminated construction with arbitrary lay-ups. The plate structures may have general boundary conditions. The capability embraces analyses based on the use of first-order shear deformation plate theory and of classical plate theory, and utilizes substructuring procedures which include the use of superstrips. The theoretical development is not detailed since the present paper reports a very direct extension of a theoretical study developed for the analysis of single plates in an earlier paper in this Journal. A considerable range of buckling and vibration applications is documented and comparison of spline finite strip numerical values of buckling stresses and frequencies is made with results generated using the semi-analytical finite strip method and, in some cases, the finite element method. Buckled and vibrational mode shapes are presented for some applications.     

A humidity generator with a test chamber system

For the calibration of relative humidity hygrometers and dew-point hygrometers with an open sensor, a test chamber system was constructed and connected to a dew-point generator. The system includes several small chambers connected in series. By reversing the flow direction, humidity and temperature gradients in the test chamber system are monitored during calibration measurements. This paper reports the construction of the test chamber system and the improvements in the construction and the analysis of the dew-point generator. A full uncertainty analysis is presented. The expanded uncertainty of the dew-point temperature and the relative humidity with the coverage factor k=2 are from ±0.05°C to ±0.08°C and from ±0.1%rh to ±1.0%rh, respectively. Although the dew-point temperature range is from −40°C to +77°C, the limits for the temperature range of the test chamber system are −20°C and +60°C. The system was not tested with relative humidity values lower than 10% or higher than 95%.     

Upgrading a microscope with a spiral phase plate

We present the implementation of a spiral phase plate in a standard bright-field microscope to enhance the contrast of phase and amplitude samples. The method can be employed in all types of microscopy where standard phase contrast methods are applicable, for example, in bright-field transmission or reflection microscopy using an illumination source with partial spatial coherence. The spiral phase filter is placed into an accessible Fourier plane of the imaging path of the microscope. It is shown that this produces not only a strong contrast enhancement but in theory also improves the spatial resolution of the microscope for white light. A series of different set-ups for transmissive or reflective samples, including epi-illumination, are presented to demonstrate the practical range of applications of this contrasting method. A minute shift of the spiral phase plate out of the centre results in relief-like images that are similar to those obtained by differential interference contrast microscopy. A series of such relief-like images can be numerically processed to obtain quantitative phase and amplitude information of the sample.     

Shear force microscopy with a nanoscale resolution

This paper presents a shear force microscope having a nanometric resolution at high scan rates. Current techniques were reviewed and tested, and a design based on the use of a tuning fork is described. The use of a low quality factor enabled us to decrease the response time and increase the stability of the tracking. The microscope was coupled with a tunneling current detection, in order to study the interactions between the sample and the probe during scanning. As an example, a sharp nickel nanotip was used to image a gold surface, showing details down to a few nanometers, even at scanning rates of 4Hz.     

热轧带钢摆动台升降液压系统的改进

针对原液压系统设计及使用中存在的缺点,分析了故障原因,提出了改进方案,使之更符合生产现场及工艺要求,从而有效地提高系统的可靠性及稳定性,缩短设备故障时间。     

Interaction of a vortex ring with a cutting thin plate

An experimental study was made on symmetrically cut of a vortex ring by a finite length thin plate. The interaction was studied to evaluate flow features using volumetric three component flow velocimetry (V3V) system. Vortex rings were generated using a piston-cylinder mechanism at jet Reynolds numbers of 1500 and 2000 with piston stroke length-to-diameter ratios of 2 and 3. Experiments were made for the plate thickness of 0.86 mm, plate length to diameter ratio of 0.13 and 0.536, and with a cut of vortex ring on the centerline and below the centerline. The interaction of vortex ring with plate showed strong dependence on cutting depth. For the case of cutting below the centerline of the vortex ring showed formation of the three vortex rings. One moved in the same line as the primary vortex ring and other two moved perpendicular to the plate (one in each side with respect to the centerline of the primary vortex ring). On the other hand, for the case of the vortex ring cut up to the centerline axis showed generation of a centerline vortex ring with a vortical structure circulating around the vortex ring loop.     

A multibeam radio-frequency ion source with a discharge chamber inside a resonator

The design of a multibeam ion source with a discharge chamber inside a half-wavelength radio-frequency (RF) resonator with a spiral load is described. The resonator is excited by a loop insulated from the body of the resonator. The RF oscillator operating at a frequency of 38 MHz is grounded. The use of the resonator facilitates the initiation of a discharge at a low power level. The amplitude-frequency characteristics of the resonator at the operating frequencies of the ion source are presented. The effect of the RF power and the extracting voltage on the ion-beam current has been studied. The experimental results on the ion-beam extraction at a low RF power (<100 W) are presented.     

The numerical simulation of a rectifying device with a perforated plate

The aim of this research is to verify a perforated plate design technique for generating a certain velocity and turbulence distribution by introducing the connection condition that demonstrates the disturbance attenuation characteristics of the plate. The application range on the downstream side of the perforated plate is studied based on a numerical simulation of the resistance characteristics of perforated plates. The optimum numerical simulations of turbulent flows through perforated plates are then clarified. The numerical simulation results and the experimental data for the disturbance attenuation are highly consistent with the numerical simulation and experimental data for the perforated plates with fixed opening ratios and pore diameters. In addition, the calculation results for the downstream disturbance distribution almost correspond with the experimental results when the opening ratio of the perforated plate is fixed but the pore diameter is variable. Consequently, the disturbance numerical simulation technique developed in this research by utilising the connection conditions for perforated plates clarifies the reliability of the rectifying device design method used to generate the velocity and turbulence distribution of perforated plates.     

An integrated environmental perfusion chamber and heating system for long-term, high resolution imaging of living cells

This communication presents the design and application of an integrated environmental perfusion chamber and stage heating blanket suitable for time-lapse video microscopy of living cells. The system consists of two independently regulated components: a perfusion chamber suitable for the maintenance of cell viability and the variable delivery of environmental factors, and a separate heating blanket to control the temperature of the microscope stage and limit thermal conduction from the perfusion chamber. Two contrasting experiments are presented to demonstrate the versatility of the system. One long-term sequence illustrates the behaviour of cells exposed to ceramic fibres. The other shows the shrinking response of cultured articular cartilage chondrons under dynamic hyper-osmotic conditions designed to simulate joint loading. The chamber is simple in design, economical to produce and permits long-term examination of dynamic cellular behaviour while satisfying the fundamental requirements for the maintenance of environmental factors that influence cell viability.     

Operation of a centrifugal pump and a liquid ejector with an isobaric mixing chamber

The influence of simultaneous operation of a centrifugal pump and an isobaric ejector on the pump??s cavitational stability is investigated.     

Increasing the frontal thrust of a pulsating thermojet with a constant-volume multicavity combustion chamber

The operation of a pulsating thermojet with a constant-volume multicavity combustion chamber is studied by means of a mathematical model. The engine??s thrust ensures supersonic flight.     

波导光存储信息读出方法实验研究

波导多层光存储器件是由多层平面光波导结构叠加而成,一层光波导结构记录一层信息.基于波导原理,信息逐层读出时可以有效地防止层间串扰从而实现多层信息连续读出,因而单层信息的读出是波导多层光存储的关键技术之一.本文对波导单层信息读出方法进行实验研究,实现了单层信息的静态读出,对该技术的进一步研究及实用化有重要的参考价值.