Novel mechanism for boring non-cylinder piston pinhole based on giant magnetostrictive materials

To bear more loads for heavy truck pistons, the shape of heavy truck piston pinhole is often designed as noncylinder form. Current methods cannot meet the needs for precision machining on non-cylinder piston pinhole （NCPPH）. A novel mechanism based on giant magnetostrictive materials （GMM） is presented. New models are established for the servo mechanism, GMM, and magnetizing force of the control solenoid to characterize the relationship between the control current of the solenoid and the displacement of the giant magnetostrictive actuator （GMA）. Experiments show that the novel mechanism can meet the needs to perform fine machining on NCPPH effectively.

Control of Pinhole Defects Formation in Semi-flexible Coaxial Cable by Vertical Tin-Plating Process

Holistic tin-plating on the outer conductor is one of the key processes in the manufacture of semi-flexible coaxial cable, which is widely applied to the third generation (3G) mobile communication system. However, in the traditional horizontal tin-plating process, disadvantages such as the pinhole defects and low productivity effect cannot be avoided. In this paper, a vertical tin-plating process was proposed to reduce the pinhole defects and improve the tincoating quality. Compared with the traditional horizontal tin-plating process, the immersion length was reduced from 300-400 mm to 10-100 mm and the tin-plating time was reduced from 7 s to 3 s in the proposed method. The experimental results indicate that immersion length and time are key parameters for the tin-plating quality. With this new tin-plating process, the experimental results show that the pinhole defects can be eliminated effectively by controlling the immersion depth below 100 mm and tin-plating time at 3 s. The thickness of tin-coating increased from not more than 5 μm to 12.3 μm with the proposed vertical tin-plating process. Meanwhile, the thickness of the intermetallic compounds (IMCs) layer between the tin-coating and copper wires was reduced from 3.26 μm to 0.62 μm if the immersion time decreased from 30 s to 1 s. Besides, a self-developed flux, which possesses a boiling point or decomposed temperature of active components over 300℃, exhibits a better efficiency in reducing the pinhole formation.

Spatial resolution and image processing for pinhole camera-based X-ray fluorescence imaging: a simulation study

Spatial resolution and image-processing methods for full-field X-ray fluorescence(FF-XRF)imaging using X-ray pinhole cameras were studied using Geant4simulations with different geometries and algorithms for image reconstruction.The main objectives were:(1)calculating the quantum efficiency curves of specific cameras,(2)studying the relationships between the spatial resolution and the pinhole diameter,magnification,and camera binning value,and(3)comparing image-processing methods for pinhole camera systems.Several results were obtained using a point and plane source as the X-ray fluorescence emitter and an array of 100×100 silicon pixel detectors as the X-ray camera.The quantum efficiency of a back-illuminated deep depletion(BI-DD)structure was above 30%for the XRF energies in the 0.8–9 keV range,with the maximum of 93.7%at 4 keV.The best spatial resolution of the pinhole camera was 24.7μm and 31.3 lp/mm when measured using the profile function of the point source,with the diameter of 20μm,magnification of 3.16,and camera bin of 1.A blind deconvolution algorithm with Gaussian filtering performed better than the Wiener filter and Richardson iterative methods on FF-XRF images,with the signal-to-noise ratio of 7.81 dB and improved signalto-noise ratio of 7.24 dB at the diameter of 120μm,magnification of 1.0,and camera bin of 1.

Monte-Carlo simulation of pinhole collimator of a small field of view gamma camera for small animal imaging

Needs in scintimammography applications,especially for small animal cardiac imaging,lead to develop a small field of view,high spatial resolution gamma camera with a pinhole collimator.However the ideal pinhole collimator must keep a compromise between spatial resolution and sensitivity.In order to design a pinhole collimator with an optimized sensitivity and spatial resolution,the spatial resolution and the geometric sensitivity response as a function of the source to collimator distance has been obtained by means of Monte-Carlo simulation for a small field of view gamma camera with a pinhole collimator of various-hole diameters.The results show that the camera with pinhole of 1 mm,1.5 mm and 2 mm diameter has respectively spatial resolution of 1.5 mm,2.25 mm and 3 mm and geometric sensitivity of 0.016%,0.022%and 0.036%,while the source to collimator distance is 3 cm.We chose the pinhole collimator with hole diameter size of 1.2 mm for our the gamma camera designed based on the trade-off between sensitivity and resolution.

The pinhole SPECT for animal model of bone metastasis with SPC-A-1BM human pulmonary adenocarcinoma bone metastasis cell line

The study was to investigate the role of pinhole single photon emission computed tomography (SPECT), the human pulmonary adenocarcinoma bone-seeking metastasis cell line SPC-A-1BM was used.These cells form typical osteolytic bone metastases when inoculated into the arterial circulation of NIH-Beige-Nude-XD (BNX) mice via the left ventricle.In order to evaluate the irradiation impact of ^(99m)Tc-MDP versus X-ray on cells growth,we used six groups of SPC-A-1BM cells in our imaging scheme and irradiated by various doses of ^(99m)Tc-MDP (37,74,111, 370,740 MBq) and X-ray(40 kV,2 mA,6 s) respectively.The cell's number of each group was well recorded in different exposure time(4,8,12,24,48,72,96 hours).After that,SPC-A-1BM cells(1×106) were inoculated into the mice via left ventricle.We compared the results obtained with those different doses of ^(99m)Tc-MDP using pinhole SPECT and conventional X-ray skeletal surveys.The data show that the cell-survival number of 111 MBq group has insignificant difference with that of X-ray and the dose is adequate to have an ideal image.Besides,it is important that the chromosome of the cells in the group of 111 MBq showed no irradiation-related damages in our test.These results implied that ^(99m)Tc-MDP pinhole SPECT may provide another way other than conventional X-ray skeletal surveys in detecting bone metastasis of pulmonary adenocarcinoma in BNX mice.

Point spread functions for a small gamma camera with pinhole collimator

A set of point spread functions (PSF) has been obtained by means of Monte-Carlo simulation for asmall gamma camera with a pinhole collimator of various hole diameters. The FOV (field of view) of the camera isexpended from 45 mm to 70 mm in diameter. The position dependence of the variances of PSF is presented, and theacceptance for the 140 kev gamma rays is explored. A phantom of 70 mm in diameter was experimentally imaged inthe camera with effective FOV of only 45 mm in diameter.

Development and application of an online pinhole detector for cold-rolled strips

An online pinhole detector based on the photoelectric inspection of cold-rolled steel strips was introduced. Pinhole detection is important to guarantee the quality of cold-rolled steel strips. The detector here was developed independently by Baosteel,and is designed based on the principle of photoelectric transfer. Typically, an inspection light source is installed above the steel strip to be inspected, and a photoelectric receiver is installed beneath the steel strip. The pinhole detector consists of a super-bright LED light source and a photoelectric receiver, which is composed primarily of photomultipliers. The super-bright LED light source illuminates the strip surface, and the light that permeates from pinholes is detected and amplified by a photoelectric receiver. The photomultiplier transforms the detected light into an electrical signal ,which is later recognized and classified by a signal-processing circuit and collected by a data-acquisition card. The detector can accurately track the strip edge and shield the strip edge from outside light. As a result,this system can detect a pinhole in the strip edge with a small blind zone on the edge. Most importantly, the detector exhibits good inspection accuracy and can accurately detect a pinhole with a diameter of 15 μm.

Microperforate (Pinhole) hymen and infertility;a rare case report

Inroduction Female genital tract anomalies may have a devastating impact on the potential for sexual activity and fertility. Microperforate (pinhole) hymen is one of them. Microperforate hymen can lead to infertility, primary amenorrhea, acute or chronic pelvic pain, abnormal vaginal bleeding, dysuria, pollakiuria or a foul-smelling vaginal discharge. Aim We aim to report a patient who had intercourse problems and infertility complaints later found to have a microper-forate hymen. Discussion Pinhole opening of hymen may permit passage of fluids. Consequently spontaneous pregnancy can occur rarely. A few reports showed pregnancies with intact hymen without penetration of penis. But in general patients have fertility problems. Conclusion The results of the surgery are similar in all techniques and the particular surgical centre will have its own preference of which technique it prefers since after diagnosis definitive treatment is surgical and effective. Failure to manage these patients correctly may have long-term sequelae for their psychological, sexual and reproductive health.

Detailed characterization of polycapillary focusing x-ray lenses by a charge-coupled device detector and a pinhole

A method to measure the detailed performance of polycapillary x-ray optics by a pinhole and charge coupled device(CCD)detector was proposed in this study.The pinhole was located between the x-ray source and the polycapillary x-ray optics to determine the illuminating region of the incident x-ray beam on the input side of the optics.The CCD detector placed downstream of the polycapillary x-ray optics ensured that the incident x-ray beam controlled by the pinhole irradiated a specific region of the input surface of the optics.The intensity of the output beam of the polycapillary x-ray optics was obtained from the far-field image of the output beam of the optics captured by CCD detector.As an application example,the focal spot size,gain in power density,transmission efficiency,and beam divergence of different parts of a polycapillary focusing x-ray lenses(PFXRL)were measured by a pinhole and CCD detector.Three pinholes with diameters of 500,1000,and 2000μm were used to adjust the diameter of the incident x-ray beam illuminating the PFXRL from 500μm to the entire surface of the input side of the PFXRL.The focal spot size of the PFXRL,gain in power density,transmission efficiency,and beam divergence ranged from 27.1μm to 34.6μm,400 to 3460,26.70%to 5.38%,and 16.8 mrad to 84.86 mrad,respectively.

Study of Supper Resolution Processing Methods for Thick Pinhole Image

An image super resolution reconstruction method was used to improve the spatial resolution of the thick pinhole imaging system and to mitigate the limitations of the image spatial resolution of the hardware of the image diagnostic system. The thick pinhole is usually applied into the diagnostics of the high energy neutron radiation image. Due to the impacts among its energy flux, spatial resolution and effective field of view, in dealing with the large area radiation source, the spatial resolution of the thick pinhole neutron image cannot meet the requirements for high precision modeling of the radiation source image. In this paper, the Lucy-Richardson image super resolution reconstruction method was used to simulate the thick pinhole imaging and super resolution image reconstruction. And the spatial resolution of the image could be increased by over three times after the image super resolution reconstruction. Besides, in dealing with the pseudo-noise, plum blossom shape appeared in the image super resolution reconstruction. The analysis of the source of the pseudo-noise was made based on the simulation of the image reconstruction under various conditions according to the characteristics of the thick pinhole image configuration.

Performance Evaluation of the Thick Pinhole Gamma Rays Diagnostic System

The diagnostic methods for the profile of the radiation source were estab-lished at first based on the pinhole imaging principle. In this paper, the relationships among various parameters of the gamma-rays crammer such as the modulation transfer function (MTF), the noise power spectrum (NPS), the signal-noise ratio (SNR) and the detective quantum efficiency (DQE) are developed and studied experimentally on the cobalt radiation source. The image diagnostic system is consisting with rays-fluorescence convertor (YAG crystal), optical imaging system, MCP image intensifier, CCD camera and other devices. The spatial resolution of the modulation transfer function (MTF) at 10% intensity was measured as 1 lp/mm by knife-edge method. The quantum of the measurement system is about 150 under weak radiation condition due to the single particle detection efficiency of the system. The dynamic range was inferred preliminarily as about 437. The required radiation intensity was calculated using the experiment result for the (SNR) = 1, 5, 10, respectively. The theoretical investigation results show that the radiation image with (SNR) = 1 can be only obtained when the pinhole diameter is 0.7 mm, object distance and image distance are both 200 cm, and the radiation intensity is about 1.0 × 1012 Sr-1·cm-2.

Micro-Sized Pinhole Inspection with Segmented Time Reversal and High-Order Modes Cluster Lamb Waves Based on EMATs

Pinhole corrosion is difficult to discover through conventional ultrasonic guided waves inspection,particularly for micro-sized pinholes less than 1 mm in diameter.This study proposes a new micro-sized pinhole inspection method based on segmented time reversal(STR)and high-order modes cluster(HOMC)Lamb waves.First,the principle of defect echo enhancement using STR is introduced.Conventional and STR inspection experiments were conducted on aluminum plates with a thickness of 3 mm and defects with different diameters and depths.The parameters of the segment window are discussed in detail.The results indicate that the proposed method had an amplitude four times larger than of conventional ultrasonic guided waves inspection method for pinhole defect detection and could detect micro-sized pinhole defects as small as 0.5 mm in diameter and 0.5 mm in depth.Moreover,the segment window location and width(5-10 times width of the conventional excitation signal)did not affect the detection sensitivity.The combination of low-power and STR is more conducive to detection in different environments,indicating the robustness of the proposed method.Compared with conventional ultrasonic guided wave inspection methods,the proposed method can detect much smaller defect echoes usually obscured by noise that are difficult to detect with a lower excitation power and thus this study would be a good reference for pinhole defect detection.

An analytical simulation technique for cone-beam CT and pinhole SPECT

This study was aimed at developing an efficient simulation technique with an ordinary PC.The work involved derivation of mathematical operators,analytic phantom generations,and effective analytical projectors developing for cone-beam CT and pinhole SPECT imaging.The computer simulations based on the analytical projectors were developed by ray-tracing method for cone-beam CT and voxel-driven method for pinhole SPECT of degrading blurring.The 3D Shepp-Logan,Jaszczak and Defrise phantoms were used for simulation evaluations and image reconstructions.The reconstructed phantom images were of good accuracy with the phantoms.The results showed that the analytical simulation technique is an efficient tool for studying cone-beam CT and pinhole SPECT imaging.

Pinhole imaging to observe spatial jitters of a triple-pulse X-ray source on the Dragon-Ⅱ LIA

In high-energy flash radiography,scattered photons degrade the acquiring image,which limits the resolving power of interfaces and density of dense object.The application of large anti-scatter grid can reduce the scattered photons remarkably,but this requires a stable source position in order to reduce the loss of signal photons in the grid structure.The pinhole imaging technique is applied to observe spatial jitters of a triple-pulse radiographic source of a linear induction accelerator.Numerical simulations are conducted to analyze the imaging performance with the same or close parameters of the pinhole object and experimental alignment.Experiments are carried out to observe spatial jitters of the source between different measurements.Deviations of the source position between different pulses are measured in each experiment.

Effects of pinholes on zerooffset of single-axis normal-tracking measurement system

A single-axis normal-tracking measurement system is proposed, which can solve the problem of measuring large curved surface. According to Collins formula, the tilt dependent error of the measurement system is studied, which uses Gaussian beam as the light source. By theoretical analysis and numerical simulation, the influence of the error is presented. The results show that there is the difference between point source and Gaussian beam for differential confocal microscopy. The opti-mal diameter of pinhole can be determined by the mathematical model and the actual parameters of the measurement system. The optimal pinhole diameter of this measurement system is 20 to 35 pm for 633 nm wavelength light source.

Single-pinhole diffraction of few-cycle isolated attosecond pulses with a two-color field

The spatio-temporal characterization of an isolated attosecond pulse is investigated theoretically in a two-color field. Our results show that a few-cycle isolated attosecond pulse With the center wavelength of 16 nm can be generated effectively by adding a weak controlling field. Using the split and delay units, the isolated attosecond pulse can be split to the two same ones, and then single-pinhole diffractive patterns of the two pulses with different delays can be achieved. The diffractive patterns depend severely on the periods of the attosecond pulses, which can be helpful to obtain temporal information of the coherent sources.

Upgrade of the X-ray pinhole camera system at SSRF

An X-ray pinhole camera has been used to determine the transverse beam size and emittance on the diagnostic beam line of the storage ring at SSRF since2009.The performance of the beam size measurement is determined by the width of the point spread function of the X-ray pinhole camera.Beam-based calibration was carried in 2012 out by varying the beam size at the source point and measuring the image size.However,this calibration method requires special beam conditions.In order to overcome this limitation,the pinhole camera was upgraded and an X-ray quasi-monochromator was installed.A novel experimental method was introduced by combining the pinhole camera with the monochromator to calibrate the point spread function.The point spread function can be accurately resolved by adjusting the angle of the monochromator and measuring the image size.The X-ray spectrum can also be obtained.In this work,the X-ray quasi-monochromator and the novel beam-based calibration method will be presented in detail.

Triad-displaced ULAs configuration for non-circular sources with larger continuous virtual aperture and enhanced degrees of freedom

Non-uniform linear array(NULA)configurations are well renowned due to their structural ability for providing increased degrees of freedom(DOF)and wider array aperture than uniform linear arrays(ULAs).These characteristics play a significant role in improving the direction-of-arrival(DOA)estimation accuracy.However,most of the existing NULA geometries are primarily applicable to circular sources(CSs),while they limitedly improve the DOF and continuous virtual aperture for noncircular sources(NCSs).Toward this purpose,we present a triaddisplaced ULAs(Tdis-ULAs)configuration for NCS.The TdisULAs structure generally consists of three ULAs,which are appropriately placed.The proposed antenna array approach fully exploits the non-circular characteristics of the sources.Given the same number of elements,the Tdis-ULAs design achieves more DOF and larger hole-free co-array aperture than its sparse array competitors.Advantageously,the number of uniform DOF,optimal distribution of elements among the ULAs,and precise element positions are uniquely determined by the closed-form expressions.Moreover,the proposed array also produces a filled resulting co-array.Numerical simulations are conducted to show the performance advantages of the proposed Tdis-ULAs configuration over its counterpart designs.

THEORETICAL TOOTH PROFILE AND ITS SUBSTITUTE CURVE OF THE PINION CUTTER FOR PINHOLES

The formula for the engaging curve of the pinion cutter with pitholes and the formula forthe theoretical tooth profile of the tinion cutter for the generating gearing of pinhoes are developedbased on the engaging theory. The substitute curve of the theoretical tooth profile of the pinion cut-ter is determined by the least square method.