Batchelorhensley4450

Satellite Laser Ranging (SLR) is a well established space geodetic technique measuring the satellite distance, which implements time of flight. Up to now, second harmonic NdYAG laser pulses have been frequently used for range measurement, since the silicon detector technology allows us to detect single photon echoes reflected from satellites with required high detection probability, millimeter precision, and an acceptable dark count rate. On the other hand, the fundamental wavelength (1064 nm) provides a significantly better overall energy budget, but there were no suitable detectors available. More recently, the use of InGaAs/InP became feasible for developing single photon avalanche diodes, which exhibit high photon detection probability and acceptable timing resolution. Both these properties are important and allow the SLR measurement at the fundamental wavelength. In this Note, we report on construction and testing of a single photon detector package based on the InGaAs/InP diode optimized for the SLR measurement.Based on the C4D technique and cross correlation velocity measurement technique, a new method for bubble/slug velocity measurement of the gas-liquid two-phase flow in small channels is proposed. A new C4D sensor, which is suitable for the parameter measurement of the gas-liquid two-phase flow in small channels, is developed by introducing the principle of capacitive reactance elimination. With two new C4D sensors, a bubble/slug velocity measurement system is developed, and the bubble/slug velocity is determined by the cross correlation velocity measurement technique. To verify the effectiveness of the proposed bubble/slug velocity measurement method, three prototypes of bubble/slug velocity measurement systems with different diameters (1.82 mm, 2.65 mm, and 2.96 mm, respectively) were established, and the bubble/slug measurement experiments were carried out. The research results show that the capacitive reactance elimination is an effective way to overcome the unfavorable influence of the coupled capacitances on measurement results. The experimental results indicate that the proposed method can successfully realize the bubble/slug velocity measurement in small channels, and the velocity measurement accuracy is satisfactory. For the three prototypes of the bubble/slug velocity measurement system, the maximum relative errors of the bubble/slug velocity measurement are all less than 5%.Using a solenoid with a laser ion source can suppress divergence of the expanding plasma; however, it has been found that the plasma becomes unstable in a certain magnetic field region. In the previous research, instability of the plasma after the solenoid was found. In this study, we investigated how the plasma instability changes inside the solenoid. A Faraday cup was placed in the solenoid, and the unstable magnetic field range was investigated. This experiment was conducted while changing the Faraday cup position from the inlet to the outlet of the solenoid. By increasing the magnetic field strength, the Faraday cup position indicating a condition triggering instability moved toward upstream in the solenoid. In addition, the instability is gradually mitigated by transporting the laser ablation plasma through the rest of the solenoid. The detailed good working range of the solenoid for the Au1+ beam was also shown.Recent studies have shown that head movements associated with cardiac activity contain a heart rate (HR) signal. In most previous studies, subjects were required to remain stationary in a specific environment during HR measurements, and measurement accuracy depended on the choice of target in the scene, i.e., the specified region of the face. In this paper, we proposed a robust HR measurement method based on ballistocardiogram (BCG) technology. This method requires only a camera and does not require that users establish a complex measurement environment. In addition, a bidirectional optical flow algorithm is designed to select and track valid feature points in the video captured by using the camera. Experiments with 11 subjects show that the HR values measured using the proposed method differ slightly from the reference values, and the average error is only 1.09%. Overall, this method can improve the accuracy of BCG without limitations related to skin tone, illumination, the state of the subject, or the test location.The electromagnetic environment under transmission lines is a concern for high-voltage transmission. For transmission corridors in which alternating-current (AC) and direct-current (DC) transmission lines are on the same tower, the electromagnetic environment at ground level is complex because of the AC/DC hybrid electric field. Generally, different instruments are used for measuring AC and DC electric fields, making it difficult to measure such fields simultaneously. Thus, we propose a method for AC/DC hybrid electric field measurement based on the Pockels effect and electric field modulation. The principle of the measurement is discussed in detail. AZD3229 order An experimental platform is set up to verify the feasibility and effectiveness of the proposed method and to calibrate the sensor. It shows that the sensor realizes simultaneous measurement of AC and DC electric field intensities as well as judgment of the polarity of the DC electric field. The measurable range is 1.05-150 kV/m (peak-to-peak value) for the AC electric field and 1.23-150 kV/m for the DC electric field with a maximum measurement error of less than 5%. The sensor has good repeatability, linearity, and low hysteresis, which can be used in power grids for AC/DC hybrid electric field measurements.In this paper, a scanning tunneling microscope (STM) is presented that operates in a 27.5 T magnetic field within a hybrid magnet. The coarse approach of the STM is realized by using an inertial piezoelectric motor, and the scanning is realized by using a miniature scanner, which stands alone on a sapphire base. A combined vibration isolation system consisting of a brick-rubber-brick stack and two springs is used to isolate the vibration generated from the magnet. An enclosed copper shield is used to prevent sound from entering the tip-sample junction. The sound and vibration isolation measures highly improve the stability of the STM imaging. All the materials selected to construct the STM head are nonmagnetic. The drift rates of the STM in the X-Y plane and Z direction are as low as 26.2 pm/min and 34.6 pm/min, respectively, under ambient conditions. The high performance of the homebuilt STM was demonstrated by graphite hexagonal lattice images obtained in magnet fields ranging from 0 T to 27.5 T even without the protection of a vacuum and low temperatures.