Huffkhan4881

Plasma window is a feasible device as an atmosphere-vacuum interface, which can withstand energetic particle beams. It is, however, essential to enlarge the diameter to several tens of millimeters for actual beam passing in the accelerator applications. The pressure separation performance and discharge voltage V current I characteristics should be investigated in detail to design the plasma window for each purpose. Therefore, a cascade arc discharge device with a diameter of up to 20 mm was developed, and its characteristics as a function of diameter were examined. As a result, with an increase in the channel diameter, the discharge pressure that was achieved decreased, whose values were smaller compared with the values by the prediction formula, assuming the viscous gas flow with a constant plasma temperature. It showed that the bulk plasma temperature for the larger discharge channel was low because of the low-current density over the channel. Furthermore, the transition of the V-I slope was observed with an increase in the diameter.A new type of hydrothermal diamond-anvil cell (HDAC-VII) and its accompanied cooling system were designed. The design of HDAC-VII in which the three posts work simultaneously as guideposts and screw posts greatly shortened the horizontal size of HDAC compared with older types. It provides more open space and shorter distance to analyze and observe the sample chamber from side access. Moreover, four ports were used to connect the upper and lower spaces between windows and anvils, so mixed gas (Ar + H2) can pass through both of them. In the heating experiments, the mixed gas prevents diamond anvils and other parts from being oxidized as well as cooling the observing windows. Dry gas can be passed through those spaces during cooling, preventing condensation on the table faces of anvils and the observing windows. The cooling system can cool the sample chamber to -170 °C with an accuracy of ±0.5 °C by using a nitrogen stream cooled through a stainless steel coil immersed in a liquid nitrogen Dewar. The heating rates while reheating a frozen sample can be controlled to be 0.1 °C/min with a temperature fluctuation of 0.1 °C. These improvements extend the HDAC applications especially in low temperature conditions. For example, (1) we measured the salinities of NaCl-H2O loaded in the sample chamber, (2) we observed the ice I and VI-melting process and correspondingly calculated the density of water in the sample chamber, and (3) we performed lepidolite crystallization in an aqueous solution with 10 wt. % NaCl to simulate its natural forming conditions.We have developed a trapped ion system for producing two-dimensional (2D) ion crystals for applications in scalable quantum computing, quantum simulations, and 2D crystal phase transition and defect studies. The trap is a modification of a Paul trap with its ring electrode flattened and split into eight identical sectors and its two endcap electrodes shaped as truncated hollow cones for laser and imaging optics access. All ten trap electrodes can be independently DC-biased to create various aspect ratio trap geometries. We trap and Doppler cool 2D crystals of up to 30 Ba+ ions and demonstrate the tunability of the trapping potential both in the plane of the crystal and in the transverse direction.Uranium enrichment measurement is an essential quality inspection for fuel rods before delivery to users. Generally, compared with active neutron assay (ANA) equipment, passive gamma-ray assay (PGA) equipment is more economical and safer. learn more However, the current PGA equipment based on photomultipliers is too slow (1 m/min) to meet the growing needs in China. Recently, we have developed a set of compact high-speed PGA equipment including four detection modules (128 units in total), a 128-channel data acquisition system (DAS), a power supply, special software, and an automatic loading and unloading mechanism. The detection unit is based on silicon photomultipliers in virtue of its compact size and good performance. The DAS processes signals of all units in parallel into a sequence of data packets carrying the energy information and the corresponding unit ID. The software integrates the data packets into a fluctuating count curve in a time-delay superposition method and identifies possible abnormal pellets. After calibrations, our equipment can locate abnormal pellets accurately at a speed of 6 m/min. In addition, it can directly measure the enrichment of fresh pellets not in secular equilibrium without waiting for two months. So far, the equipment has been successfully run for one year on the assembly line of China North Nuclear Fuel Co. and shows good potential to replace the traditional ANA equipment.Rotational vibration isolation is of critical importance for many airborne instrumentation applications. Such isolators require very low frequency isolation for the rotational degrees of freedom combined with translational rigidity and negligible translation to rotation coupling. This paper describes a vibration isolator using neutrally buoyant flotation to provide high translation rigidity combined with very low rotational rigidity. The isolator reduces the rotational vibration at all frequencies above its resonance (0.18 ± 0.01 Hz) and has a large dynamic range (±30°) suitable for airborne surveying. Viscous, inviscid, and mechanical coupling inside the isolator have been analyzed. A recent fixed wing flight test shows the isolator reducing the rotational vibration by more than a factor of 1000 at frequencies above 10 Hz.In this paper, a method of incipient fault diagnosis and amplitude estimation based on Kullback-Leibler (K-L) divergence is proposed. An incipient fault is usually regarded as the precursor of a significant system fault, but due to a low amplitude and non-obvious characteristics, it is easy for such a fault to be hidden by disturbance and noise. Based on this and considering the sensitivity of the K-L divergence method in data feature extraction, a method of diagnosing incipient faults is designed. In order to consider the safety performance and lay a foundation for the fault tolerance of the system, an amplitude estimation method for incipient faults is also proposed. By mapping the characteristic change in the residual data to the numerical change in the K-L divergence, the amplitude of the incipient fault can be measured with high sensitivity. Considering the generality of the method, a Gaussian mixture model is used to model the residual data in order to increase the accuracy of fault amplitude estimation.