Optical shaping of gas targets for laser–plasma ion sources

We report on the experimental demonstration of a technique to generate steep density gradients in gas-jet targets of interest to laser–plasma ion acceleration. By using an intentional low-energy prepulse, we generated a hydrodynamic blast wave in the gas to shape the target prior to the arrival of an intense CO$_{2}$ (${\it\lambda}\approx 10~{\rm\mu}\text{m}$) drive pulse. This technique has been recently shown to facilitate the generation of ion beams by shockwave acceleration (Tresca et al., Phys. Rev. Lett., vol. 115 (9), 2015, 094802). Here, we discuss and introduce a model to understand the generation of these blast waves and discuss in depth the experimental realisation of the technique, supported by hydrodynamics simulations. With appropriate prepulse energy and timing, this blast wave can generate steepened density gradients as short as $l\approx 20~{\rm\mu}\text{m}$ ($1/e$), opening up new possibilities for laser–plasma studies with near-critical gaseous targets.

Development of Methods and Research on High Voltage Capacitor Welding

The report shows the classification of methods of high-voltage capacitor welding (HVCW) with magnetic drive pulse applied to the preparation of joints such as "rod - drive" of non-ferrous metals and alloys. Researches of processing methods of process of HVCW are provided. The ranges of energetic, geometrical parameters are defined and dependences of durability of welded connections are given. The hypothesis is offered and usage considerations on HVCW are made.

Assembly of a Versatile Micro Dispenser Using Off-The-Shelf Components for Applications in Microfluidics

We designed and constructed a drop-on-demand (DOD) droplet dispenser using the piezo inkjet technique that is simple to construct and operate and makes use of readily available components. The droplet dispenser can be easily fitted with cost effective glass nozzles and can be readily tuned to produce consistent drop sizes. The dynamics of the droplet motion are obtained using a calibrated analog video imaging system. We observed very high accelerations for the ejected droplets that corroborate with the applied drive pulse amplitudes. The acceleration measured, near the ejection nozzle, was many times the acceleration of gravity with the largest value of 34g’s. We successfully dispensed glycol water solutions and aqueous suspensions of titanium oxide nanoparticles, with values greater than 10 in the measured pH. For the inkjet droplets deposited on smooth gold/chromium substrates (±3nm surface roughness variation), we observed the well-known coffee ring effect using optical microscopy and nanoparticle morphology using an atomic force microscope.

A Novel Subnanosecond Monocycle Pulse Generator for UWB Radar Applications

A novel ultra-wideband (UWB) monocycle pulse generator with good performance is designed and demonstrated in this paper. It contains a power supply circuit, a pulse drive circuit, a unique pulse forming circuit, and a novel monopolar-to-monocycle pulse transition circuit. The drive circuit employs wideband bipolar junction transistors (BJTs) and linear power amplifier transistor to produce a high amplitude drive pulse, and the pulse forming circuit uses the transition characteristics of step recovery diode (SRD) effectively to produce a negative narrow pulse. At last, the monocycle pulse forming circuit utilizes a novel inductanceLshort-circuited stub to generate the monocycle pulse directly. Measurement results show that the waveform of the generated monocycle pulses is over 76 V in peak-to-peak amplitude and 3.2 ns in pulse full-width. These characteristics of the monocycle pulse are advantageous for obtaining long detection range and high resolution, when it is applied to ultra-wideband radar applications.

The Design of High-Speed Synchronization Data Collection Node Machine for Multi-Chip CCD Measurement

The high-speed synchronous node machine is developed for collecting high-precision and synchronous data from multi-chip CCD to measure the dynamic object with large field coverage by Visual technology. Node machine contains core, A/D converter module and Ethernet communication module. The FPGA of 600,000 gates which have a built-in FLASH chip is used as the core, which provides work-frequency of 10MHz and drive pulse for multi-chip CCD. A/D converter module configures the differential amplifier and builds 3-way 30MHz 16-bit A / D converter. 10/100M Ethernet protocol stack controller and RJ45 interface are internally installed in Ethernet module. This module also uses CC2430 chip to perform fast wireless synchronization control. Paper emphasizes how to implement the key technologies of multi-chip CCD for synchronous and precision measurement, and test the node machine by 5-chip CCD image data synchronous collecting with large field of vision. The node machine runs smoothly and reliably .The performance results of test show that the speed of image data collecting reaches up to 1800 frames/s, the speed of data processing reaches up to 150M Bytes/s and the transporting speed reaches up to 50M Bytes/s. The time of synchronous control is within 2 us.

The Design of High-Speed Synchronization Data Collection Node Machine for Multi-Chip CCD Measurement

The high-speed synchronous node machine is developed for collecting high-precision and synchronous data from multi-chip CCD to measure the dynamic object with large field coverage by Visual technology. Node machine contains core, A/D converter module and Ethernet communication module. The FPGA of 600,000 gates which have a built-in FLASH chip is used as the core, which provides work-frequency of 10MHz and drive pulse for multi-chip CCD. A/D converter module configures the differential amplifier and builds 3-way 30MHz 16-bit A / D converter. 10/100M Ethernet protocol stack controller and RJ45 interface are internally installed in Ethernet module. This module also uses CC2430 chip to perform fast wireless synchronization control. Paper emphasizes how to implement the key technologies of multi-chip CCD for synchronous and precision measurement, and test the node machine by 5-chip CCD image data synchronous collecting with large field of vision. The node machine runs smoothly and reliably .The performance results of test show that the speed of image data collecting reaches up to 1800 frames/s, the speed of data processing reaches up to 150M Bytes/s and the transporting speed reaches up to 50M Bytes/s. The time of synchronous control is within 2 us.

Open CNC System for Winding Machines

This paper introduces a new open CNC system for winding machines which can overcome the shortcomings the traditional winding machine existed, such as the low control-accuracy, the low speed and the poor quality of its product. The system takes Microprocessor MC68HC000 as the core and its working mode is centralized control and time-sharing processing. The highest drive pulse of the system reaches 500 KPPS and the drive aufloesung can be as high as 0.001mm/Pulse. So, the system software, together with the winding machines’ development kits and operating software, can provide an open design platform of the controller for the winding machine, and it may cater to the market’s needs for winding machines