Abstract: A dual-pulse MIG welding power source based on SiC power devices may include a main circuit and a digital control circuit. The main circuit may include a power frequency rectifier filter module, a first SiC high frequency inverter module, a first high frequency transformer, and a first SiC fast full-wave rectifier filter module connected sequentially. The power frequency rectifier filter module may be connected to a three-phase AC power supply, and the first SiC fast full-wave rectifier filter module may be connected to a load. The digital control circuit may include a digital human-machine interaction module, a core control module, a SiC high-frequency drive module, a load voltage and current detection feedback module, and a wire feeding control module. The digital human-machine interaction module may be connected to the core control module.

Abstract: Provided is an underwater repair system for a cavity region of a concrete panel rock-fill dam panel, including a moving platform, a work cabin, a pressure drainage apparatus, a traction apparatus, and a positioning apparatus; the traction apparatus controlling the movement of the moving platform on the surface of a dam concrete panel; the positioning apparatus transmits a detection position; the work cabin is a pressure cabin, the work cabin being connected to the pressure drainage apparatus, and a drill apparatus and grouting apparatus being arranged in the work cabin; the moving platform moves into the cavity region, and the pressure drainage apparatus starts up to drain the water in the work cabin, a partially closed waterless space being formed inside the work cabin, the drill apparatus drilling the concrete panel at the upper end of the cavity region and the grouting apparatus subsequently implementing grouting to complete the repair.

Abstract: Provided is an underwater repair system for a cavity region of a concrete panel rock-fill dam panel, including a moving platform, a work cabin, a pressure drainage apparatus, a traction apparatus, and a positioning apparatus; the traction apparatus controlling the movement of the moving platform on the surface of a dam concrete panel; the positioning apparatus transmits a detection position, the work cabin is a pressure cabin, the work cabin being connected to the pressure drainage apparatus, and a drill apparatus and grouting apparatus being arranged in the work cabin; the moving platform moves into the cavity region, and the pressure drainage apparatus starts up to drain the water in the work cabin, a partially closed waterless space being formed inside the work cabin, the drill apparatus drilling the concrete panel at the upper end of the cavity region and the grouting apparatus subsequently implementing grouting to complete the repair.

Abstract: Carbonaceous insertion compounds and methods for preparation are described wherein the compounds comprise a highly disordered, impurity free, hard pre-graphitic carbonaceous host. Carbonaceous insertion compounds can be prepared which have large reversible capacity for lithium yet low irreversible capacity and voltage hysteresis. Such insertion compounds can be prepared by simple pyrolysis of suitable epoxy, phenolic resin, or carbohydrate precursors at an appropriate temperature. These insertion compounds may be suitable for use as high capacity anodes in lithium ion batteries.

Abstract: Carbonaceous insertion compounds and methods for preparation are described wherein the compounds comprise a highly disordered, impurity free, hard pre-graphitic carbonaceous host. Carbonaceous insertion compounds can be prepared which have large reversible capacity for lithium yet low irreversible capacity and voltage hysteresis. Such insertion compounds can be prepared by simple pyrolysis of suitable epoxy, phenolic resin, or carbohydrate precursors at an appropriate temperature. These insertion compounds may be suitable for use as high capacity anodes in lithium ion batteries.

Abstract: The loss in delivered capacity as a function of the number of charge/discharge cycles in non-aqueous rechargeable lithium batteries can be reduced by exposing the electrolyte therein to P.sub.2 O.sub.5. The exposure to P.sub.2 O.sub.5 can be accomplished by incorporating P.sub.2 O.sub.5 in either electrode or other locations that contact the electrolyte. Alternately, the electrolyte can be exposed prior to assembling the battery. The invention is particularly suited to certain lithium ion rechargeable battery electrochemistries.

Abstract: Spinel insertion compounds Li.sub.1+x Mn.sub.2-x-y M.sub.y O.sub.4 wherein M is a transition metal, 0<x< about 0.33, 0.ltoreq.y<about 1, can have relatively low surface area at relatively large values of x when prepared with a novel two step heating method. Li.sub.1 Mn.sub.2-y M.sub.y O.sub.4 is first prepared between a critical temperature, T.sub.c, and about 900.degree. C. Then, a lithium salt is mixed therewith and reacted at a temperature between about 400.degree. C. and T.sub.c. These compounds are suitable for use as a cathode in a lithium battery. The use of LiCl as the lithium salt can provide improved cycle life results in such a battery.

Abstract: The viscosity of certain non-aqueous electrolytes comprising a first lithium salt which can gel on the addition of P.sub.2 O.sub.5 can be reduced substantially by incorporating therein a small amount of a suitable viscosity reducing salt. In particular, the viscosity of a LiPF.sub.6 salt based electrolyte can be reduced by orders of magnitude by incorporating a small amount of LiBF.sub.4 therein. Such electrolytes are suitable for use in lithium ion batteries.

Abstract: Insertion compounds having the formula Li.sub.x+y M.sub.z Mn.sub.2-y-z O.sub.4 wherein the crystal structure is spinel-like, M is a transition metal, 0.ltoreq.x<1, 0.ltoreq.y<0.33, and 0<z< about 1, can reversibly insert significant amounts of lithium at potentials greater than about 4.5 volts versus Li/Li.sup.+. In particular, M can be Ni or Cr. The reversible amount of lithium at such voltages can be greater for greater values of z. Such insertion compounds are suitable cathode materials for high voltage lithium batteries.