Abstract: The present invention discloses a method for preparing nanometer silicon powder by induction plasma pyrolysis of silane, which comprises the following steps: exciting working gas in an induction plasma reactor to form stable high-temperature plasma; mixing gaseous silane with dilution gas; injecting into a high-temperature plasma thermal field; decomposing the gaseous silane under a joint action of a hot airflow and a high-temperature circulating cooling airflow in the high-temperature plasma thermal field; cooling and condensing silicon atoms generated by pyrolysis into nanometer-scale spherical silicon powder; filtering an airflow wrapped with the silicon powder by filters; depositing the nanometer silicon powder on the surfaces of the filters; then blowing off the nanometer silicon powder by a periodic back blowing airflow; and collecting the nanometer silicon powder.

Abstract: A nano-silicon-graphite composite negative electrode material with carbon coating and aluminum metaphosphate composite modification layer on surface and its preparation method are disclosed, which is mainly prepared from following components by mass percentage: 4-10 wt. % of aluminum metaphosphate, 10 wt. % of asphalt cracking carbon, 15 wt. % of spherical nano-silicon powder, and 71-65 wt. % of graphite powder. A nano-silicon powder is added to deionized water for ultrasonic dispersion to obtain a uniform dispersion, then graphite powder is added to mix uniformly, and then waterborne asphalt is added. After stirring and mixing evenly, spray drying is carried out, and the dried powder is compounded with metaphosphate for mechanical fusion. Finally, the same is transferred into vacuum furnace for high-temperature carbonization to obtain the product.

Abstract: A turn-on signal is transmitted from an in-vehicle stop-sign-command transmitter in a vehicle waiting to make a left turn from a first direction of travel to an on-demand stop sign for a second direction of travel, which is opposite to the first direction of travel. Reception of the turn-on signal by the on-demand stop sign causes the on-demand stop sign to transition from off to on thereby causing traffic in the second direction to yield the right of way to the vehicle waiting to make the left turn. After the vehicle waiting to make the left turn has made the left turn, the stop sign is turned back off again.