43results about How to "Reduce air density" patented technology

Disclosed is a method for producing a blade for a turbomachine, which method comprises:providing a blade root, having a first platform region, from a first material;providing on the first platform region at least one capsule that is filled with a metallic and / or ceramic powder that comprises at least one second material which is different from the first material, for producing a blade airfoil having a second platform region;producing and shaping a blade airfoil from the capsule that is filled with the powder by at least one thermal input method, thereby connecting the blade root to the blade airfoil in respective platform regions.Also disclosed is a blade which is obtainable and / or obtained by this method.

The invention provides an adjustable sub vacuum earplug, and relates to the field of sound-proof devices. The earplug comprises a sound-proof shell, a speaking diaphragm and an air pump cylinder, wherein the sound-proof shell is internally provided with a cavity, a sound transmission channel is formed in the sound-proof shell, and the sound transmission channel is communicated with the cavity; the speaking diaphragm is packaged on the sound transmission path of the sound transmission channel; the air pump cylinder is communicated with the cavity and used for pumping or restoring partial air in the cavity. According to the adjustable sub vacuum earplug, the air density state in the earplug is adjusted easily, tension degree change of the speaking diaphragm is matched, and on one hand, the sound insulation and noise reducing effect of the earplug can be enhanced to protect hearing; one the other hand, the sound insulation and noise reducing effect of the earplug can be reduced to ensure the communication ability of a wearer, and a sound insulation state and a communication state are switched according to needs.

A helicopter tail rotor pitch-range altering device is disclosed. The device is incorporated into the existing helicopter tail rotor pitch-change control system of a helicopter and automatically alters the amount of tail rotor pitch available from the helicopter's tail rotor pitch-change control system based on changes in density altitude. The device comprises an ambient air density sensing device and a movable member located within or located in proximity to the helicopter tail rotor pitch-change flight control system. In one embodiment, a sealed bellows is connected directly to a movable member within the helicopter tail rotor pitch-change control system. As density altitude changes, the length of the bellows changes accordingly and moves the movable member within the helicopter's tail rotor pitch-change control system providing a varying tail rotor pitch-range based on density altitude.

The invention discloses a light emitting diode with a nitrogen polar surface n-type electron barrier layer. The light emitting diode comprises a substrate, a nitrogen polar nitride layer, a polarity reversal nitride layer, an n-type nitride ohmic contact layer, the n-type nitrogen polar surface electron barrier layer, a non-doped superlattice structure layer, a multi-quantum well active layer and a p-type nitride ohmic contact layer distributed from bottom to top in sequence; and an n-type electrode and a p-type electrode are respectively arranged on the n-type nitride ohmic contact layer and the p-type nitride ohmic contact layer. The nitrogen polar surface n-type electron blocking layer can limit spatially the number of electrons entering an active region; and since a traditional p-type doped electron barrier layer is removed, the injection rate of the holes can be increased, the number of the holes and the number of the electrons injected into the active region are kept at a balanced level, and the probability of electron and hole radiation recombination luminescence in the active region can be improved, so that the performance of the light emitting diode is improved.

The disclosure provides a near-space real-time in-site wind speed and direction sensor based on wind pressure prediction. The sensor comprises a housing in a cylindrical shape, a top cover arranged above the housing, n differential pressure amplifying structures, windward-zone differential pressure detection devices, and air-out differential pressure detection devices. The n differential pressureamplifying structures are used for amplifying the differential pressure of wind fluid, wherein the n is larger than or equal to 3; the differential pressure amplifying structures have hollow tube shapes with the thin middle parts and two thick ends and are arranged along different cross sections of the housing; circular holes are formed at connection parts between the two ends of the differentialpressure amplifying structures and the cylindrical wall of the housing; and the differential pressure amplifying structures includes windward zones, middle sections, and air-out zones. The windward-zone differential pressure detection devices are arranged at the windward zones by differential pressure detecting tubes and are used for measuring the differential pressures in the windward zones. Theair-out differential pressure detection devices arranged in the air-out zones by the differential pressure detecting tubes are used for measuring the differential pressures in the air-out zones. And then the wind speed and wind direction of near space are calculated based on the pressure differences in the windward zones and the air-out zones. Therefore, a technical problem that the wind speed anddirection measurement of the near space is affected by the temperature and height greatly in the prior art can be solved.