56results about How to "Increase radiant energy" patented technology

The invention relates to a wood electro-thermal floor with far infrared electro-thermal wave of health physiotherapy, which is installed conveniently and quickly. It comprises floor base and electrical heating layer. The technical point is that insulation thermal reflecting layer, far infrared electrical heating layer, insulation heat-transferring layer and solid-wood panel layer with face paint layer are set in turn upwards from the floor base. Because electro-thermal physiotherapy structure with far infrared electro-thermal wave of health physiotherapy is added on prior solid-wood floor, characteristics are shown as follows. Because the physiotherapy far infrared electro-thermal structure is set in the interlayer of floor, the thermal efficiency is high. The room is heated while physiotherapy wave absorbed by foot is provided for human. It is provided with high thermal efficiency, small starting current, no pollution, no noise, energy saving, good anti-aging performance and long service life. It also has the action that by infrared ray radiation of carbon fiber, human blood cycle is promoted; cell viability is strengthened and human health function is improved. It is killing two birds with one stone.

An optical pattern generator uses a single rotating component. The rotating component includes a number of deflection sectors. Each sector deflects an incident optical beam by a substantially constant angular amount although this amount may vary from one sector to the next. The rotating component may be combined with an imaging lens group that produces, for example, image points, spots, or lines displaced along a line locus.

The invention discloses a transient ultraviolet multispectral radiometer, comprising a plug-pull type aiming lens, a guide rail component, a cassegrain imaging system, an ultraviolet spectrograph, a CCD driving circuit, a high-speed collection storage system and a computer which is provided with a spectrum measure data processing soft package. The cassegrain imaging system aims at a light source to be detected with the help of the aiming lens, adjusts self-focal distance and makes the light source to be detected for imaging clearly on the incidence slit of the ultraviolet spectrograph; the output optical signal of the ultraviolet spectrograph is converted to an electrical signal through the CCD driving circuit and is collected and stored by the high-speed system, and then is transmitted to the computer by a USB line. The spectrum measure data processing soft package calculates the spectrum power curve, the peak value wavelength, the corresponding power value of the light source to be detected according to relevant calculation means. The invention not only can detect the ultraviolet spectrum of the microsecond transient line light source and the transient side light source during single flashing time, but also can detect the ultraviolet spectrum of the steady state radiation light source including weak energy or the far radiation light source, and has good application prospect.

The invention relates to an internal-condensation capacity-reducing solar medium and high temperature heat collection pipe and a method for manufacturing the same. The heat collection pipe comprises a vacuum internal-condensation solar heat collector, wherein the vacuum internal-condensation solar heat collector consists of an outer cover tube which is made of a light-transmitting material, a heat absorption tube which is coaxial with the outer cover tube and a composite parabolic reflecting plate which is assembled between the outer cover tube and the heat absorption tube; a heat energy conductor is arranged in the vacuum internal-condensation solar heat collector; the heat energy conductor consists of a metal sleeve, a metal flow guide cavity tube which is assembled in the metal sleeve, and heat conduction media which are filled in the metal sleeve and the metal flow guide cavity tube; the metal sleeve is inserted into an internal cavity of the heat absorption tube and tightly contacted with the heat absorption tube; and a heat conduction heat medium transmission path is formed between the metal flow guide cavity tube and the metal sleeve. The preparation steps of the high temperature heat collection pipe are as following: manufacturing focus solar collector in vacuum, processing heat sensor, and then assembling and moulding. The internal-condensation capacity-reducing solar medium and high temperature heat collection pipe is high in heat collection efficiency, high in heat transfer speed and safe, and can convert solar energy into a medium and high temperature heat source for use.

Gamma radiation imaging system for non-destructive inspection of the luggage contains a DR sub-system, which obtains the projected image of the luggage by translationally scanning, and a CT sub-system, which obtains the tornograph image of the luggage by rotating scanning. Said DR sub-system includes a fixed gantry, a conveyor system, a radiation source mounted on the fixed gantry, front and back collimators, and the array detector. Said CT sub-system includes a rotating gantry, a conveyor system, a radiation source mounted on the rotating gantry, front and back collimators, and the array detector, wherein, the radiation source in said CT sub-system is 192Ir or 75Se radioactive isotope gamma source with high specific activity. Said gamma source is enclosed in a shield chamber with a projecting opening. The shield chamber is mounted on said rotating gantry. Said array detector is adapted for detecting gamma ray of 192Ir or 75Se radioactive isotope; The radiation source in said DR sub-system is 192Ir or 75Se radioactive isotope gamma source with high specific activity, said gamma source is enclosed in a shield chamber with a projecting opening. The shield chamber is mounted on said fixed gantry. Said array detector is adapted for detecting gamma ray of 192Ir or 75Se radioactive isotope.

An optical pattern generator uses a rotating component that includes a number of deflection sectors containing optical elements. Each sector deflects an incident optical beam by a substantially constant angle although this angle may vary from one sector to the next. The constant deflection angle is achieved by symmetry within the deflection sector, specifically gut-ray symmetry. The rotating component may be combined with an imaging group that produces, for example, image points, spots, or lines displaced along a line locus. The image spots can also be displaced to either side of a line, for example by introducing a tilt in the orthogonal direction or by introducing light beams at various angles to the plane of symmetry.

The invention relates to a method for synthesizing three direction dendrimer core by microwave, comprising the following steps: synthesizing dinitrile: dissolving trolamine in a reaction vessel with 1,4-dioxane, adding a strong base catalyst and a crown ether phase transfer catalyst; then adding acrylonitrile in the reaction system, placing the solution in a microwave reactor for microwave irradiation to obtain dinitrile; synthesizing triester: dissolving the obtained dinitrile in a reaction vessel with methanol, adding concentrated sulphuric acid; placing the solution in the microwave reactor for microwave irradiation to obtain triester; synthesizing triamine: dissolving the obtained triester in a reaction vessel with methanol, adding ethylene diamine; placing the solution in the microwave reactor for microwave irradiation to obtain three direction dendrimer core. Compared with the existing art, the invention has the following advantages: the radiation energy is large by microwave heating, the synthetic reaction time of dendrimer core is effectively shortened; the productivity can be obviously improved, which is obvious for the alcoholysis of nitrile.

The invention relates to the technical field of communication, especially relates to a signal coverage control method and system of a WiFi access point. The method provided by the invention comprises following steps of receiving state signals transmitted by terminals; determining antenna sections in which the terminals are located according to the state signals; and controlling the access point so as to maximize the signal output powers with the radiation units corresponding to the antenna sections. Therefore, according to the method and the system, the antenna sections in which the terminals are located can be judged relatively accurately; the access point is relatively accurately controlled so as to adjust the signal output powers with the radiation units corresponding to the antenna sections in which the terminals are located; the terminals in the antenna sections are allocated and receive relatively rational network signal strengths; further the communication qualities of the terminals in the antenna sections are prevented from being influenced by the fact that the network signals in the corresponding antenna sections are relatively poor; the wastes of network signal resources and related resources can be reduced; and the use experience effects of the users are comprehensively increased.

The invention discloses a small-sized planar high-gain inverted-F antenna comprising a primary radiant section, a second signal transmission section, and a secondary radiant section. The primary radiant section is disposed on a primary matching line which is a wire reaching a grounding point from a signal feed-in point via a signal input section, an antenna impedance match section, a first signal transmission section, and a signal conversion section. The primary radiant section is a first radiation portion extended from signal transmission section. The second signal transmission section is a transmission section extended from the primary radiant section opposite to the direction of the signal transmission section. The secondary radiant section is a second radiation portion extended from the second signal transmission section. The improved inverted-F antenna is increased in gain, provided with miniaturized and low overall dimension characteristics, and decreased in cost, and keeps the overall product appearance.

The invention relates to a special rare earth composite phosphor for a three-band plant growth lamp and a preparation method thereof. The rare earth composite phosphor comprises a base material with an activator including, by weight, 10-30 parts of strontium hydrogen phosphate, 10-25 parts of magnesium oxide, 10-30 parts of alumina, 3-18 parts of germanium oxide, 5-15 parts of europia, 5-18 parts of cerium oxide, 15-20 parts of terbium oxide, with the sum of the components being 100%, and also comprises a cosolvent aluminium fluoride and a special gas. Wherein, the additive amount of aluminium fluoride accounts for 3-20% of the gross weight of the base material, and the special gas includes 7% of hydrogen, 1% of helium and 92% of nitrogen. According to the invention, a light source made with the special rare earth composite phosphor for a ZW-2 three-band plant growth lamp has three-band spectrums, containing a suitable visible spectrum which is high in radiation energy and contributes to the growth and development of plants and ultraviolet light which inhibits excessive growth and promote the formation of anthocyanidin and various pigments, thus enjoying an absolute advantage in light supplement for plants.

The invention relates to the technical field of UV curing, in particular to a UVLED curing assembly for backlight. The UVLED curing assembly for the backlight comprises a plurality of UVLED light-emitting units and is characterized by further comprising a heat dissipation substrate, a heat dissipation system and a reflector, wherein the UVLED light-emitting units are arranged on the obverse side of the heat dissipation substrate; the heat dissipation system is arranged on the reverse side of the heat dissipation substrate; the reflector forms a reflection peripheral wall on the obverse side of the heat dissipation substrate, and the reflection peripheral wall is used for reflecting rays emitted by the UVLED light-emitting units; the reflector forms a light-transmitting plate on the top of the reflection peripheral wall, and the light-transmitting plate is used for allowing the rays emitted by the UVLED light-emitting units to pass through; the positions, corresponding to all the UVLED light-emitting units, of the light-transmitting plate are respectively provided with a reflector cup used for converging the rays emitted by the UVLED light-emitting units. The UVLED curing assembly for the backlight is simple in structure and high in curing efficiency.

The embodiment of the invention discloses and electronic device. The electronic device comprises a first antenna branch knot, a second antenna branch knot, a feed source and a grounding circuit; the first antenna branch knot is connected with the second antenna branch knot; the feed source is electrically connected with the connection point of the first antenna branch knot and the second antenna branch knot through a feeder line and is used for feeding excitation signals into the first antenna branch knot and the second antenna branch knot; the first end of the grounding circuit is connected with the feeder line, and the second end of the grounding circuit is grounded; the feed source, the first antenna branch knot and the grounding circuit form a first antenna, the feed source, the second antenna branch knot and the grounding circuit form a second antenna, and the first antenna and the second antenna have the same main radiation mode.

A radiograph system with an anode plate, a cathode plate, and a power source coupled to said anode plate and the cathode plate. At least two wires coupled between the anode plate and the cathode plate provide a configuration to form an X-pinch having a photon source size of less than five microns at energies above 2.5 keV. Material at the configuration forming the X-pinch vaporizes upon application of a suitable current to the wires forming a dense hot plasma and emitting a single x-ray pulse with sufficient photons having energies in the range of from about 2.5 keV to about 20 keV to provide a phase contrast image of an object in the path of the photons. Multiple simultaneous images may be formed of a plurality of objects. Suitable filters and x-ray detectors are provided.

Microwave synthesis of poly-2, 2'-5, 5'-benzimidazole and poly-2, 5-benzimidazole are disclosed. The process of poly-2, 2'-5, 5'-benzimidazole is carried out by taking paraphosphoric acid PPA as solvent, condensation polymerizing under nitrogen protection, adding into 3,3'-diamino-benzidine, dissolving, adding into isophthalic acid, putting mixed liquid into microwave oven, programmed raising temperature at 300-500W, pouring reactant into deionized water, washing by water to become neutral, adding into saturated sodium bicarbonate solution, neutralizing, decompressing, extraction filtering, washing by water, washing by alcohol, drying and grinding into powders; process of poly-2, 5-benzimidazole is carried out by taking PPA as solvent, condensation polymerizing under nitrogen protection, agitating while heating to 200 degree, adding into 3, 4-diamino-benzoic acid, putting mixed liquid into microwave oven, programmed raising temperature at 300-500W, pouring reactant into deionized water, washing by water to become neutral, adding into caustic soda solution 1 mol / L, neutralizing, boiling at 100 degree for 6 hrs remove caustic soda, decompressing, extraction filtering, washing by water, washing by alcohol, drying and grinding into powders. It' efficient, has better radiant energy and shorter reactive time.

The invention discloses a novel leaky cable for an Internet of things application. The novel leaky cable comprises an inner conductor, a dielectric layer, an outer conductor, an insulating protective layer which are orderly arranged from an inner layer to an outer layer. The outer conductor is provided with continuous slots along an axial direction, and two sides of the continuous slots are provided with periodic slots. The continuous slots are wavy bend slots or straight line type slots, and the periodic slots at two sides of the continuous slots are mutually staggered. The periodic slots are single triangular slots or combined slots of multiple triangular slots, and the periodic slots are L-shaped or U-shaped slots. The novel leaky cable is suitable for an Internet of things RFID sensing application and has high coupling loss. As an ultra-high frequency (UHF) networking antenna, the high coupling loss leaky coaxial cable has the advantages that large radiation energy can be provided, and thus a label is remotely activated to achieve the purpose of reading.

The invention provides a circular waveguide antenna based on a dielectric lens, so as to solve the technical problem of insufficient collection of incident waves in the prior art. The circular waveguide antenna based on the dielectric lens comprises a circular waveguide and a dielectric lens fixed with the receiving end, wherein the upper bottom surface of the dielectric lens is located at one side of the receiving end of the circular waveguide; the dielectric lens comprises a cylindrical medium and multiple circular cylindrical medium layers which are nested sequentially from inside to outside with the cylindrical medium as a center, the lower bottom surface is thus a spherical surface, the upper bottom surface is a planer surface, the side surface has a round table body structure with aninward concave arc surface, the cylindrical medium and the circular cylindrical mediums comprise multiple first cylindrical mediums and first circular cylindrical mediums laminated vertically respectively, and the first cylindrical medium and the first circular cylindrical medium are formed by multiple first basic units and second basic units in a joint mode. Material parameters at different positions can be realized through changing the size of spherical space inside the first basic unit and the second basic unit, electromagnetic waves can be effectively converged, and the manufacturing costis low.

The invention relates to an antenna with high isolation and low cross polarization level, a base station and a terminal. The antenna comprises at least one radiation layer, a feed layer and an aperture coupling layer arranged between the radiation layer and the feed layer, and the aperture coupling layer comprises a metal sheet. The metal sheet is provided with a first feed gap, a second feed gap and a middle gap, and the middle gap is located between the first feed gap and the second feed gap and located in a weak electric field area of the metal sheet. By arranging the middle gap between the first feed gap and the second feed gap of the metal sheet, the boundary condition of the antenna can be changed under the condition that the radiation electric field of the antenna is not changed due to the existence of the middle gap, so that on one hand, the current in the cross polarization direction generated on the antenna is weakened, and the cross polarization level is reduced; and on the other hand, the energy coupling phenomenon of the antenna is effectively weakened, so that the isolation of the antenna is remarkably improved.

The invention provides an electronic tag. The electronic tag includes a chip and an antenna. The antenna is a directional antenna. The electronic tag provided by the invention can receive and transmit microwave signals directionally through the directional antenna; when applied to a road vehicle driving scenario, with the maximum radiation direction toward a vehicle radar, the electronic tag can receive microwave signals transmitted by the vehicle radar directionally and transmits an electronic code thereof directionally to the vehicle radar; the anti-interference performance and the effective availability of radiation energy are improved; and the road vehicle driving requirement is met.

The invention discloses acrylpimaric acid diallyl ester and a microwave-assisted synthesis method thereof. The method comprises steps as follows: rosin and acrylic acid react, a modified product is prepared, then acrylpimaric acid sodium salt is prepared and has a microwave-assisted synthesis reaction with chloropropene in the presence of a quaternary ammonium salt catalyst and a polymerization inhibitor at a certain temperature for a period of time, NaCl is filtered and removed after the reaction, a certain quantity of an organic solvent is added for extraction, an obtained solution is poured into a separating funnel, is shaken up and then is left to stand for layering, an organic solvent layer is taken and washed with distilled water to be neutral, the organic solvent is removed through rotary evaporation, and a sticky liquid, namely a product, is obtained. The product yield is high, the purity is good, the yield can be up to 92.2%, and the GC content is 98.6%. N, N-dimethylformamide or dimethyl sulfoxide is taken as a reaction medium for the reaction. With the adoption of microwave heating, the radiation energy is high, the efficiency is high, the reaction time is short, the operation is simple and convenient, the product is easy to separate, the product yield is high, and the purity is good.

The invention provides an X-ray tube comprising a first inner cylinder with both ends sealed. The inner portion of the first inner cylinder is set to be of a vacuum structure; a first sealing end of the first inner cylinder is provided with a high pressure receiver, a cable input of which is arranged outside the first sealing end; and an outer wall of an anode tube coaxially disposed inside the first inner cylinder is provided with a plurality of through holes disposed along the radial direction. The X-ray tube also comprises a cathode assembly comprising a cathode holder and a filament. Both ends of the cathode holder are respectively connected with the high pressure receiver and the anode tube; the filament electrically connected with the cathode holder axially extends along the anode tube a free end of which is provided with an electrical protective cover bonded with the anode tube and the filament. When the high pressure receiver receives energy, electricity is transmitted to the filament to generate electrons. The inner wall of the anode tube is bombarded during the injection of the electrons, and generated X-ray injects out of the anode tube. The surface of the anode tube transmits and reflects X-ray energy so that X-ray radiation energy and radiation efficiency are improved.

The invention provides a radioactive glass microsphere, which is composed of yttrium oxide with a molar percentage of 10-30%, silicon oxide with a molar percentage of 35-70%, and strontium carbonate with a molar percentage of 0-25%. Any one of manganese oxide and potassium oxide at 0-40 mole percent, praseodymium oxide at 0-25 mole percent, cesium oxide at 0-25 mole percent, 0-25 mole percent 25% zirconium oxide and 0-25% tantalum oxide by mole. The 10-30% yttrium oxide contained in the radioactive glass microspheres can release a certain dose of radioactive element yttrium-90 after being activated in vivo to provide higher radiation energy, and the radioactive microspheres have 2 ‑3.7 g / cm3 low density, composed of inorganic substances, non-shrinkable and radiopaque, which is conducive to smooth delivery to the tumor site in the body and uniform distribution in the tumor site, so as to facilitate the delivery process Visual guidance using CT scans, fluoroscopy, and X-ray imaging.

The invention relates to the field of intelligent control, and discloses a tracking type photovoltaic power generation system control method capable of identifying weather types. The control method comprises the following steps: 1, acquiring weather data of a local area; 2, calculating a weather type index according to the weather data, and dividing the weather of the region into different weathertypes; 3, determining the real-time weather type of the region; 4, calculating a solar altitude angle and a solar azimuth angle; 5, selecting different tracking control modes according to weather types; 6, judging the solar altitude angle: if the solar altitude angle is greater than or equal to 10 degrees, returning to the step 2; and if the solar altitude angle is smaller than 10 degrees, stopping working. According to the tracking type photovoltaic power generation system control method capable of identifying the weather type, corresponding tracking strategies can be adopted in different weather states to obtain the maximum radiation energy, and the energy consumption for adjusting and operating the tracking system is reduced.

The invention discloses a stove burner. The stove burner comprises a base, a burner cap set, a gas mixing chamber and a plurality of injection pipes, wherein the top and the bottom of the gas mixing chamber are connected to the burner cap set and the base correspondingly and form three gas cavities, and the injection pipes are connected below the base and communicate with the three gas cavities; the burner cap set comprises an inner ring burner cap, a middle ring burner cap and an outer ring burner cap which are sequentially arranged from inside to outside, the inner ring burner cap uses an atmospheric combustion mode, and the strength of fire holes is 6-6.5 W / mm<2>; the outer ring burner cap uses an infrared combustion mode, and the strength of fire holes is 0.3-0.8 W / mm<2>; and the middle ring burner cap uses a half-atmosphere and half-infrared combustion mode, and the strength of fire holes is 2.5-3 W / mm<2>. According to the stove burner, burner cap structures with different three-ring burning modes are arranged, so that flame radiation energy of the burner is greatly increased, the defect that the temperature of a traditional stove with a single burning mode is not uniform is overcome, the heat efficiency of the burner is improved, and the heat loss is reduced.

The invention discloses a commercial efficient high-speed-combustion infrared pressure casting crucible aluminum smelting furnace. The commercial efficient high-speed-combustion infrared pressure casting crucible aluminum smelting furnace comprises a shell, an upper cover, a crucible, a base and a high-speed-rotation flame combustion head. The high-speed-rotation flame combustion head is fixed to the base. The crucible is arranged in the outer shell on the high-speed-rotation flame combustion head. The upper cover covers the crucible. The high-speed-rotation flame combustion head is provided with a combustion chamber. The high-speed-rotation flame combustion head is provided with an input flame channel and a plurality of rotary flame spray nozzles. The input flame channel and the rotary flame spray nozzles communicate with the combustion chamber. The commercial efficient high-speed-combustion infrared pressure casting crucible aluminum smelting furnace is reasonable in overall design, good in heat preservation effect and high in heating efficiency, the service life of the crucible is long, the waste heat of smoke can be fully utilized, the combustion heat efficiency reaches up to 78.2%-86% in actual use, and the combustion heat efficiency is quite high.

An ultraviolet device packaging structure disclosed by the present invention comprises a chip, a lens and a substrate, the chip is arranged in a light-condensing accommodating hole of the lens, the chip can be conducted with an external element by using a first conduction element, the substrate blocks the accommodating hole, the chip is packaged in a packaging cavity, and the packaging cavity is filled with a protective gas. Inert gases such as nitrogen can be selected as the protective gas, and the chip is prevented from being influenced by the atmosphere, so that the radiation energy of the deep ultraviolet light-emitting diode is improved, and the sterilization and disinfection effects of the deep ultraviolet light-emitting diode are enhanced. Meanwhile, the invention further provides a manufacturing method of the ultraviolet device packaging structure, a eutectic furnace is used for enabling protective gas to enter the space between the substrate and the lens, eutectic welding is achieved between the first conduction element and the lens, the chip and the protective gas are packaged in the packaging cavity, and therefore the influence of the atmosphere on the chip is effectively avoided, and the packaging quality of the ultraviolet device is improved. And the performance of the deep ultraviolet light-emitting diode is improved.

The invention relates to a special rare earth composite phosphor for a three-band plant growth lamp and a preparation method thereof. The rare earth composite phosphor comprises a base material with an activator including, by weight, 10-30 parts of strontium hydrogen phosphate, 10-25 parts of magnesium oxide, 10-30 parts of alumina, 3-18 parts of germanium oxide, 5-15 parts of europia, 5-18 parts of cerium oxide, 15-20 parts of terbium oxide, with the sum of the components being 100%, and also comprises a cosolvent aluminium fluoride and a special gas. Wherein, the additive amount of aluminium fluoride accounts for 3-20% of the gross weight of the base material, and the special gas includes 7% of hydrogen, 1% of helium and 92% of nitrogen. According to the invention, a light source made with the special rare earth composite phosphor for a ZW-2 three-band plant growth lamp has three-band spectrums, containing a suitable visible spectrum which is high in radiation energy and contributes to the growth and development of plants and ultraviolet light which inhibits excessive growth and promote the formation of anthocyanidin and various pigments, thus enjoying an absolute advantage in light supplement for plants.

The present invention provides an antenna, comprising a reference ground and at least one radiation source, wherein the radiation source is adjacent to the reference ground to form a radiation gap between the radiation source and the reference ground , wherein the radiation source is electrically connected to the reference ground to ground the radiation source, thereby narrowing the bandwidth of the antenna. When an electromagnetic excitation signal is connected from a feeding point of the radiation source, the narrowing of the bandwidth of the antenna can prevent the electromagnetic wave signal received or generated by the antenna from being affected by the electromagnetic radiation frequency or frequency of the adjacent adjacent frequency band. Spurious radiation frequency interference.

The invention discloses a self-heating wood floor and a manufacturing method thereof. The self-heating wood floor comprises a substrate layer, a composite layer and an electric heating assembly. The bottom surface of the substrate layer is provided with a containing groove for allowing the electric heating assembly to be embedded in. The composite layer covers the bottom surface of the substrate layer in an attached mode, so that the electric heating assembly is sealed in the containing groove. The two ends of the substrate layer are provided with connection openings penetrating through the substrate layer in the thickness direction of the substrate layer, and the connection openings are internally provided with electric conduction sockets connected with a positive electrode and a negative electrode of the electric heating assembly. By means of the technical scheme, according to the self-heating wood floor and the manufacturing method thereof, previous circulating water heat supply is replaced with electric heating assembly heat emitting, and heat is transferred indoors according to the far infrared radiation principle, so that the problems that the bonding strength of the substrate layer, the electric heating assembly and a wood veneer layer is small, and the integration is poor are solved, the self-heating wood floor is not prone to cracking after being used for a long time, the phenomena of exposure and looseness of the electric heating assembly are even not prone to occurring, and the product service life is prolonged; and meanwhile existed safety hidden danger is eliminated.