46 results about "Environmental pressure" patented technology

The invention discloses a robot system with tactile perception, and belongs to the technical field of tactile robots. The problem that an existing robot is poor in environment pressure sensing capacity is solved. Comprising a head module, an integrated vision-inertial navigation sensing module and a head controller, two side surfaces are provided with a pair of rotatable connecting ends, and the outer surface is provided with a tactile sensor; the head controller transmits data to the upper computer through the communication module; the driving body module comprises a plurality of modularized joints which are connected end to end, touch sensors are arranged on the two side faces of each modularized joint, and the adjacent modularized joints are orthogonally connected; the modularized joint is integrated with a joint controller and a joint steering engine; the tail module integrates a tail controller and a tail steering engine, and tactile sensors are arranged on the two side faces of the tail module. The tail controller carries out data transmission with the head controller through the adjacent previous joint controller in sequence, and the head controller receives a control instruction of the upper computer and carries out data transmission with all other controllers. According to the invention, the environmental pressure can be sensed in all directions.

The invention belongs to the field of multi-room negative pressure gradient control, and discloses a multi-room negative pressure gradient automatic control method and system based on reinforcement learning. An environment model containing multi-dimensional dynamic parameters such as an environment pressure state, an access control state, a fan air volume and a room coupling relation is constructed, so that the method can directly obtain an optimal control strategy through interactive learning on the premise of not needing an accurate physical model. Through the self-adaptive decision-making capability of reinforcement learning, linkage adjustment of the exhaust air volume and the fresh air volume of each room and the power of a total exhaust fan and a fresh air fan of the whole system is achieved, so that the stability of gradients of a corridor-5Pa, a ward-10Pa, a semi-polluted area-15Pa, a polluted area-20Pa and the like is kept, and it is ensured that the pressure difference of all areas is always within the safety range of-7Pa to-2Pa.

The application provides a device for testing a rotating part in a high-temperature environment, comprising: a test section for providing a simulated high-temperature environment for the rotating part, and provided with a first through hole and a second through hole; a first tension assembly for pulling an end of the rotating part extending out of the first through hole; a second tension assembly for pulling an end of the rotating part extending out of the second through hole; a first sleeve connected outside the first through hole and sleeved outside the first tension assembly, and provided with at least one first air inlet channel; a second sleeve connected outside the second through hole and sleeved outside the second tension assembly, and provided with at least one second air inlet channel; and an air pressure source connected to the at least one first air inlet channel and / or the at least one second air inlet channel and providing an air pressure greater than or equal to the environmental pressure in the test section. The application can accurately simulate the thermal-mechanical coupling loading environment in which the rotating part is in actual work, and effectively improve the reliability and accuracy of the test results.

The invention relates to the technical field of carbon dioxide cured concrete, and discloses a carbon cured concrete wall forming system which is characterized in that gas pulse injection is carried out through a unit integrated with a pressure sensor and a temperature sensor, and the water content is estimated through pressure fluctuation before injection to set an initial strategy; the environment pressure sensor is synchronously utilized to calibrate and compensate collected pressure attenuation data during injection, closed-loop self-adaptive control over an injection strategy is achieved, gas injection and internal state sensing subjected to environment calibration are coupled, each time of injection is adjusted according to real physical response of a wall, and the injection accuracy is improved. By means of the design, the dependence on the external environment stability and the internal initial condition uniformity in the curing process is eliminated, and the homogeneity and reliability of wall curing under large-scale site construction are ensured.

The utility model relates to the technical field of environmental test equipment, and particularly discloses a window sealing device of a high-low temperature damp-heat low-pressure test box, which comprises a window frame, and a multi-sealing component, an elastic component and a buffer layer are arranged on the inner wall of the window frame; the multi-sealing assembly is composed of an outer-layer sealing ring, an inner-layer sealing ring and a middle supporting ring, the elastic assembly comprises a plurality of annular spring sets which are arranged on the outer wall of the extension plate and are annularly distributed, and the outer-layer sealing ring resists high temperature, chemical corrosion and friction loss and bears external environment pressure; low-temperature elastic compensation and deformation self-adaption capacity are provided through the inner-layer sealing ring, stress is dispersed in the middle of the supporting ring, the situation that single-layer sealing loses efficacy due to local overload is avoided, and therefore multi-layer sealing protection is achieved. The pre-tightening force of the annular spring set is transmitted to the supporting ring through the inner-layer sealing ring, overall supporting of the sealing structure is formed, and the annular array design of the annular spring set ensures that the pressure of the sealing face is evenly distributed.

The application is a kind of simulation field drilling experimental device and experimental method for hydrate drilling fluid, which comprises a multilayer experimental cylinder, a water depth environment simulation device, a drilling running device, a drilling fluid feeding device, a slurry returning device and a data acquisition system. The multilayer experimental cylinder comprises at least two cylinder sections, and each cylinder section is independently configured with rock layers to simulate various formation environments. The water depth environment simulation device injects pressure into the multilayer experimental cylinder to simulate the environmental pressure of water depth. The drilling running device simulates downhole drilling. The drilling fluid feeding device is used to circulate and inject drilling fluid into the multilayer experimental cylinder through a drill pipe and a drill bit. The slurry returning device is used to circulate and return the drilling fluid to the drilling fluid feeding device and evaluate the hydrate content in the returned fluid. The application simulates the temperature and pressure environment of offshore gas field with low temperature and high pressure in the laboratory experimental device, and sets different rock layer compositions and experimental conditions of hydrate content, which can optimize the formula of drilling fluid and reduce the risk of hydrate generation during drilling.

A pressure equalization device includes a retaining part having a gas passage opening and a membrane made of a flexible rubber material, where the membrane is retained on the retaining part and covers the gas passage opening. An ambient pressure is applied on one side of the membrane and pressure to be equalized is applied on the other side of the membrane, where the membrane has a metastable first state and a stable second state depending on differential pressure. The membrane, starting from a retained position in which it sealingly covers the gas passage opening, is metastable, and is sealingly retained on the retaining part, snaps into an open position in which it is stable, is released from the retaining part, and opens the gas passage opening.

A non-submerged cavitation-erosion synergistic damage simulation device, system and method belong to the field of hydraulic machinery working condition simulation, including a sediment jet channel and a cleaning fluid channel in its periphery; high-speed sand-containing fluid is introduced into the sediment jet channel to form a central high-speed jet impacting the sample surface, high-speed cleaning fluid is introduced into the cleaning fluid channel to form a peripheral low-speed water curtain surrounding the central high-speed jet after being ejected from the annular steady flow pipe, and the peripheral low-speed water curtain impacts the sample surface to form a local liquid phase confining pressure zone together with the central high-speed jet. The present application not only realizes the true simulation of the actual working condition under non-submerged conditions, but also can adjust the flow and pressure of the cleaning fluid to adjust the cavitation number and cavitation collapse intensity around the high-speed sand-containing jet without changing the atmospheric environmental pressure, and quickly adjust the simulation test parameters.

The application relates to a compressed air control type sealing execution mechanism of a ship stern sealing device, which comprises a sealing bush and a sealing seat body, the sealing bush is a dynamic ring, is connected with a propeller and rotates with a propeller shaft; the sealing seat body is a static ring, is installed in a propeller shell, and a wear-resistant ring and four lip type seals are arranged between the sealing seat body and the sealing bush, five cavities are formed, the lip type seal holding force is adjustable, the holding forces of the two lip type seals facing seawater are different, the holding force on the outside is smaller than that on the inside, and the pressure loss generated when compressed air passes through the inside seal can be compensated. When the water depth changes or the environmental pressure changes greatly, the lip type seal inner-outer pressure difference changes rapidly, the lip type seal opening does not become large due to the sudden increase of the pressure difference to cause seawater leakage, and the lip type seal does not become small due to the sudden decrease of the pressure difference to cause the lip type seal abrasion, and the working reliability and service life of the stern sealing device are improved.

1. Name of the product in this design: Multi-environment testing device. 2. Purpose of this design: To conduct high and low temperature environmental pressure tests and port accuracy tests on vehicle-mounted displays and controllers. 3. The key design feature of this product is its shape. 4. The image or photograph that best illustrates the design's key points: 3D view 1.

This invention discloses a method for designing ventilation parameters for a supercavitating vehicle. Referring to the vehicle's shape and speed, the required ventilation volumetric flow rate for generating a suitable cavitation bubble size is calculated using the ventilation rate formula. The gas density inside the bubble is determined based on the environmental pressure and required cavitation number. The combustion surface of the solid propellant grain in the gas generator is designed in conjunction with fuel characteristics. Supercavitating vehicles designed using this invention are launched from underwater UUVs and surface ships, primarily for countering underwater targets. The method of this invention can efficiently obtain the ventilation parameters required for generating the appropriate supercavitation size when the vehicle is operating under variable conditions. Furthermore, through reasonable propellant design, the supercavitation size of the vehicle can be easily changed to adapt to changes in operating conditions. This avoids the problem of the vehicle not being fully covered by a supercavitation size that is too small after changing operating conditions, as well as the waste and even performance degradation caused by a supercavitation size that is too large.

The invention belongs to the technical field of filter sticks, and discloses a filter stick storage environment temperature and humidity regulation and control method and system based on pressure feedback. The method comprises the steps of obtaining the current temperature and the current humidity in a filter stick storage tank, determining a regulation and control target and generating regulation and control parameters when regulation and control triggering conditions are met, obtaining real-time environment pressure, and calculating correction parameters in combination with the regulation and control target and the pressure change trend so as to be applied to the regulation and control parameters. The regulation and control parameters are evaluated based on the temperature and humidity rising time period and the temperature and humidity falling time period, if the evaluation result is not passed, the step of generating the regulation and control parameters is executed again, the real-time temperature and humidity data is obtained to generate a risk level, and when the risk level is a high risk level, adjustment operation on the temperature and humidity regulation and control system is triggered. According to the method, the real-time environment pressure is introduced and fed back, multiple closed loops are formed in combination with parameter evaluation and risk early warning, regulation and control parameters are dynamically optimized, and the regulation and control accuracy, self-adaptive capacity and reliability are improved.

The invention relates to a gas turbine engine, a turbine tip clearance control method and system thereof and a medium. The control method comprises the steps that S1, the steady-state wall temperature of a casing, the total pressure of an ACC pipeline inlet, the total temperature of the ACC pipeline inlet, the environment pressure of an engine, the total temperature of a gas compressor outlet and the flow of the gas compressor inlet when the ACC is closed are obtained; s2, according to the data obtained in the step S1, the temperature drop and the cooling flow of the casing are obtained; and S3, according to the data obtained in the S2, the ACC valve angle is obtained.

The application belongs to the technical field of electric power robots. A transformer oil sample collection pressure dynamic adjustment control method and system are proposed. The flow characteristics are analyzed. Based on the real-time pressure and the environmental pressure difference, the oil density and the valve coefficient are combined to calculate the discharge flow. The feedforward-feedback composite control is executed. The pressure deviation is calculated and the instantaneous flow is estimated. The valve new opening degree instruction is output by using the adaptive control law containing the feedforward compensation term. The pressure mutation is actively inhibited. The multi-dimensional parameter online adaptive scheduling is implemented. The PID gain is dynamically adjusted according to the oil temperature and the oil type. The effective volume elastic modulus and the oil density are corrected. The application solves the problems of response lag and poor parameter adaptability of the traditional control, significantly improves the safety of the sampling process, and avoids the equipment damage caused by pressure impact.

The application discloses an end sealing welding process of a uniform temperature plate with a capillary structure, which can effectively reduce the invalid length and improve the welding strength, and the welding sealing reliability is obviously improved. The technical scheme is as follows: an end sealing welding process of a uniform temperature plate with a capillary structure, comprising the following steps: step 1: the end part of the uniform temperature plate with the capillary structure filled with a phase-changeable working medium is sealed by extrusion to obtain a sealed end with a certain invalid length; step 2: the part of the uniform temperature plate away from the sealed end is in heat conduction contact with a temperature control module, so that the vapor pressure of the phase-changeable working medium in the uniform temperature plate reaches a first pressure P1 and is stable; at this time, the environmental pressure is P0, the surface tension of the molten aluminum liquid generates a maximum pressure difference P2 on the heat conduction pipe; the absolute value of P1-P0 is less than P2; step 3: the invalid length part of the sealed end is fused by a welding process, so that the invalid length part of the sealed end is shortened, and the end face of the end part of the sealed end changes from a sharp end to an arc surface. Meanwhile, the application further discloses a uniform temperature plate and belongs to the field of uniform temperature plates.

The invention relates to the technical field of petroleum processing, and discloses a pre-mixing type hydrogenation reactor for petroleum processing, which comprises the following steps: acquiring current operation state data of the pre-mixing type hydrogenation reactor and environment monitoring data in the reactor; matching an adjustment factor in a preset rule base according to a load weight value in the current operation state data and an environment pressure value in the environment monitoring data; determining a safe lifting speed limit value according to the adjustment factor and the basic lifting speed of the pre-mixing type hydrogenation reactor, generating a lifting control instruction, and regulating and controlling lifting equipment in the pre-mixing type hydrogenation reactor according to the lifting control instruction; adjusting a weight parameter of the safe lifting speed limit value based on the vibration data of the lifting equipment, and generating a target safe lifting speed limit value according to the adjusted weight parameter; lifting the premixed hydrogenation reactor to a target state according to the target safe lifting speed limit value; the efficiency of the hydrogenation reactor in the working process can be improved.

Cost effective pressure sensors for gas meters are described herein. In an example, responsive to an abnormal condition at an ultrasonic metrology unit of a gas meter, rates of pressure sensor operation are increased. In the example, the operations may include: measuring gas-environment pressure values; measuring contemporaneous air-environment pressure values; calculating pressure difference values of the gas-environment pressure values minus the contemporaneous air-environment pressure values; and comparing pressure difference values to one or more threshold values.

A hydraulic motor for energy conversion and a method for operating a hydraulic motor 5 for energy conversion are provided. The target is achieved through the pressure eliminating unit, and the pressure eliminating unit can selectively eliminate the environment pressure outside the pressure eliminating unit.

The invention discloses a community diversity-based water ecological environment stability evaluation method and device, and belongs to the technical field of water ecological environment monitoring and evaluation. The method comprises the steps of collecting environmental parameters and community data of a plurality of sampling points of a target water area; respectively calculating an environment distance matrix and a community dissimilarity matrix between the samples; constructing a prediction model taking the environment distance as an independent variable and the community dissimilarity as a dependent variable; calculating an expected community dissimilarity of a target sample by using the prediction model, and comparing the expected community dissimilarity with a measured value; and quantifying the ecological stability of the water area of the target sample according to the deviation. Based on the theory of replacing time with space, objective correlation between environmental pressure and community response is established through a zero model, and the problems that traditional stability evaluation highly depends on long-time-sequence monitoring data, the evaluation period is long, and cross-point comparison is difficult are solved. The method is suitable for rapid evaluation in a single sampling scene, the evaluation result is objective, and the method can be widely applied to ecological health evaluation and pollution early warning of rivers, lakes, reservoirs and other water areas.

The present application belongs to the technical field of hydraulic components, and discloses a plug-in type two-position four-way reversing valve, which comprises a valve cover, a valve sleeve and a valve core. The valve sleeve is internally provided with a through hole penetrating from top to bottom, and the valve core is slidably arranged in the through hole. The valve cover, the valve sleeve and the upper part of the valve core enclose a control cavity, and the control cavity is filled with control oil. The control oil pushes the valve core to move downward from the first position to the second position through pressure boosting. A reset structure is arranged between the valve core and the valve sleeve, and the reset structure resets the valve core to the first position when the control oil is depressurized. The valve core is internally provided with an oil channel penetrating through the lower end of the valve core, and the oil channel is in communication with a return oil port T, so that the internal and external cavities of the valve core are both filled with hydraulic oil, thereby the environmental pressures inside and outside the valve core can be offset, and the force acting on the valve core in the working process is the effective pressure applied by the control cavity to overcome the reset structure, which is beneficial to the stable operation of the reversing valve in a wide pressure range and improves the environmental pressure adaptability.

The application relates to the field of automatic control, and discloses a valve regulation method and system based on deep-sea environmental pressure self-adaptive regulation, which comprises the following steps: synchronously collecting flow field disturbance state, external hydrostatic pressure evolution characteristics and speed change information in the diving process of a water area where a valve is located, and generating environmental response characteristic parameters; performing disturbance level division on pressure change behavior, and forming a hierarchical linkage control structure; combining the hierarchical linkage control structure, determining the disturbance level of the current water area, and generating subsystem trigger instruction information; when the disturbance level corresponding to the subsystem trigger instruction information satisfies a preset switching condition, corresponding pressure regulation control instructions are generated; in the process of executing pressure regulation by the regulation execution subsystem according to the pressure regulation control instructions, a feedback regulation mechanism is formed by combining valve internal and external pressure difference feedback information and safety pressure interval constraints. The application has the advantages of improving the hierarchical response and self-adaptive regulation capability of the valve to deep-sea transient pressure difference disturbance.

The invention relates to the technical field of industrial automatic control system device manufacturing, and discloses a safety self-locking state control system for tail water maintenance operation, which comprises a multi-source heterogeneous signal acquisition unit for acquiring displacement, load and environment pressure signals of a controlled object; the logic verification controller is used for executing multi-dimensional state time sequence operation on the collected signals based on energy zero potential energy verification logic; according to the invention, by using the exponential attenuation and convergence characteristics of an environment pressure signal, the energy zero potential energy verification logic is constructed, and the problem that the dead value of a sensor or physical leakage cannot be identified by static position detection is solved; by means of environment perturbation decoupling verification logic, external water level fluctuation serves as detection excitation, and dynamic diagnosis of hidden sealing failure is achieved; and through the XOR verification of ectopic potential monitoring and physical blocking, hidden faults of contact fusion welding of the executing mechanism are eliminated, and the intrinsic safety and the system stability of maintenance operation in a limited space are improved.

The application relates to a method and system for predicting the dynamic characteristics of a bubble near a water boundary considering phase transition effects, and relates to the field of cavitation bubble dynamics. The method solves the problems that existing analytical models are difficult to accurately reflect the deformation and migration track of a bubble when dealing with the bubble near a boundary, and the prediction results deviate from the actual situation, because the wall effect and the non-uniformity of a flow field are ignored. The method comprises the following steps: inputting initial conditions and environmental parameters of the bubble; calculating a boundary-induced flow field pressure; calculating a flow field environmental pressure based on the boundary-induced pressure and the hydrostatic pressure; calculating the internal pressure of the bubble based on the thermodynamic phase transition effect; calculating the enthalpy difference of the bubble surface based on the flow field environmental pressure and the internal pressure of the bubble; substituting the obtained result into a unified form of a bubble equation considering phase transition and migration effects and solving the bubble equation to obtain the equivalent radius and migration distance of the bubble changing with time. The method is also suitable for the field of predicting the equivalent radius calculation of a single cavitation bubble during boundary movement.

The application discloses a wafer non-contact flatness correction method and relates to the technical field of wafer calibration. The method is used for the correction process of a wafer sheet and provides a supporting force to the lower side of the wafer body by taking gas as a soft medium. The key purpose is to forcibly drive the wafer sheet to deform upwards by gas pressure to offset the downward deformation process caused by gravity. The specific process is to fix the wafer sheet in a negative pressure adsorption mode, and then to continuously blow gas into the positive pressure bin in a positive pressure blowing mode. The key role is to split the two actions of global positive pressure compensation and single-area positive pressure compensation when blowing gas. The pressure sensor is used to acquire the environmental pressure in the positive pressure bin in real time, the gas volume blown in is limited by simulating the environmental pressure, and the gas flow and the blowing mode are limited in an incremental mode. On the basis of correcting the flatness of the wafer sheet, secondary deformation damage is avoided.

The application discloses a wide-temperature-range low-air-pressure loading test method for a propulsion motor, relates to the field of propulsion motor testing, and aims at simulating high-altitude and high-altitude severe climate environment conditions by comprehensively considering wide-temperature-range high-low temperature alternating stress, variable environmental pressure stress, mechanical vibration and impact stress caused by air flow disturbance and alternating load stress. The application can realize comprehensive and accurate evaluation on the performance of the propulsion motor.

The invention relates to a method and a system for regulating and controlling an anti-explosion dynamic threshold value of a robot. The method comprises the following steps: acquiring pressure data in an operation environment of the robot in real time through a high-precision pressure sensor; inputting the pressure data into a pre-trained long-short-term memory network model for time sequence prediction processing, and generating a pressure prediction value in a future preset time period; calculating a dynamic explosion-proof threshold value according to the pressure prediction value, wherein the threshold value changes along with time and is associated with the pressure prediction value; the current risk level is determined according to the relation between the actual value of the pressure data and the dynamic anti-explosion threshold value, then the anti-explosion control strategy is adjusted based on the risk level, and a corresponding anti-explosion control instruction is generated and sent to the robot to achieve dynamic regulation and control; according to the scheme, the safety and adaptability of the robot in the anti-explosion environment are improved, potential safety hazards caused by environment pressure changes are effectively reduced, and meanwhile the production efficiency can be improved on the premise that safety is guaranteed.

The invention relates to the field of explosion pressure prediction, in particular to a heat loss-considered environment pressure prediction method under an explosion scene in a closed space. The method comprises the following steps: S1, acquiring an explosion environment parameter and an explosive parameter; s2, based on the explosion environment parameters and the explosive parameters, determining each explosion product, the amount of substance of each explosion product and the total release heat of the explosive; s3, calculating the temperature in the sealed space after explosion; s4, based on the amount of substance and the specific heat ratio of each gas component in the sealed space after explosion, calculating the average specific heat ratio in the sealed space; s5, calculating heat loss; wherein the heat loss comprises heat conduction loss, heat radiation loss and condensation latent heat loss of water vapor in the explosion process; and S6, calculating the environment pressure in the explosion scene in the closed space. According to the method, a humidity-heat loss-pressure coupling calculation framework is constructed, and the pressure prediction precision is improved.

This invention discloses a free positioning device and its control method, comprising: a housing with a flexible sealing structure at its open edge; a flexible seal for fitting against the surface to be positioned to form a seal, creating a sealed space between them; the flexible seal is directly or indirectly connected to the housing for transmitting pressure to the housing; and a fluid interface disposed on the housing for filling the cavity with pressurized fluid and maintaining the pressure state within the cavity after filling. When the device is pressed against the surface, pressurized fluid is filled into the cavity to form a high-pressure zone, creating a pressure difference between the high-pressure zone and the sealed space between the flexible seal and the surface. This pressure difference drives the flexible seal to press firmly against the surface to be positioned, achieving a secure fixation. After releasing the pressure, the device can be easily removed. This device actively controls the adsorption force by adjusting the fluid pressure within the cavity; the adsorption force is positively correlated with the fluid pressure. The housing isolates the external environment from the cavity, ensuring that the high-pressure state within the cavity is unaffected by external environmental pressure conditions. This device can operate in vacuum environments in space, high-pressure environments in the deep sea, and conventional environments on Earth. It is adaptable to a wide range of surface types, from smooth to rough, and can be integrated and installed as a functional component on other objects. This invention also provides a depth- and load-based intelligent pressure control method to achieve dynamic adjustment of the adsorption force.

The application relates to a robot explosion-proof dynamic threshold regulation method and system, which comprises the following steps: collecting pressure data in a robot operation environment in real time through a high-precision pressure sensor; inputting the pressure data into a long short-term memory network model which has been pre-trained to perform time series prediction processing, so as to generate a pressure prediction value in a future preset time period; calculating a dynamic explosion-proof threshold according to the pressure prediction value, wherein the threshold changes with time and is associated with the pressure prediction value; determining a current risk level according to the relationship between the actual value of the pressure data and the dynamic explosion-proof threshold, and then adjusting an explosion-proof control strategy based on the risk level, generating corresponding explosion-proof control instructions and sending the instructions to the robot to realize dynamic regulation; the scheme improves the safety and adaptability of the robot in an explosion-proof environment, effectively reduces the safety hidden danger caused by the change of the environmental pressure, and improves the production efficiency on the premise of ensuring safety.

The invention discloses a micromechanical structure device, a manufacturing method and a sensor. The micromechanical structure device comprises a wafer assembly, a second wafer and a packaging layer. The first wafer comprises a supporting structure and at least one group of micro-mechanical resonance structures, one side, far away from the substrate silicon wafer, of the supporting structure is bonded with one side of the groove of the second wafer, and gaps are formed between the at least one group of micro-mechanical resonance structures and the groove and between the at least one group of micro-mechanical resonance structures and the substrate silicon wafer. The packaging layer comprises a protruding part, and the protruding part sequentially penetrates through the substrate silicon wafer and the first buried oxide layer and is in contact with the supporting structure. According to the invention, exposure of the first buried oxide layer can be avoided, and reduction or failure of performance of the micro-mechanical resonant structure caused by change of environmental pressure due to the fact that external gas enters the micro-mechanical structural device through the first buried oxide layer in a special gas environment is avoided.