1027results about How to "Regulating pressure" patented technology

A method of treating glaucoma in an eye by managing fluid flow past an implanted shunt having an elastomeric plate and a non-valved elastomeric drainage tube. The plate is positioned over a sclera of the eye with an outflow end of the elastomeric drainage tube open to an outer face of the plate. An inflow end of the drainage tube tunnels through the sclera to the anterior chamber of the eye. The plate may have regions of greater propensity for cell adhesion alternating with regions of lesser cell adhesion. For example, regions of texturing around the plate or drainage tube may be provided to control the size of a bleb that forms over the implant. The effective surface area of the plate may be balanced against a number of fenestrations. The drainage tube has a reduced profile and may be shaped with a non-circular external cross-section to reduce its height. A scleral groove may be used to further reduce the height of the drainage tube on the sclera. A flow restrictor for the early post operative period will immediately lower the intraocular pressure (IOP) and simultanously prevent hypotony.

In certain embodiments, a vial adaptor comprises a housing member, a connector configured to couple the adaptor with a vial, and an extractor channel formed in the housing member. The extractor channel is configured to facilitate withdrawal of fluid from the vial when the adaptor is coupled to the vial. In some embodiments, an anti-reflux valve is positioned within the extractor channel. The anti-reflux valve can be configured to impede or obstruct fluid returning to a fluid source after withdrawal of the fluid from the fluid source.

Some embodiments provide a cooking apparatus having a dual wall structure, including inner and outer shells. The inner shell is disposed adjacent the outer shell and the edges of the shells are hermetically sealed to form a cavity between the shells. In some embodiments, the cooking apparatus has a low-pressure creating lid, including a disk with an aperture, a pressure release valve installed on the aperture, and a rim that surround the disk.

The invention discloses an electric rice cooker and an electric rice cooker cooking control method. The electric rice cooker comprises a cooker body, a cooker cover and a pressure regulating device arranged on the cooker cover. The cooking control method comprises following steps of receiving a cooking instruction, and obtaining the type of food to be cooked in dependence on the cooking instruction; obtaining a corresponding cooking control program in dependence on the type of food to be cooked, controlling the pressure regulating device in dependence on the obtained cooking control program in order to make the internal pressure of the cooker after the electric rice cooker enters a boiling phase satisfy the cooking pressure corresponding to the corresponding cooking control program. By means of the electric rice cooker cooking control method, the cooking pressure can be concretely adjusted in dependence on different types of rice, the demand of different types of rice on the cooking pressure can be satisfied, one electric rice cooker can cook various kinds of rice well, and taste, appearance and quality of various kinds of rice after being boiled are optimal.

A method for forming a semiconductor structure includes providing a substrate comprising a first device region, forming a metal-oxide-semiconductor (MOS) device in the first device region, forming a stressed layer over the MOS device, and performing a post-treatment to modulate a stress of the stressed layer. The post-treatment is selected from the group consisting essentially of ultra-violet (UV) curing, laser curing, e-Beam curing, and combinations thereof.

This invention discloses an entrained bed gasifier, which comprises: a shell, a jacket, a quenching ring, a water-sealing tank, a draft tube, a baffling tube, an inlet for raw materials and gasifying agent, a crude coal gas outlet, and a residue outlet. The jacket, the quenching ring, the water-sealing tank, the draft tube and the baffling tube are set inside the shell from top to bottom. The inlet for raw materials and gasifying agent is set at the top of the shell, and is connected with the jacket. The crude coal gas outlet is set below the water-sealing tank. The residue outlet is set at the bottom of the shell. A positioning support is set at the upside of the shell inner wall, and a residue outlet support is set at the bottom of the shell inner wall. This invention also provides a method for gasifying by using the entrained bed gasifier. The entrained bed gasifier has such advantages as simple structure, and convenient maintenance.

The invention discloses a full-automatic solder paste printer. The full-automatic solder paste printer comprises a rack subassembly, wherein a Z-axis lifting system is installed at the bottom end of the rack subassembly, and a platform correcting system is installed at the top end of the Z-axis lifting system and provided with a guide rail transporting system; the rack subassembly is provided with a steel screen frame clamping system, a scraper blade printing system and an automatic cleaning system; the Z-axis lifting system makes lifting movement stable and positioning fast and accurate and solves the problem that responding speed is low because large-inertia lifting control is low in positioning accuracy; the difficult problem that manual PCB correction is not accurate is solved through the platform correcting system, and printing quality is improved; a steel screen frame is cleaned in any combination mode of a drying cleaning mode, a wet cleaning mode and a vacuum cleaning mode, so that the cleaning effect of the steel screen frame is greatly improved, manual cleaning time is shortened, and labor intensity is relieved; through the scraper blade printing system, pressure of a scraper blade can be accurately controlled and regulated, and the problem that the scraper blade pressure of a traditional printer cannot be controlled is solved.

The invention discloses a fast tool servo device with adjustable rigidity. According to the device, a tool rest component is additionally arranged on an assembly of a frame, a flexible hinge, piezoelectric ceramic, a tool holder, a diamond cutting tool and the like, and comprises a spring bracket, a spring sleeve, a spring, a locking ring and the like; the spring bracket is arranged at the front end of the frame; the middle part of the spring bracket is provided with a threaded hole; the spring sleeve is matched with the threaded hole through external thread on the wall of the sleeve; the spring is arranged in the spring sleeve; one end of the spring is in contact with the bottom of an inner hole of the spring sleeve, and the other end of the spring is in contact with the flexible hinge on the frame; and pressure which is applied to the flexible hinge by the spring can be adjusted by turning the spring sleeve, so that the rigidity of the fast tool servo device is adjusted.

The invention provides a constant wind temperature control system for a hot blast stove, comprising the hot blast stove (2), a detection element, a regulating valve, a data acquisition unit (1) and a computer (26). The control method of the control system comprises the following processes: detection of fluid parameters and valve location signals, data acquisition, data transmission, data comparison and data correction and control adjustment, wherein the detection element and the regulating valve are arranged in a pipeline, and temperature measuring equipment is arranged on the surface of a stove body. Specific steps are as follows: dynamically calculating parameters such as the heat storage capacity of checker bricks, temperature-rise ratio, theoretical wind temperature and the like during the combustion process, and carrying out on-line adjustment of parameters such as combustion air and gas flow, preheating temperature and the like; controlling direction change of the hot blast stove by the highest setting temperature of the checker bricks, a stove top and fume; and during the air supply period, taking hot blast temperature control as a target to determine an air supply curve and air supply time. The method based on calculation of dynamic balance of on-line energy of the hot blast stove effectively controls the heat storage capacity of the checker bricks of the hot blast stove, adjusts air supply quantity and air supply time, and ensures stable output of wind temperature of the hot blast stove.

The invention discloses a comprehensive test platform for the dynamic performance of a hydraulic cylinder of an engineering machine. The comprehensive test platform for the dynamic performance of the hydraulic cylinder of the engineering machine comprises a test platform body, a hydraulic system and an electrical test control system. The hydraulic system comprises a drive system unit and a loading system unit. The drive system unit comprises a first hydraulic pump, a first filter and three liquid inlet valve banks. Oil outlets of the three liquid inlet valve banks are connected with an oil inlet of the tested hydraulic cylinder. The loading system unit supplies oil to a loading hydraulic cylinder. The electrical test control system controls all the valve banks of the hydraulic system according to feedback signals. According to the comprehensive test platform for the dynamic performance of the hydraulic cylinder of the engineering machine, a drive system, a loading system and a gas-liquid supercharging system which are independently arranged are used for meeting test and control needs under different loads and different working conditions; and the comprehensive test platform also utilizes the feedback signals to control the test process, when the oil pressure, the flow, the filter precision, the system temperature and other indexes are not at the normal level, the system gives out an alarm to remind people and stops, and therefore system operation reliability is guaranteed.

The invention discloses a hydraulic brake system and method with a double hydraulic cylinder four-wheel failure backup. The hydraulic brake system comprises a hydraulic control unit (HCU), a brake pedal, a manpower cylinder, a liquid storage tank, a stroke simulator, a main cylinder, a ball screw, a first motor, an electronic control unit (ECU), a plurality of connecting pieces, a solenoid valve, a sensor and a brake. According to the hydraulic brake system with the double hydraulic cylinder four-wheel failure backup, the idea of more reliable and safer braking and quicker and more accurate control is embodied.

The invention relates to a technology of a novel structure of a semi-active damping-adjustable vibration absorber for suspension of automobiles, locomotives and rolling stocks. The vibration absorber comprises two end part connecting rings, a piston rod, a sealing and guiding device, a cylinder body, a vibration absorber cover in threaded connection with the cylinder body, a piston valve assembly and a bottom valve assembly, and also comprises a tensile unloading electromagnetic valve assembly embedded in the piston valve assembly and the piston rod, a compression unloading electromagnetic valve assembly embedded in the bottom of the bottom valve assembly, and an external high-pressure small oil chamber arranged in a lug boss and provided with a master control valve assembly and a safety valve assembly; and the tensile unloading electromagnetic valve assembly, the compression unloading electromagnetic valve assembly and the master control valve assembly are controlled by a controller. By the vibration absorber, the magnitude and the direction of a damping force can be controlled without the relative speed for auxiliary judgment, and both the unloading control related to movement and the control of the magnitude of the damping force are provided.

The invention provides a device and a method for evaluating the sand carrying capacity of carbon dioxide dry-process fracturing fluid. The device comprises a high-pressure visual stirring vessel, a carbon dioxide pressurization system, a viscosity improving agent injecting system, a supporting agent adding system, a temperature control system and a data acquisition system, wherein the carbon dioxide pressurization system, the viscosity improving agent injecting system, the supporting agent adding system, the temperature control system and the data acquisition system are connected with the high-pressure visual stirring vessel. All constituent parts are connected with one another through a pipeline and valves to form the device for the sand carrying capacity of the carbon dioxide dry-process fracturing fluid. The device provided by the invention is used for evaluating the sand carrying capacity of the carbon dioxide dry-process fracturing fluid under different phase states (a liquid state or a supercritical state), realizes the visualization and is simple in structure and higher in measuring precision; an operation method is easy to implement; the stirring speed, the temperature and the pressure can be regulated; the quantitative measurement of the sand carrying capacity of the carbon dioxide fracturing fluid from the liquid state to the supercritical state within a greater pressure and temperature range can be realized, so that reliable sand carrying capacity data is provided for fracturing design and field test.

The invention provides raw paper for thermal transfer paper and a preparation process thereof. The raw paper for the thermal transfer paper has grammage of 70 to 95 g / m2, cross file grammage tolerance of no more than 5 g / m2, apparent density of 0.8 to 0.85 g / cm3, smoothness of 45 / 36S, transverse tearability of no less than 600 mN, vertical dry tensile strength of no less than 70 N / 15mm, vertical wet tensile strength of no less than 12 N / 15 mm, air permeability of no less than 60 S, a water absorption value of 30 to 50 g / m2, a deformation rate of no more than 1.5% and dust of no more than 10 / m2. The preparation process for the raw paper for the thermal transfer paper comprises the steps consisting of pulping, mixing, beating and rewinding so as to prepare the raw paper for the thermal transfer paper, and then packaging is carried out, wherein a surface sizing solution and a filling material are added during beating. The raw paper for the thermal transfer paper prepared in the invention has the advantages of low cost, good paper formation, great apparent density, small air permeability, high tensile strength, high heat resistance, etc.

The invention relates to a cooling method used for directional solidification and a cooling device therefor. In the method, liquid metal is taken as cooling liquid, and a formwork is cooled by adopting the spray cooling method independently or adopting the spray cooling method and the immersion cooling method simultaneously. For the cooling device, a liquid metal spraying device is arranged under a direction solidification holding furnace, and the liquid metal is taken as the cooling liquid to cool the pull-down formwork by spraying independently or accompanying with the immersion. The invention has the advantages that the thermal radiation of a heating area and a cooling area for direction solidification can be insulated; and the cooling liquid is recycled, so as to cool the cooling liquid in cycling.

The invention relates to an electro-deionization method and device for concentrating and purifying heavy metal wastewater synchronously, belonging to a wastewater treatment technique, which adopts first-stage two-section or first-stage multi-section electro-deionization device, wherein the inner sides of the positive and negative poles are arranged with corresponding pole protection chambers, the desalting chamber is filled with large-hole strong-acid strong-base mixed bed resin with narrow particles distributed; cation exchange film is adopted as the direction-turning film, after direction-turning, two adjacent concentration chambers are arranged continuously, both are separated by cation exchange film, simultaneously after direction-turning, the first concentration chamber is filled with large-hole mixed bed resin with the volume of cathode resin more than 50 percent, the heavy metal wastewater to be treated enters the desalting chamber and the concentration chamber in two paths, the heavy metal ion and cathode in the desalted water flow are transferred into the concentration chamber so as to obtain the desalted water, the concentrated water flow is partially circulated or closely circulated so as to obtain the concentrated liquid of metal wastewater, thereby recycling valence metals and pure water resources synchronously and realizing zero emission and resource treatment of wastewater. Compared with the prior art, the wastewater treatment process has higher separation efficiency, more reliable operation, more convenient operation, continuous process operation and no secondary pollution.

The invention relates to a sealing mechanism preventing gas exchange. The sealing mechanism comprises a stress block (3), a pressing block (4) and a compressing mechanism (5), wherein the stress block (3) is connected with a fixed part (1) and is in clearance fit with a rotating part (2); the pressing block (4) is in clearance fit with the rotating part (2) in a rotating mode; the compressing mechanism (5) is fixedly connected with the rotating part (2); the pressing block (4) presses the stress block (3) through the compressing mechanism; the stress block (3) is provided with a first sealing strip (3c); a second sealing strip (4e) is placed in a cavity (4d) of the pressing block (4); a first gap (2a) formed between the pressing block (4) and the outer wall surface of the rotating part (4) is sealed through the second sealing strip (4e); a threaded rod (7a) of a compressing screw (7) of the compressing mechanism (5) applies pressure to a force applying surface (4a2) of the pressing block (4), and the pressing block (4) compresses the first sealing strip (3c) of the stress block (3) through a first pressing surface (4a2) of a compressing surface (4a1) so that a second gap (8) formed between the pressing block (4) and the stress block (3) can be sealed. The sealing function is achieved through the simple mechanical sealing mechanism, gas exchange through the gap formed between the fixed part and the rotating part is prevented, in this way, external gas is prevented from entering the rotating part through the gap, and meanwhile gas inside the rotating part is prevented from leaking outwards through the gap.

The invention discloses an inflation / deflation valve assembly for a central tire inflation / deflation system of an automobile and relates to tire inflation / deflation technology of a vehicle. The inflation / deflation valve assembly comprises an inflation valve cover, a hexagon lobular socket head cap screw, a spring washer, an inflation / deflation valve body, a deflation solenoid valve cover, a hexagon socket tapered screw plug, a first steel ball, a gasket, a diaphragm, a first spring, an O-ring, a second steel ball, a curved single coil spring lock washer, a solenoid valve assembly, a dust-proof cushion, a second spring and a slotted screw plug. The inflation / deflation valve assembly has the advantages of big air passage size, high inflation / deflation speed, compact structure, small volume and convenient assembly, and is applicable to a driving state or a parking state of the vehicle, so that a driver can perform inflation, an deflation or pressure measurement on the tires of the vehicle through simple operation in a driving cab so as to regulate the pressure of the tire; and therefore, the capacity of the tires or the vehicle for passing complex road surfaces, such as desert, muddy road surfaces or snowy and icy road surfaces and the like is improved, and the maneuverability and the viability of the vehicle are improved.

The invention discloses a test method for simulating a thermal environment in an aircraft flight process. The simulation of the thermal environment is realized through an arc tunnel test, and comprises the following steps: (1) a curve of heat flow density, changed along with the time, of an aircraft trajectory is fitted to a curve of heat flow density changed along with time in the arc tunnel test; (2) multiple time periods on the curve of heat flow density changed along with time in the arc tunnel test are read; each time period is corresponding to a heat flow density; and input parameters of laminated type arc heaters are set according to the time periods and the heat flow densities corresponding to the time periods; and (3) the input parameters corresponding to the multiple time periods are set in a controller in sequence to control the completion of the simulation test of the thermal environment in the aircraft flight process. The test method, provided by the invention, uses a computer for controlling, operates the thermal environment changed in the aircraft flight process in primary test process, and can simulate the thermal environment of an aircraft in the flight process more really.

The invention discloses an independent external-mounting maintenance-free multi-stage oil and gas separator assembly. The oil and gas separator assembly is characterized in that a first cyclone separation cavity consists of an oil and gas separator outer shell and an oil and gas separator body shell; a second dispersing separation cavity consists of the oil and gas separator body shell, an oil and gas separator cover and the outer walls of three refine separation conical pipes which are distributed on the circumference at 90 degrees; a third refine cyclone separation cavity consists of the three refine separation conical pipes which are distributed on the circumference at 90 degrees and a central pipe; a fourth reinforcement cyclone separation cavity consists of the three refine separation conical pipes which are distributed on the circumference at 90 degrees, a central pipe, and a cyclone blade; a fifth refine cyclone separation cavity consists of a small refine separation conical pipe arranged in the center of the circumference; a sixth compact and dispersing safety separation cavity consists of a safety valve cavity and a safety valve; an eighth separation cavity consists of a respirator compact plate and a safety damping net; a flow pressure adjusting valve consists of a flow pressure adjusting diaphragm in a respirator and a flow pressure adjusting spring; any installation mechanism consists of an installation support and variable air inlet and outlet pipe included angles; and an oil return cavity consists of a separation conical pipe bottom and an independent separator shell.

The present invention relates to an ink supply system used for an ink-jet printer, and an ink pressure control method in the system. Aiming at an ink gun 1 possessing a nozzle 41 and a pressure chamber 48, the ink is supplied circularly from a sub can 3 via an ink circulation path 2, at the upstream side of the ink gun 1, a pressure sensor 21 is configured, and at the downstream side, a pressure sensor 22 is configured. The flow path resistance R1 between the pressure sensor 21 and the ink gun 1 and the flow path resistance R2 between the pressure sensor 22 and the ink gun 1 are set to be equal R1=R2. A controller 10 calculates the ink pressure at the nozzle 41 according to the detection values of the pressure sensors 21, 22, so that the pressure in the sub can 3 is controlled in a manner of enabling the pressure to be a specified value.

The invention discloses a variable-volume pressure fixing device and method for measuring the solubility of gas in liquid. The variable-volume pressure fixing device includes a gas sample bottle, a gas cavity, a balance cavity, a thermostatic bath with a magnetic stirrer, a pressure sensor, a thermometer, a gas chromatograph, a pressure reducing valve, a pressure control gas cylinder, a vacuum pump and a real-time data acquisition system. The gas cavity is used for controlling and calculating the sample quantity of gas in the balance cavity. The balance cavity is provided with a visual window and a movable piston, the liquid level can be observed, and the pressure inside the balance cavity can be regulated. The constant pressure in the balance cavity is kept by adjusting the movable piston through the pressure control gas cylinder.The method stabilizes the pressure in the balance cavity through the external large-volume gas cylinder, achieves measurement of the solubility of a pure gas substance and a mixture in liquid under constant pressure and can avoid solubility equilibrium offset caused by sampling.

The invention discloses a frequency conversion multi-connected type heat pump system and a control method of a bypass electronic expansion valve. The system comprises a gas-liquid separator, a compressor and the bypass electronic expansion valve; the inlet end of the gas-liquid separator is connected with a first port of a four-way reversing valve; and the suction end of the compressor is connected with the outlet end of the gas-liquid separator, and the exhaust end of the compressor is connected with a third port of the four-way reversing valve. One end of the bypass electronic expansion valve is connected with the exhaust end of the compressor, the other end of the bypass electronic expansion valve is connected with the inlet end of the gas-liquid separator, and the bypass electronic expansion valve is used for throttling refrigerants output by the compressor by adjusting the opening degree. The bypass electronic expansion valve is arranged between the gas-liquid separator and the compressor, and therefore when the system is started, the proper system pressure can be rapidly built, so that the system can work under the optimum pressure state; the surplus capacity of the system can be effectively unloaded, and it is ensured that the system can safely and stably operate; and on the basis that an existing refrigerant piping scheme of the system is not changed, real-time adjustment and control over the capacity unloading amount of the system can be achieved.

The invention relates to the technical field of vehicle cleaning equipment, and particularly relates to a vehicle cleaning robot. The vehicle cleaning robot comprises a travelling chassis, a lifting platform arranged above the travelling chassis, a manipulator arranged on the lifting platform, and a scrubbing assembly arranged at an operation end of the manipulator. The vehicle cleaning robot further comprises an image acquisition device, a distance monitoring device and a control device. With the adoption of the vehicle cleaning robot, the automation of vehicle cleaning working is realized, and the labor intensity of the vehicle cleaning working is reduced; and in addition, the vehicle cleaning robot is capable of analyzing the dimensions of a vehicle to be cleaned and planning the running track of the scrubbing assembly before the cleaning working, and in this way, the cleaning efficiency of the vehicle cleaning robot is increased, and on the other hand, the overall running track length of the scrubbing assembly in the cleaning process is reduced, so that consumption for water is reduced.

The invention discloses a large-diameter proportional pneumatic valve directly driven by an alternating-current servo motor. The large-diameter proportional pneumatic valve directly driven by the alternating-current servo motor comprises the alternating-current servo motor, wherein an output shaft of the alternating-current servo motor is connected with a ball screw to drive a screw nut to reciprocate up and down so as to control the position of a valve core; the upper valve core is in sliding seal fit with a valve body and an upper end cover through a sealing ring respectively; a cavity formed by the seal is communicated with an air source inlet on the valve body through air guide holes formed in the valve body and the upper end cover; the acting force of the lower surface of the valve core is compensated with the acting area so as to reduce load; and the output shaft of the alternating-current servo motor only transfers torque but does not bear the axial force. According to the large-diameter proportional pneumatic valve directly driven by the alternating-current servo motor, the alternating-current servo motor directly drives the valve core to do linear motion by utilizing a ball screw assembly, so that the drive efficiency is high; the output flow and pressure of the valve can be adjusted and the real-time position of the valve core can be easily detected; and an electric control servo system is established to realize closed-loop control so as to improve the dynamic performance of the valve.

A solids supply systems having a solids deaeration zone and a solids pump zone, and to methods for supplying the solids e.g., pulverized dry coal, to an application, e.g., gasification process. The solids deaeration zone includes a roller system containing a plurality of porous roller assemblies, or a belt system containing a plurality of porous belt assemblies. The solids deaeration zone is operable to deaerate and convey the solids to the solids pump zone. In the solids deaeration zone, the solids become sufficiently compacted prior to and upon entry into the solids pump zone to be effectively conveyed through the solids pump zone.

An electro-proportional pressure continuously-adjustable hydraulic motor / pump is characterized in that an electromagnetic switching valve, a main-control pressure valve, a pilot proportional valve, damping holes, a displacement sensor and a proportional amplifier are additionally arranged on the basis of a variable plunger motor or a variable plunger pump. According to the hydraulic motor / pump provided by the invention, the functions of a hydraulic motor and a hydraulic pump are integrated; the working conditions of the hydraulic pump and the hydraulic motor can be switched over by controllingthe diversion of the electromagnetic switching valve and a spindle of the hydraulic motor / pump; the pressure of an oil inlet / outlet of the hydraulic motor / pump can be adjusted in real time by adjusting the set value of the pilot proportional valve and changing the swing angle of a swash plate, thereby continuously adjusting the inlet / outlet pressure of the hydraulic motor / pump; the hydraulic motor / pump is simple in structure and convenient to control, and can be combined with a motor / power generator into an electrical recycling system; accordingly, the energy of engineering machinery and thelike can be recycled without throttling loss, and the impact and vibration generated at the beginning of recycling can be inhibited; and the hydraulic motor / pump has great application prospects and popularization value.

The invention discloses an intelligent traffic control method. The method comprises the steps of receiving real-time road condition information of each direction of an intersection; conducting identification analysis on the real-time road condition information, and obtaining traffic flow data; adjusting the display time of each indicator light in a traffic signal light according to the traffic flow data, and obtaining a control signal of the traffic signal light after adjustment; sending the control signal to the traffic signal light. By means of the intelligent traffic control method, unnecessary traffic jams can be reduced. The invention further discloses an intelligent traffic control device and system which have the advantages above.

The invention discloses a dynamic feedback adjusting shield tunneling earth pressure balance control method. In earth pressure balance shield tunneling construction, the water and earth pressure of an excavated formation is determined at first and is taken as a reference value of earth bin pressure after being corrected; afterwards, in the shield tunneling test pushing process, ground surface settlement is detected in real time, and data obtained through monitoring is subjected to ground surface settlement analysis; and analysis results are transmitted to a shield tunneling control system, and the earth pressure balance of the excavated face is achieved by judging and adjusting the earth bin pressure. According to the method, formation deformation caused when shield tunneling penetrating downwards through important buildings such as existing railways and building compact districts is effectively controlled, and the influence of shield tunneling construction to the ground surface is reduced.