CN112611879A - Analysis method of control system applied to material element analysis of internal combustion engine parts - Google Patents

Analysis method of control system applied to material element analysis of internal combustion engine parts Download PDF

Info

Publication number
CN112611879A
CN112611879A CN202011307891.7A CN202011307891A CN112611879A CN 112611879 A CN112611879 A CN 112611879A CN 202011307891 A CN202011307891 A CN 202011307891A CN 112611879 A CN112611879 A CN 112611879A
Authority
CN
China
Prior art keywords
gas
control
analysis
solid sample
software analysis
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202011307891.7A
Other languages
Chinese (zh)
Inventor
卢铭
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Guangxi Yuchai Machinery Co Ltd
Original Assignee
Guangxi Yuchai Machinery Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Guangxi Yuchai Machinery Co Ltd filed Critical Guangxi Yuchai Machinery Co Ltd
Priority to CN202011307891.7A priority Critical patent/CN112611879A/en
Publication of CN112611879A publication Critical patent/CN112611879A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N35/00Automatic analysis not limited to methods or materials provided for in any single one of groups G01N1/00 - G01N33/00; Handling materials therefor
    • G01N35/00584Control arrangements for automatic analysers
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/35Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
    • G01N21/3504Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing gases, e.g. multi-gas analysis
    • G01N21/3518Devices using gas filter correlation techniques; Devices using gas pressure modulation techniques
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N35/00Automatic analysis not limited to methods or materials provided for in any single one of groups G01N1/00 - G01N33/00; Handling materials therefor
    • G01N35/00584Control arrangements for automatic analysers
    • G01N35/00722Communications; Identification
    • G01N35/00871Communications between instruments or with remote terminals
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N35/00Automatic analysis not limited to methods or materials provided for in any single one of groups G01N1/00 - G01N33/00; Handling materials therefor
    • G01N35/00584Control arrangements for automatic analysers
    • G01N35/00722Communications; Identification
    • G01N2035/00891Displaying information to the operator

Landscapes

  • Physics & Mathematics (AREA)
  • Biochemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Abstract

The invention discloses an analysis method of a control system applied to the material element analysis of internal combustion engine parts, which comprises the following steps: testing a system; setting parameters; starting a combustion system to ensure that the solid sample is fully combusted in the combustion furnace; introducing the combusted gas into a filtering system for filtering; introducing the filtered gas into a sulfur dioxide analyzer for verification; the gas is then filtered again, the remaining CO2Introducing the gas into a carbon dioxide analyzer for verification; c and S content is compared with a sample for analysis; and closing the gas circuit, collecting the sample residue on the site, and ending the system. The invention solves the defects existing in manual sampling analysis, is stable for a long time within 24 hours and does not need to be recalibrated; the environmental interference is small, and the temperature in the specified range has no influence on the analysis; a visual window is analyzed, and the operation is flexible; the production efficiency is improved.

Description

Analysis method of control system applied to material element analysis of internal combustion engine parts
Technical Field
The invention relates to the technical field of internal combustion engines, in particular to an analysis method of a control system applied to material element analysis of internal combustion engine parts.
Background
The mechanical properties of the materials of the parts of the internal combustion engine are greatly influenced by the chemical components, the influence of some elements on the properties of the materials is positive, the influence of some elements on the properties of the materials is negative, and the key for determining the overall performance guarantee of the internal combustion engine is to scientifically, effectively and accurately analyze and control the elements of the materials. The current method comprises the following steps: the method of manual sampling is adopted for chemical element analysis, and the data accuracy is reduced if environmental factors are slightly changed; the data is not completed within the specified time and needs to be recalibrated; the instrument operation process is complex and the visualization is poor; the requirement on professional skills of common workers is high, and the operation is not easy.
In the prior art, the invention patent with the name of 'a novel material element detection and analysis system' and the application number of CN201810757155.8 discloses a novel material element detection and analysis system, which comprises a carbon-sulfur analyzer, a sampling device, a sample test board and a computer, wherein the carbon-sulfur analyzer comprises a combustion furnace and an analysis host, the analysis host is connected with the computer, a crucible support is arranged below the combustion furnace, the sample test board is used for placing a crucible containing a sample to be detected, and the sampling device is arranged between the crucible support and the sample test board and is used for conveying the crucible on the sample test board to the crucible support; the analysis host is provided with a first two-dimensional code scanner, and the first two-dimensional code scanner is connected with the computer. The two-dimensional code scanner is arranged on the analysis host, the two-dimensional code label on the detection sample is read through the two-dimensional code scanner during detection, the information of the detection sample is obtained, the information is automatically stored in the computer, and the problem caused by manual entry in the detection process is reduced.
In the invention patent, the structure is simple, the function is single, and the carbon and sulfur detection and analysis are not filtered before, so that the analysis result can be influenced.
Disclosure of Invention
Aiming at the problems, the invention provides an analysis method of a control system applied to the material element analysis of internal combustion engine parts, which solves the defects of the manual sampling analysis, is stable for a long time within 24 hours and does not need to be recalibrated; the environmental interference is small, and the temperature in the specified range has no influence on the analysis; a visual window is analyzed, and the operation is flexible; the production efficiency is improved.
The invention adopts the following technical scheme to realize the purpose:
an analysis method applied to a control system for analyzing material elements of parts of an internal combustion engine, wherein the control system comprises a combustion system, a filtering system, a weighing system, a control software analysis system and a control center, the control center is respectively connected with the combustion system, the filtering system, the weighing system and the control software analysis system, and the method comprises the following steps:
step 1, the control center sends out an instruction, the control system starts to check a gas circuit, power supply and a material sample of a part of an internal combustion engine, and the combustion system, the weighing system and the control software analysis system are tested to ensure the normal operation of the system;
step 2, inputting the weight data of the solid sample into the control software analysis system; setting parameters in the control software analysis system;
step 3, the combustion system is provided with a combustion furnace and a ceramic crucible positioned in the combustion furnace, the solid sample is placed in the ceramic crucible, and oxygen is introduced at the same time; the control center sends out an instruction to control the combustion system to start so that the solid sample is fully combusted in the combustion furnace;
step 4, introducing the combusted gas into the filtering system for filtering, wherein the residual gas from the filtering system for the first time is SO2And CO2Introducing all the residual gas into a gas collector;
step 5, the control software analysis system comprises a sulfur dioxide analyzer and a carbon dioxide analyzer, and the gas in the gas collector is introduced into the sulfur dioxide analyzer for verification; then the gas in the gas collector is filtered by the filtering system again, and finally the CO is remained2Gas, the CO2Introducing gas into the carbon dioxide analyzer for verification;
step 6, the control center is connected with a screen, the analysis and signal performance tasks are displayed and operated on the screen, and control is realized through buttons arranged on the screen;
and 7, closing the gas circuit, collecting the sample residues on the site, sending an instruction by the control center, and finishing the control system.
Preferably, in step 2, the weight data of the solid sample is input into the control software analysis system through manual input or the weighing system.
Preferably, in step 2, the set parameters include an HF power parameter and a time parameter.
Preferably, in the step 2-3, the solid sample is added with a cosolvent.
Preferably, in step 3, the heating power of the combustion furnace may be adjusted according to the material.
Preferably, in step 5, the control software analysis system adopts a high-selectivity nonlinear dispersion infrared detector to extract and measure the SO2The detection signals generated by the infrared absorption of the gas and the infrared absorption are automatically read by an external computer, and a vulcanization curve is designed and displayed on the screen according to the corresponding relation between the sulfur element and the weight of the solid sample.
Preferably, in step 5, the control software analysis system adopts a high-selectivity nonlinear dispersion infrared detector to extract and measure the CO2The detection signals generated by gas and infrared absorption are automatically read by a peripheral computer, and a carbonization curve is designed and displayed on the screen through the corresponding relation between the carbon element and the weight of the solid sample.
Preferably, in step 6, according to the user requirement, setting the average value, the standard deviation, the deviation coefficient and the minimum maximum value of the statistical window; selecting single-point calibration, two-point calibration or multi-point calibration for testing through a calibration window, and finally displaying the analysis current signal in the form of a chart or a curve; the results of the last five analyses are displayed in the data column.
The invention has the beneficial effects that:
the analysis method applied to the control system for the element analysis of the internal combustion engine part material solves the defects of manual sampling analysis, is stable for a long time within 24 hours, and does not need to be recalibrated; the environmental interference is small, and the temperature in the specified range has no influence on the analysis; a visual window is analyzed, and the operation is flexible; the production efficiency is improved.
Drawings
FIG. 1 is a block diagram of a control system for elemental analysis of a material of a component of an internal combustion engine according to an embodiment of the present invention;
FIG. 2 is a flow chart of a control system applied to material element analysis of internal combustion engine components according to an embodiment of the present invention;
FIG. 3 is a diagram of a data analysis screen of a control system applied to elemental analysis of materials of parts of an internal combustion engine according to an embodiment of the present invention.
In the figure, 1-a combustion system, 2-a filtering system, 3-a weighing system, 4-a control software analysis system and 5-a control center.
Detailed Description
The present invention will be described in detail with reference to the accompanying fig. 1 to 3 and the embodiments.
Referring to fig. 1 to 3, the present embodiment provides an analysis method for a control system applied to elemental analysis of a material of an internal combustion engine component, where the control system includes a combustion system 1, a filtering system 2, a weighing system 3, a control software analysis system 4, and a control center 5. The control center 5 is respectively connected with the combustion system 1, the filtering system 2, the weighing system 3 and the control software analysis system 4, and comprises the following steps:
step 1, a control center 5 sends out an instruction, a control system starts to check a gas circuit (oxygen), power supply (220VAC) and a material sample (solid) of a part of an internal combustion engine, preparation work is done, a combustion system 1, a weighing system 3 and a control software analysis system 4 are tested, and normal operation of the system is ensured;
step 2, inputting the weight (unit: g) data of the solid sample into a control software analysis system 4; and parameters are set in the control software analysis system 4;
step 3, the combustion system 1 is provided with a combustion furnace and a ceramic crucible positioned in the combustion furnace, and a solid sample is placed in the ceramic crucible while oxygen is introduced; the control center 5 sends out an instruction to control the starting of the combustion system 1 so as to ensure that the solid sample is fully combusted in the combustion furnace;
step 4, the combusted gas is introduced into the filtering system 2 for filtering, and the residual gas from the filtering system 2 for the first time is SO2And CO2Introducing all residual gas into a gas collector;
step 5, controlling the softThe analysis system 4 comprises a sulfur dioxide analyzer and a carbon dioxide analyzer, and the gas in the gas collector is introduced into the sulfur dioxide analyzer for verification; then the gas in the gas collector is filtered again by the filtering system 2, and finally the residual CO is filtered2Gas of CO2Introducing the gas into a carbon dioxide analyzer for verification;
step 6, the control center 5 is connected with a screen, the analysis and signal performance tasks are displayed and operated on the screen, and control is realized through buttons arranged on the screen;
and 7, closing the gas path, collecting the field sample residues, sending an instruction by the control center 5, and finishing the control system.
The invention relates to an analysis method applied to a control system for analyzing element of a material of a part of an internal combustion engine, a solid sample is weighed by a weighing system 3 and then combusted in a combustion system 1, gas generated after the combustion of the solid sample is introduced into a filtering system 2 to be filtered, and residual SO is2And CO2The gas is analyzed by a sulfur dioxide analyzer and a carbon dioxide analyzer in the control software analysis system 4 to respectively detect and analyze SO2And CO2And finally, obtaining the comparative analysis of the carbon and sulfur element and the solid sample, thereby obtaining the content of the carbon and sulfur element in the solid sample, and further judging the mechanical properties of the internal combustion engine part material according to the result. The analysis method applied to the control system for the element analysis of the internal combustion engine part material solves the defects of manual sampling analysis, is stable for a long time within 24 hours, and does not need to be recalibrated; the environmental interference is small, and the temperature in the specified range has no influence on the analysis; a visual window is analyzed, and the operation is flexible; the production efficiency is improved.
In the invention, the gas after the solid sample is combusted is firstly introduced into the filtering system 2 for primary filtering, and the residual SO2And CO2Gas, first of all SO2The presence of other gases is prevented from affecting the results of the sulfur detection and thus the final analysis of the results. Then the residual SO2And CO2The gas is again passed to the filtration system 2 for a second filtration with only the remaining CO2Gas, then proceedDetection of CO2The presence of other gases is prevented from affecting the detection result of the carbon and thus the final analysis of the result.
As a preference of this embodiment, in step 2, the weight data of the solid sample can be input to the control software analysis system 4 via the weighing system 3 (balance). When the weighing system 3 is out of order, the weight data of the solid sample can be manually input into the control software analysis system 4, so that the limitation of the whole system is reduced. The recorded data of weighing can be preserved a period of time, conveniently retrieves at any time within the term.
As a preferred mode of the present embodiment, in step 2, the set parameters include an HF power parameter and a time parameter. The parameters can be stored in configuration files named arbitrarily, and different application environments can call different configuration files.
In a preferred embodiment of the present invention, in steps 2 to 3, a cosolvent is added to the solid sample. The cosolvent is selected from any one of pure tin particles, pure tungsten particles or pure iron particles. In this embodiment, the cosolvent is selected as pure tungsten particles.
As a preferable aspect of the present embodiment, in step 3, the heating power of the combustion furnace can be adjusted according to the material, and the effect of sufficient combustion can be achieved.
Preferably, in step 5, CO is detected2After the gas is discharged, the gas in the gas collector is passed to a filtering system 3 for removing CO2And the remaining exhaust gas is discharged to the air. After the analysis and detection are finished, the gas in the filtering system 3 is emptied so as to be put into use next time.
Preferably, in step 5, the software analysis system 4 is controlled to extract and measure SO using a highly selective nonlinear dispersion infrared detector2The detection signals generated by the infrared absorption of the gas are automatically read by an external computer, and a vulcanization curve is designed and displayed on a screen through the corresponding relation between the sulfur element and the weight of the solid sample.
Preferably, in step 5, the software analysis system 4 is controlled to use highly selective nonlinear dispersion infraredThe detector extracts and measures CO2The detection signals generated by the gas and infrared absorption are automatically read by a peripheral computer, and a carbonization curve is designed and displayed on a screen through the corresponding relation between the carbon element and the weight of the solid sample.
As a preferred aspect of the present embodiment, in step 6, an average value, a standard deviation, a deviation coefficient, and a minimum maximum value are set in a statistical window according to a user request; selecting single-point calibration, two-point calibration or multi-point calibration for testing through a calibration window, and finally displaying the analysis current signals in the form of graphs and curves (as shown in FIG. 3); the results of the last five analyses may be displayed in the data field, or the past data may be reloaded into the display window, and a report may be output after the data is processed, or the data may be directly printed.
In fig. 3, curve a represents the carbon content of the solid sample, and curve b represents the sulfur content of the solid sample. The carbon and sulfur content is within the standard content value, so that the content of carbon and sulfur in the solid sample is not overproof, and the mechanical properties of parts and materials of the internal combustion engine are not affected.
Although the invention has been described in detail above with reference to specific embodiments, it will be apparent to one skilled in the art that modifications or improvements may be made based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.

Claims (8)

1. An analysis method applied to a control system for analyzing material elements of internal combustion engine parts is characterized in that the control system comprises a combustion system, a filtering system, a weighing system, a control software analysis system and a control center, the control center is respectively connected with the combustion system, the filtering system, the weighing system and the control software analysis system, and the method comprises the following steps:
step 1, the control center sends out an instruction, the control system starts to check a gas circuit, power supply and a material sample of a part of an internal combustion engine, and the combustion system, the weighing system and the control software analysis system are tested to ensure the normal operation of the system;
step 2, inputting the weight data of the solid sample into the control software analysis system; setting parameters in the control software analysis system;
step 3, the combustion system is provided with a combustion furnace and a ceramic crucible positioned in the combustion furnace, the solid sample is placed in the ceramic crucible, and oxygen is introduced at the same time; the control center sends out an instruction to control the combustion system to start so that the solid sample is fully combusted in the combustion furnace;
step 4, introducing the combusted gas into the filtering system for filtering, wherein the residual gas from the filtering system for the first time is SO2And CO2Introducing all the residual gas into a gas collector;
step 5, the control software analysis system comprises a sulfur dioxide analyzer and a carbon dioxide analyzer, and the gas in the gas collector is introduced into the sulfur dioxide analyzer for verification; then the gas in the gas collector is filtered by the filtering system again, and finally the CO is remained2Gas, the CO2Introducing gas into the carbon dioxide analyzer for verification;
step 6, the control center is connected with a screen, the analysis and signal performance tasks are displayed and operated on the screen, and control is realized through buttons arranged on the screen;
and 7, closing the gas circuit, collecting the sample residues on the site, sending an instruction by the control center, and finishing the control system.
2. The method of claim 1, wherein in step 2, the weight data of the solid sample is manually inputted or the weighing system is inputted into the control software analysis system.
3. The method according to claim 1, wherein the parameters set in step 2 include HF power parameters and time parameters.
4. The method according to claim 1, wherein the solid sample is added with a cosolvent in steps 2-3.
5. The method as claimed in claim 1, wherein the heating power of the burner is adjusted according to the material in step 3.
6. The method as claimed in claim 1, wherein in step 5, the control software analysis system uses a highly selective nonlinear dispersion infrared detector to extract and measure SO2The detection signals generated by the infrared absorption of the gas and the infrared absorption are automatically read by an external computer, and a vulcanization curve is designed and displayed on the screen according to the corresponding relation between the sulfur element and the weight of the solid sample.
7. The method as claimed in claim 1, wherein in step 5, the control software analysis system uses a highly selective nonlinear dispersion infrared detector to extract and measure the CO2The detection signals generated by gas and infrared absorption are automatically read by a peripheral computer, and a carbonization curve is designed and displayed on the screen through the corresponding relation between the carbon element and the weight of the solid sample.
8. The method for analyzing a control system applied to material element analysis of internal combustion engine parts according to claim 1, wherein in step 6, the average value, the standard deviation, the deviation coefficient and the minimum and maximum values of the statistical window are set according to the requirements of a user; selecting single-point calibration, two-point calibration or multi-point calibration for testing through a calibration window, and finally displaying the analysis current signal in the form of a chart or a curve; the results of the last five analyses are displayed in the data column.
CN202011307891.7A 2020-11-20 2020-11-20 Analysis method of control system applied to material element analysis of internal combustion engine parts Pending CN112611879A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202011307891.7A CN112611879A (en) 2020-11-20 2020-11-20 Analysis method of control system applied to material element analysis of internal combustion engine parts

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202011307891.7A CN112611879A (en) 2020-11-20 2020-11-20 Analysis method of control system applied to material element analysis of internal combustion engine parts

Publications (1)

Publication Number Publication Date
CN112611879A true CN112611879A (en) 2021-04-06

Family

ID=75224856

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202011307891.7A Pending CN112611879A (en) 2020-11-20 2020-11-20 Analysis method of control system applied to material element analysis of internal combustion engine parts

Country Status (1)

Country Link
CN (1) CN112611879A (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110716060A (en) * 2018-07-11 2020-01-21 四川赛恩思仪器有限公司 Novel material element detection and analysis system
CN111141696A (en) * 2020-02-19 2020-05-12 长沙开元仪器有限公司 System and method for analyzing carbon and sulfur in underground mine

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110716060A (en) * 2018-07-11 2020-01-21 四川赛恩思仪器有限公司 Novel material element detection and analysis system
CN111141696A (en) * 2020-02-19 2020-05-12 长沙开元仪器有限公司 System and method for analyzing carbon and sulfur in underground mine

Similar Documents

Publication Publication Date Title
Marshall et al. Computer-aided flow-analysis for laboratory use and process analysis
CN104964945A (en) Method for measuring content of carbon in vanadium-nitrogen alloy
CN101839817A (en) Experimental method for intelligent detection of poisonous and harmful gas alarm equipment and device thereof
US20130262008A1 (en) Measurement of light-absorption qualities in the visible spectrum using a camera
CN108956529A (en) For comparing the portable NH of monitoring3, HCl analysis system
US6196051B1 (en) Apparatus for determining odor levels in gas streams
CN111178909A (en) Vegetable safety detection two-dimensional code storage method based on satellite positioning and website system
CN112611879A (en) Analysis method of control system applied to material element analysis of internal combustion engine parts
EP1099103B1 (en) Apparatus for determining oder levels in gas streams
JP4746471B2 (en) Accuracy management system, accuracy management server and computer program
CN216747538U (en) Electrochemical analysis sensitivity self-adjusting device suitable for on-site rapid detection
CN111239332A (en) Device and method for automatically correcting data of measuring instrument
JP4382702B2 (en) Environmental measurement system and environmental measurement program
CN113189269A (en) Method and system for automatically testing smoke dust
US6901349B2 (en) Analysis apparatus and analysis method
JPS5821144A (en) Highly accurate and fully automatic analyzing method for icp
JPH0328762A (en) Data processing method for water quality analyzer
JP2742490B2 (en) Data analysis plan creation device in part quality inspection plan creation system
CN113791128B (en) Safety alarm system and method for gas concentration in converter gas
US20110287372A1 (en) Method and Device for Monitoring the Combustion Process in a Power Station on the Basis of an Actual Concentration Distribution of a Material
JPH04144051A (en) Data processing device for gas chromatograph mass spectrometer
TWI796829B (en) Gas detection system and detection method using the same
CN212207288U (en) Methane detecting instrument stability test device
JPH0723879B2 (en) Sample heating furnace in gas extraction type sample analyzer
JPH08105770A (en) Inspecting device

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination