The platen superheater tube of a domestic flame boiler burst and leaked after one month operation. The burst causes of superheater tube were analyzed by means of macroscopic examination, chemical composition analysis, hardness test, metallographic examination, scanning electron microscope and energy spectrum analysis. The results show that long-time over temperature operation caused tube burst. Weld beadings inside the girth weld of superheater tube joint blocked the steam flow, and oxide skin impacted heat transfer, which caused partial wall overheating for a long time. Serious aging of microstructure and obvious creep damage of burst mouth reduced the strength of tube material, and the pressure bearing capacity of tube wall and finally led to burst and leakage of superheater tube.

The welding procedure qualification test is performed to verify the correctness of the proposed weldment welding process and to evaluate the test process and results. At present, the commonly used welding procedure qualification standards and specifications at home and abroad are mainly GB 50661-2011, NB/T 47014-2011, EN ISO 15614-1:2004+A2:2012, ASME IX-2013, AWS D1.1/D1.1M-2015 and so on. The above standards and specifications were compared and analyzed from the aspects of welding procedure qualification procedure, specimen preparation, test procedure and evaluation basis. The sampling problems of butt joints for tensile, bend and impact test during the qualification were mainly discussed, and the similarities and differences of various standards and specifications were summarized. The results show that each standard or specification has its own requirements in terms of test content, sampling quantity and location, specimen size, etc. Special attentions should be paid during the actual qualification.

In order to promote the revision of grain size testing standards at home and abroad, facilitate international steel trade exchanges, and promote the development and progress of grain size testing technology, the grain size testing standards at home and abroad and their evolution process are introduced, and the characteristics and differences of each standard are analyzed and compared.

Precipitation of detrimental secondary phases such as σ, χ, R phase, chromium carbides and nitrides will inevitably occur at the grain boundary, phase boundary and its surrounding areas at 300~1 000 ℃ which leads to the formation of Cr depleted zones around grain boundary and precipitation of austenite-ferrite duplex stainless steel. This may seriously deteriorate the intergranular corrosion of the austenitic-ferrite duplex stainless steel in specific environment, so it needs to be accurately measured in the laboratory. The laboratory intergranular corrosion test methods of the austenite-ferrite duplex stainless steel were summarized, including chemical immersion method and electrochemical method. The problems needing attention in the test were put forward, which provided reference for corrosion testers.

By measuring the change of thermal expansion coefficient of materials with temperature, the thermophysical properties of materials and the chemical reactions in the process of temperature change can be studied. the application of measuring the thermal expansion coefficient of materials by means of push rod method in the measurement of thermophysical properties, research and technological development of materials were reviewed, and it was introduced the background and test points of various applications in detail, and the development trend of the thermal expansion test equipment in the future was pointed out.

This paper first introduced the causes of internal stress, then introduced the basic principles, advantages and disadvantages, and research status of nondestructive testing methods (X-ray diffraction method, neutron diffraction method, magnetic measurement method and ultrasonic detection method) and destructive testing method (blind hole method), respectively. Finally, the application prospect of internal stress testing method was prospected.

In order to improve the speed and accuracy of the insulation resistance detection method of electric vehicle, and improve the high voltage safety of vehicle. The detection principles, advantages and disadvantages of the common active detection and passive detection methods of insulation resistance of electric vehicle power battery and high voltage system were compared and analyzed. The influence factors of insulation resistance detection accuracy were discussed, and the measures to improve the detection accuracy were pointed out. Finally, an integrated on-line detection method of electric vehicle insulation resistance was developed. The results show that the active detection method of insulation resistance can identify the insulation failure of positive and negative sides at the same time and calculate the insulation resistance value, but it takes a long time. The passive detection method of insulation resistance can judge the vehicle insulation state in real time, but can not identify the insulation failure of positive and negative sides at the same time, and insulation resistance value can not be detected accurately. The improved integrated insulation resistance detection method can give consideration to the accuracy of insulation resistance detection results in normal state and insulation fault, improve the accuracy of active detection method, and improve the high voltage safety performance of vehicle.

Mechanisms of several measurement methods for thermal conductivity were summarized and the characteristics of these methods were analyzed through comparing the basic parameters of typical measurement apparatuses set up at home and abroad. The results show that steady-state methods have good accuracy and repeatability in materials with low thermal conductivity, with small measurement range, narrow temperature range, long measurement cycle time and rigid measurement environment. On the contrary, transient methods have great characteristics including large measurement range, wide temperature range, short measurement cycle time and mild environment requirements, but they are poorer in accuracy and repeatability compared with steady-state methods in measuring insulation materials. It is necessary to synthetically consider materials, methods, apparatuses and measurement requirements when choosing measurement method for thermal conductivity.

Destructive test on welds in metallic materials is one of the test methods to provide important data for quality evaluation of welded joints. The development progress of destructive test standards on welds in metallic materials were introduced, and put forward some suggestions for the development of destructive test standards for metallic materials in China.

Reasonable metallographic sample preparation method is the guarantee to obtain clear and high quality microstructure image, and is the basis of metallographic study of materials. The metallographic preparation techniques and specific methods of high purity tungsten, high nitrogen stainless steel, automobile steel plate and coating material were analyzed, and the problems encountered in the process of cutting, inlaying, grinding and polishing and etching in sample preparation were solved. The results show that the hardness of high purity tungsten is high, so grinding and polishing time should be ensured. High nitrogen stainless steel agent can obtain uniform microstructure by etching with ferric chloride and glycerin hydrochloride mixture. The sample preparation of automobile steel plate should ensure that the sample is upright and not inclined, and avoid scratches during polishing. During the cutting, inlaying and grinding and polishing process of coating material sample preparation, the protective work should be done to ensure the integrity of coating.

The relevant important standards involved in the attribute identification of imported scrap metal solid wastes were introduced. The important inspection technology in the attribute identification of imported scrap metal solid wastes were expounded. The key points in the application of attribute identification methods for imported scrap metal solid wastes were discussed. It is expected that the relevant elaboration can play a guiding and technical support role in the inspection and supervision of imported scrap metal solid wastes.

The service environments for aerospace equipments are very complex and severe, and the surface properties of the materials affect the abilities of the aerospace equipments directly to serve in the harsh and complex environments for a long time. Surface treatment technology is one of the effective means to improve the surface properties of the aerospace materials. The surface treatment technologies used in the aerospace industry in recent years, including anodic oxidation, micro arc oxidation, electroplating, thermal spraying, vapor deposition and other surface treatment technologies, were introduced generally. The research hotspots of various surface treatment technologies as well as the applied research status and the latest progress in different aerospace materials were reviewed. The development directions of the surface treatment technologies for aerospace industry were briefly pointed out.

Firstly, each step of metallographic sample preparation was introduced, and the operation key points that should be paid attention to in each step were explained. Then, the grinding and polishing parameters and actual effects of metallographic samples prepared by automatic sample preparation equipment for different steel grades were exemplified, so as to provide reference for metallographic inspection technicians.

Due to its high corrosion resistance, it was difficult to quickly and clearly show the microstructure of 2205 duplex stainless steel in the material performance evaluation. On the basis of the existing corrosion methods of duplex stainless steel, the formula of oxalic acid,sodium bicarbonate,nitric and glycerol was used to optimize the corrosion solution, and the clear microstructure of duplex stainless steel could be obtained in a short period time by using the method of electrolytic corrosion.

The 10.9 grade bolts made of SCM435 steel were subjected to overload, fatigue and hydrogen embrittlement fracture. Combined with the macro and micro morphology, the formation mechanism of different fracture types of bolt surfaces were studied. The results show that each fracture surface occurred in the thread part, and the micro characteristics were obvious. The overload fracture surface shows the characteristics of dimple, and the dimple of the screw fracture surface of the blind hole was shear dimple. The fatigue fracture surface had bright fatigue lines, the fatigue area of high and low cycle fatigue fracture surface accounted for 2/3 and 1/2 of the whole section. The grain of hydrogen embrittlement fracture surface was clear and the characteristics of intergranular fracture were obvious. Among different types of fracture surfaces, tightening+stretching fracture surfaces necking and thread elongation were the most obvious, the high and low cycle fatigue fracture surfaces basically had no necking and elongation, and the other types of thread fracture surfaces had a slight elongation.

In order to make up to the hot rolling and cold rolling process for the lack of processing capacity or high cost of seamless steel tubes for large-caliber thin-wall gas cylinders, the technology of thermal expansion and cold drawing was developed and improved to manufacture the seamless steel tubes. The test results prove that:the cylinder steel tubes manufactured by this technology could meet the requirements of GB 28884-2012, and also meet the agreement requirements of customers in performance, dimension and so on, and they could make up for the lack of such gas steel tubes in the market.

Based on GB/T 230.1-2009, national standard GB/T 230.1-2018 was got from revising and applying international standard ISO 6508-1:2016. Through comparing with the previous version standard, the new standard revision contents including the name, scope, normative references, principle, symbols, abbreviated terms and designations, testing machine, test piece, procedure, test report, annex C and annex D were introduced and analyzed in detail. The result shows that revisions such as introducing JJG 112, stipulating that a daily check for hardness tester should be done before test, revising annex C, changing annex C and annex D from informative annex to normative annex etc., were all very important modification for the new standard. Compared with previous version standard, GB/T 230.1-2018 is more complete, more rigorous and easier to carry out, and has obvious progress.

In order to evaluate the overburned structure of aluminum alloy more accurately in metallographic examination process, taking 2A02 wrought aluminum alloy as an example, metallographic samples were prepared by superheating quenching. The traditional metallographic examination method was improved, and the characteristics and mechanical properties of overburned structure were analyzed. The results show that the volume ratio of 0.5% hydrofluoric acid etching is helpful to accurately determine the critical overburned structure under optical microscope. Scanning electron microscope and energy spectrum analysis can help operators to distinguish the characteristics and phase of critical overburned structure accurately. The microstructure of 2A02 aluminum alloy is normal when the solid solution temperature is below 510 ℃, and the hardness increases slightly with the increase of solid solution temperature. When the solid solution temperature is above 510 ℃, the primary melting ball gradually appears with slight overburned phenomenon. The intermittent network remelting grain boundary appears at 520 ℃, which is typical overburned structure. The grain boundary remelts and coarsens, and large-size remelting ball appears at 530 ℃, which is serious overburned structure. The local remelting ball becomes cavity at 550 ℃. The hardness and corrosion resistance of aluminum alloy decrease sharply after being overburned.

The existence of non-metallic inclusions in steel is inevitable. How to correctly judge and identify the properties of non-metallic inclusions is very important. The types of non-metallic inclusions in steel were identified by optical microscope, scanning electron microscope and energy dispersive spectrometer according to the optical and morphological characteristics of non-metallic inclusions. The grade of inclusions shall be evaluated according to relevant standards, and the composition and source of inclusions were accurately confirm in combination with the qualitative and quantitative analysis results of inclusions composition energy spectrum. It provided a scientific basis for improving the production process of steelmaking and continuous casting, reducing the number of harmful inclusions, improving the purity of steel and producing high-quality steel.

Ultrafine grained titanium with multilayer and gradient structure was designed and prepared by combining cold rolling and surface mechanical wear treatment. The mechanical properties of the prepared ultrafine grained titanium were tested. The microstructure was observed by scanning electron microscopy, and the deformation mechanism of the material was studied in detail by transmission electron microscopy. The results show that each layer had its own specific deformation and failure mechanism. The deformation mechanism included a large number of shear banding of amorphous nanocrystalline mixed layer, grain boundary induced deformation of nanocrystalline layer and local shear of ultrafine grain core. The gradient at the connection between layers reduced the degree of interface damage, increased the crack arrest effect, and improved the contact bearing capacity. This complex plastic deformation improved the strength and work hardening properties of multilayer gradient titanium.

With epoxy resins cured by different curing agents as the matrix, hollow glass beads (HGB) as the dispersed phase, and silane coupling agents as the additive, solid buoyancy materials were prepared. The effects of additive contents of silane coupling agents on water absorption and compression strength of the solid buoyancy materials before and after water absorbing under the condition of hydrostatic pressure of 45 MPa and after drying were studied. The differences in the properties of the two curing system solid buoyancy materials were discussed. The results show that adding 6% (mass fraction) coupling agents could improve the water absorption and compression strength of the solid buoyancy materials. The compression strength of the solid buoyancy material cured by acid anhydride curing agent MeTHPA was higher than that of the solid buoyancy material cured by amine curing agent DDM. The compression strength of the solid buoyancy materials decreased in varying degrees after water absorbing under the condition of hydrostatic pressure of 45 MPa and after drying, and adding coupling agents could reduce the decrease of compression strength.

Taking the epoxy glass fiber reinforced plastic pressed by unidirectional glass fiber/epoxy resin prepreg and a plain glass fiber/epoxy resin prepreg as the research object, the bending tests were carried out, and the bending strength of samples were compared and analyzed. The results show that for the laying mode of unidirectional fiber and single angle, the 0° fiber sample has higher bending strength. For the unidirectional fiber cross ply, the specimens with 0° fiber and 90° fiber alternating ply have higher bending strength. For different lamination methods, the bending strength of the specimen with 0° fiber placed on the outermost side is higher than that of the specimen with 90° fiber placed on the outermost side. The bending strength of unidirectional glass fiber specimen is slightly higher than that of plain glass fiber specimen.

The national standard of non-metallic inclusion inspection will be revised soon. In order to improve the standard, the GB/T 10561—2005 Steel—Determination of content of nonmetallic inclusions—Micrographic method using standard diagrams was studied in detail, and compared with the old national standard and corresponding international standards. The results show that GB/T 10561—2005 is more perfect than the old version of GB/T 10561—1989. It stipulates that the inclusion should be graded according to the length, thickness, diameter, particle number and distribution of inclusions, which is convenient for the test personnel to operate and is conducive to the accurate evaluation of steel quality. GB/T 10561—2005 needs to be further improved in the aspects of text editing, principle formula, actual inspection rules, result expression and atlas making.

The effect of different solution heat treatment processes on Huey corrosion properties of urea grade 316Lmod stainless steel tube was studied by Huey test. The surface corrosion morphology of the specimens with different heat treatment processes during Huey test was observed by optical microscope and scanning electron microscope, and the corrosion mechanism of Huey test was analyzed. The results show that the average corrosion rates of the specimens solution heat treated at 1 000-1 150 ℃ decrease with the increase of solution temperature, but the Huey corrosion resistance increases with the increase of solution temperature. With the increase of corrosion test cycle, the number of corrosion pits on grain boundaries of specimens, the area of corrosion pits and the corrosion rate increase. With the increase of solution temperature, the number of corrosion pits and the total area of corrosion pits on the grain boundary of specimens in the same corrosion test cycle decrease, and the Huey corrosion resistance improves. The average grain size is proportional to the solution temperature, the larger the average grain size is, the better the non sensitized intergranular corrosion resistance of the material is, and the better the Huey corrosion resistance is.

The differences of results of Leeb hardness converted into tensile strength of building structure steel in three standards, such as GB/T 50344—2019, were compared, the reasons for the differences were discussed based on theoretical analysis and experimental research, and the conversion relationship between hardness and strength of steel for building steel structure was studied. Through regression analysis, the conversion formula and relative deviation of conversion of strength by Leeb hardness were given and compared with the standard conversion value. The results show that due to the different processing and fixation methods of samples, the results of conversion of building structure steel tensile strength by Leeb hardness in the three standards are quite different. In the engineering field test, if the appropriate support or coupling is not carried out, the test results of different positions of the same steel plate will have obvious differences, and the thinner the steel plate is, the greater the difference is. There is a positive correlation between the Leeb hardness and strength of steel plate when the coupling method is used for the test of the hardness of steel plate, and the relative deviation of conversion value can basically meet the requirements of field engineering testing, which can be applied to engineering practice.

The XGF-6X ZL102 aluminum alloy suspension clamp of a 220 kV transmission line fractured during operation. The causes of fracture on suspension clamp were analyzed by means of macro analysis, chemical composition analysis, hardness test, mechanical failure load test, radiographic inspection and fracture analysis.The results show that the size of suspension clamp did not meet the design requirements, and there were some casting defects such as pores and slag inclusions in suspension clamp, which made the mechanical failure load of suspension clamp lower than the standard requirements. During operation, the vertical load of suspension clamp increased due to icing, and finally overload fracture occurred.

Inter-granular corrosion sensitivity is one of the important test items of stainless steel. GB/T 4334-2020 has been issued and implemented the content of standard update was interpreted and analyzed. The new standard has made a series of changes in the name, sampling, preparation and sensitization system. The test methods have been greatly updated, including the abolition of nitric acid-hydrofluoric acid method, the addition of copper-copper sulfate-35% wt sulfuric acid method and 40% wt sulfuric acid-iron sulfate method. The use conditions and scope of various test methods have been clarified, and the test parameters of the bending evaluation method have been modified.

High grade offshore wind turbine steel with yield strength of 460 MPa was successfully R&D based on ultra fast thermo mechanical control process (TMCP), and based on the principle of low carbon content, low carbon equivalent, micro alloying in composition design and high heat input in welding. The chemical composition design and trial production process of the developed two kinds of steel were described, and their comprehensive mechanical properties were analyzed. The results show that the two developed steels have the characteristics of short production cycle, high strength, good toughness, good lamellar tear resistance, good fatigue resistance, excellent crack arrest performance and can be welded with high heat input, which is in line with the development direction of offshore wind turbine steel.

The latest progress in toughening modification research of epoxy resin at home and abroad was reviewed. The research status of toughening epoxy resin with rubber elastomer, nanoparticles, thermoplastic resin and liquid crystal polymer was introduced. The mechanism and results of various toughening methods were analyzed.The development direction of toughening epoxy resin was expected.

The requirements in lubricity evaluation of lubricants were summarized, the application of four-ball tester method, ball-plate tester method, loop-block tester method and V-block tester method in the tribological property evaluation tests of lubricating fluid and lubricating grease was introduced, and the advantages and disadvantages of these four methods were analyzed. The limitations and improvements of the evaluation methods were also discussed:four-ball tester method was the most widely applied method; ball-plate tester method was only suitable for lubricating grease; loop-block tester method and V-block tester method were usually used in extreme-pressure property evaluation. Additionally, further exploration of friction and wear formation process and lubrication mechanism would be accomplished by combining tribological methods with instrumental analysis methods.

The effects of heat input, alloying elements, cooling rate and strain rate on microstructure of high strength steel welded joint and the latest research progress in situ observation of microstructure of high strength steel by high temperature confocal microscope were reviewed. The transformation mechanism of microstructure in coarse grain heat affected zone of welded joint of high strength steel was summarized. The results show that the contents of martensite, granular bainite and acicular ferrite in the microstructure of high strength steel welded joint can be controlled to reach the optimal proportion by prolonging cooling time, reducing heat input, controlling the content of alloying elements and increasing strain rate by pretreatment, so as to optimize the mechanical properties of high strength steel welded joint. The dynamic process of phase transformation of high strength steel can be observed by high temperature confocal microscope, and the phase transformation principle of high strength steel can be obtained, which can provide guidance for the formulation of high strength steel welding process.

The pitting corrosion test of ferric chloride is mainly used to evaluate the pitting corrosion resistance of corrosion resistant alloys. The pitting corrosion test of ferric chloride in ASTM G48-11 was analyzed. The technical points and practical experiences of pitting corrosion test of ferric chloride were introduced from the aspects of test equipments, test solutions, sample preparation and test methods. The results show that there could be some errors in the details of solution preparation, sample surface treatment, sample placement time node and so on during the pitting corrosion test of ferric chloride for corrosion resistant alloy welded joints, and which would affect the accuracy of the test results. In daily inspection work, the regularity of test details should be strengthened, the accuracy of test results should be continuously improved, and reliable test data should be provided for enterprise production.

Digital image correlation (DIC) has the advantages of automation, simple optical path, good universality and strong anti-interference ability, which is widely used in many fields and materials mechanical properties testing. The application progress of digital image correlation in mechanical properties testing, functional structural properties research and product quality inspection of composite material since 2017 was reviewed, and the development direction was put forward.

It is common to use the Oliver-Pharr method to measure the elastic modulus of materials by nanoindentation. Numerical simulation methods were used to study the influence of the residual stress on the measurement of the elastic modulus when using the Oliver-Pharr method. Fused silica material and aluminum alloy material were selected in this study. The results show that due to the pile-up effect of aluminum alloy material during the indentation process, it had large error when measuring the elastic modulus of aluminum alloy material without the residual stress. Especially, the error caused by compressive residual stress was as high as 41. 3%. On the contrary, it had an error of 0. 9% when measuring the elastic modulus of the fused silica material without the residual stress. However, the stress state of tensile and compressive residual stress will both caused large error when using the Oliver-Pharr method. The Oliver-Pharr method had better recognition accuracy when measuring the elastic modulus of harder materials like fused silica when there was no residual stress, but it was no longer applicable to softer materials such as aluminum alloy. It was advised that the effect of residual stress should be fully considered when measuring elastic modulus of materials by the nanoindentation method.

For the phenomenon of low-temperature impact toughness disqualification of S355NL steel, the steel plates were analyzed from the aspects of chemical composition, mechanical property, microstructure, inclusions, fracture and so on. The main parameters of the smelting, continuous casting, the rolling process were discussed with an emphasis. The results show that:the non-uniform grain size and coarse impurity particles were the main reasons leading to the low impact toughness of S355NL steel. By optimizing the smelting process to control the chemical compositions and inclusions, and optimizing the rolling process parameters to ensure the grain size of the steel plates, the qualified rate of the impact toughness of the S355NL steel was effectively improved.

The non-oriented silicon steel with silicon content of 2. 5%-3. 5% (mass fraction) was selected as the analysis object, and the microstructure and texture changes during the whole process (hot rolling, normalizing, cold rolling, annealing) were studied. The results show that due to the distribution characteristics of deformation and temperature field, the non-oriented silicon steel hot rolled plate formed hierarchical structure, the surface layer was recrystallization structure, the central layer was banded recovery structure, and the transition region was mixed with recrystallization and recovery structure. At the same time, there was a large texture gradient in the thickness direction, which will be inherited to the finished plate, but the texture gradient will be weakened with the deformation and recrystallization. After normalizing, the hot rolled banded structure disappeared and the recrystallized grains grown sufficiently. After cold rolling, the microstructure of non-oriented silicon steel was mainly strip structure extending along the rolling direction. The general rule of deformation and recrystallization behavior of the non-oriented silicon steel is that α line texture was formed during deformation, and then transformed into γ line texture and α^* texture after recrystallization.

The effect of heat treatment process on the microstructure and mechanical properties of 12Cr1MoV steel was studied by heat treatment simulation test with different normalizing and tempering process. The results show that the normal microstructure of 12Cr1MoV steel after normalizing and tempering was bainite and ferrite, or bainite, ferrite and pearlite, or ferrite and pearlite. If the tempering temperature was too high or the normalizing cooling rate was too low, it would generate yellow martensite in two-phase region or carbide containing vanadium precipitating accumulatively along the grain boundary and in the grain respectively, which would significantly reduce the mechanical properties of the steel.

High pressure turbine blade of an engine cracked is made of nickel based single crystal alloy blade, the blade after vibration fatigue test at room temperature. The causes of cracking on blade were analyzed by means of macroscopic observation, metallographic examination and scanning electron microscope analysis. The results show that the fatigue cracking of inlet blade root and blade root stretch section was found. There were many small notches in the inner wall of air film holes of inlet blade root and the loose defects on the sub surface of blade root stretch section. The defects were easy to form crack sources, which promoted the crack initiation, and finally led to cracking failure after crack propagation.

Three kinds of metal materials with different plasticity of 10CrNi3MoV steel, 5083 aluminum alloy and 500-7 nodular cast iron were used as the research objects, and the smooth and notched specimens were processed respectively. The effect of notch on the fracture behavior of the metals with different plasticity was studied by comparing the tensile property and fracture morphology of specimen. The results show that the notch changed the stress state of material, reduced the deformation in the shear direction and improved the proportion of normal tensile fracture. For plastic materials, the notch root could alleviate the stress concentration through plastic deformation, and the larger the notch depth, the better the plasticity of material and the higher the tensile strength. For brittle materials, the stress concentration on the notch root would lead to the premature fracture of specimen during the tensile process and reduce the tensile strength of materials.

The working principle and application of X-ray energy dispersive spectrometer (EDS) in scanning electron microscope were briefly introduced. The common problems of spectral peak identification during the energy dispersive spectrometer analysis were false peaks and overlapping peaks. The identification methods of false peaks and overlapping peaks were emphatically introduced. The false peaks generally can be recognized by the instrument, and the overlapping peaks can be identified by following four methods:identifying by increasing the accelerating voltage and using multiple spectral lines, identifying by using the spectral reconstruction function and increasing the acquisition time, identifying by calculating the height ratio of actual peak and theoretical peak, and identifying by quantitative optimization method. Correctly identifying energy spectral peaks can improve the accuracy of qualitative and quantitative analysis of energy dispersive spectrometers.