In recent years, the rapid innovation and development of financial industry has made financial enterprises have a lot of information. However, the large amount of information is tampered with and fragmented, which can...In recent years, the rapid innovation and development of financial industry has made financial enterprises have a lot of information. However, the large amount of information is tampered with and fragmented, which cannot be shared. With the constant innovation of science and technology, it is the most effective way to solve the information lag and asymmetry of financial products. This article aims to start from the problem of asymmetric information of financial products, the analysis of the emerging block chain technology applied in the financial sector, and with the development of asset securitization information known as the typical scenario for the first time, a concrete analysis information game process, and discuss about the application of chain blocks in securitization feasibility.展开更多
The singing of birds is among the most common sounds in nature.We all hear these songs from time to time. But few of us have had thechance to hear one of nature’s unusual sounds-the song of the hump-backedwhale. Scie...The singing of birds is among the most common sounds in nature.We all hear these songs from time to time. But few of us have had thechance to hear one of nature’s unusual sounds-the song of the hump-backedwhale. Scientists do not know how hump-backed whales produce theirsongs. But scientist Roger Pain has an idea. Mr. Pain has展开更多
The red-backed ratsnake（Elaphe rufodorsata） is widely distributed in East Asia, especially China. This species is a common snake in plain river network region. In the past several decades, E. rufodorsata has dramati...The red-backed ratsnake（Elaphe rufodorsata） is widely distributed in East Asia, especially China. This species is a common snake in plain river network region. In the past several decades, E. rufodorsata has dramatically declined due to the effect of human activities and over hunting for traditional Chinese medicine. We developed nine species-specific microsatellite loci in 190 individuals collected from Huzhou, Zhejiang province in China. These markers revealed a high degree of genetic diversity（13–41 alleles per locus） and heterozygosity（H O ranged from 0.266 to 0.941, and H E ranged from 0.851 to 0.937）. No locus exhibited significant deviations from Hardy–Weinberg equilibrium. There was no evidence of linkage disequilibrium among pairs of loci. These microsatellite markers were described in our study will be valuable tools for the long term management and population-level studies（e.g. the population structure, genetic diversity and variation, individual paternity and evolutionary history） of the species.展开更多
This research presents a compact,high-gain millimeter-wave antenna tailored for reliable 5 G communication in high-speed railway environments.The proposed antenna supports dual-band operation at 28 GHz(n257/n258)and 3...This research presents a compact,high-gain millimeter-wave antenna tailored for reliable 5 G communication in high-speed railway environments.The proposed antenna supports dual-band operation at 28 GHz(n257/n258)and 38 GHz(n260),enabling robust Vehicle-to-Infrastructure(V2I)links required for next-generation railway systems.The radiator occupies only 12 mm×8mm on a Rogers 6010LM substrate(ε_(r)=10.2,h=0.64 mm).A Metallic Ground-Backing(MGB)reflector,positioned 9mm behind the patch—λ/4 at 28 GHz—enhances forward radiation,suppresses back-lobes,and ensures highly directional coverage along railway tracks.The antenna achieves measured peak gains of 7.96 dBi at 28 GHz and 8.20 dBi at 38 GHz,with excellent impedance matching and stable radiation patterns under mobility scenarios.Its unique combination of compact footprint,reflectoraided gain enhancement,and stable dual-band performance under dynamic conditions distinguishes it from conventional millimeter-wave solutions,making it a strong candidate for 5G-based high-speed railway communication modules and arrays.展开更多
BACKGROUND The need for an emergency upgrade of a hospitalized trauma patient from the floor to the trauma intensive care unit(ICU)is an unanticipated event with possible life-threatening consequences.Unplanned ICU ad...BACKGROUND The need for an emergency upgrade of a hospitalized trauma patient from the floor to the trauma intensive care unit(ICU)is an unanticipated event with possible life-threatening consequences.Unplanned ICU admissions are associated with increased morbidity and mortality and are an indicator of trauma service quality.Two different types of unplanned ICU admissions include upgrades(patients admitted to the floor then moved to the ICU)and bounce backs(patients admitted to the ICU,discharged to the floor,and then readmitted to the ICU).Previous studies have shown that geriatric trauma patients are at higher risk for unfavorable outcomes.AIM To analyze the characteristics,management and outcomes of trauma patients who had an unplanned ICU admission during their hospitalization.METHODS This institutional review board approved,retrospective cohort study examined 203 adult trauma patients with unplanned ICU admission at an urban level 1 trauma center over a six-year period(2017-2023).This included 134 upgrades and 69 bounce backs.Analyzed variables included:(1)Age;(2)Sex;(3)Comorbidities;(4)Mechanism of injury(MOI);(5)Injury severity score(ISS);(6)Glasgow Coma Scale(GCS);(7)Type of injury;(8)Transfusions;(9)Consultations;(10)Timing and reason for unplanned admission;(11)Intubations;(12)Surgical interventions;(13)ICU and hospital lengths of stay;and(14)Mortality.RESULTS Unplanned ICU admissions comprised 4.2%of total ICU admissions.Main MOI was falls.Mean age was 70.7 years,ISS was 12.8 and GCS was 13.9.Main injuries were traumatic brain injury(37.4%)and thoracic injury(21.7%),and main reason for unplanned ICU admission was respiratory complication(39.4%).The 47.3%underwent a surgical procedure and 46.8%were intubated.Average timing for unplanned ICU admission was 2.9 days.Bounce backs occurred half as often as upgrades,however had higher rates of transfusions(63.8%vs 40.3%,P=0.002),consultations(4.8 vs 3.0,P<0.001),intubations(63.8%vs 38.1%%,P=0.001),longer ICU lengths of stay(13.2 days vs 6.4 days,P<0.001)and hospital lengths of stay(26.7 days vs 13.0 days,P<0.001).Mortality was 25.6%among unplanned ICU admissions,31.9%among geriatric unplanned ICU admissions and 11.9%among all trauma ICU patients.CONCLUSION Unplanned ICU admissions constituted 4.2%of total ICU admissions.Respiratory complications were the main cause of unplanned ICU admissions.Bounce backs occurred half as often as upgrades,but were associated with worse outcomes.展开更多
The coupled structural sound equation of a sandwich panel backed by a cavity is derived by using the concept of forced damped normal modes, and the effects of the sandwich core parameter on the panel vibration and int...The coupled structural sound equation of a sandwich panel backed by a cavity is derived by using the concept of forced damped normal modes, and the effects of the sandwich core parameter on the panel vibration and internal sound field are investigated through the numerical calculation. The results show that the panel vibration and induced sound transmissioncan be suppressed by the shear effect of the viscoelastic layer展开更多
Brittle materials,such as silicon,glass,and ceramics,are widely used in engineering via adhesive bonding.The assessment of adhesive strength of brittle materials to other adherends is essential for their applications....Brittle materials,such as silicon,glass,and ceramics,are widely used in engineering via adhesive bonding.The assessment of adhesive strength of brittle materials to other adherends is essential for their applications.Compared with metals and composites,for which standard testing methods have been established,the experimental method for brittle adherends has been much less explored.During the adhesive strength test,the brittleness of these materials makes them prone to failure,rather than the interface.It remains a challenge to measure the adhesive strength of brittle adherends.Here we develop an experimental method to address this issue by using a strap joint specimen with a backing layer.We use a single crystal silicon wafer and two PCB(printed circuit board)strips as adherends to make a strap joint specimen.A steel backing layer is glued to the silicon wafer to prevent the failure of silicon.This method enables the measurement of adhesive strength up to 35 MPa.In contrast,that without backing layer can only measure the adhesive strength below 10 MPa.It is found that the backing layer can reduce the stress in the silicon remarkably,while it has much less effect on the stress in the adhesive layer.We confirm that the backing layer has a negligible effect on the measured adhesive strength but expands the working space greatly.Combining finite element analysis and experiments,we establish the phase diagram for the failure modes.This work provides guidance for the measurement of adhesive strength of brittle materials.展开更多
I love singing very much and I entered a singing competition last year.Every person around me says,"You are quite a talent.You will sure① become a great singer when you grow up."Therefore,I had confident② ...I love singing very much and I entered a singing competition last year.Every person around me says,"You are quite a talent.You will sure① become a great singer when you grow up."Therefore,I had confident② in myself.I thought I would at least enter the finals.However,there were too many competitors who sang much better than me.I was knocked out in the first round.I couldn't help 3 cry③sadly.展开更多
Chinese Premier Li Peng ended his four-day visit to the Democratic People’s Republic of Korea and flew back to Beijing on May 6. On May 6, Japanese Prime Minister Toshiki Kaifu ended a five-nation tour of Southeast A...Chinese Premier Li Peng ended his four-day visit to the Democratic People’s Republic of Korea and flew back to Beijing on May 6. On May 6, Japanese Prime Minister Toshiki Kaifu ended a five-nation tour of Southeast Asia during which he strongly backed the US military presence in the region. Throughout his 10-day trip, which took him to Malaysia, Brunei, Thailand and Singapore, Kaifu vowed his country would never again become a military power.展开更多
The aim of this study was to investigate the effect of backing films on transdermal delivery of cyclobenzaprine patch. Different backing films were chosen to prepare the cyclobenzaprine transdermal patch. The cumulati...The aim of this study was to investigate the effect of backing films on transdermal delivery of cyclobenzaprine patch. Different backing films were chosen to prepare the cyclobenzaprine transdermal patch. The cumulative amount of cyclobenzaprine released from different patches was evaluated in vitro. To investigate the interaction between cyclobenzaprine and backing films, the partitioning experiments and attenuated total reflectance Fourier transform infrared(ATR-FTIR) spectroscopy were performed. The cumulative amount of cyclobenzaprine released from the patch with Cotran? 9700 as backing film was less than that of other patches with different backing films. Furthermore, the cumulative amount of cyclobenzaprine released from the patch with Cotran? 9700 as backing film decreased significantly after 7 d storage at room condition. The partitioning experiments indicated a strong adsorption of cyclobenzaprine onto the Cotran? 9700, which could explain the decrease of cumulative amount of cyclobenzaprine released from the patch with Cotran? 9700 as backing film. According to the ATR-FTIR results, there was no interaction between Cotran? 9700 and cyclobenzaprine. The effect of backing films on the release behavior of cyclobenzaprine transdermal patch was attributed to the adsorption of cyclobenzaprine onto the Cotran? 9700.展开更多
The dynamic thermal process during double-sided asymmetrical TIG backing welding of large thick plates （ 1 000 mm×700 mm×50 mm） is numerically simulated using MSC. MARC. The effect of arc distance on the t...The dynamic thermal process during double-sided asymmetrical TIG backing welding of large thick plates （ 1 000 mm×700 mm×50 mm） is numerically simulated using MSC. MARC. The effect of arc distance on the thermal cycle in weld zone during double-sided asymmetrical T1G backing welding is investigated. The results show that the workpiece experiences double-peak thermal cycle in double-sided asymmetrical TIG backing welding. On the one hand, the fore arc has the pre- heating effect on the rear pass, and the pre-heating temperature depends on the distance between the double arcs, the heat input of fore arc, and the initial temperature of workpiece. On the other hand, the rear arc has the post-heating effect on the fore pass. The mutual effects of two heat sources decrease with the increase of arc distance.展开更多
The geology, sediment and soil studies are important due to its significant impacts on agriculture, mining, constructions materials, industries, environment, ground water percolation, air pollution, surface and ground...The geology, sediment and soil studies are important due to its significant impacts on agriculture, mining, constructions materials, industries, environment, ground water percolation, air pollution, surface and ground water pollutions, earthquakes and geo-hazards in Afghanistan. In this research, we studied petrography, Sediment, tectonic structures, soil fraction selection by using hydrometer, sieving analysis, and geological mapping. Results show different kinds of metamorphic rocks of low grade and medium grade metamorphisms, Garnete mica Schist, Garnete Schist, Quarsite, different types of minerals among rocks. Further, type of sediment consisting residual angular (Autochthonous) and rounded (Allochthonous) transported by water, among sediments consisting Garnete, Gneiss, Schist, Quarsite, Biotite and consisting different type of sizes boulders, Cobble, Granule, Sand, Silt. Hydrometer analysis shows different types of soil clayey loam, sandy loam, silty loam. Moreover, Geological mapping shows complex tectonic structures like joints, cracks, faults, folds, anticline and syncline. The obtained<i> </i><span style="font-family:Verdana;">results suggest that the petrography, sediments and soil researches can be used efficiently for catchments of the Kabul Basin and other basins in Afghanistan.</span>展开更多
As a result of the lower backing weld efficiency, the applying of automatic welding is seriously limited. So a kind of special automatic welder is designed and manufactured for backing weld. This paper introduces the ...As a result of the lower backing weld efficiency, the applying of automatic welding is seriously limited. So a kind of special automatic welder is designed and manufactured for backing weld. This paper introduces the character of the assembled pulse CO2 arc welding machine which has strong penetrability. It specifies the technology of controlling the parameters of all position automatic welding by computer and multi-axis controller. Moreover typical welding procedure parameters are provided. It is proved by examination that the economical and practical equipment and technology are suitable for the long-distance transmission pipeline, and it has a good foreground of spreading and applying.展开更多
Electrochemical Discharge Machining(ECDM)is potentially applicable for the fabrication of film-cooling holes.However,It is extremely difficult for the holes to achieve higher precision and machining quality owing to t...Electrochemical Discharge Machining(ECDM)is potentially applicable for the fabrication of film-cooling holes.However,It is extremely difficult for the holes to achieve higher precision and machining quality owing to the working liquid diminish in the lateral machining gap.In this study,a non-metallic backing layer was proposed to overcome the diminish of working liquid,and the electrochemical reaming,as a post-processing method for ECDM,was used to further improve the machining accuracy and quality of the holes.First,the three-dimensional morphology of the melted pit of a paraffin backing layer was scanned to obtain the geometric parameters.Then,simulation analysis and experimental verification of auxiliary flushing by using the non-metallic backing layer were performed.The machining performance of the holes machined with electrochemical reaming based on non-metallic backing layer was confirmed by the observations of the surface topography of the hole wall and orifice,measurement of the orifice precision,and analysis of the element composition on the surface of the orifice wall.Finally,an optimum combination of machining parameters for electrochemical reaming is obtained through a process parameter optimization experiment.展开更多
文摘In recent years, the rapid innovation and development of financial industry has made financial enterprises have a lot of information. However, the large amount of information is tampered with and fragmented, which cannot be shared. With the constant innovation of science and technology, it is the most effective way to solve the information lag and asymmetry of financial products. This article aims to start from the problem of asymmetric information of financial products, the analysis of the emerging block chain technology applied in the financial sector, and with the development of asset securitization information known as the typical scenario for the first time, a concrete analysis information game process, and discuss about the application of chain blocks in securitization feasibility.
文摘The singing of birds is among the most common sounds in nature.We all hear these songs from time to time. But few of us have had thechance to hear one of nature’s unusual sounds-the song of the hump-backedwhale. Scientists do not know how hump-backed whales produce theirsongs. But scientist Roger Pain has an idea. Mr. Pain has
基金supported by grants from Natural Science Foundation of China (31200283,31272294 and 31270571)the Priority Academic Program Development of Jiangsu Higher Education Institutions,Teaching Reform Research of Nanjing Normal University (2014-61)Postgraduate Research Innovation Projects (KYLX_0716) of Nanjing Normal University
文摘The red-backed ratsnake（Elaphe rufodorsata） is widely distributed in East Asia, especially China. This species is a common snake in plain river network region. In the past several decades, E. rufodorsata has dramatically declined due to the effect of human activities and over hunting for traditional Chinese medicine. We developed nine species-specific microsatellite loci in 190 individuals collected from Huzhou, Zhejiang province in China. These markers revealed a high degree of genetic diversity（13–41 alleles per locus） and heterozygosity（H O ranged from 0.266 to 0.941, and H E ranged from 0.851 to 0.937）. No locus exhibited significant deviations from Hardy–Weinberg equilibrium. There was no evidence of linkage disequilibrium among pairs of loci. These microsatellite markers were described in our study will be valuable tools for the long term management and population-level studies（e.g. the population structure, genetic diversity and variation, individual paternity and evolutionary history） of the species.
文摘This research presents a compact,high-gain millimeter-wave antenna tailored for reliable 5 G communication in high-speed railway environments.The proposed antenna supports dual-band operation at 28 GHz(n257/n258)and 38 GHz(n260),enabling robust Vehicle-to-Infrastructure(V2I)links required for next-generation railway systems.The radiator occupies only 12 mm×8mm on a Rogers 6010LM substrate(ε_(r)=10.2,h=0.64 mm).A Metallic Ground-Backing(MGB)reflector,positioned 9mm behind the patch—λ/4 at 28 GHz—enhances forward radiation,suppresses back-lobes,and ensures highly directional coverage along railway tracks.The antenna achieves measured peak gains of 7.96 dBi at 28 GHz and 8.20 dBi at 38 GHz,with excellent impedance matching and stable radiation patterns under mobility scenarios.Its unique combination of compact footprint,reflectoraided gain enhancement,and stable dual-band performance under dynamic conditions distinguishes it from conventional millimeter-wave solutions,making it a strong candidate for 5G-based high-speed railway communication modules and arrays.
文摘BACKGROUND The need for an emergency upgrade of a hospitalized trauma patient from the floor to the trauma intensive care unit(ICU)is an unanticipated event with possible life-threatening consequences.Unplanned ICU admissions are associated with increased morbidity and mortality and are an indicator of trauma service quality.Two different types of unplanned ICU admissions include upgrades(patients admitted to the floor then moved to the ICU)and bounce backs(patients admitted to the ICU,discharged to the floor,and then readmitted to the ICU).Previous studies have shown that geriatric trauma patients are at higher risk for unfavorable outcomes.AIM To analyze the characteristics,management and outcomes of trauma patients who had an unplanned ICU admission during their hospitalization.METHODS This institutional review board approved,retrospective cohort study examined 203 adult trauma patients with unplanned ICU admission at an urban level 1 trauma center over a six-year period(2017-2023).This included 134 upgrades and 69 bounce backs.Analyzed variables included:(1)Age;(2)Sex;(3)Comorbidities;(4)Mechanism of injury(MOI);(5)Injury severity score(ISS);(6)Glasgow Coma Scale(GCS);(7)Type of injury;(8)Transfusions;(9)Consultations;(10)Timing and reason for unplanned admission;(11)Intubations;(12)Surgical interventions;(13)ICU and hospital lengths of stay;and(14)Mortality.RESULTS Unplanned ICU admissions comprised 4.2%of total ICU admissions.Main MOI was falls.Mean age was 70.7 years,ISS was 12.8 and GCS was 13.9.Main injuries were traumatic brain injury(37.4%)and thoracic injury(21.7%),and main reason for unplanned ICU admission was respiratory complication(39.4%).The 47.3%underwent a surgical procedure and 46.8%were intubated.Average timing for unplanned ICU admission was 2.9 days.Bounce backs occurred half as often as upgrades,however had higher rates of transfusions(63.8%vs 40.3%,P=0.002),consultations(4.8 vs 3.0,P<0.001),intubations(63.8%vs 38.1%%,P=0.001),longer ICU lengths of stay(13.2 days vs 6.4 days,P<0.001)and hospital lengths of stay(26.7 days vs 13.0 days,P<0.001).Mortality was 25.6%among unplanned ICU admissions,31.9%among geriatric unplanned ICU admissions and 11.9%among all trauma ICU patients.CONCLUSION Unplanned ICU admissions constituted 4.2%of total ICU admissions.Respiratory complications were the main cause of unplanned ICU admissions.Bounce backs occurred half as often as upgrades,but were associated with worse outcomes.
文摘The coupled structural sound equation of a sandwich panel backed by a cavity is derived by using the concept of forced damped normal modes, and the effects of the sandwich core parameter on the panel vibration and internal sound field are investigated through the numerical calculation. The results show that the panel vibration and induced sound transmissioncan be suppressed by the shear effect of the viscoelastic layer
基金supported by the National Key R&D Program of China(2021YFB3201700).
文摘Brittle materials,such as silicon,glass,and ceramics,are widely used in engineering via adhesive bonding.The assessment of adhesive strength of brittle materials to other adherends is essential for their applications.Compared with metals and composites,for which standard testing methods have been established,the experimental method for brittle adherends has been much less explored.During the adhesive strength test,the brittleness of these materials makes them prone to failure,rather than the interface.It remains a challenge to measure the adhesive strength of brittle adherends.Here we develop an experimental method to address this issue by using a strap joint specimen with a backing layer.We use a single crystal silicon wafer and two PCB(printed circuit board)strips as adherends to make a strap joint specimen.A steel backing layer is glued to the silicon wafer to prevent the failure of silicon.This method enables the measurement of adhesive strength up to 35 MPa.In contrast,that without backing layer can only measure the adhesive strength below 10 MPa.It is found that the backing layer can reduce the stress in the silicon remarkably,while it has much less effect on the stress in the adhesive layer.We confirm that the backing layer has a negligible effect on the measured adhesive strength but expands the working space greatly.Combining finite element analysis and experiments,we establish the phase diagram for the failure modes.This work provides guidance for the measurement of adhesive strength of brittle materials.
文摘I love singing very much and I entered a singing competition last year.Every person around me says,"You are quite a talent.You will sure① become a great singer when you grow up."Therefore,I had confident② in myself.I thought I would at least enter the finals.However,there were too many competitors who sang much better than me.I was knocked out in the first round.I couldn't help 3 cry③sadly.
文摘Chinese Premier Li Peng ended his four-day visit to the Democratic People’s Republic of Korea and flew back to Beijing on May 6. On May 6, Japanese Prime Minister Toshiki Kaifu ended a five-nation tour of Southeast Asia during which he strongly backed the US military presence in the region. Throughout his 10-day trip, which took him to Malaysia, Brunei, Thailand and Singapore, Kaifu vowed his country would never again become a military power.
文摘The aim of this study was to investigate the effect of backing films on transdermal delivery of cyclobenzaprine patch. Different backing films were chosen to prepare the cyclobenzaprine transdermal patch. The cumulative amount of cyclobenzaprine released from different patches was evaluated in vitro. To investigate the interaction between cyclobenzaprine and backing films, the partitioning experiments and attenuated total reflectance Fourier transform infrared(ATR-FTIR) spectroscopy were performed. The cumulative amount of cyclobenzaprine released from the patch with Cotran? 9700 as backing film was less than that of other patches with different backing films. Furthermore, the cumulative amount of cyclobenzaprine released from the patch with Cotran? 9700 as backing film decreased significantly after 7 d storage at room condition. The partitioning experiments indicated a strong adsorption of cyclobenzaprine onto the Cotran? 9700, which could explain the decrease of cumulative amount of cyclobenzaprine released from the patch with Cotran? 9700 as backing film. According to the ATR-FTIR results, there was no interaction between Cotran? 9700 and cyclobenzaprine. The effect of backing films on the release behavior of cyclobenzaprine transdermal patch was attributed to the adsorption of cyclobenzaprine onto the Cotran? 9700.
文摘The dynamic thermal process during double-sided asymmetrical TIG backing welding of large thick plates （ 1 000 mm×700 mm×50 mm） is numerically simulated using MSC. MARC. The effect of arc distance on the thermal cycle in weld zone during double-sided asymmetrical T1G backing welding is investigated. The results show that the workpiece experiences double-peak thermal cycle in double-sided asymmetrical TIG backing welding. On the one hand, the fore arc has the pre- heating effect on the rear pass, and the pre-heating temperature depends on the distance between the double arcs, the heat input of fore arc, and the initial temperature of workpiece. On the other hand, the rear arc has the post-heating effect on the fore pass. The mutual effects of two heat sources decrease with the increase of arc distance.
文摘The geology, sediment and soil studies are important due to its significant impacts on agriculture, mining, constructions materials, industries, environment, ground water percolation, air pollution, surface and ground water pollutions, earthquakes and geo-hazards in Afghanistan. In this research, we studied petrography, Sediment, tectonic structures, soil fraction selection by using hydrometer, sieving analysis, and geological mapping. Results show different kinds of metamorphic rocks of low grade and medium grade metamorphisms, Garnete mica Schist, Garnete Schist, Quarsite, different types of minerals among rocks. Further, type of sediment consisting residual angular (Autochthonous) and rounded (Allochthonous) transported by water, among sediments consisting Garnete, Gneiss, Schist, Quarsite, Biotite and consisting different type of sizes boulders, Cobble, Granule, Sand, Silt. Hydrometer analysis shows different types of soil clayey loam, sandy loam, silty loam. Moreover, Geological mapping shows complex tectonic structures like joints, cracks, faults, folds, anticline and syncline. The obtained<i> </i><span style="font-family:Verdana;">results suggest that the petrography, sediments and soil researches can be used efficiently for catchments of the Kabul Basin and other basins in Afghanistan.</span>
文摘As a result of the lower backing weld efficiency, the applying of automatic welding is seriously limited. So a kind of special automatic welder is designed and manufactured for backing weld. This paper introduces the character of the assembled pulse CO2 arc welding machine which has strong penetrability. It specifies the technology of controlling the parameters of all position automatic welding by computer and multi-axis controller. Moreover typical welding procedure parameters are provided. It is proved by examination that the economical and practical equipment and technology are suitable for the long-distance transmission pipeline, and it has a good foreground of spreading and applying.
基金supported by the National Natural Science Foundation of China(No.51705239)。
文摘Electrochemical Discharge Machining(ECDM)is potentially applicable for the fabrication of film-cooling holes.However,It is extremely difficult for the holes to achieve higher precision and machining quality owing to the working liquid diminish in the lateral machining gap.In this study,a non-metallic backing layer was proposed to overcome the diminish of working liquid,and the electrochemical reaming,as a post-processing method for ECDM,was used to further improve the machining accuracy and quality of the holes.First,the three-dimensional morphology of the melted pit of a paraffin backing layer was scanned to obtain the geometric parameters.Then,simulation analysis and experimental verification of auxiliary flushing by using the non-metallic backing layer were performed.The machining performance of the holes machined with electrochemical reaming based on non-metallic backing layer was confirmed by the observations of the surface topography of the hole wall and orifice,measurement of the orifice precision,and analysis of the element composition on the surface of the orifice wall.Finally,an optimum combination of machining parameters for electrochemical reaming is obtained through a process parameter optimization experiment.
