Imaging the spatial precession cone-shaped targets with narrowband radar is a new technical approach in mid-course recognition problem. However, most existing time-frequency methods still have some inevitable deficien...Imaging the spatial precession cone-shaped targets with narrowband radar is a new technical approach in mid-course recognition problem. However, most existing time-frequency methods still have some inevitable deficiencies for extracting microDoppler information in practical applications, which leads to blurring of the image. A new narrowband radar imaging algorithm for the precession cone-shaped targets is proposed. The instantaneous frequency of each scattering point is gained by using the improved Hilbert-Huang transform, then the positions of scattering points in the parameter domain are reconstructed. Numerical simulation and experiment results confirm the effectiveness and high precision of the proposed algorithm.展开更多
National navies equip their submarines with Autonomous Underwater Vehicle(AUV)technology.It has become an important component of submarine development in technologically-advanced countries.Employing advanced and relia...National navies equip their submarines with Autonomous Underwater Vehicle(AUV)technology.It has become an important component of submarine development in technologically-advanced countries.Employing advanced and reliable recovery systems directly improves the safety and operational efficiency of submarines equipped with AUVs.In this paper,based on aerial refueling technology,a cone-shaped recovery system with two different guiding covers(closed structure and frame structure)is applied to the submarine.By taking the Suboff model as the research object,STAR-CCM was used to study the influence of the installation position of the recovery system,and the length of the rigid rod,on the Suboff model.It was found that when the recovery system is installed in the middle and rear of the Suboff model at the same velocity and the same length of the rigid rod,the Suboff model has the good stability and less drag.It experiences the largest drag when being installed in the front of the rigid rod.Moreover,when the recovery system is installed in the front and middle of the rigid rod,the drag increases as its length increases,and the lift decreases as its length increases.Compared with the closed structure guiding cover,the Suboff model will have less drag and better stability when the recovery system uses the frame structure guiding cover.Besides,the deflection and vibration of the rigid rod were also analyzed via mathematical theory.展开更多
Using the rigid visco-plastic Finite Element Method (FEM), the process offorging for long cone-shaped posts made of aluminum alloys was modeled and the correspondingdistributions of the field variables were obtained b...Using the rigid visco-plastic Finite Element Method (FEM), the process offorging for long cone-shaped posts made of aluminum alloys was modeled and the correspondingdistributions of the field variables were obtained based on considering aberrance of grids, dynamicboundary conditions, non-stable process, coupled thermo-mechanical behavior and other specialproblems. The difficulties in equipment selection and die analysis caused by the long cone shape ofpost, as well as by pressure calculation were solved.展开更多
Rationale:Acute caustic ingestion from suicidal intent is not usual in emergency departments in developed countries.One of the substances commonly ingested by suicidal patients,phosphoric acid,tends to cause multi-sys...Rationale:Acute caustic ingestion from suicidal intent is not usual in emergency departments in developed countries.One of the substances commonly ingested by suicidal patients,phosphoric acid,tends to cause multi-system derangements.Patient’s Concern:A 41-year-old male patient presented with complaints of throat discomfort,severe generalized abdominal pain,and multiple episodes of hematemesis after ingesting a restroom cleaning solution.Diagnosis:Poisoning by acute caustic ingestion(containing<30%phosphoric acid and<4%ethylene glycol).Interventions:The patient was administered 50 mL of 8.4%sodium bicarbonate solution followed by an isotonic sodium bicarbonate solution running at 500 mL/h,a hyperkalemia kit,ceftriaxone,metronidazole,omeprazole,and atropine.The patient then underwent urgent hemodialysis.Outcomes:The patient suffered gastrointestinal bleeding as a result of local caustic injury.In addition,his course of illness was complicated by severe acidemia from high anion gap metabolic acidosis and deranged electrolytes(hyperphosphatemia,hyperkalemia,and hypocalcemia).He developed multi-organ failure and eventually demised.Lessons:The clinician needs to be mindful of the multi-system complications arising from such a caustic ingestion.These patients need to be monitored closely for deterioration,and have prompt management of the various arising complications,to reduce the high morbidity and mortality associated with this condition.展开更多
基金supported by the China National Funds for Distinguished Young Scientists(61025006)
文摘Imaging the spatial precession cone-shaped targets with narrowband radar is a new technical approach in mid-course recognition problem. However, most existing time-frequency methods still have some inevitable deficiencies for extracting microDoppler information in practical applications, which leads to blurring of the image. A new narrowband radar imaging algorithm for the precession cone-shaped targets is proposed. The instantaneous frequency of each scattering point is gained by using the improved Hilbert-Huang transform, then the positions of scattering points in the parameter domain are reconstructed. Numerical simulation and experiment results confirm the effectiveness and high precision of the proposed algorithm.
基金This work was financially supported by the Innovation Fund from Chinese Academy of Sciences(Grant No.CXJJ-17-M130)the Research Fund of the State Key Laboratory of Robotics(Gant No.Y91Z0904).
文摘National navies equip their submarines with Autonomous Underwater Vehicle(AUV)technology.It has become an important component of submarine development in technologically-advanced countries.Employing advanced and reliable recovery systems directly improves the safety and operational efficiency of submarines equipped with AUVs.In this paper,based on aerial refueling technology,a cone-shaped recovery system with two different guiding covers(closed structure and frame structure)is applied to the submarine.By taking the Suboff model as the research object,STAR-CCM was used to study the influence of the installation position of the recovery system,and the length of the rigid rod,on the Suboff model.It was found that when the recovery system is installed in the middle and rear of the Suboff model at the same velocity and the same length of the rigid rod,the Suboff model has the good stability and less drag.It experiences the largest drag when being installed in the front of the rigid rod.Moreover,when the recovery system is installed in the front and middle of the rigid rod,the drag increases as its length increases,and the lift decreases as its length increases.Compared with the closed structure guiding cover,the Suboff model will have less drag and better stability when the recovery system uses the frame structure guiding cover.Besides,the deflection and vibration of the rigid rod were also analyzed via mathematical theory.
文摘Using the rigid visco-plastic Finite Element Method (FEM), the process offorging for long cone-shaped posts made of aluminum alloys was modeled and the correspondingdistributions of the field variables were obtained based on considering aberrance of grids, dynamicboundary conditions, non-stable process, coupled thermo-mechanical behavior and other specialproblems. The difficulties in equipment selection and die analysis caused by the long cone shape ofpost, as well as by pressure calculation were solved.
文摘Rationale:Acute caustic ingestion from suicidal intent is not usual in emergency departments in developed countries.One of the substances commonly ingested by suicidal patients,phosphoric acid,tends to cause multi-system derangements.Patient’s Concern:A 41-year-old male patient presented with complaints of throat discomfort,severe generalized abdominal pain,and multiple episodes of hematemesis after ingesting a restroom cleaning solution.Diagnosis:Poisoning by acute caustic ingestion(containing<30%phosphoric acid and<4%ethylene glycol).Interventions:The patient was administered 50 mL of 8.4%sodium bicarbonate solution followed by an isotonic sodium bicarbonate solution running at 500 mL/h,a hyperkalemia kit,ceftriaxone,metronidazole,omeprazole,and atropine.The patient then underwent urgent hemodialysis.Outcomes:The patient suffered gastrointestinal bleeding as a result of local caustic injury.In addition,his course of illness was complicated by severe acidemia from high anion gap metabolic acidosis and deranged electrolytes(hyperphosphatemia,hyperkalemia,and hypocalcemia).He developed multi-organ failure and eventually demised.Lessons:The clinician needs to be mindful of the multi-system complications arising from such a caustic ingestion.These patients need to be monitored closely for deterioration,and have prompt management of the various arising complications,to reduce the high morbidity and mortality associated with this condition.
基金Foundation item:Project(2022YFC2904204)supported by the National Key R&D Program of ChinaProjects(52364048,52004115)supported by the National Natural Science Foundation of China+5 种基金Projects(202101BE070001-019,202101AT070116,202001AU070045)supported by the Yunnan Fundamental Research Projects,ChinaProject(2020)supported by the Yang Bin Scientist Studio of Yunnan Province,ChinaProject(2022)supported by the Yunnan Talents Support Project,ChinaProject(202302AB080002)supported by the Yunnan Key S&T Special Projects,ChinaProject(231100320300)supported by the Henan Key S&T Special Projects,ChinaProject(KKZ7201952006)supported by the High-level Talent Construction of Kunming University of Science and Technology,China。
