Modeling of bistatic scattering from an underwater non-penetrable target using a Kirchhoff approximation method

A numerical triangulation and transformation into the time domain of a Kirchhoff approximation(KA)method is proposed for the modeling of bistatic scattering from an underwater non-penetrable target.The time domain solution in this approximation can be split up into two parts:the solution of reflected field,contributing around the specular direction,and the solution of shadow radiation,contributing around the forward direction.An average solution in the time domain satisfying the reciprocity principle is presented.The solution is expressed in terms of non-singular functions.The proposed method is validated against a normal mode method for bistatic scattering from a rigid sphere.Moreover,the reflected and shadow highlights on the surface of the sphere are shown to verify the integration surface of the reflected field and shadow radiation.It is also tested against a finite element method and an experiment involving a scaled Benchmark Target Strength Simulation Submarine model.The time-angle bistatic spectra for the model are evaluated by the direct and transformed average solutions of KA,and the former accelerates its speed of calculation.The results are good,and show that this method can be used to predict the bistatic scattered field of a non-penetrable target.

Treatment of lower part of glenoid fractures through a novel axillary approach:A case report

BACKGROUND Based on the location and size of the fracture block,open reduction and internal fixation can be employed or assisted for shoulder arthroscopy in the treatment of glenoid fractures.However,the treatment of lower part of glenoid fractures through a novel axillary approach has not been reported so far.CASE SUMMARY A 22-year-old right-handed man was transferred to our outpatient clinic because of right shoulder injury during a traffic accident.X-ray examination after admission suggested the fracture of the lower part of the right glenoid and an ipiselial proximal humeral fracture.Three-dimensional(3D)computed tomography(CT)further suggested that the size of the fracture block of the lower part of the right glenoid was 3.4 mm×16.2 mm.The patient was diagnosed as the fracture of the lower part of the glenoid,also known as bony Bankart lesion without shoulder dislocation.After general anesthesia,the patient was surgically treated with the open reduction internal fixation through a novel axillary approach.3D CT and shoulder joint function were reexamined at 12 mo of followup,showing acceptable recovery.CONCLUSION This case report describes a novel axillary approach adopted in an open reduction with cannulated screw and wire anchor internal fixation.After a follow-up for more than 12 mo,3D CT and shoulder joint function examinations display a good recovery.