On the basis of the canard configuration a contour stealth design including chiefly the wing, the fuselage and their connection type is projected. The prime project of a blended wing body vehicle with canard is provid...On the basis of the canard configuration a contour stealth design including chiefly the wing, the fuselage and their connection type is projected. The prime project of a blended wing body vehicle with canard is provided and through the change of the fuselage head form and the different fin disposals, the radar cross section (RCS) is optimized. The average value of RCS and the value of RCS in the ± 45 ° front sector for different designs are illustrated. The model measurement proves that the project having a sharp head fuselage and 30 ° angle double fin has the minimum value of RCS. The wind tunnel test to the model with RCS optimized proved that the vehicle project has excellent aerodynamic characteristics such as high lift curve slope, up to 26° stalling angle, high lift / drag ratio equal to 8, and also has low RCS value in the front sector and in the lateral sector.展开更多
Background: Orthodontic treatment poses challenges such as discomfort, aesthetic concerns, dietary restrictions, time commitment, and financial considerations for patients. These challenges can deter individuals from ...Background: Orthodontic treatment poses challenges such as discomfort, aesthetic concerns, dietary restrictions, time commitment, and financial considerations for patients. These challenges can deter individuals from pursuing treatment or cause anxiety during the process. However, patients are motivated by the desire to improve their appearance, boost self-confidence, and enhance oral health. They also value the long-term benefits of treatment, including improved dental function and overall well-being. Professional recommendations from dentists and orthodontists, along with social support from family and friends, further encourage patients to undergo treatment. Understanding these challenges and motivating factors is crucial for orthodontic professionals to tailor treatment plans and ensure positive experiences and successful outcomes for their patients. Objective: To determine the challenges and motivating factors of orthodontic treatment among patients attending Komfo Anokye Teaching Hospital. Method: The study was conducted at Komfo Anokye Teaching Hospital in Kumasi, Ghana, with a sample size of 60 orthodontic patients. Data was collected using self-administered questionnaires and analyzed using SPSS software. Ethical approval was obtained, and the findings were shared with stakeholders. Results: Findings showed a higher representation of females (63.3%) seeking orthodontic treatment. Common motivations for seeking orthodontic treatment included aesthetic Concerns (38.2%), misaligned teeth (28.1%) and recommendation from dentist (19.2%). Challenges reported included pain and discomfort (36.7%), difficulty chewing (15%), expensive treatment (14.4%) and missed appointments (11.7%). Factors motivating treatment continuation were visible improvements (30%), achieving optimal results (23%), reducing pain and discomfort (17%). External influences, such as family pressure, also played a role. Patients appreciated the support of healthcare providers during treatment but suggested better pain management and education. Conclusion: The study provided valuable insights into patient motivations, challenges and factors influencing satisfaction and adherence to orthodontic treatment at KATH.展开更多
This paper presents the fully differential cross sections （FDCS） for 102eV electron impact single ionization of helium for both the coplanar and perpendicular plane asymmetric geometries within the framework of dyna...This paper presents the fully differential cross sections （FDCS） for 102eV electron impact single ionization of helium for both the coplanar and perpendicular plane asymmetric geometries within the framework of dynamically screened three-Coulomb-wave theory. Comparisons are made with the experimental data and those of the three-Coulomb wave function model and second-order distorted-wave Born method. The angular distribution and relative heights of the present FDCS is found to be in very good agreement with the experimental data in the perpendicular plane geometry. It is shown that dynamical screening effects are significant in this geometry. Three-body coupling is expected to be weak in the coplanar geometry, although the precise absolute value of the cross section is still sensitive to the interaction details.展开更多
This article proposes use of extruded compound materials with optimized resistant cross-sections as an alternative, in this case, seeking the maximum energy density as a design criterion. The advantage of this proposa...This article proposes use of extruded compound materials with optimized resistant cross-sections as an alternative, in this case, seeking the maximum energy density as a design criterion. The advantage of this proposal is that it extends the life cycle and decreases fatigue issues.展开更多
An external carriage and a wing have a high radar cross section (RCS) level in a wide range of angles of pitch because they form an efficient corner reflector. Coupling scattering between the external carriage and the...An external carriage and a wing have a high radar cross section (RCS) level in a wide range of angles of pitch because they form an efficient corner reflector. Coupling scattering between the external carriage and the wing is controlled by designing a saw tooth structure of the external carriage on condition that the wing structure is not changed. A low RCS saw tooth scheme of the external carriage is given in the paper. The ray tracing method and the physical theory of diffraction are used to calculate the radar scattering characteristics of low RCS structures of the external carriage and wing. The results show that the saw tooth scheme of the external carriage is feasible and effective for low RCS design.展开更多
Radar cross section (RCS) reduction technologies are very important in survivability of the military naval vessels. Ship appearance shaping as an effective countermeasure of RCS reduction redirects the scattered energ...Radar cross section (RCS) reduction technologies are very important in survivability of the military naval vessels. Ship appearance shaping as an effective countermeasure of RCS reduction redirects the scattered energy from one angular region of interest in space to another region of little interest. To decrease the scattering electromagnetic signals from ship scientifically, optimization methods should be introduced in shaping design. Based on the assumption of the characteristic section design method, mathematical formulations for optimal shaping design were established. Because of the computation-intensive analysis and singularity in shaping optimization, the response surface method (RSM) combined genetic algorithm (GA) was proposed. The poly-nomial response surface method was adopted in model approximation. Then genetic algorithms were employed to solve the surrogate optimization problem. By comparison RCS of the conventional and the optimal design, the superiority and effectiveness of proposed design methodology were verified.展开更多
A method to reparametrize G retional curve to obtain a C^1 curve is given. A practical G^1 continual connective between adjacent NURUS patches along common guadratic boundary curve is presented in this paper, and a s...A method to reparametrize G retional curve to obtain a C^1 curve is given. A practical G^1 continual connective between adjacent NURUS patches along common guadratic boundary curve is presented in this paper, and a specific algorithm for control points and weights of NURBS patches is discussed.展开更多
文摘On the basis of the canard configuration a contour stealth design including chiefly the wing, the fuselage and their connection type is projected. The prime project of a blended wing body vehicle with canard is provided and through the change of the fuselage head form and the different fin disposals, the radar cross section (RCS) is optimized. The average value of RCS and the value of RCS in the ± 45 ° front sector for different designs are illustrated. The model measurement proves that the project having a sharp head fuselage and 30 ° angle double fin has the minimum value of RCS. The wind tunnel test to the model with RCS optimized proved that the vehicle project has excellent aerodynamic characteristics such as high lift curve slope, up to 26° stalling angle, high lift / drag ratio equal to 8, and also has low RCS value in the front sector and in the lateral sector.
文摘Background: Orthodontic treatment poses challenges such as discomfort, aesthetic concerns, dietary restrictions, time commitment, and financial considerations for patients. These challenges can deter individuals from pursuing treatment or cause anxiety during the process. However, patients are motivated by the desire to improve their appearance, boost self-confidence, and enhance oral health. They also value the long-term benefits of treatment, including improved dental function and overall well-being. Professional recommendations from dentists and orthodontists, along with social support from family and friends, further encourage patients to undergo treatment. Understanding these challenges and motivating factors is crucial for orthodontic professionals to tailor treatment plans and ensure positive experiences and successful outcomes for their patients. Objective: To determine the challenges and motivating factors of orthodontic treatment among patients attending Komfo Anokye Teaching Hospital. Method: The study was conducted at Komfo Anokye Teaching Hospital in Kumasi, Ghana, with a sample size of 60 orthodontic patients. Data was collected using self-administered questionnaires and analyzed using SPSS software. Ethical approval was obtained, and the findings were shared with stakeholders. Results: Findings showed a higher representation of females (63.3%) seeking orthodontic treatment. Common motivations for seeking orthodontic treatment included aesthetic Concerns (38.2%), misaligned teeth (28.1%) and recommendation from dentist (19.2%). Challenges reported included pain and discomfort (36.7%), difficulty chewing (15%), expensive treatment (14.4%) and missed appointments (11.7%). Factors motivating treatment continuation were visible improvements (30%), achieving optimal results (23%), reducing pain and discomfort (17%). External influences, such as family pressure, also played a role. Patients appreciated the support of healthcare providers during treatment but suggested better pain management and education. Conclusion: The study provided valuable insights into patient motivations, challenges and factors influencing satisfaction and adherence to orthodontic treatment at KATH.
基金Project supported by the Natural Science Foundation of Shanxi Province,China (Grant No 20051008)the Science Foundation for Returnee of Shanxi Province of China (Grant No 02-16)
文摘This paper presents the fully differential cross sections （FDCS） for 102eV electron impact single ionization of helium for both the coplanar and perpendicular plane asymmetric geometries within the framework of dynamically screened three-Coulomb-wave theory. Comparisons are made with the experimental data and those of the three-Coulomb wave function model and second-order distorted-wave Born method. The angular distribution and relative heights of the present FDCS is found to be in very good agreement with the experimental data in the perpendicular plane geometry. It is shown that dynamical screening effects are significant in this geometry. Three-body coupling is expected to be weak in the coplanar geometry, although the precise absolute value of the cross section is still sensitive to the interaction details.
文摘This article proposes use of extruded compound materials with optimized resistant cross-sections as an alternative, in this case, seeking the maximum energy density as a design criterion. The advantage of this proposal is that it extends the life cycle and decreases fatigue issues.
基金Aeronautical Science F oundation of China!( 97B5 10 40 )
文摘An external carriage and a wing have a high radar cross section (RCS) level in a wide range of angles of pitch because they form an efficient corner reflector. Coupling scattering between the external carriage and the wing is controlled by designing a saw tooth structure of the external carriage on condition that the wing structure is not changed. A low RCS saw tooth scheme of the external carriage is given in the paper. The ray tracing method and the physical theory of diffraction are used to calculate the radar scattering characteristics of low RCS structures of the external carriage and wing. The results show that the saw tooth scheme of the external carriage is feasible and effective for low RCS design.
基金the National Natural Science Founda-tion of China (No. 10672100)
文摘Radar cross section (RCS) reduction technologies are very important in survivability of the military naval vessels. Ship appearance shaping as an effective countermeasure of RCS reduction redirects the scattered energy from one angular region of interest in space to another region of little interest. To decrease the scattering electromagnetic signals from ship scientifically, optimization methods should be introduced in shaping design. Based on the assumption of the characteristic section design method, mathematical formulations for optimal shaping design were established. Because of the computation-intensive analysis and singularity in shaping optimization, the response surface method (RSM) combined genetic algorithm (GA) was proposed. The poly-nomial response surface method was adopted in model approximation. Then genetic algorithms were employed to solve the surrogate optimization problem. By comparison RCS of the conventional and the optimal design, the superiority and effectiveness of proposed design methodology were verified.
文摘A method to reparametrize G retional curve to obtain a C^1 curve is given. A practical G^1 continual connective between adjacent NURUS patches along common guadratic boundary curve is presented in this paper, and a specific algorithm for control points and weights of NURBS patches is discussed.
