The areas used to be covered by shifting sand dunes have been reclaimed rapidly in recent years. However, it is a challenge to reclaim high sand dunes because it is rather costly to level the high dunes to gentle arab...The areas used to be covered by shifting sand dunes have been reclaimed rapidly in recent years. However, it is a challenge to reclaim high sand dunes because it is rather costly to level the high dunes to gentle arable lands. In this study, a wind guide plate was used to change the characteristics of natural wind to level the sand dunes. The use of wind energy could significantly increase the efficiency of dune leveling and decrease the cost. Low wind velocity is a typical characteristic in Ulan Buh Desert of China where the average wind speed is much lower than the threshold velocity for sand movement. The experiment of this study was conducted to accelerate the wind velocity by a wind guide plate to level a sand dune. Results show that the threshold velocity for sand movement is 3.32 m/s at 10 cm above the sand surface in Ulan Buh Desert. A wind guide plate set at an angle less than 50° could significantly increase the wind velocity. The wind velocity could be accelerated up to the threshold velocity for sand movement behind a plate when the plate is at the angles of 20°, 25°, 35° and 40°. The most significant acceleration of wind velocity appears at 1.5 and 3.0 m behind the plate with an angle of 25°. An obvious wind velocity acceleration zone exists behind the wind guide plate when the angles are at 25°, 35°, 40° and 45°, with the most obvious zone under the angle of 45°. The results also show that the total amount of sand transferred over the experimental period increased by 6.1% under the effects of wind guide plates compared to the sand moved without wind guide plates. The results of the study will provide theoretical and practical supports for desert management in sand dune areas.展开更多
BACKGROUND Dentition defect,a common clinical oral disease developed in humans,not only causes masticatory dysfunction and articulation difficulties but also affects facial appearance and increases the burden on the i...BACKGROUND Dentition defect,a common clinical oral disease developed in humans,not only causes masticatory dysfunction and articulation difficulties but also affects facial appearance and increases the burden on the intestinal tract.Restorative treatment is the primary option for this disease.However,traditional restorations have many drawbacks,such as mismatch with the body,low reliability,and incomplete occlusal function recovery.AIM to analyze the efficacy of orthodontics combined with 3D printing guide plate implant restoration in treating patients with dentition defects and its influence on masticatory and phonic functions.METHODS A prospective study was carried out in 86 patients with dentition defects who received implant prosthesis after orthodontic treatment in our hospital between January 2018 and January 2019.Those patients were divided into a control group and an intervention group with 43 patients in each group using a random number table.The control group received traditional implant restoration,whereas the intervention group received 3D printing guide plate implant restoration.Treatment outcomes,cosmetic appearance,dental function,implant deviation,and quality of life were compared between the two groups.RESULTS The overall response rate in the intervention group was significantly higher than that in the control group(95.35%vs 81.40%,χ^(2)=4.071,P=0.044).The number of cases with neatly trimmed cosmetic appearance(χ^(2)=4.497,P=0.034),complete coverage(χ^(2)=4.170,P=0.041),and normal occlusion(χ^(2)=5.512,P=0.019)in the intervention group was higher than that in the control group.After treatment,mastication,swallowing,and articulation were significantly improved in both groups.Masticatory(t=2.980,P=0.004),swallowing(t=2.199,P=0.031),and phonic functions(t=3.950,P=0.004)were better in the intervention group than those in the control group.The deviation value and the deviation angle(t=5.440,P=0.000)at the top(t=6.320,P=0.000)and middle parts of the implants(t=22.295,P=0.000)in the intervention group were lower than those in the control group after treatment.Functional limitations,psychosocial and physical pain and discomfort,and total scores decreased in both groups.The functional limitation(t=2.379,P=0.020),psychosocial(t=2.420,P=0.000),physical pain and discomfort(t=6.581,P=0.000),and total scores(t=2.140,P=0.035)were lower in the intervention group than those in the control group.CONCLUSION Orthodontic treatment combined with 3D printing guide plate implant restoration can significantly improve the masticatory and phonic functions,quality of life,and psychological health of patients with dentition defects.Therefore,it is highly recommended in clinic application.展开更多
We investigate the three-dimensional （3D） scattering problem of an incident plane shear horizontal wave by a partly through-thickness hole in an isotropic plate, in which the Lamb wave modes are also included due to...We investigate the three-dimensional （3D） scattering problem of an incident plane shear horizontal wave by a partly through-thickness hole in an isotropic plate, in which the Lamb wave modes are also included due to the mode conversions by the scattering obstacle in the 3D problem. An analytical model is presented such that the wave fields are expanded in all of propagating and evanescent SH modes and Lamb modes, and the scattered far-fields of three fundamental guided wave modes are analyzed numerically for different sizes of the holes and frequencies. The numerical results are verified by comparing with those obtained by using the approximate Poisson/Mindlin plate model for small hole radius and low frequency. It is also found that the scattering patterns are different from those of the SO wave incidence. Our work is useful for quantitative evaluation of the plate-like structure by ultrasonic guided waves.展开更多
This research is the analysis of rib and groove type wind guide plate for wind generation power system. This device generates electricity by the air flow producing by the high-speed vehicles driving on the road. It ca...This research is the analysis of rib and groove type wind guide plate for wind generation power system. This device generates electricity by the air flow producing by the high-speed vehicles driving on the road. It can produce electricity as long as there are car passing on the high way. The effect is much more efficient in heavy traffic with high speed. If we can set up a large number of this system along the highway, it can provide the lighting in the highway at night but also sell the extra electricity to the power companies with low cost, high performances and improvement of environmental benefits.展开更多
Pressure guide plate plays a certain role in the safe operation of elevator.Based on understanding the respective performance of new and old pressure guide plates,this paper analyses the problems existing in the origi...Pressure guide plate plays a certain role in the safe operation of elevator.Based on understanding the respective performance of new and old pressure guide plates,this paper analyses the problems existing in the original pressure guide plate.It also conducts stress analysis according to the function of pressure guide plate on elevator,and designs a new type of pressure guide plate combined with technological capability and equipment.According to the stress characteristics,a test device is designed and a comparative test is made between the new type of pressure guide plate and the old in order to test the reliability of the new type of pressure guide plate.The test proves that the new pressure guide plate of elevator can meet the requirements of product use and safe operation of elevator products.展开更多
基金supported by the National Key Technology Research and Development Program of the Ministry of Science and Technology of China(2015BAC06B00) the Natural Science Foundation of the Inner Mongolia Autonomous Region of China (2014ZD03)
文摘The areas used to be covered by shifting sand dunes have been reclaimed rapidly in recent years. However, it is a challenge to reclaim high sand dunes because it is rather costly to level the high dunes to gentle arable lands. In this study, a wind guide plate was used to change the characteristics of natural wind to level the sand dunes. The use of wind energy could significantly increase the efficiency of dune leveling and decrease the cost. Low wind velocity is a typical characteristic in Ulan Buh Desert of China where the average wind speed is much lower than the threshold velocity for sand movement. The experiment of this study was conducted to accelerate the wind velocity by a wind guide plate to level a sand dune. Results show that the threshold velocity for sand movement is 3.32 m/s at 10 cm above the sand surface in Ulan Buh Desert. A wind guide plate set at an angle less than 50° could significantly increase the wind velocity. The wind velocity could be accelerated up to the threshold velocity for sand movement behind a plate when the plate is at the angles of 20°, 25°, 35° and 40°. The most significant acceleration of wind velocity appears at 1.5 and 3.0 m behind the plate with an angle of 25°. An obvious wind velocity acceleration zone exists behind the wind guide plate when the angles are at 25°, 35°, 40° and 45°, with the most obvious zone under the angle of 45°. The results also show that the total amount of sand transferred over the experimental period increased by 6.1% under the effects of wind guide plates compared to the sand moved without wind guide plates. The results of the study will provide theoretical and practical supports for desert management in sand dune areas.
文摘BACKGROUND Dentition defect,a common clinical oral disease developed in humans,not only causes masticatory dysfunction and articulation difficulties but also affects facial appearance and increases the burden on the intestinal tract.Restorative treatment is the primary option for this disease.However,traditional restorations have many drawbacks,such as mismatch with the body,low reliability,and incomplete occlusal function recovery.AIM to analyze the efficacy of orthodontics combined with 3D printing guide plate implant restoration in treating patients with dentition defects and its influence on masticatory and phonic functions.METHODS A prospective study was carried out in 86 patients with dentition defects who received implant prosthesis after orthodontic treatment in our hospital between January 2018 and January 2019.Those patients were divided into a control group and an intervention group with 43 patients in each group using a random number table.The control group received traditional implant restoration,whereas the intervention group received 3D printing guide plate implant restoration.Treatment outcomes,cosmetic appearance,dental function,implant deviation,and quality of life were compared between the two groups.RESULTS The overall response rate in the intervention group was significantly higher than that in the control group(95.35%vs 81.40%,χ^(2)=4.071,P=0.044).The number of cases with neatly trimmed cosmetic appearance(χ^(2)=4.497,P=0.034),complete coverage(χ^(2)=4.170,P=0.041),and normal occlusion(χ^(2)=5.512,P=0.019)in the intervention group was higher than that in the control group.After treatment,mastication,swallowing,and articulation were significantly improved in both groups.Masticatory(t=2.980,P=0.004),swallowing(t=2.199,P=0.031),and phonic functions(t=3.950,P=0.004)were better in the intervention group than those in the control group.The deviation value and the deviation angle(t=5.440,P=0.000)at the top(t=6.320,P=0.000)and middle parts of the implants(t=22.295,P=0.000)in the intervention group were lower than those in the control group after treatment.Functional limitations,psychosocial and physical pain and discomfort,and total scores decreased in both groups.The functional limitation(t=2.379,P=0.020),psychosocial(t=2.420,P=0.000),physical pain and discomfort(t=6.581,P=0.000),and total scores(t=2.140,P=0.035)were lower in the intervention group than those in the control group.CONCLUSION Orthodontic treatment combined with 3D printing guide plate implant restoration can significantly improve the masticatory and phonic functions,quality of life,and psychological health of patients with dentition defects.Therefore,it is highly recommended in clinic application.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11474195,11274226,51478258 and 51405287
文摘We investigate the three-dimensional （3D） scattering problem of an incident plane shear horizontal wave by a partly through-thickness hole in an isotropic plate, in which the Lamb wave modes are also included due to the mode conversions by the scattering obstacle in the 3D problem. An analytical model is presented such that the wave fields are expanded in all of propagating and evanescent SH modes and Lamb modes, and the scattered far-fields of three fundamental guided wave modes are analyzed numerically for different sizes of the holes and frequencies. The numerical results are verified by comparing with those obtained by using the approximate Poisson/Mindlin plate model for small hole radius and low frequency. It is also found that the scattering patterns are different from those of the SO wave incidence. Our work is useful for quantitative evaluation of the plate-like structure by ultrasonic guided waves.
文摘This research is the analysis of rib and groove type wind guide plate for wind generation power system. This device generates electricity by the air flow producing by the high-speed vehicles driving on the road. It can produce electricity as long as there are car passing on the high way. The effect is much more efficient in heavy traffic with high speed. If we can set up a large number of this system along the highway, it can provide the lighting in the highway at night but also sell the extra electricity to the power companies with low cost, high performances and improvement of environmental benefits.
文摘Pressure guide plate plays a certain role in the safe operation of elevator.Based on understanding the respective performance of new and old pressure guide plates,this paper analyses the problems existing in the original pressure guide plate.It also conducts stress analysis according to the function of pressure guide plate on elevator,and designs a new type of pressure guide plate combined with technological capability and equipment.According to the stress characteristics,a test device is designed and a comparative test is made between the new type of pressure guide plate and the old in order to test the reliability of the new type of pressure guide plate.The test proves that the new pressure guide plate of elevator can meet the requirements of product use and safe operation of elevator products.
