There is a close functional relationship between the jaw and neck regions and it has been suggested that trigeminal sensory impairment can follow whiplash injury.Inclusion of manageable routines for valid assessment o...There is a close functional relationship between the jaw and neck regions and it has been suggested that trigeminal sensory impairment can follow whiplash injury.Inclusion of manageable routines for valid assessment of the facial sensory capacity is thus needed for comprehensive evaluations of patients exposed to such trauma.The present study investigated facial thermal thresholds in patients with chronic whiplash-associated disorders（WADs）with both a qualitative method and quantitative sensory testing（QST）.Ten women with pain and dysfunction following a whiplash injury were compared to 10 healthy age-matched women.Thermal detection thresholds were assessed by qualitative chair-side testing and by QST according to the method-of-limits.Seven test sites in the facial skin（overlying each trigeminal branch bilaterally,and the midpoint of the chin）were examined.The detection warm and cold thresholds were defined as the mean values of 10 individual thresholds.For the WAD patients,the qualitative assessment demonstrated both reduced and increased sensitivity compared to the healthy,whereas QST systematically showed significantly higher detection thresholds（i.e.,decreased sensitivity）for both cold and warm stimuli.For the individuals who were assessed as having increased sensitivity in the qualitative assessment,the QST displayed either normal or higher thresholds,i.e.,decreased sensitivity.The results suggest that QST is more sensitive for detecting thermal sensory disturbances in the face than a qualitative method.The impaired thermal sensitivity among the patients corroborates the notion of altered thermal detection capacity induced by WAD-related pain.展开更多
In this paper, we demonstrate that thermal stress is the main mechanism in the process of paint removal by Q-switched Nd：YAG laser （λ = 1064 nm, τ = 10 ns）. A theoretical model ofpaint removal by short-pulse lase...In this paper, we demonstrate that thermal stress is the main mechanism in the process of paint removal by Q-switched Nd：YAG laser （λ = 1064 nm, τ = 10 ns）. A theoretical model ofpaint removal by short-pulse laser is established from the perspective of thermal stress. Thermal stress is generated by thermal expansion, and the temperatures of different samples are calculated according to the one-dimensional （1D） heat conduction equation. The theoretical cleaning threshold can be obtained by comparing thermal stress with the adhesion of paint, and the theoretical damage threshold is obtained by calculating the temperature. Moreover, the theoretical calculations are verified by experimental results. It is shown that the thermal stress model of the laser cleaning is very useful to choose the appropriate laser fluence in the practical applications of paint removal by Q-switched Nd： YAG laser because our model can validly balance the efficiency of laser cleaning and the safety of the substrate.展开更多
Spectroscopic properties of flashlamp pumped Nd^3＋：YAG laser are studied as a function of temperature in a range from-30℃ to 60℃. The spectral width and shift of quasi three-level 946.0-nm inter-Stark emission wit...Spectroscopic properties of flashlamp pumped Nd^3＋：YAG laser are studied as a function of temperature in a range from-30℃ to 60℃. The spectral width and shift of quasi three-level 946.0-nm inter-Stark emission within the respective intermanifold transitions of ^4F3/2→^4I9/2are investigated. The 946.0-nm line shifts toward the shorter wavelength and broadens. In addition, the threshold power and slope efficiency of the 946.0-nm laser line are quantified with temperature.The lower the temperature, the lower the threshold power is and the higher the slope efficiency of the 946.0-nm laser line is,thus the higher the laser output is. This phenomenon is attributed to the ion-phonon interaction and the thermal population in the ground state.展开更多
针对传统特征匹配算法计算效率低、误匹配率高和双目视觉测量精度不足等问题,提出了一种基于自适应几何约束和随机抽样一致性方法的ORB(Oriented FAST and Rotated BRIEF)红外双目测距方法。首先,通过FAST(Features from Accelerated Se...针对传统特征匹配算法计算效率低、误匹配率高和双目视觉测量精度不足等问题,提出了一种基于自适应几何约束和随机抽样一致性方法的ORB(Oriented FAST and Rotated BRIEF)红外双目测距方法。首先,通过FAST(Features from Accelerated Segment Test)算法与BRIEF(Binary Robust Independent Elementary Features)算法检测并描述关键点,采用快速最近邻搜索的算法完成特征点初始匹配。然后,根据初始匹配点对的斜率与距离选择相应的阈值,构建基于斜率与距离的几何约束,剔除明显错误匹配点对。最后利用随机抽样一致性方法去除异常点完成精匹配,结合热像仪标定参数计算出目标物体的距离。实验结果表明,改进的ORB算法与传统算法相比,具有较好的特征点质量和较高的测量精度,测距平均绝对误差为1.64%,具有较好的实用价值。展开更多
基金supported by the Department of Odontology and the Faculty of Medicine,Umea University,the Folksam Research Foundation and grants from Vasterbotten County Council(TUA)
文摘There is a close functional relationship between the jaw and neck regions and it has been suggested that trigeminal sensory impairment can follow whiplash injury.Inclusion of manageable routines for valid assessment of the facial sensory capacity is thus needed for comprehensive evaluations of patients exposed to such trauma.The present study investigated facial thermal thresholds in patients with chronic whiplash-associated disorders（WADs）with both a qualitative method and quantitative sensory testing（QST）.Ten women with pain and dysfunction following a whiplash injury were compared to 10 healthy age-matched women.Thermal detection thresholds were assessed by qualitative chair-side testing and by QST according to the method-of-limits.Seven test sites in the facial skin（overlying each trigeminal branch bilaterally,and the midpoint of the chin）were examined.The detection warm and cold thresholds were defined as the mean values of 10 individual thresholds.For the WAD patients,the qualitative assessment demonstrated both reduced and increased sensitivity compared to the healthy,whereas QST systematically showed significantly higher detection thresholds（i.e.,decreased sensitivity）for both cold and warm stimuli.For the individuals who were assessed as having increased sensitivity in the qualitative assessment,the QST displayed either normal or higher thresholds,i.e.,decreased sensitivity.The results suggest that QST is more sensitive for detecting thermal sensory disturbances in the face than a qualitative method.The impaired thermal sensitivity among the patients corroborates the notion of altered thermal detection capacity induced by WAD-related pain.
基金supported by the National Natural Science Foundation of China(Grant No.61067002)the Foundation for Department of Education of Jiangxi Province,China(Grant No.GJJ12581)+1 种基金the Natural Science Foundation of Jiangxi Province,China(Grant No.20132BAB212008)the Foundation for GannanNormal University,China(Grant No.11kyz12)
文摘In this paper, we demonstrate that thermal stress is the main mechanism in the process of paint removal by Q-switched Nd：YAG laser （λ = 1064 nm, τ = 10 ns）. A theoretical model ofpaint removal by short-pulse laser is established from the perspective of thermal stress. Thermal stress is generated by thermal expansion, and the temperatures of different samples are calculated according to the one-dimensional （1D） heat conduction equation. The theoretical cleaning threshold can be obtained by comparing thermal stress with the adhesion of paint, and the theoretical damage threshold is obtained by calculating the temperature. Moreover, the theoretical calculations are verified by experimental results. It is shown that the thermal stress model of the laser cleaning is very useful to choose the appropriate laser fluence in the practical applications of paint removal by Q-switched Nd： YAG laser because our model can validly balance the efficiency of laser cleaning and the safety of the substrate.
基金Project supported by Estahban Branch,Islamic Azad University
文摘Spectroscopic properties of flashlamp pumped Nd^3＋：YAG laser are studied as a function of temperature in a range from-30℃ to 60℃. The spectral width and shift of quasi three-level 946.0-nm inter-Stark emission within the respective intermanifold transitions of ^4F3/2→^4I9/2are investigated. The 946.0-nm line shifts toward the shorter wavelength and broadens. In addition, the threshold power and slope efficiency of the 946.0-nm laser line are quantified with temperature.The lower the temperature, the lower the threshold power is and the higher the slope efficiency of the 946.0-nm laser line is,thus the higher the laser output is. This phenomenon is attributed to the ion-phonon interaction and the thermal population in the ground state.
文摘针对传统特征匹配算法计算效率低、误匹配率高和双目视觉测量精度不足等问题,提出了一种基于自适应几何约束和随机抽样一致性方法的ORB(Oriented FAST and Rotated BRIEF)红外双目测距方法。首先,通过FAST(Features from Accelerated Segment Test)算法与BRIEF(Binary Robust Independent Elementary Features)算法检测并描述关键点,采用快速最近邻搜索的算法完成特征点初始匹配。然后,根据初始匹配点对的斜率与距离选择相应的阈值,构建基于斜率与距离的几何约束,剔除明显错误匹配点对。最后利用随机抽样一致性方法去除异常点完成精匹配,结合热像仪标定参数计算出目标物体的距离。实验结果表明,改进的ORB算法与传统算法相比,具有较好的特征点质量和较高的测量精度,测距平均绝对误差为1.64%,具有较好的实用价值。
