In order to solve excessive insertion loss and low on/off ratio in quantum well reflection-type waveguide optical switches, a novel InGaAs/InAlAs coupled quantum well structure is proposed. In the case of low applied ...In order to solve excessive insertion loss and low on/off ratio in quantum well reflection-type waveguide optical switches, a novel InGaAs/InAlAs coupled quantum well structure is proposed. In the case of low applied electric field （F=19 kV/cm） and low absorption loss （ et ~ 61.2 cm-1）, a large negative field-induced refractive index change （ A n=-0.0134） is obtained in the novel coupled quantum well structure at the operating wavelength （ 2 =1550 rim）. The value is larger by over one to two order of maL, nitude comoared to that in a rectanaular ouantum well （ROW） on the above same work conditions.展开更多
The optical absorption of Ti：Al2O3 single crystal has been measured at room temperature, in the wavelength region between 200 nm and 800 nm. The main absorption peaks at 491 nm and 562 nm, the weak infrared absorptio...The optical absorption of Ti：Al2O3 single crystal has been measured at room temperature, in the wavelength region between 200 nm and 800 nm. The main absorption peaks at 491 nm and 562 nm, the weak infrared absorption band with a peak at 650 nm and the strong UV absorption band below 300 nm were observed. The refractive index is discussed by using Fresnel＇s equation. In particular, the Sellmeier equation was determined in the visible region by means on non-conventional method based on the measurement of refraction by using UV-visible spectroscopy. The refractive indices decreased from 3.71 to 1.28 with wavelength in the range 400-800 nm.展开更多
Objective: In order to identify the quality of different geological conditions and plant ages of Xiling Zhimu. Methods: This article uses the terahertz spectroscopy to detect and analyze different geological condition...Objective: In order to identify the quality of different geological conditions and plant ages of Xiling Zhimu. Methods: This article uses the terahertz spectroscopy to detect and analyze different geological conditions and ages of Zhimu (Anemarrhenae Rhizoma) from the same origin. Results: The terahertz time-domain spectroscopy of different geological conditions and ages has a decrease relative to the reference amplitude and has a delay. The refractive index has obvious differences, and the refractive index can be used as a way to identify the tablets. The absorption coefficients of different ages Zhimu samples has significant differences in the range of 1.0-2.0 THz. The absorption coefficients of different geological conditions Zhimu samples has significant differences in the range of 1.1-2.0 THz. Conclusions: The differences caused by different production methods should be considered in the identification of genuine regional drug. When the Zhimu is grown due to different geological conditions and plant ages, its efficacy will also change. we can detect this change by terahertz spectroscopy.展开更多
Objective: Provide a rapid and simple method to identify Yunpian Lurong. Method: Terahertz spectroscopy was used to detect Yunpian Lurong. Result: Compared with the reference wave, the spectral amplitude of Yunpian Lu...Objective: Provide a rapid and simple method to identify Yunpian Lurong. Method: Terahertz spectroscopy was used to detect Yunpian Lurong. Result: Compared with the reference wave, the spectral amplitude of Yunpian Lurong decreases significantly. The frequency - domain spectra of Yunpian Lurong are different from conventional Lurong. Compared with the spectrum of free space, both of them have obvious absorption to THz wave, but the intensity and location of absorption are different, which provides a basis for the identification of Yunpian Lurong. The refractive index of the two samples is obviously different, which may be related to the different internal structure and composition content of the samples. The absorption coefficient of the two samples are different as well, when the frequency ranges from 0 to 2.4 THz, the absorption coefficients of the two kinds of Lurong samples have obvious difference, which makes it easy to distinguish the Yunpian Lurong. Conclusion: This study proves that terahertz spectroscopy can be used as an efficient and convenient method to identify Yunpian Lurong.展开更多
β-Crystallins are the major structural proteins existing in the vertebrate lens, and their conformational stability is critical in maintaining the life-long transparency and refraction index of the lens. Seven subuni...β-Crystallins are the major structural proteins existing in the vertebrate lens, and their conformational stability is critical in maintaining the life-long transparency and refraction index of the lens. Seven subunits of β-crystallins naturally assemble into various heteroge- neous oligomers with different sizes. Here, we systematically investigated the thermal sta- bility of the different secondary structures present in β-Crystallins and then the dynamic process for the thermal-induced unfolding of β-crystallins by Fourier transform infrared spectroscopy-monitored thermal titration and temperature-jump nanosecond time-resolved IR difference absorbance spectra. Our results show that the N-terminal anti-parallel β-sheets in β-crystallin are the most unstable with a transition midpoint temperature at 36.0-2.1℃, leading to the formation of an intermediate consisting vastly of random coil structures. This intermediate structure is temporally assigned to that of the monomer generated by the thermal-induced disassembly of β-crystallin oligomers with a transition midpoint tempera- ture of 40.4-0.7℃. The global unfolding of β-crystallins that leads to denaturation and aggregation indicated by the formation of intermolecular anti-parallel β-sheets has a transi- tion midpoint temperature determined as 72.4-0.2 ℃. Temperature-jump time-resolved IR absorbance difference spectroscopy analysis further reveals that thermal-induced unfolding of β-crystallins occurs firstly in the anti-parallel β-sheets in the N-terminal domains with a time constant of 50 ns.展开更多
Objective： To evaluate the effectiveness of the rigid internal fixation for comminuted and redisplaced zygomatic arch fractures by modified preauriculartemporal approach with the resorbable bone fixation. Methods： ...Objective： To evaluate the effectiveness of the rigid internal fixation for comminuted and redisplaced zygomatic arch fractures by modified preauriculartemporal approach with the resorbable bone fixation. Methods： Totally twenty patients aged from 14 to 68 years and admitted to our hospital between September 2006 and June 2011 were reviewed, of whom seventeen had a unilateral comminuted zygomatic arch fracture and three re displaced arch fracture after failed closed reduction. The fracture segments were aligned to restore the preinjury form of the arch by rigid fixation with resorbable plates and screws through a modified preauriculartemporal incision. Results： The fractures were well reduced, preauricu lartemporal scar and lateral facial contour were aestheti cally satisfying, and no case had limited mouth opening as well as facial palsy. The resorbable plates were not palpated one year after the operation. Conclusion： The rigid internal fixation through the preauriculartemporal approach with the resorbable bone is an effective method for the comminuted and redisplaced zyomatic arch fractures.展开更多
Objective： To observe the therapeutic effect of absorbable screw in medial malleolus fracture and discuss its clinical application in orthopedics. Methods： A total of 129 patients with simple medial malleolus fract...Objective： To observe the therapeutic effect of absorbable screw in medial malleolus fracture and discuss its clinical application in orthopedics. Methods： A total of 129 patients with simple medial malleolus fracture were studied. Among them, 64 patients were treated with poly-D, L-lactic acid （PDLLA） absorbable screws, while the others were treated with metal screws. All the patients were followed up for 12-20 months （averaged 18.4 months） and the therapeutic effect was evaluated according to the American Orthopaedic Foot and Ankle Society clinical rating systems. Results： In absorbable screw group, we obtained excel- lent and good results in 62 cases （96.88%）; in steel screw group, 61 cases （93.85%） achieved excellent and good results. There was no significant difference between the two groups. Conclusion： In the treatment of malleolus fracture, absorbable screw can achieve the same result compared with metal screw fixation. Absorbable screw is preferred due to its advantages of safety, cleanliness and avoiding the removal procedure associated with metallic implants.展开更多
Objective: To dynamically monitor the bone mineral density (BMD) and the histomorphological changes during fracture healing in a rat femoral fracture model and to explore the role of dual energy X-ray absorptiometry (...Objective: To dynamically monitor the bone mineral density (BMD) and the histomorphological changes during fracture healing in a rat femoral fracture model and to explore the role of dual energy X-ray absorptiometry (DEXA) in evaluating bone fracture healing. Methods: Sixty three-month-old female Sprague Dawley rats were used to establish right femoral fracture models. The BMD of the callus of the fractured right femur were scanned by DEXA at 2, 4, 6, 8, 10 and 12 weeks after operation, respectively. A light microscope was used to evaluate the callus of each rat at the same time. The corresponding segment of the left femur was taken as a control. Results: The BMD at the fractured site increased significantly during the process of facture healing, which shows an obvious healing trend. The callus BMDs were 29.5%, 48.3%, 85.3%, and 105.2% of the BMD of the control limb at 2, 4, 6 and 8 weeks after fracture, respectively. There was a significantly difference between the groups. A compatibility on time was found between the BMD and the histomorphological characteristics at the fractured site during the process of fracture healing. The fracture healing was almost completed at 8 weeks after fracture as assessed by its histomorphological characteristics when the callus BMD reached to 105.2% of the BMD of the control limb. The BMD of the distal metaphysis decreased until 12 weeks after fracture. Conclusions: DEXA can evaluate the mineralization of the callus during the facture healing process accurately and quantitatively and is more sensitive than plain radiography in detecting impaired bone unions, which indicates that it may play an important role in monitoring fracture healing.展开更多
Various musculoskeletal injuries are well known complications of epilepsy either because of direct trauma or because of unbalanced forceful muscle contraction. We report a case of non-traumatic bilateral central aceta...Various musculoskeletal injuries are well known complications of epilepsy either because of direct trauma or because of unbalanced forceful muscle contraction. We report a case of non-traumatic bilateral central acetabular fracture dislocation due to seizure activity induced by neurocysticercosis of the brain, which was managed conservatively and obtained reasonable good outcome. This case highlights the importance of proper evaluation in young non-osteoporotic patients who have experienced an epileptic attack without any previous history. It is also imperative to mention that these patients should be thoroughly examined neurologically to find out the exact etiology and should be treated accordingly to prevent future seizure activity.展开更多
The absorption spectra and the refractive index changes are calculated theoretically for an exeiton in a core/shell quantum dot. The advantage of our methodology is that one can investigate the influence of the repuls...The absorption spectra and the refractive index changes are calculated theoretically for an exeiton in a core/shell quantum dot. The advantage of our methodology is that one can investigate the influence of the repulsive core by varying two parameters in the confinement potential. The dimensionality effect of exciton quantum dots on the optical absorptions has been studied. It has been found that in the same regime, the optical absorption intensities of excitons axe much smaller for the core/shell quantum dots than for the two-dimensional quantum rings. The linear and the nonlinear optical absorption coefficients and refractive index changes have been examined with the change of the confinement potential. The results show that the optical absorptions and the refractive index changes are strongly affected by the repulsive core of core/shell quantum dots. Moreover, the calculated results also reveal that as the inner radius increases, the peak values of the absorption coefficients and the refractive index changes of an exciton will show the optical Aharonov-Bohm oscillation in core/shell quantum dots.展开更多
This paper intends to realize negative refraction with absorption suppressed by the electromagnetically induced transparency (EIT) in a dense four-level atomic system.Without the two equal transition frequencies respo...This paper intends to realize negative refraction with absorption suppressed by the electromagnetically induced transparency (EIT) in a dense four-level atomic system.Without the two equal transition frequencies responding to the probe field,the atomic system displays a negative refraction with the simultaneously negative permittivity and negative permeability (left-handedness).The response of the probe field is amplified and propagates transparency in some frequency extents.Therefore,our aim for searching the low-loss negative refraction can be achieved in the scheme,given the main applied limitation of the negative refractive materials is the large amount of dissipation and absorption.However,an excessive signal field intensity would increase the absorption near the resonance in our scheme.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No. 60277034 and 60436020
文摘In order to solve excessive insertion loss and low on/off ratio in quantum well reflection-type waveguide optical switches, a novel InGaAs/InAlAs coupled quantum well structure is proposed. In the case of low applied electric field （F=19 kV/cm） and low absorption loss （ et ~ 61.2 cm-1）, a large negative field-induced refractive index change （ A n=-0.0134） is obtained in the novel coupled quantum well structure at the operating wavelength （ 2 =1550 rim）. The value is larger by over one to two order of maL, nitude comoared to that in a rectanaular ouantum well （ROW） on the above same work conditions.
文摘The optical absorption of Ti：Al2O3 single crystal has been measured at room temperature, in the wavelength region between 200 nm and 800 nm. The main absorption peaks at 491 nm and 562 nm, the weak infrared absorption band with a peak at 650 nm and the strong UV absorption band below 300 nm were observed. The refractive index is discussed by using Fresnel＇s equation. In particular, the Sellmeier equation was determined in the visible region by means on non-conventional method based on the measurement of refraction by using UV-visible spectroscopy. The refractive indices decreased from 3.71 to 1.28 with wavelength in the range 400-800 nm.
文摘Objective: In order to identify the quality of different geological conditions and plant ages of Xiling Zhimu. Methods: This article uses the terahertz spectroscopy to detect and analyze different geological conditions and ages of Zhimu (Anemarrhenae Rhizoma) from the same origin. Results: The terahertz time-domain spectroscopy of different geological conditions and ages has a decrease relative to the reference amplitude and has a delay. The refractive index has obvious differences, and the refractive index can be used as a way to identify the tablets. The absorption coefficients of different ages Zhimu samples has significant differences in the range of 1.0-2.0 THz. The absorption coefficients of different geological conditions Zhimu samples has significant differences in the range of 1.1-2.0 THz. Conclusions: The differences caused by different production methods should be considered in the identification of genuine regional drug. When the Zhimu is grown due to different geological conditions and plant ages, its efficacy will also change. we can detect this change by terahertz spectroscopy.
文摘Objective: Provide a rapid and simple method to identify Yunpian Lurong. Method: Terahertz spectroscopy was used to detect Yunpian Lurong. Result: Compared with the reference wave, the spectral amplitude of Yunpian Lurong decreases significantly. The frequency - domain spectra of Yunpian Lurong are different from conventional Lurong. Compared with the spectrum of free space, both of them have obvious absorption to THz wave, but the intensity and location of absorption are different, which provides a basis for the identification of Yunpian Lurong. The refractive index of the two samples is obviously different, which may be related to the different internal structure and composition content of the samples. The absorption coefficient of the two samples are different as well, when the frequency ranges from 0 to 2.4 THz, the absorption coefficients of the two kinds of Lurong samples have obvious difference, which makes it easy to distinguish the Yunpian Lurong. Conclusion: This study proves that terahertz spectroscopy can be used as an efficient and convenient method to identify Yunpian Lurong.
文摘β-Crystallins are the major structural proteins existing in the vertebrate lens, and their conformational stability is critical in maintaining the life-long transparency and refraction index of the lens. Seven subunits of β-crystallins naturally assemble into various heteroge- neous oligomers with different sizes. Here, we systematically investigated the thermal sta- bility of the different secondary structures present in β-Crystallins and then the dynamic process for the thermal-induced unfolding of β-crystallins by Fourier transform infrared spectroscopy-monitored thermal titration and temperature-jump nanosecond time-resolved IR difference absorbance spectra. Our results show that the N-terminal anti-parallel β-sheets in β-crystallin are the most unstable with a transition midpoint temperature at 36.0-2.1℃, leading to the formation of an intermediate consisting vastly of random coil structures. This intermediate structure is temporally assigned to that of the monomer generated by the thermal-induced disassembly of β-crystallin oligomers with a transition midpoint tempera- ture of 40.4-0.7℃. The global unfolding of β-crystallins that leads to denaturation and aggregation indicated by the formation of intermolecular anti-parallel β-sheets has a transi- tion midpoint temperature determined as 72.4-0.2 ℃. Temperature-jump time-resolved IR absorbance difference spectroscopy analysis further reveals that thermal-induced unfolding of β-crystallins occurs firstly in the anti-parallel β-sheets in the N-terminal domains with a time constant of 50 ns.
文摘Objective： To evaluate the effectiveness of the rigid internal fixation for comminuted and redisplaced zygomatic arch fractures by modified preauriculartemporal approach with the resorbable bone fixation. Methods： Totally twenty patients aged from 14 to 68 years and admitted to our hospital between September 2006 and June 2011 were reviewed, of whom seventeen had a unilateral comminuted zygomatic arch fracture and three re displaced arch fracture after failed closed reduction. The fracture segments were aligned to restore the preinjury form of the arch by rigid fixation with resorbable plates and screws through a modified preauriculartemporal incision. Results： The fractures were well reduced, preauricu lartemporal scar and lateral facial contour were aestheti cally satisfying, and no case had limited mouth opening as well as facial palsy. The resorbable plates were not palpated one year after the operation. Conclusion： The rigid internal fixation through the preauriculartemporal approach with the resorbable bone is an effective method for the comminuted and redisplaced zyomatic arch fractures.
文摘Objective： To observe the therapeutic effect of absorbable screw in medial malleolus fracture and discuss its clinical application in orthopedics. Methods： A total of 129 patients with simple medial malleolus fracture were studied. Among them, 64 patients were treated with poly-D, L-lactic acid （PDLLA） absorbable screws, while the others were treated with metal screws. All the patients were followed up for 12-20 months （averaged 18.4 months） and the therapeutic effect was evaluated according to the American Orthopaedic Foot and Ankle Society clinical rating systems. Results： In absorbable screw group, we obtained excel- lent and good results in 62 cases （96.88%）; in steel screw group, 61 cases （93.85%） achieved excellent and good results. There was no significant difference between the two groups. Conclusion： In the treatment of malleolus fracture, absorbable screw can achieve the same result compared with metal screw fixation. Absorbable screw is preferred due to its advantages of safety, cleanliness and avoiding the removal procedure associated with metallic implants.
文摘Objective: To dynamically monitor the bone mineral density (BMD) and the histomorphological changes during fracture healing in a rat femoral fracture model and to explore the role of dual energy X-ray absorptiometry (DEXA) in evaluating bone fracture healing. Methods: Sixty three-month-old female Sprague Dawley rats were used to establish right femoral fracture models. The BMD of the callus of the fractured right femur were scanned by DEXA at 2, 4, 6, 8, 10 and 12 weeks after operation, respectively. A light microscope was used to evaluate the callus of each rat at the same time. The corresponding segment of the left femur was taken as a control. Results: The BMD at the fractured site increased significantly during the process of facture healing, which shows an obvious healing trend. The callus BMDs were 29.5%, 48.3%, 85.3%, and 105.2% of the BMD of the control limb at 2, 4, 6 and 8 weeks after fracture, respectively. There was a significantly difference between the groups. A compatibility on time was found between the BMD and the histomorphological characteristics at the fractured site during the process of fracture healing. The fracture healing was almost completed at 8 weeks after fracture as assessed by its histomorphological characteristics when the callus BMD reached to 105.2% of the BMD of the control limb. The BMD of the distal metaphysis decreased until 12 weeks after fracture. Conclusions: DEXA can evaluate the mineralization of the callus during the facture healing process accurately and quantitatively and is more sensitive than plain radiography in detecting impaired bone unions, which indicates that it may play an important role in monitoring fracture healing.
文摘Various musculoskeletal injuries are well known complications of epilepsy either because of direct trauma or because of unbalanced forceful muscle contraction. We report a case of non-traumatic bilateral central acetabular fracture dislocation due to seizure activity induced by neurocysticercosis of the brain, which was managed conservatively and obtained reasonable good outcome. This case highlights the importance of proper evaluation in young non-osteoporotic patients who have experienced an epileptic attack without any previous history. It is also imperative to mention that these patients should be thoroughly examined neurologically to find out the exact etiology and should be treated accordingly to prevent future seizure activity.
文摘The absorption spectra and the refractive index changes are calculated theoretically for an exeiton in a core/shell quantum dot. The advantage of our methodology is that one can investigate the influence of the repulsive core by varying two parameters in the confinement potential. The dimensionality effect of exciton quantum dots on the optical absorptions has been studied. It has been found that in the same regime, the optical absorption intensities of excitons axe much smaller for the core/shell quantum dots than for the two-dimensional quantum rings. The linear and the nonlinear optical absorption coefficients and refractive index changes have been examined with the change of the confinement potential. The results show that the optical absorptions and the refractive index changes are strongly affected by the repulsive core of core/shell quantum dots. Moreover, the calculated results also reveal that as the inner radius increases, the peak values of the absorption coefficients and the refractive index changes of an exciton will show the optical Aharonov-Bohm oscillation in core/shell quantum dots.
基金supported by the National Natural Science Foundation of China (Grant Nos.60768001 and 10464002)
文摘This paper intends to realize negative refraction with absorption suppressed by the electromagnetically induced transparency (EIT) in a dense four-level atomic system.Without the two equal transition frequencies responding to the probe field,the atomic system displays a negative refraction with the simultaneously negative permittivity and negative permeability (left-handedness).The response of the probe field is amplified and propagates transparency in some frequency extents.Therefore,our aim for searching the low-loss negative refraction can be achieved in the scheme,given the main applied limitation of the negative refractive materials is the large amount of dissipation and absorption.However,an excessive signal field intensity would increase the absorption near the resonance in our scheme.
