Raman spectra of xLa203-（1-x）TeO2 （x=0, 0.05, 0.10, 0.15, 0.20, and 0.25） lanthanum tellurite glasses were measured and analyzed over the entire glass-forming region in an effort to quantitatively follow the struc...Raman spectra of xLa203-（1-x）TeO2 （x=0, 0.05, 0.10, 0.15, 0.20, and 0.25） lanthanum tellurite glasses were measured and analyzed over the entire glass-forming region in an effort to quantitatively follow the structural changes caused by lanthanum oxide variation. For the first time, systematic intensity measurements have been performed to elucidate the composition induced structural changes in tile high-frequency stretching vibration region and a possible mechanism was proposed. The network structure of the glasses is formed by mixing TeO4 trigonal bipyramid and Te03 trigonal pyramid units. The change of the lanthanum oxide content results in conversion of the TeO4 units to TeO3 units with a varying number of non-bridging oxygen atoms. Analysis of the Raman band contours in terms of vibrations due to different oxygen bridged trigonal bipyramid and trigonal pyramid tellurite structural units, allowed to calculate the relative amounts of the species involved in the structural changes with composition. The fraction of the terminal oxygen atoms has been estimated from the Raman intensities with the aid of a structural model concerning the structure of tellurite network systems. The simulation of the experimental density of lanthanum tellurite glasses with modifier content up to 25% revealed that the short range order building units assumed here are sufficient to account for the overall structure in these glasses.展开更多
Highly active Ir‐La‐S/AC catalyst was successfully prepared by co‐impregnation of an activated carbon（AC） carrier with a sulfuric acid solution of Ir and La species and compared with a tradition‐ally prepared Ir...Highly active Ir‐La‐S/AC catalyst was successfully prepared by co‐impregnation of an activated carbon（AC） carrier with a sulfuric acid solution of Ir and La species and compared with a tradition‐ally prepared Ir‐La/AC catalyst. High angle annular dark‐field‐scanning transmission electron mi‐croscopy（HAADF‐STEM） measurement results show that most of the Ir species on Ir‐La‐S/AC exist as single atomic sites, while those on Ir‐La/AC exist as nanoparticles with an average diameter of 1.5 nm. Evaluation of Ir‐La‐S/AC as a catalyst for heterogeneous carbonylation of methanol to acetyl gave a maximum TOF （turn‐over‐frequency） of 2760 h^–1, which was distinctly higher than that achieved by the Ir‐La/AC catalyst（approximately 1000 h^-1）. Temperature‐programmed desorption of ammonia（NH3‐TPD） result shows that the addition of sulfuric acid during the preparation pro‐cedure results in significantly more acidic sites on Ir‐La‐S/AC than those on Ir‐La/AC, which plays a key role in the enhancement of CO insertion as the rate‐determining step. Tempera‐ture‐programmed reduction（TPR） and in situ X‐ray photoelectron spectroscopy reveal that Ir spe‐cies are more reducible, and that more Ir^＋ might be formed by activation of Ir‐La‐S/AC than those on the Ir‐La/AC catalyst, which is thought to be beneficial for reductive elimination of AcI from Ir^3＋ species as an essential step for CH3I regeneration and acetyl formation.展开更多
In this paper, we present a probabilistic teleportation scheme for unknown bipartite entangled state. By using linear optical elements, we convert the Bell-state measurement into separated single-qubit measurements.
Aiming at the defects of traditional four-wheel aligner such as many sensors,complex operation and slow detection speed,a fast and accurate 3D four-wheel alignment detection method is studied.Firstly,a new and special...Aiming at the defects of traditional four-wheel aligner such as many sensors,complex operation and slow detection speed,a fast and accurate 3D four-wheel alignment detection method is studied.Firstly,a new and special circle center target board is designed to calibrate the camera,and then the registration of the homography matrix is optimized by using the improved RANSAC(Random sample consensus)algorithm combined with the designed special target board,and the parameters of the wheel alignment system are adjusted by using the space vector principle.Accurate measurements are made to obtain the parameters of the four-wheel alignment.Design a calibration comparison experiment between the traditional target board and the new type of target board,and conduct a comparative test with the existing four-wheel aligner of the depot.The experimental results show that the use of the new target board-binding optimization algorithm can improve the calibration efficiency by about 9%to 21%,while improving the calibration accuracy by about 10.6%to 17.8%.And through the real vehicle test,it is verified that the use of the new target combined with the optimization algorithm can ensure the accuracy and reliability of the four-wheel positioning.This method has a certain significance in the rapid detection of vehicle four-wheel alignment parameters.展开更多
To investigate diagnostic accuracy of 2-hour protocol of rest thallium-201/stress technetium-99m sestamibi dual-isotope myocardial perfusion SPECT in chronic coronary artery disease. Sixty-seven patients with suspecte...To investigate diagnostic accuracy of 2-hour protocol of rest thallium-201/stress technetium-99m sestamibi dual-isotope myocardial perfusion SPECT in chronic coronary artery disease. Sixty-seven patients with suspected CAD were enrolled in the prospective study. All patients underwent myocardial perfusion scintigraphy in SPECT with dual isotopes of T1-201 and dipyridamole stress Tc-99m sestamibi. Rest and stress imaging protocol were performed in 2 hours by dose of 3 mCi TI-201 and 25 mCi Tc-99m sestamibi. The acquisition parameters includes LEHR collimator, energy peak of 72 and 167 keV for T1-201 and 140 keV for Tc-99m, 180-degree rotation from RAO to LPO, matrix size 64x64, and 25second/frame/64 frames. The 20-segment model of left ventricle was used in automatic quantitation software. Coronary angiography was used as gold standard. CAD was defined as 50% of lumen stenosis on coronary angiography. Rest TI-201/stress tc-99m sestamibi dual-isotope SPECT demonstrated a sensitivity of 94.59% and specificity of 70%, positive predictive value of 79.54% and negative predictive value of 91.3% in detection of coronary artery disease. Sensitivity and specificity for detecting multi-vessel coronary artery disease were 82.75% and 81.57% for the left anterior descending, 77.77% and 91.83% for left circumflex and 94.11% and 82% for right coronary artery. 2-hour protocol of rest thallium-201/stress technetium-99m sestamibi dual-isotope myocardial perfusion SPECT has high sensitivity, specificity, positive predictive value and negative predictive value in detecting chronic coronary artery disease with greater than 50% stenosis assessed by coronary angiography Moreover, this imaging protocol gives high imaging quality, time-saving and convenience.展开更多
Quillen proved that if a Hermitian bihomogeneous polynomial is strictly positive on the unit sphere, then repeated multiplication of the standard sesquilinear form to this polynomial eventually results in a sum of Her...Quillen proved that if a Hermitian bihomogeneous polynomial is strictly positive on the unit sphere, then repeated multiplication of the standard sesquilinear form to this polynomial eventually results in a sum of Hermitian squares. Catlin-D'Angelo and Varolin deduced this positivstellensatz of Quillen from the eventual positive-definiteness of an associated integral operator. Their arguments involve asymptotic expansions of the Bergman kernel. The goal of this article is to give an elementary proof of the positive-definiteness of this integral operator.展开更多
文摘Raman spectra of xLa203-（1-x）TeO2 （x=0, 0.05, 0.10, 0.15, 0.20, and 0.25） lanthanum tellurite glasses were measured and analyzed over the entire glass-forming region in an effort to quantitatively follow the structural changes caused by lanthanum oxide variation. For the first time, systematic intensity measurements have been performed to elucidate the composition induced structural changes in tile high-frequency stretching vibration region and a possible mechanism was proposed. The network structure of the glasses is formed by mixing TeO4 trigonal bipyramid and Te03 trigonal pyramid units. The change of the lanthanum oxide content results in conversion of the TeO4 units to TeO3 units with a varying number of non-bridging oxygen atoms. Analysis of the Raman band contours in terms of vibrations due to different oxygen bridged trigonal bipyramid and trigonal pyramid tellurite structural units, allowed to calculate the relative amounts of the species involved in the structural changes with composition. The fraction of the terminal oxygen atoms has been estimated from the Raman intensities with the aid of a structural model concerning the structure of tellurite network systems. The simulation of the experimental density of lanthanum tellurite glasses with modifier content up to 25% revealed that the short range order building units assumed here are sufficient to account for the overall structure in these glasses.
基金supported by the National Key R&D Program of China (2017YFB0602203)~~
文摘Highly active Ir‐La‐S/AC catalyst was successfully prepared by co‐impregnation of an activated carbon（AC） carrier with a sulfuric acid solution of Ir and La species and compared with a tradition‐ally prepared Ir‐La/AC catalyst. High angle annular dark‐field‐scanning transmission electron mi‐croscopy（HAADF‐STEM） measurement results show that most of the Ir species on Ir‐La‐S/AC exist as single atomic sites, while those on Ir‐La/AC exist as nanoparticles with an average diameter of 1.5 nm. Evaluation of Ir‐La‐S/AC as a catalyst for heterogeneous carbonylation of methanol to acetyl gave a maximum TOF （turn‐over‐frequency） of 2760 h^–1, which was distinctly higher than that achieved by the Ir‐La/AC catalyst（approximately 1000 h^-1）. Temperature‐programmed desorption of ammonia（NH3‐TPD） result shows that the addition of sulfuric acid during the preparation pro‐cedure results in significantly more acidic sites on Ir‐La‐S/AC than those on Ir‐La/AC, which plays a key role in the enhancement of CO insertion as the rate‐determining step. Tempera‐ture‐programmed reduction（TPR） and in situ X‐ray photoelectron spectroscopy reveal that Ir spe‐cies are more reducible, and that more Ir^＋ might be formed by activation of Ir‐La‐S/AC than those on the Ir‐La/AC catalyst, which is thought to be beneficial for reductive elimination of AcI from Ir^3＋ species as an essential step for CH3I regeneration and acetyl formation.
基金The project supported by the Natural Science Foundation of the Education Department of Anhui Province under Grant Nos. 2006kj070A and 2006kj057B, National Natural Science Foundation of China under Grant No. 10574001, and the Talent Foundation of Anhui University
文摘In this paper, we present a probabilistic teleportation scheme for unknown bipartite entangled state. By using linear optical elements, we convert the Bell-state measurement into separated single-qubit measurements.
基金Anhui Province Key Research and Development Program(No.2022107020012)Shenzhen Science and Technology Innovation Project(No.JSGG20191129102008260)。
文摘Aiming at the defects of traditional four-wheel aligner such as many sensors,complex operation and slow detection speed,a fast and accurate 3D four-wheel alignment detection method is studied.Firstly,a new and special circle center target board is designed to calibrate the camera,and then the registration of the homography matrix is optimized by using the improved RANSAC(Random sample consensus)algorithm combined with the designed special target board,and the parameters of the wheel alignment system are adjusted by using the space vector principle.Accurate measurements are made to obtain the parameters of the four-wheel alignment.Design a calibration comparison experiment between the traditional target board and the new type of target board,and conduct a comparative test with the existing four-wheel aligner of the depot.The experimental results show that the use of the new target board-binding optimization algorithm can improve the calibration efficiency by about 9%to 21%,while improving the calibration accuracy by about 10.6%to 17.8%.And through the real vehicle test,it is verified that the use of the new target combined with the optimization algorithm can ensure the accuracy and reliability of the four-wheel positioning.This method has a certain significance in the rapid detection of vehicle four-wheel alignment parameters.
文摘To investigate diagnostic accuracy of 2-hour protocol of rest thallium-201/stress technetium-99m sestamibi dual-isotope myocardial perfusion SPECT in chronic coronary artery disease. Sixty-seven patients with suspected CAD were enrolled in the prospective study. All patients underwent myocardial perfusion scintigraphy in SPECT with dual isotopes of T1-201 and dipyridamole stress Tc-99m sestamibi. Rest and stress imaging protocol were performed in 2 hours by dose of 3 mCi TI-201 and 25 mCi Tc-99m sestamibi. The acquisition parameters includes LEHR collimator, energy peak of 72 and 167 keV for T1-201 and 140 keV for Tc-99m, 180-degree rotation from RAO to LPO, matrix size 64x64, and 25second/frame/64 frames. The 20-segment model of left ventricle was used in automatic quantitation software. Coronary angiography was used as gold standard. CAD was defined as 50% of lumen stenosis on coronary angiography. Rest TI-201/stress tc-99m sestamibi dual-isotope SPECT demonstrated a sensitivity of 94.59% and specificity of 70%, positive predictive value of 79.54% and negative predictive value of 91.3% in detection of coronary artery disease. Sensitivity and specificity for detecting multi-vessel coronary artery disease were 82.75% and 81.57% for the left anterior descending, 77.77% and 91.83% for left circumflex and 94.11% and 82% for right coronary artery. 2-hour protocol of rest thallium-201/stress technetium-99m sestamibi dual-isotope myocardial perfusion SPECT has high sensitivity, specificity, positive predictive value and negative predictive value in detecting chronic coronary artery disease with greater than 50% stenosis assessed by coronary angiography Moreover, this imaging protocol gives high imaging quality, time-saving and convenience.
文摘Quillen proved that if a Hermitian bihomogeneous polynomial is strictly positive on the unit sphere, then repeated multiplication of the standard sesquilinear form to this polynomial eventually results in a sum of Hermitian squares. Catlin-D'Angelo and Varolin deduced this positivstellensatz of Quillen from the eventual positive-definiteness of an associated integral operator. Their arguments involve asymptotic expansions of the Bergman kernel. The goal of this article is to give an elementary proof of the positive-definiteness of this integral operator.
