Based on the hydrodynamic stability theory of distorted laminar flow and the kind of distortion profiles on the mean velocity in parallel shear flow given in paper [1], this paper investigates the linear stability beh...Based on the hydrodynamic stability theory of distorted laminar flow and the kind of distortion profiles on the mean velocity in parallel shear flow given in paper [1], this paper investigates the linear stability behaviour of parallel shear flow, presents unstable results of plane Couette flow and pipe Poiseuille flow to two-dimensional or axisymmetric disturbances for the first time, and obtains neutral curves of these two motions under certain definition.展开更多
Based on the hydrodynamic stability theory of distorted laminar flow and the kind of distortion profiles on the mean velocity in parallel shear flow given in paper [1], this paper investigates the nonlinear stability ...Based on the hydrodynamic stability theory of distorted laminar flow and the kind of distortion profiles on the mean velocity in parallel shear flow given in paper [1], this paper investigates the nonlinear stability behaviour of parallel shear flow, carries on stability calculation taking account of the perturbations of background turbulence noise under certain assumption, and obtains some results in accordance qualitatively with those of experiment for plane Poiseuille flow and pipe Poiseuille flow.展开更多
An experimental system based on the background-oriented schlieren（BOS） technique is built to reconstruct the density and temperature distribution of a flame-induced distorted flow field which has a density gradient....An experimental system based on the background-oriented schlieren（BOS） technique is built to reconstruct the density and temperature distribution of a flame-induced distorted flow field which has a density gradient. The cross-correlation algorithm with sub-pixel accuracy is introduced and used to calculate the background-element displacement of a disturbed image and a fourth-order difference scheme is also developed to solve the Poisson equation. An experiment for a disturbed flow field caused by a burning candle is performed to validate the built BOS system and the results indicate that density and temperature distribution of the disturbed flow field can be reconstructed accurately. A notable conclusion is that in order to make the reconstructed results have a satisfactory accuracy, the inquiry step length should be less than the size of the interrogation window.展开更多
We evaluated the effect of various error sources in fishery harvest/effort data on the maximum sustainable yield （MSY） and corresponding fishing effort （EMsv） using Monte Carlo simulation analyses. A high coeffici...We evaluated the effect of various error sources in fishery harvest/effort data on the maximum sustainable yield （MSY） and corresponding fishing effort （EMsv） using Monte Carlo simulation analyses. A high coefficient of variation （CV） of the catch and effort values biased the estimates of MSY and EMsv. Thus, the state of the fisheries resource and its exploitation was overestimated. We compared the effect using three surplus production models, Hilborn-Waters （H-W）, Schnute, and Prager models. The estimates generated using the H-W model were significantly affected by the CV. The Schnute model was least affected by errors in the underlying data. The CVof the catch data had a greater impact on the assessment than the CV of the fishing effort. Similarly, the changes in CV had a greater impact on the estimated maximum sustainable yield （MSY） than on the corresponding estimate of fishing effort （EMsY）. We discuss the likely effect of these biases on management efforts and provide suggestions for the improvement of fishery evaluations.展开更多
Background: It is said that after ICU discharge, 40% of patients suffer from acute stress symptoms, such as anxiety and depression, caused by “distorted memories” (memory loss and delusions) due to various treatment...Background: It is said that after ICU discharge, 40% of patients suffer from acute stress symptoms, such as anxiety and depression, caused by “distorted memories” (memory loss and delusions) due to various treatments in the ICU. This study focused on the quantitative and qualitative effects of ICU diaries on distorted memories that patients encountered during their time in the ICU. Aim: To assess improving distorted memories by providing information during ICU admission to patients to relieve the acute stress symptoms after ICU discharge. Design and Methods: This nonrandomized controlled trial included patients aged ≥20 years who had received treatment for ≥3 days in the ICU. Using ICU memory tool, the Hospital Anxiety and Depression Scale (HADS) and the Acute Stress Disorder Scale (ASDS) approximately 1 week after ICU discharge, then HADS and ASDS prior to hospital discharge, the change in mean values were compared between two groups (control and intervention) using a Wilcoxon signed-rank test. The intervention group was surveyed prior to hospital discharge using semi-structured interviews, and descriptions were analyzed by the content analysis method of Krippendorff. Results: Twenty-three participants were included in the control group, and 17 in the intervention group. When comparing subjects with distorted memories between the groups, we found reduced values for HADS anxiety (7.1 ± 3.8 to 5.7 ± 2.7, p = 0.011), HADS depression (8.6 ± 5.0 to 7.2 ± 4.3, p = 0.003), and ASDS (46.9 ± 13.8 to 43.8 ± 11.4, p = 0.012) in the intervention group. Based on the narrations, patients wanted to investigate facts in the ICU diary while having someone help them to remember these events. Conclusion: Improving distorted memories during ICU admissions may relieve acute stress symptoms. In addition, these patients needed someone to investigate facts from the ICU admission.展开更多
S-a, S-b and S-c are three loci for F1 pollen sterility in cultivated rice （Oryza sativa L.）. Taichung 65 （T65） is all Sj/Sj at these three loci, while its F1 pollen sterile near-isogenic lines, TISL2 （S-b）, TIS...S-a, S-b and S-c are three loci for F1 pollen sterility in cultivated rice （Oryza sativa L.）. Taichung 65 （T65） is all Sj/Sj at these three loci, while its F1 pollen sterile near-isogenic lines, TISL2 （S-b）, TISL4 （S-a） and TISL5 （S-c） is Sj/Sj according to their respective sterility locus. Using SSR molecular marker to detect the segregation of the allele Si and Sj in pollen calli population induced from different hybrid F1, which have different pollen sterility locus, showed that the segregation of allele Si and Sj was distorted. The distorted direction of pollen calli population in vitro was not the same as F2 population in vivo. The quantities of pollen callus carrying Sj were much more than that of carrying Siat S-a and S-c locus, the ratio of Si and Sj were 1：4.81 and 1：1.96 respectively. But the opposite tendency was observed at S-b locus, the ratio of Si and Sj being 1：0.35. At the same time, all these results were undisturbed by either culture medium or culture period.展开更多
In this short review paper, the significant and profound impacts of the distorted key theory for developing peptide drugs have been briefly recalled with crystal clear convincingness.
After 900 ℃ high-vacuum annealing and air cooling, a special band was observed in pure titanium. Energy-dispersive spectrum showed that the composition of the band and the matrix is the same. By tilting the band to d...After 900 ℃ high-vacuum annealing and air cooling, a special band was observed in pure titanium. Energy-dispersive spectrum showed that the composition of the band and the matrix is the same. By tilting the band to different zone axes and taking selected-area electron diffraction (SAED) patterns, we found that the structure of the band is distorted face-centered cubic (fcc) with the lattice constants a, b, and c deviating slightly from each other on the basis of the analyses of the SAED patterns together with the tilting angles. The lattice constants a, b, and c are calculated based on the measurement of interplanar spacing according to high-resolution transmission electron microscopy (HRTEM) images. The orientation relation between the hexagonal-close-packed (hcp) matrix and the distorted fcc band is [11(2)0]hcp//[110]fcc and (0001)hcp//(1(1)1)fcc according to SAED analysis. The phase boundary between the matrix and the band was observed to demonstrate serrated configuration composed of two kinds of micro-steps: ((1)11)//(0002) and ((1)11)//(10(1)1) on the basis of Cs-corrected HRTEM characterization. The distorted fcc band is deduced to be a thermal-induced metastable phase transformed from the high-temperature body-centered cubic (bcc) structure during the allotropic transformation from bcc to hcp based on orientation relation analysis.展开更多
Distortion of planar aromatics occurs in the fused rings conjugated with bulky substituents,which generates racemic enantiomers with high transformation energy barriers.However,direct synthesis of homochiral distorted...Distortion of planar aromatics occurs in the fused rings conjugated with bulky substituents,which generates racemic enantiomers with high transformation energy barriers.However,direct synthesis of homochiral distorted aryl compounds is a very challenging task.Here,we presented a molecular folding strategy to control distorted aryl homochirality.Amino acids and their derivatives conjugated on the polycyclic aromatic hydrocarbons including benzenes,naphthalenes and triphenylenes,which formed parallelβ-sheet arrays through intramolecular hydrogen bonds.The folding behavior enabled distorted or twisted geometry of aromatics,of which the handedness was associated with the absolute chirality of amino acids.X-ray crystallography,theoretical calculations and circular dichroism spectroscopy verified the distorted homochirality in the solid and solution phase.The relatively small rotational barrier between the enantiomers made the molecule sensitive to the environment and thus realized the solvent-controlled chiral inversion.Theβ-sheet folding strategy can be widely used in polycyclic aromatic hydrocarbons with various functions,which provided a promising strategy to control inherent chirality of aromatics with adaptive chiroptical responses.展开更多
Due to development of distribution systems and increase in electricity demand,the use of capacitor banks increases.From the other point of view,nonlinear loads generate and inject considerable harmonic currents into p...Due to development of distribution systems and increase in electricity demand,the use of capacitor banks increases.From the other point of view,nonlinear loads generate and inject considerable harmonic currents into power system.Under this condition if capacitor banks are not properly selected and placed in the power system,they could amplify and propagate these harmonics and deteriorate power quality to unacceptable levels.With attention of disadvantages of passive filters,such as occurring resonance,nowadays the usage of this type of harmonic compensator is restricted.On the other side,one of parallel multi-function compensating devices which are recently used in distribution system to mitigate voltage sag and harmonic distortion,performs power factor correction,and improves the overall power quality as active power conditioner(APC).Therefore,the utilization of APC in harmonic distorted system can affect and change the optimal location and size of shunt capacitor bank under harmonic distortion condition.This paper presents an optimization algorithm for improvement of power quality using simultaneous optimal placement and sizing of APC and shunt capacitor banks in radial distribution networks in the presence of voltage and current harmonics.The algorithm is based on particle swarm optimization(PSO).The objective function includes the cost of power losses,energy losses and those of the capacitor banks and APCs.展开更多
We report a measurement of electron momentum distributions of valence orbitals of cyclopentene employing symmetric noncoplanar(e,2e)kinematics at impact energies of 1200 and 1600 eV plus the binding energy.Experimenta...We report a measurement of electron momentum distributions of valence orbitals of cyclopentene employing symmetric noncoplanar(e,2e)kinematics at impact energies of 1200 and 1600 eV plus the binding energy.Experimental momentum profiles for individual ionization bands are obtained and compared with theoretical calculations considering nuclear dynamics by harmonic analytical quantum mechanical and thermal sampling molecular dynamics approaches.The results demonstrate that molecular vibrational motions including ring-puckering of this flexible cyclic molecule have obvious influences on the electron momentum profiles for the outer valence orbitals,especially in the low momentum region.Forπ^(*)-like molecular orbitals 3a′′,2a′′,and 3a′,the impact-energy dependence of the experimental momentum profiles indicates a distorted wave effect.展开更多
This paper suggests a hydrodynamic stability theory of distorted laminar flow, and presents a kind of distortion profile of mean velocity in parallel shear flow. With such distortion profiles, the new theory can be us...This paper suggests a hydrodynamic stability theory of distorted laminar flow, and presents a kind of distortion profile of mean velocity in parallel shear flow. With such distortion profiles, the new theory can be used to investigate the stability behaviour of parallel shear flow, and thus suggests a new possible approach to instability.展开更多
The relativistic and distorted wave effects are investigated for the electron momentum distributions of Xe 4d electrons.The theoretical results show good agreements with the experimental data measured previously with ...The relativistic and distorted wave effects are investigated for the electron momentum distributions of Xe 4d electrons.The theoretical results show good agreements with the experimental data measured previously with electron momentum spectroscopy. The distorted wave effect and the relativistic effect are found to play important roles in the low and high momentum regions, respectively.展开更多
This paper proposes a current control scheme for a grid-connected pulse width modulator(PWM) voltage source converter(GC-VSC) under imbalanced and distorted supply voltage conditions.The control scheme is implemented ...This paper proposes a current control scheme for a grid-connected pulse width modulator(PWM) voltage source converter(GC-VSC) under imbalanced and distorted supply voltage conditions.The control scheme is implemented in the positive synchronously rotating reference frame and composed of a single proportional integral(PI) regulator and multi-frequency resonant controllers tuned at the frequencies of 2ω and 6ω,respectively.The experimental results,with the target of eliminating the active power oscillations and current harmonics on a prototype GC-VSC system,validate the feasibility of the proposed current control scheme during supply voltage imbalance and distortion.展开更多
The influence of the distorted plane of the active phased array antenna on the electromagnetic performance is of great significance to the research on and development of the high-performance antennas. On the bent and ...The influence of the distorted plane of the active phased array antenna on the electromagnetic performance is of great significance to the research on and development of the high-performance antennas. On the bent and bowl-shape distortion, the model is established of the relationship between the electromagnetic performance and the position error of the radiated elements. The method is presented of analyzing the far-field pattern of the distorted rectangular active phased array antenna. The analysis results of a planar phased array antenna with different distortions grades prove the validity of the model. Therefore, by the method, the antenna designers may set the reasonable requirement on the structural tolerance in manufacturing antenna.展开更多
In certain exceptional cases,capillary samples must be used to measure X-ray absorption spectra(XAS).However,the inho-mogeneous thickness of capillary samples causes XAS distortion.This study discusses the distortion ...In certain exceptional cases,capillary samples must be used to measure X-ray absorption spectra(XAS).However,the inho-mogeneous thickness of capillary samples causes XAS distortion.This study discusses the distortion and correction of the XAS curve caused by the inhomogeneous thickness of capillary samples.The relationship between the distorted XAS curveμ′d_(eq)(measured values)and the real absorption coefficientμ_(s)d_(eq)(true values)of the sample was established.The distortion was slight and negligible when the vertical size(2h)of the X-ray beam spot was smaller than 60%of the capillary tube’s inner diameter(2R_(in)).When h/R_(in)>1,X-ray leakage is inevitable and should be avoided during measurement.Partial X-ray leakage caused by an X-ray beam spot size larger than the inner diameter of the capillary tube leads to serious compressed distortion of the XAS curve.When h/R_(in)<1,the distorted XAS data were well corrected.Possible errors and their influence on the corrected XAS are also discussed.Simulations and corrections for distortions verify the feasibility and effectiveness of the corrected method.展开更多
This study prepared 17 strains of Lentinula edodes, including wild and cultivated strains as materials, and statistically analyzed the ratios of spores from different aspects via mating types＇ analysis and the OWE-SO...This study prepared 17 strains of Lentinula edodes, including wild and cultivated strains as materials, and statistically analyzed the ratios of spores from different aspects via mating types＇ analysis and the OWE-SOJ technique. The results from this study first systematically identified skewed expected distribution of mating-type factors segregation in Lentinula edodes spores has commonly statistical meanings in wild and cultivated strains. Genetic analysis of positive and negative parental-recombined fruiting showed that the nuclear type of F1 progeny spores among those strains segregated through theoretical distribution mainly depended on the combined state of parental dikaryons, and the predominant spores were those with the mating type identical to the dikaryotic parent, indicating that the genetic basis of segregation distortion of spores is different from that of protoplast monokaryons in which the B factor takes predominant responsibility for that phenomenon, and it cooperates A factor with B factor to influence the ratio of spores.展开更多
In this paper, a reduced-cost method of measuring residual nonlinearities in an adaptive digitally predistorted amplifier is proposed. Measurements obtained by selective sampling of the amplifier output are integrated...In this paper, a reduced-cost method of measuring residual nonlinearities in an adaptive digitally predistorted amplifier is proposed. Measurements obtained by selective sampling of the amplifier output are integrated over the input envelope range to adapt a fourth-order polynomial predistorter with memory correction. Results for a WCDMA input with a 101 carrier configuration show that a transmitter using the proposed method can meet the adjacent channel leakage ratio （ACLR） specification. Inverse modeling of the nonlinearity is proposed as a future extension that will reduce the cost of the system further.展开更多
Image restoration is the problem of restoring a real degraded image.Previous studies mostly focused on single distortion.However,most of the real images experience multiple distortions,and single distortion image rest...Image restoration is the problem of restoring a real degraded image.Previous studies mostly focused on single distortion.However,most of the real images experience multiple distortions,and single distortion image restoration algorithms can not effectively improve the image quality.Moreover,few existing hybrid distortion image restoration algorithms can not deal with single distortion.Therefore,an end-to-end pipeline network based on stagewise training is proposed in this paper.Specifically,the network selects three typical image restoration tasks:denoising,inpainting,and super resolution.The whole training process is divided into single distortion training,hybrid distortion training of two types,and hybrid distortion training of three types.The design of loss function draws on the idea of deep supervision.Experimental results prove that the proposed method is not only superior to other methods in hybrid-distorted image restoration,but also suitable for single distortion image restoration.展开更多
This paper proposes a corrected method of distorted image based on adaptive control. First, the adaptive control relationship of pixel point positions between distorted image and its corrected image is given by using ...This paper proposes a corrected method of distorted image based on adaptive control. First, the adaptive control relationship of pixel point positions between distorted image and its corrected image is given by using polynomial fitting, thus control point pairs between the distorted image and its corrected image are found. Secondly, the value of both image distortion centre and polynomial coefficient is obtained with least square method, thus the relationship of each control point pairs is deduced. In the course of distortion image processing, the gray value of the corrected image is changed into integer with bilinear interpolation. Finally, the experiments are performed to correct two distorted printed circuit board images. The results are perfect and the mean square errors of residual error are tiny.展开更多
文摘Based on the hydrodynamic stability theory of distorted laminar flow and the kind of distortion profiles on the mean velocity in parallel shear flow given in paper [1], this paper investigates the linear stability behaviour of parallel shear flow, presents unstable results of plane Couette flow and pipe Poiseuille flow to two-dimensional or axisymmetric disturbances for the first time, and obtains neutral curves of these two motions under certain definition.
文摘Based on the hydrodynamic stability theory of distorted laminar flow and the kind of distortion profiles on the mean velocity in parallel shear flow given in paper [1], this paper investigates the nonlinear stability behaviour of parallel shear flow, carries on stability calculation taking account of the perturbations of background turbulence noise under certain assumption, and obtains some results in accordance qualitatively with those of experiment for plane Poiseuille flow and pipe Poiseuille flow.
基金supported by the Key Program of the National Natural Science Foundation of China(Grant No.NSFC 91441205)
文摘An experimental system based on the background-oriented schlieren（BOS） technique is built to reconstruct the density and temperature distribution of a flame-induced distorted flow field which has a density gradient. The cross-correlation algorithm with sub-pixel accuracy is introduced and used to calculate the background-element displacement of a disturbed image and a fourth-order difference scheme is also developed to solve the Poisson equation. An experiment for a disturbed flow field caused by a burning candle is performed to validate the built BOS system and the results indicate that density and temperature distribution of the disturbed flow field can be reconstructed accurately. A notable conclusion is that in order to make the reconstructed results have a satisfactory accuracy, the inquiry step length should be less than the size of the interrogation window.
基金Supported by the National Natural Science Foundation for Young Scientists of China (No. 40801225)the Natural Science Foundation of Zhejiang Province (No. Y3090038)
文摘We evaluated the effect of various error sources in fishery harvest/effort data on the maximum sustainable yield （MSY） and corresponding fishing effort （EMsv） using Monte Carlo simulation analyses. A high coefficient of variation （CV） of the catch and effort values biased the estimates of MSY and EMsv. Thus, the state of the fisheries resource and its exploitation was overestimated. We compared the effect using three surplus production models, Hilborn-Waters （H-W）, Schnute, and Prager models. The estimates generated using the H-W model were significantly affected by the CV. The Schnute model was least affected by errors in the underlying data. The CVof the catch data had a greater impact on the assessment than the CV of the fishing effort. Similarly, the changes in CV had a greater impact on the estimated maximum sustainable yield （MSY） than on the corresponding estimate of fishing effort （EMsY）. We discuss the likely effect of these biases on management efforts and provide suggestions for the improvement of fishery evaluations.
文摘Background: It is said that after ICU discharge, 40% of patients suffer from acute stress symptoms, such as anxiety and depression, caused by “distorted memories” (memory loss and delusions) due to various treatments in the ICU. This study focused on the quantitative and qualitative effects of ICU diaries on distorted memories that patients encountered during their time in the ICU. Aim: To assess improving distorted memories by providing information during ICU admission to patients to relieve the acute stress symptoms after ICU discharge. Design and Methods: This nonrandomized controlled trial included patients aged ≥20 years who had received treatment for ≥3 days in the ICU. Using ICU memory tool, the Hospital Anxiety and Depression Scale (HADS) and the Acute Stress Disorder Scale (ASDS) approximately 1 week after ICU discharge, then HADS and ASDS prior to hospital discharge, the change in mean values were compared between two groups (control and intervention) using a Wilcoxon signed-rank test. The intervention group was surveyed prior to hospital discharge using semi-structured interviews, and descriptions were analyzed by the content analysis method of Krippendorff. Results: Twenty-three participants were included in the control group, and 17 in the intervention group. When comparing subjects with distorted memories between the groups, we found reduced values for HADS anxiety (7.1 ± 3.8 to 5.7 ± 2.7, p = 0.011), HADS depression (8.6 ± 5.0 to 7.2 ± 4.3, p = 0.003), and ASDS (46.9 ± 13.8 to 43.8 ± 11.4, p = 0.012) in the intervention group. Based on the narrations, patients wanted to investigate facts in the ICU diary while having someone help them to remember these events. Conclusion: Improving distorted memories during ICU admissions may relieve acute stress symptoms. In addition, these patients needed someone to investigate facts from the ICU admission.
基金This work was supported by the National Natural Science Foundation of China(39970048)Guangdong Provincial Natural Science Foundation(990707)the Fok Ying Tung Education Foundation(71021).
文摘S-a, S-b and S-c are three loci for F1 pollen sterility in cultivated rice （Oryza sativa L.）. Taichung 65 （T65） is all Sj/Sj at these three loci, while its F1 pollen sterile near-isogenic lines, TISL2 （S-b）, TISL4 （S-a） and TISL5 （S-c） is Sj/Sj according to their respective sterility locus. Using SSR molecular marker to detect the segregation of the allele Si and Sj in pollen calli population induced from different hybrid F1, which have different pollen sterility locus, showed that the segregation of allele Si and Sj was distorted. The distorted direction of pollen calli population in vitro was not the same as F2 population in vivo. The quantities of pollen callus carrying Sj were much more than that of carrying Siat S-a and S-c locus, the ratio of Si and Sj were 1：4.81 and 1：1.96 respectively. But the opposite tendency was observed at S-b locus, the ratio of Si and Sj being 1：0.35. At the same time, all these results were undisturbed by either culture medium or culture period.
文摘In this short review paper, the significant and profound impacts of the distorted key theory for developing peptide drugs have been briefly recalled with crystal clear convincingness.
文摘After 900 ℃ high-vacuum annealing and air cooling, a special band was observed in pure titanium. Energy-dispersive spectrum showed that the composition of the band and the matrix is the same. By tilting the band to different zone axes and taking selected-area electron diffraction (SAED) patterns, we found that the structure of the band is distorted face-centered cubic (fcc) with the lattice constants a, b, and c deviating slightly from each other on the basis of the analyses of the SAED patterns together with the tilting angles. The lattice constants a, b, and c are calculated based on the measurement of interplanar spacing according to high-resolution transmission electron microscopy (HRTEM) images. The orientation relation between the hexagonal-close-packed (hcp) matrix and the distorted fcc band is [11(2)0]hcp//[110]fcc and (0001)hcp//(1(1)1)fcc according to SAED analysis. The phase boundary between the matrix and the band was observed to demonstrate serrated configuration composed of two kinds of micro-steps: ((1)11)//(0002) and ((1)11)//(10(1)1) on the basis of Cs-corrected HRTEM characterization. The distorted fcc band is deduced to be a thermal-induced metastable phase transformed from the high-temperature body-centered cubic (bcc) structure during the allotropic transformation from bcc to hcp based on orientation relation analysis.
基金supported by the National Natural Science Foundation of China(Nos.21901145,22171165)the financial support from Youth cross-scientific innovation group of Shandong University(No.2020QNQT003).
文摘Distortion of planar aromatics occurs in the fused rings conjugated with bulky substituents,which generates racemic enantiomers with high transformation energy barriers.However,direct synthesis of homochiral distorted aryl compounds is a very challenging task.Here,we presented a molecular folding strategy to control distorted aryl homochirality.Amino acids and their derivatives conjugated on the polycyclic aromatic hydrocarbons including benzenes,naphthalenes and triphenylenes,which formed parallelβ-sheet arrays through intramolecular hydrogen bonds.The folding behavior enabled distorted or twisted geometry of aromatics,of which the handedness was associated with the absolute chirality of amino acids.X-ray crystallography,theoretical calculations and circular dichroism spectroscopy verified the distorted homochirality in the solid and solution phase.The relatively small rotational barrier between the enantiomers made the molecule sensitive to the environment and thus realized the solvent-controlled chiral inversion.Theβ-sheet folding strategy can be widely used in polycyclic aromatic hydrocarbons with various functions,which provided a promising strategy to control inherent chirality of aromatics with adaptive chiroptical responses.
文摘Due to development of distribution systems and increase in electricity demand,the use of capacitor banks increases.From the other point of view,nonlinear loads generate and inject considerable harmonic currents into power system.Under this condition if capacitor banks are not properly selected and placed in the power system,they could amplify and propagate these harmonics and deteriorate power quality to unacceptable levels.With attention of disadvantages of passive filters,such as occurring resonance,nowadays the usage of this type of harmonic compensator is restricted.On the other side,one of parallel multi-function compensating devices which are recently used in distribution system to mitigate voltage sag and harmonic distortion,performs power factor correction,and improves the overall power quality as active power conditioner(APC).Therefore,the utilization of APC in harmonic distorted system can affect and change the optimal location and size of shunt capacitor bank under harmonic distortion condition.This paper presents an optimization algorithm for improvement of power quality using simultaneous optimal placement and sizing of APC and shunt capacitor banks in radial distribution networks in the presence of voltage and current harmonics.The algorithm is based on particle swarm optimization(PSO).The objective function includes the cost of power losses,energy losses and those of the capacitor banks and APCs.
基金supported by the National Natural Science Foundation of China(No.11534011,No.11874339,No.11804328)the National Key Research and Development Program of China(No.2017YFA0402300)。
文摘We report a measurement of electron momentum distributions of valence orbitals of cyclopentene employing symmetric noncoplanar(e,2e)kinematics at impact energies of 1200 and 1600 eV plus the binding energy.Experimental momentum profiles for individual ionization bands are obtained and compared with theoretical calculations considering nuclear dynamics by harmonic analytical quantum mechanical and thermal sampling molecular dynamics approaches.The results demonstrate that molecular vibrational motions including ring-puckering of this flexible cyclic molecule have obvious influences on the electron momentum profiles for the outer valence orbitals,especially in the low momentum region.Forπ^(*)-like molecular orbitals 3a′′,2a′′,and 3a′,the impact-energy dependence of the experimental momentum profiles indicates a distorted wave effect.
基金Project Supported by National Natural Science Foundation of China
文摘This paper suggests a hydrodynamic stability theory of distorted laminar flow, and presents a kind of distortion profile of mean velocity in parallel shear flow. With such distortion profiles, the new theory can be used to investigate the stability behaviour of parallel shear flow, and thus suggests a new possible approach to instability.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11327404 and U1432118)the Natural Science Research Programme of Education Department of Anhui Province,China(Grant Nos.KJ2013A260 and KJ2016A749)
文摘The relativistic and distorted wave effects are investigated for the electron momentum distributions of Xe 4d electrons.The theoretical results show good agreements with the experimental data measured previously with electron momentum spectroscopy. The distorted wave effect and the relativistic effect are found to play important roles in the low and high momentum regions, respectively.
基金supported by the National Natural Science Foundation of China(No.50907057)the National High-Tech Research and Development Program (863) of China(No.2007AA05Z419)
文摘This paper proposes a current control scheme for a grid-connected pulse width modulator(PWM) voltage source converter(GC-VSC) under imbalanced and distorted supply voltage conditions.The control scheme is implemented in the positive synchronously rotating reference frame and composed of a single proportional integral(PI) regulator and multi-frequency resonant controllers tuned at the frequencies of 2ω and 6ω,respectively.The experimental results,with the target of eliminating the active power oscillations and current harmonics on a prototype GC-VSC system,validate the feasibility of the proposed current control scheme during supply voltage imbalance and distortion.
基金supported partly by the National Natural Science Foundation of China(50805111)the Natural Science Basic Research Plan in Shaanxi Province of China(SJ08E_203.)
文摘The influence of the distorted plane of the active phased array antenna on the electromagnetic performance is of great significance to the research on and development of the high-performance antennas. On the bent and bowl-shape distortion, the model is established of the relationship between the electromagnetic performance and the position error of the radiated elements. The method is presented of analyzing the far-field pattern of the distorted rectangular active phased array antenna. The analysis results of a planar phased array antenna with different distortions grades prove the validity of the model. Therefore, by the method, the antenna designers may set the reasonable requirement on the structural tolerance in manufacturing antenna.
基金the National Key R&D Program of China(Nos.2022YFA1603802 and 2017YFA0403000)1W2B and 4B9A at the Beijing Synchrotron Radiation Facility.
文摘In certain exceptional cases,capillary samples must be used to measure X-ray absorption spectra(XAS).However,the inho-mogeneous thickness of capillary samples causes XAS distortion.This study discusses the distortion and correction of the XAS curve caused by the inhomogeneous thickness of capillary samples.The relationship between the distorted XAS curveμ′d_(eq)(measured values)and the real absorption coefficientμ_(s)d_(eq)(true values)of the sample was established.The distortion was slight and negligible when the vertical size(2h)of the X-ray beam spot was smaller than 60%of the capillary tube’s inner diameter(2R_(in)).When h/R_(in)>1,X-ray leakage is inevitable and should be avoided during measurement.Partial X-ray leakage caused by an X-ray beam spot size larger than the inner diameter of the capillary tube leads to serious compressed distortion of the XAS curve.When h/R_(in)<1,the distorted XAS data were well corrected.Possible errors and their influence on the corrected XAS are also discussed.Simulations and corrections for distortions verify the feasibility and effectiveness of the corrected method.
文摘This study prepared 17 strains of Lentinula edodes, including wild and cultivated strains as materials, and statistically analyzed the ratios of spores from different aspects via mating types＇ analysis and the OWE-SOJ technique. The results from this study first systematically identified skewed expected distribution of mating-type factors segregation in Lentinula edodes spores has commonly statistical meanings in wild and cultivated strains. Genetic analysis of positive and negative parental-recombined fruiting showed that the nuclear type of F1 progeny spores among those strains segregated through theoretical distribution mainly depended on the combined state of parental dikaryons, and the predominant spores were those with the mating type identical to the dikaryotic parent, indicating that the genetic basis of segregation distortion of spores is different from that of protoplast monokaryons in which the B factor takes predominant responsibility for that phenomenon, and it cooperates A factor with B factor to influence the ratio of spores.
文摘In this paper, a reduced-cost method of measuring residual nonlinearities in an adaptive digitally predistorted amplifier is proposed. Measurements obtained by selective sampling of the amplifier output are integrated over the input envelope range to adapt a fourth-order polynomial predistorter with memory correction. Results for a WCDMA input with a 101 carrier configuration show that a transmitter using the proposed method can meet the adjacent channel leakage ratio （ACLR） specification. Inverse modeling of the nonlinearity is proposed as a future extension that will reduce the cost of the system further.
文摘Image restoration is the problem of restoring a real degraded image.Previous studies mostly focused on single distortion.However,most of the real images experience multiple distortions,and single distortion image restoration algorithms can not effectively improve the image quality.Moreover,few existing hybrid distortion image restoration algorithms can not deal with single distortion.Therefore,an end-to-end pipeline network based on stagewise training is proposed in this paper.Specifically,the network selects three typical image restoration tasks:denoising,inpainting,and super resolution.The whole training process is divided into single distortion training,hybrid distortion training of two types,and hybrid distortion training of three types.The design of loss function draws on the idea of deep supervision.Experimental results prove that the proposed method is not only superior to other methods in hybrid-distorted image restoration,but also suitable for single distortion image restoration.
基金Project supported by the Research Foundation of the State Key Laboratory,China(Grant No.9140C1406020708)the Program Research Foundation of Hunan Province Science-Technology Department,China(Grant No.2009FJ3187)the 11th Five Year Plan for Key Construction Academic Subject(Optics)of Hunan Province,China(Grant No.06GXCD02)
文摘This paper proposes a corrected method of distorted image based on adaptive control. First, the adaptive control relationship of pixel point positions between distorted image and its corrected image is given by using polynomial fitting, thus control point pairs between the distorted image and its corrected image are found. Secondly, the value of both image distortion centre and polynomial coefficient is obtained with least square method, thus the relationship of each control point pairs is deduced. In the course of distortion image processing, the gray value of the corrected image is changed into integer with bilinear interpolation. Finally, the experiments are performed to correct two distorted printed circuit board images. The results are perfect and the mean square errors of residual error are tiny.
