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
The rhombohedralα-GeTe can be approximated as a slightly distorted rock-salt structure along its[111]direction and possesses superb thermoelectric performance.However,the role of such a ferroelectric-like structural ...The rhombohedralα-GeTe can be approximated as a slightly distorted rock-salt structure along its[111]direction and possesses superb thermoelectric performance.However,the role of such a ferroelectric-like structural distortion on its transport properties remains unclear.Herein,we performed a systematic study on the crystal structure and electronic band structure evolutions of Ge_(1-x)Sn_(x)Te alloys where the degree of ferroelectric distortion is continuously tuned.It is revealed that the band gap is maximized while multiple valence bands are converged at x=0.6,where the ferroelectric distortion is the least but still works.Once undistorted,the band gap is considerably reduced,and the valence bands are largely separated again.Moreover,near the ferro-to-paraelectric phase transition Curie temperature,the lattice thermal conductivity reaches its minima because of significant lattice softening enabled by ferroelectric instability.We predict a peak ZT value of 2.6 at 673 K inα-GeTe by use of proper dopants which are powerful in suppressing the excess hole concentrations but meanwhile exert little influence on the ferroelectric distortion.展开更多
Platinum-based alloy nanoparticles are the most attractive catalysts for the oxygen reduction reaction at present,but an in-depth understanding of the relationship between their short-range structural information and ...Platinum-based alloy nanoparticles are the most attractive catalysts for the oxygen reduction reaction at present,but an in-depth understanding of the relationship between their short-range structural information and catalytic performance is still lacking.Herein,we present a synthetic strategy that uses transition-metal oxide-assisted thermal diffusion.PtCo/C catalysts with localized tetragonal distortion were obtained by controlling the thermal diffusion process of transition-metal elements.This localized structural distortion induced a significant strain effect on the nanoparticle surface,which further shortened the length of the Pt-Pt bond,improved the electronic state of the Pt surface,and enhanced the performance of the catalyst.PtCo/C catalysts with special short-range structures achieved excellent mass activity(2.27 Amg_(Pt)^(-1))and specific activity(3.34 A cm^(-2)).In addition,the localized tetragonal distortion-induced surface compression of the Pt skin improved the stability of the catalyst.The mass activity decreased by only 13% after 30,000 cycles.Enhanced catalyst activity and excellent durability have also been demonstrated in the proton exchange membrane fuel cell configuration.This study provides valuable insights into the development of advanced Pt-based nanocatalysts and paves the way for reducing noble-metal loading and increasing the catalytic activity and catalyst stability.展开更多
Pb(Zr,Ti)O_(3)-based ceramics are the mainstream materials for commercial multilayer piezoelectric ceramic actuators,but to date,large strains at low electric fields have not been well solved.Herein,0.95Pb(Zr_(0.56)Ti...Pb(Zr,Ti)O_(3)-based ceramics are the mainstream materials for commercial multilayer piezoelectric ceramic actuators,but to date,large strains at low electric fields have not been well solved.Herein,0.95Pb(Zr_(0.56)Ti_(0.44))O_(3)–0.05(Bi_(0.5)Na_(0.5))TiO_(3–x)BaZrO_(3)(PZT–BNT–xBZ)ceramics with efficient ferroelectric domain wall motion were designed and realized by reducing lattice distortion and changing the domain structure.It is found that the introduction of BaZrO_(3)(BZ)weakens the tetragonal phase distortion of PZT,contributing to a reduction in the mechanical stress that impedes the migration of domain walls.Moreover,the domain structures could be modified by adjusting the BZ content,where short and broad striped domains are constructed with high amplitude characteristics to enhance the domain wall motion.A large strain of 0.39%is accordingly achieved at an electric field as low as 40 kV/cm for the sample with x=0.03,accompanied by excellent temperature stability over the temperature range of 30–210℃.This study delves into the synergistic effects of reducing lattice distortion and changing domain structure on domain wall motion and provides an effective strategy to improve the strain of PZT-based piezoelectric ceramics.展开更多
We report a systematic study on layered metal SrCu_(4-x)P_(2) single crystals via transport, magnetization, thermodynamic measurements and structural characterization. We find that the crystals show large linear magne...We report a systematic study on layered metal SrCu_(4-x)P_(2) single crystals via transport, magnetization, thermodynamic measurements and structural characterization. We find that the crystals show large linear magnetoresistance without any sign of saturation with a magnetic field up to 30T. We also observe a phase transition with significant anomalies in resistivity and heat capacity at T_(p)~140 K. Thermal expansion measurement reveals a subtle lattice parameter variation near Tp, i.e.,?L_(c)/L_(c)~0.062%. The structural characterization confines that there is no structure transition below and above T_(p). All these results suggest that the nonmagnetic transition of SrCu_(4-x)P_(2) could be associated with structural distortion.展开更多
Non-penetration laser welding of lap joints in austenitic stainless steel sheets is commonly preferred in fields where the surface quality is of utmost importance.However,the application of non-penetration welded aust...Non-penetration laser welding of lap joints in austenitic stainless steel sheets is commonly preferred in fields where the surface quality is of utmost importance.However,the application of non-penetration welded austenitic stainless steel parts is limited owing to the micro bulging distortion that occurs on the back surface of the partial penetration side.In this paper,non-penetration lap laser welding experiments,were conducted on galvanized and SUS304 austenitic stainless steel plates using a fiber laser,to investigate the mechanism of bulging distortion.A comparative experiment of DC01 galvanized steel-Q235 carbon steel lap laser welding was carried out,and the deflection and distortion profile of partially penetrated side of the sheets were measured using a noncontact laser interferometer.In addition,the cold-rolled SUS304 was subjected to heat holding at different temperatures and water quenching after bending to characterize its microstructure under tensile and compressive stress.The results show that,during the heating stage of the thermal cycle of laser lap welding,the partial penetration side of the SUS304 steel sheet generates compressive stress,which extrudes the material in the heat-affected zone to the outside of the back of the SUS304 steel sheet,thereby forming a bulge.The findings of these experiments can be of great value for controlling the distortion of the partial penetrated side of austenitic stainless steel sheet during laser non-penetration lap welding.展开更多
3D elastic-plastic FE model for simulating the force controlled stretch-bending process of double-cavity aluminum profile was established using hybrid explicit−implicit solvent method.Considering the computational acc...3D elastic-plastic FE model for simulating the force controlled stretch-bending process of double-cavity aluminum profile was established using hybrid explicit−implicit solvent method.Considering the computational accuracy and efficiency,the optimal choices of numerical parameters and algorithms in FE modelling were determined.The formation mechanisms of cross-section distortion and springback were revealed.The effects of pre-stretching,post-stretching,friction,and the addition of internal fillers on forming quality were investigated.The results show that the stress state of profile in stretch-bending is uniaxial with only a circumferential stress.The stress distribution along the length direction of profile is non-uniform and the maximum tensile stress is located at a certain distance away from the center of profile.As aluminum profile is gradually attached to bending die,the distribution characteristic of cross-section distortion along the length direction of profile changes from V-shape to W-shape.After unloading the forming tools,cross-section distortion decreases obviously due to the stress relaxation,with a maximum distortion difference of 13%before and after unloading.As pre-stretching and post-stretching forces increase,cross-section distortion increases gradually,while springback first decreases and then remains unchanged.With increasing friction between bending die and profile,cross-section distortion slightly decreases,while springback increases.Cross-section distortion decreases by 83%with adding PVC fillers into the cavities of profile,while springback increases by 192.2%.展开更多
To reduce the negative impact of the power amplifier(PA)nonlinear distortion caused by the orthogonal frequency division multiplexing(OFDM)waveform with high peak-to-average power ratio(PAPR)in integrated radar and co...To reduce the negative impact of the power amplifier(PA)nonlinear distortion caused by the orthogonal frequency division multiplexing(OFDM)waveform with high peak-to-average power ratio(PAPR)in integrated radar and communication(RadCom)systems is studied,the channel estimation in passive sensing scenarios.Adaptive channel estimation methods are proposed based on different pilot patterns,considering nonlinear distortion and channel sparsity.The proposed methods achieve sparse channel results by manipulating the least squares(LS)frequency-domain channel estimation results to preserve the most significant taps.The decision-aided method is used to optimize the sparse channel results to reduce the effect of nonlinear distortion.Numerical results show that the channel estimation performance of the proposed methods is better than that of the conventional methods under different pilot patterns.In addition,the bit error rate performance in communication and passive radar detection performance show that the proposed methods have good comprehensive performance.展开更多
Maps, essential tools for portraying the Earth’s surface, inherently introduce distortions to geographical features. While various quantification methods exist for assessing these distortions, they often fall short w...Maps, essential tools for portraying the Earth’s surface, inherently introduce distortions to geographical features. While various quantification methods exist for assessing these distortions, they often fall short when evaluating actual geographic features. In our study, we took a novel approach by analyzing map projection distortion from a geometric perspective. We computed the fractal dimensions of different stretches of coastline before and after projection using the divide-and-conquer algorithm and image processing. Our findings revealed that map projections, even when preserving basic shapes, inevitably stretch and compress coastlines in diverse directions. This analysis method provides a more realistic and practical way to measure map-induced distortions, with significant implications for cartography, geographic information systems (GIS), and geomorphology. By bridging the gap between theoretical analysis and real-world features, this method greatly enhances accuracy and practicality when evaluating map projections.展开更多
为使偏分离群体连锁图矫正方法能被广泛应用,在Microsoft Visual Studio 2010操作平台下,利用C++语言研制了Windows界面友好的DistortedMap软件包。结果显示:DistortedMap软件包具有遗传群体模拟、偏分离群体连锁图矫正和数量性状基因...为使偏分离群体连锁图矫正方法能被广泛应用,在Microsoft Visual Studio 2010操作平台下,利用C++语言研制了Windows界面友好的DistortedMap软件包。结果显示:DistortedMap软件包具有遗传群体模拟、偏分离群体连锁图矫正和数量性状基因座定位的功能。使用该软件包可获得偏分离标记间遗传距离的无偏估计值并消除标记偏分离对QTL定位的影响。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
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
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
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
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
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.
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
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
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
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.
基金the financial support from the National Natural Science Foundation of China(Grant No.52171221)the National Key Research and Development Program of China(Grant No.2019YFA0704900)the support from the Core Facility of Wuhan University for their assistance with EPMA analysis
文摘The rhombohedralα-GeTe can be approximated as a slightly distorted rock-salt structure along its[111]direction and possesses superb thermoelectric performance.However,the role of such a ferroelectric-like structural distortion on its transport properties remains unclear.Herein,we performed a systematic study on the crystal structure and electronic band structure evolutions of Ge_(1-x)Sn_(x)Te alloys where the degree of ferroelectric distortion is continuously tuned.It is revealed that the band gap is maximized while multiple valence bands are converged at x=0.6,where the ferroelectric distortion is the least but still works.Once undistorted,the band gap is considerably reduced,and the valence bands are largely separated again.Moreover,near the ferro-to-paraelectric phase transition Curie temperature,the lattice thermal conductivity reaches its minima because of significant lattice softening enabled by ferroelectric instability.We predict a peak ZT value of 2.6 at 673 K inα-GeTe by use of proper dopants which are powerful in suppressing the excess hole concentrations but meanwhile exert little influence on the ferroelectric distortion.
基金supported by the National Natural Science Foundation of China (Grant No.22278123).
文摘Platinum-based alloy nanoparticles are the most attractive catalysts for the oxygen reduction reaction at present,but an in-depth understanding of the relationship between their short-range structural information and catalytic performance is still lacking.Herein,we present a synthetic strategy that uses transition-metal oxide-assisted thermal diffusion.PtCo/C catalysts with localized tetragonal distortion were obtained by controlling the thermal diffusion process of transition-metal elements.This localized structural distortion induced a significant strain effect on the nanoparticle surface,which further shortened the length of the Pt-Pt bond,improved the electronic state of the Pt surface,and enhanced the performance of the catalyst.PtCo/C catalysts with special short-range structures achieved excellent mass activity(2.27 Amg_(Pt)^(-1))and specific activity(3.34 A cm^(-2)).In addition,the localized tetragonal distortion-induced surface compression of the Pt skin improved the stability of the catalyst.The mass activity decreased by only 13% after 30,000 cycles.Enhanced catalyst activity and excellent durability have also been demonstrated in the proton exchange membrane fuel cell configuration.This study provides valuable insights into the development of advanced Pt-based nanocatalysts and paves the way for reducing noble-metal loading and increasing the catalytic activity and catalyst stability.
基金supported by the National Natural Science Foundation of China(Nos.62371366 and 52106109)the Innovation Capability Support Program of Shaanxi(Nos.2023-CX-PT-30 and 2022TD-28)+2 种基金the Open Project of Yunnan Precious Metals Laboratory Co.,Ltd.(No.YPML-2023050246)the Qinchuangyuan Citing High-level Innovation and Entrepreneurship Talent Projects(No.QCYRCXM-2022-40)the Fundamental Research Funds for the Central Universities and Innovation Fund of Xidian University(No.YJSJ23014-1).
文摘Pb(Zr,Ti)O_(3)-based ceramics are the mainstream materials for commercial multilayer piezoelectric ceramic actuators,but to date,large strains at low electric fields have not been well solved.Herein,0.95Pb(Zr_(0.56)Ti_(0.44))O_(3)–0.05(Bi_(0.5)Na_(0.5))TiO_(3–x)BaZrO_(3)(PZT–BNT–xBZ)ceramics with efficient ferroelectric domain wall motion were designed and realized by reducing lattice distortion and changing the domain structure.It is found that the introduction of BaZrO_(3)(BZ)weakens the tetragonal phase distortion of PZT,contributing to a reduction in the mechanical stress that impedes the migration of domain walls.Moreover,the domain structures could be modified by adjusting the BZ content,where short and broad striped domains are constructed with high amplitude characteristics to enhance the domain wall motion.A large strain of 0.39%is accordingly achieved at an electric field as low as 40 kV/cm for the sample with x=0.03,accompanied by excellent temperature stability over the temperature range of 30–210℃.This study delves into the synergistic effects of reducing lattice distortion and changing domain structure on domain wall motion and provides an effective strategy to improve the strain of PZT-based piezoelectric ceramics.
基金Project supported by the National Key Research and Development Program of China (Grant Nos.2023YFA1607403,2021YFA1600201,and 2022YFA1602603)the Natural Science Foundation of China (Grant Nos.U19A2093,U2032214,and U2032163)+5 种基金the Collaborative Innovation Program of Hefei Science Center,CAS (Grant No.2019HSC-CIP 001)the Youth Innovation Promotion Association of CAS (Grant No.2021117)the Natural Science Foundation of Anhui Province (No.1908085QA15)the HFIPS Director’s Fund (Grant No.YZJJQY202304)the CASHIPS Director’s Fund (Grant No.YZJJ2022QN36)supported by the High Magnetic Field Laboratory of Anhui Province。
文摘We report a systematic study on layered metal SrCu_(4-x)P_(2) single crystals via transport, magnetization, thermodynamic measurements and structural characterization. We find that the crystals show large linear magnetoresistance without any sign of saturation with a magnetic field up to 30T. We also observe a phase transition with significant anomalies in resistivity and heat capacity at T_(p)~140 K. Thermal expansion measurement reveals a subtle lattice parameter variation near Tp, i.e.,?L_(c)/L_(c)~0.062%. The structural characterization confines that there is no structure transition below and above T_(p). All these results suggest that the nonmagnetic transition of SrCu_(4-x)P_(2) could be associated with structural distortion.
文摘Non-penetration laser welding of lap joints in austenitic stainless steel sheets is commonly preferred in fields where the surface quality is of utmost importance.However,the application of non-penetration welded austenitic stainless steel parts is limited owing to the micro bulging distortion that occurs on the back surface of the partial penetration side.In this paper,non-penetration lap laser welding experiments,were conducted on galvanized and SUS304 austenitic stainless steel plates using a fiber laser,to investigate the mechanism of bulging distortion.A comparative experiment of DC01 galvanized steel-Q235 carbon steel lap laser welding was carried out,and the deflection and distortion profile of partially penetrated side of the sheets were measured using a noncontact laser interferometer.In addition,the cold-rolled SUS304 was subjected to heat holding at different temperatures and water quenching after bending to characterize its microstructure under tensile and compressive stress.The results show that,during the heating stage of the thermal cycle of laser lap welding,the partial penetration side of the SUS304 steel sheet generates compressive stress,which extrudes the material in the heat-affected zone to the outside of the back of the SUS304 steel sheet,thereby forming a bulge.The findings of these experiments can be of great value for controlling the distortion of the partial penetrated side of austenitic stainless steel sheet during laser non-penetration lap welding.
基金the National Natural Science Foundation of China(Nos.52005244,U20A20275)the Natural Science Foundation of Hunan Province,China(Nos.2021JJ30573,2023JJ60193)the Open Fund of State Key Laboratory of Advanced Design and Manufacture for Vehicle Body,China(No.31715011)。
文摘3D elastic-plastic FE model for simulating the force controlled stretch-bending process of double-cavity aluminum profile was established using hybrid explicit−implicit solvent method.Considering the computational accuracy and efficiency,the optimal choices of numerical parameters and algorithms in FE modelling were determined.The formation mechanisms of cross-section distortion and springback were revealed.The effects of pre-stretching,post-stretching,friction,and the addition of internal fillers on forming quality were investigated.The results show that the stress state of profile in stretch-bending is uniaxial with only a circumferential stress.The stress distribution along the length direction of profile is non-uniform and the maximum tensile stress is located at a certain distance away from the center of profile.As aluminum profile is gradually attached to bending die,the distribution characteristic of cross-section distortion along the length direction of profile changes from V-shape to W-shape.After unloading the forming tools,cross-section distortion decreases obviously due to the stress relaxation,with a maximum distortion difference of 13%before and after unloading.As pre-stretching and post-stretching forces increase,cross-section distortion increases gradually,while springback first decreases and then remains unchanged.With increasing friction between bending die and profile,cross-section distortion slightly decreases,while springback increases.Cross-section distortion decreases by 83%with adding PVC fillers into the cavities of profile,while springback increases by 192.2%.
基金supported by the National Natural Science Foundation of China(61931015,62071335,62250024)the Natural Science Foundation of Hubei Province of China(2021CFA002)+1 种基金the Fundamental Research Funds for the Central Universities of China(2042022dx0001)the Science and Technology Program of Shenzhen(JCYJ20170818112037398).
文摘To reduce the negative impact of the power amplifier(PA)nonlinear distortion caused by the orthogonal frequency division multiplexing(OFDM)waveform with high peak-to-average power ratio(PAPR)in integrated radar and communication(RadCom)systems is studied,the channel estimation in passive sensing scenarios.Adaptive channel estimation methods are proposed based on different pilot patterns,considering nonlinear distortion and channel sparsity.The proposed methods achieve sparse channel results by manipulating the least squares(LS)frequency-domain channel estimation results to preserve the most significant taps.The decision-aided method is used to optimize the sparse channel results to reduce the effect of nonlinear distortion.Numerical results show that the channel estimation performance of the proposed methods is better than that of the conventional methods under different pilot patterns.In addition,the bit error rate performance in communication and passive radar detection performance show that the proposed methods have good comprehensive performance.
文摘Maps, essential tools for portraying the Earth’s surface, inherently introduce distortions to geographical features. While various quantification methods exist for assessing these distortions, they often fall short when evaluating actual geographic features. In our study, we took a novel approach by analyzing map projection distortion from a geometric perspective. We computed the fractal dimensions of different stretches of coastline before and after projection using the divide-and-conquer algorithm and image processing. Our findings revealed that map projections, even when preserving basic shapes, inevitably stretch and compress coastlines in diverse directions. This analysis method provides a more realistic and practical way to measure map-induced distortions, with significant implications for cartography, geographic information systems (GIS), and geomorphology. By bridging the gap between theoretical analysis and real-world features, this method greatly enhances accuracy and practicality when evaluating map projections.
文摘为使偏分离群体连锁图矫正方法能被广泛应用,在Microsoft Visual Studio 2010操作平台下,利用C++语言研制了Windows界面友好的DistortedMap软件包。结果显示:DistortedMap软件包具有遗传群体模拟、偏分离群体连锁图矫正和数量性状基因座定位的功能。使用该软件包可获得偏分离标记间遗传距离的无偏估计值并消除标记偏分离对QTL定位的影响。
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.
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.
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.
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.
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.
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.
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.