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THE POSITION VARIATION OF THE WEST PACIFIC SUBTROPICAL HIGH AND ITS POSSIBLE MECHANISM 被引量:7
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作者 王黎娟 管兆勇 何金海 《Journal of Tropical Meteorology》 SCIE 2006年第2期113-120,共8页
Using NCEP/NCAR daily reanalysis data and SCSMEX data, an investigation is carried out of the relationship between the position variation of the west Pacific subtropical high (WPSH) and the apparcnt heating in June ... Using NCEP/NCAR daily reanalysis data and SCSMEX data, an investigation is carried out of the relationship between the position variation of the west Pacific subtropical high (WPSH) and the apparcnt heating in June 1998 based on the complete vertical vorticlty equation. It is tbund that the non-adiabatic heating plays an important role in the position variation of WPSH. In comparison with climatic mean status, the vertical change of non-adiabatic heating is stronger in the north side of WPSH in June 1998, but weaker in the south side of WPSH. The anomalous non-uniform heating induces anomalous cyclonic vorticity in South China, areas to lhe south of the Yangtze and its mid-lower valleys, but anomalous anticyclonic vorticity in the Indo-China Peninsula and South China Sea areas lead to the more southward position of WPSH than the mean. 展开更多
关键词 West Pacific subtropical high position variation apparent heating
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Variations in Carbohydrate and Protein Accumulation among Spikelets at Different Positions Within a Panicle During Rice Grain Filling 被引量:2
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作者 DONG Ming-hui CHEN Pei-feng +2 位作者 XIE Yu-lin QIAO Zhong-ying YANG Jian-chang 《Rice science》 2012年第3期223-232,共10页
The accumulation dynamics of kernel components for spikelets at different positions within a rice panicle were investigated during grain filling to understand the physiological reasons for the variation of grain quali... The accumulation dynamics of kernel components for spikelets at different positions within a rice panicle were investigated during grain filling to understand the physiological reasons for the variation of grain quality.Two rice cultivars,Yangdao 6 (indica) and Yangjing 9538 (japonica),were field-grown,and the grain filling characters and contents of starch,soluble sugar,and protein of the spikelets at different positions were studied.There were significant differences in matter accumulation among spikelets at different positions during grain filling.The early-flowering spikelets presented dominance over the late-flowering spikelets in initial time and initial rate of accumulation.At the initial and mid filling stages,the contents and the rates of starch and amylose accumulation in spikelets decreased with the flowering sequence,but soluble sugar content (SSC) exhibited the opposite trend.The difference in SSC among the spikelets of Yangjing 9538 was greater than that of Yangdao 6,but amylose content in mature spikelets showed no obvious relationship to their flowering sequence.The crude protein content (CPC) of early-flowering spikelets decreased more rapidly than that of late-flowering ones at the initial filling stage,and CPC in the spikelets on the secondary branch was higher than that on the primary branch,but CPC in early-flowering ones was lower than that in late-flowering across the whole grain filling period.Grain water content (GWC) of early-flowering spikelets decreased more rapidly than that of late-flowering spikelets on the same branch at the initial and mid filling stages,especially for the top grain on each primary branch.The results suggested that poor grain filling of late-flowering spikelets may be attributed to their low biological activity rather than carbohydrate supply limitation. 展开更多
关键词 spikelet position STARCH protein accumulation dynamic variation rice grain filling
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Estimation of annual variation of water vapor in the Arctic Ocean between 80°–87°N using shipborne GPS data based on kinematic precise point positioning 被引量:1
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作者 LUO Xiaowen ZHANG Tao +2 位作者 GAO Jinyao YANG Chunguo WU Zaocai 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2015年第6期1-4,共4页
The measurement of atmospheric water vapor (WV) content and variability is important for meteorological and climatological research. A technique for the remote sensing of atmospheric WV content using ground-based Gl... The measurement of atmospheric water vapor (WV) content and variability is important for meteorological and climatological research. A technique for the remote sensing of atmospheric WV content using ground-based Global Positioning System (GPS) has become available, which can routinely achieve accuracies for integrated WV content of 1-2 kg/m2. Some experimental work has shown that the accuracy of WV measurements from a moving platform is comparable to that of (static) land-based receivers. Extending this technique into the marine environment on a moving platform would be greatly beneficial for many aspects of meteorological research, such as the calibration of satellite data, investigation of the air-sea interface, as well as forecasting and climatological studies. In this study, kinematic precise point positioning has been developed to investigate WV in the Arctic Ocean (80°-87°N) and annual variations are obtained for 2008 and 2012 that are identical to those related to the enhanced greenhouse effect. 展开更多
关键词 annual variation estimation water vapor Arctic Ocean kinematic precise point positioning
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Precise Positioning Method for Seafloor Geodetic Stations Based on the Temporal Variation of Sound Speed Structure 被引量:2
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作者 Shuang ZHAO Zhenjie WANG +3 位作者 Zhixi NIE Kaifei HE Huimin LIU Zhen SUN 《Journal of Geodesy and Geoinformation Science》 CSCD 2023年第2期81-92,共12页
At present,GNSS-Acoustic(GNSS-A)combined technology is widely used in positioning for seafloor geodetic stations.Based on Sound Velocity Profiles(SVPs)data,the equal gradient acoustic ray-tracing method is applied in ... At present,GNSS-Acoustic(GNSS-A)combined technology is widely used in positioning for seafloor geodetic stations.Based on Sound Velocity Profiles(SVPs)data,the equal gradient acoustic ray-tracing method is applied in high-precision position inversion.However,because of the discreteness of the SVPs used in the forementioned method,it ignores the continuous variation of sound velocity structure in time domain,which worsens the positioning accuracy.In this study,the time-domain variation of Sound Speed Structure(SSS)has been considered,and the cubic B-spline function is applied to characterize the perturbed sound velocity.Based on the ray-tracing theory,an inversion model of“stepwise iteration&progressive corrections”for both positioning and sound speed information is proposed,which conducts the gradual correction of seafloor geodetic station coordinates and disturbed sound velocity.The practical data was used to test the effectiveness of our method.The results show that the Root Mean Square(RMS)errors of the residual values of the traditional methods without sound velocity correction,based on quadratic polynomial correction and based on cubic B-spline function correction are 1.43 ms,0.44 ms and 0.21 ms,respectively.The inversion model with sound velocity correction can effectively eliminate the systematic error caused by the change of SSS,and significantly improve the positioning accuracy of the seafloor geodetic stations. 展开更多
关键词 GNSS-Acoustic sound speed structure temporal variation seafloor positioning
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Body Position Changes Influence Stroke Volume Variation in Mechanically Ventilated Patients with Sepsis 被引量:3
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《麻醉与监护论坛》 2012年第1期26-31,共6页
关键词 摘要 编辑部 编辑工作 读者
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Robust SLAM localization method based on improved variational Bayesian filtering 被引量:1
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作者 Zhai Hongqi Wang Lihui +1 位作者 Cai Tijing Meng Qian 《Journal of Southeast University(English Edition)》 EI CAS 2022年第4期340-349,共10页
Aimed at the problem that the state estimation in the measurement update of the simultaneous localization and mapping(SLAM)method is incorrect or even not convergent because of the non-Gaussian measurement noise,outli... Aimed at the problem that the state estimation in the measurement update of the simultaneous localization and mapping(SLAM)method is incorrect or even not convergent because of the non-Gaussian measurement noise,outliers,or unknown and time-varying noise statistical characteristics,a robust SLAM method based on the improved variational Bayesian adaptive Kalman filtering(IVBAKF)is proposed.First,the measurement noise covariance is estimated using the variable Bayesian adaptive filtering algorithm.Then,the estimated covariance matrix is robustly processed through the weight function constructed in the form of a reweighted average.Finally,the system updates are iterated multiple times to further gradually correct the state estimation error.Furthermore,to observe features at different depths,a feature measurement model containing depth parameters is constructed.Experimental results show that when the measurement noise does not obey the Gaussian distribution and there are outliers in the measurement information,compared with the variational Bayesian adaptive SLAM method,the positioning accuracy of the proposed method is improved by 17.23%,20.46%,and 17.76%,which has better applicability and robustness to environmental disturbance. 展开更多
关键词 underwater navigation and positioning non-Gaussian distribution time-varying noise variational Bayesian method simultaneous localization and mapping(SLAM)
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Ultrasonographic identification of lateral femoral cutaneous nerve anatomical variation in persistent meralgia paresthetica:A case report
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作者 Hyeong-Woo Park Kyung-Suk Ji +2 位作者 Jun-Hyung Kim Li-Na Kim Kang-Wook Ha 《World Journal of Clinical Cases》 SCIE 2023年第31期7699-7705,共7页
BACKGROUND Meralgia paresthetica(MP)is an entrapment mononeuropathy of the lateral femoral cutaneous nerve(LFCN).Although structural abnormalities in nerve tissues can be confirmed using ultrasonography,this is not ro... BACKGROUND Meralgia paresthetica(MP)is an entrapment mononeuropathy of the lateral femoral cutaneous nerve(LFCN).Although structural abnormalities in nerve tissues can be confirmed using ultrasonography,this is not routinely performed.CASE SUMMARY Herein,we present the case of a 52-year-old woman who developed MP after laparoscopic gynecological surgery.The patient was referred to our clinic from an obstetrics and gynecology clinic with symptoms of numbness and a tingling sensation in the left anterolateral thigh,which developed after surgery performed 5 mo earlier.Tests were performed to assess the disease status and determine the underlying causes.Ultrasonographic examination revealed an anatomical variation,where the left LFCN was entrapped within the inguinal ligament.This case suggests that performing ultrasonographic examination before and after surgery in the lithotomy position could help prevent MP.CONCLUSION This case demonstrates the value of ultrasonography in detecting anatomical variation and diagnosing persistent MP.Ultrasonography should be considered an adjunct to electromyography for optimal MP management.Further,this case would help other clinicians determine patient prognosis and decide on targeted treatment strategies. 展开更多
关键词 Lateral femoral cutaneous nerve Anatomical variation Meralgia paresthetica Lithotomy position ULTRASONOGRAPHY Case report
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Normalized Positive Ground State Solutions for Nonhomogeneous Kirchhoff Equations
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作者 ZHANG Xiaocang XU Liping 《应用数学》 北大核心 2025年第3期711-720,共10页
This article studies a class of nonlinear Kirchhoff equations with exponential critical growth,trapping potential,and perturbation.Under appropriate assumptions about f and h,the article obtained the existence of norm... This article studies a class of nonlinear Kirchhoff equations with exponential critical growth,trapping potential,and perturbation.Under appropriate assumptions about f and h,the article obtained the existence of normalized positive solutions for this equation via the Trudinger-Moser inequality and variational methods.Moreover,these solutions are also ground state solutions.Additionally,the article also characterized the asymptotic behavior of solutions.The results of this article expand the research of relevant literature. 展开更多
关键词 Normalized positive ground state solution Nonhomogeneous Kirchhoff equation variational method Exponential critical growth Trapping potential
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A POSITIVE SOLUTION FOR QUASILINEAR SCHRÖDINGER-POISSON SYSTEM WITH CRITICAL EXPONENT
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作者 Lanxin HUANG Jiabao SU 《Acta Mathematica Scientia》 2025年第4期1247-1264,共18页
In this paper,we study the quasilinear Schrödinger-Poisson system with critical Sobolev exponent {-△_(p)u+|u|^(p-2)u=|u|^p^(*-2)u+ph(x)|u|^(q-2)u in R^(3),-△Φt(x)|u|^(p) in R^(3) where μ>0,3/2<p<3,p... In this paper,we study the quasilinear Schrödinger-Poisson system with critical Sobolev exponent {-△_(p)u+|u|^(p-2)u=|u|^p^(*-2)u+ph(x)|u|^(q-2)u in R^(3),-△Φt(x)|u|^(p) in R^(3) where μ>0,3/2<p<3,p≤q<p^(3)=3p/3-p and △_(p)u=div(|▽u|^(p-2)▽u)Under certain assumptions on the functions l and h, we employ the mountain pass theorem to establish the existence of positive solutions for this system. 展开更多
关键词 quasilinear Schrodinger-Poisson system variational methods critical growth positive solution
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POSITIVE GROUND STATE SOLUTIONS FOR A QUASILINEAR SCHRODINGER EQUATION
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作者 JIN Qing-fei 《数学杂志》 2025年第2期95-110,共16页
This paper is concerned with the positive ground state solutions for a quasilinear Schrodinger equation with a Hardy-type term.We obtain positive ground state solutions for the given quasilinear Schrodinger equation b... This paper is concerned with the positive ground state solutions for a quasilinear Schrodinger equation with a Hardy-type term.We obtain positive ground state solutions for the given quasilinear Schrodinger equation by using a change of variables and variational method. 展开更多
关键词 Quasilinear equation schrodinger equation positive ground state solutions variational methods
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基于VBGMM的列车卫星定位欺骗干扰检测
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作者 王思琦 刘江 +1 位作者 蔡伯根 王剑 《铁道学报》 北大核心 2026年第1期114-123,共10页
在复杂不确定的铁路运行环境下,基于全球导航卫星系统(GNSS)的列车定位亟需运用有效的欺骗干扰检测手段,在系统受到蓄意干扰攻击时及时提供安全告警与防护。针对卫星定位可能遭受的欺骗干扰威胁,提出一种基于变分贝叶斯高斯混合模型(VBG... 在复杂不确定的铁路运行环境下,基于全球导航卫星系统(GNSS)的列车定位亟需运用有效的欺骗干扰检测手段,在系统受到蓄意干扰攻击时及时提供安全告警与防护。针对卫星定位可能遭受的欺骗干扰威胁,提出一种基于变分贝叶斯高斯混合模型(VBGMM)的列车卫星定位欺骗干扰检测方法。离线训练环节中,运用历史定位数据计算卫星定位观测特征参数,构建多维观测特征向量,采用变分贝叶斯高斯混合模型拟合观测特征向量的后验概率密度分布,以概率密度函数值作为检测统计量,确定检测阈值;在线检测环节中,实时提取定位观测数据,通过调用训练所得VBGMM模型进行实时检测。运用哈木铁路现场采集数据,在实验室搭建列车卫星定位欺骗攻击测试环境,在轨迹、时间、伪距3类欺骗模式注入下的测试结果表明,所提出方法能够有效检测3类欺骗干扰,检测性能优于常规方法,对于有效识别干扰威胁、确保列车卫星定位可信性具有重要意义。 展开更多
关键词 列车定位 卫星定位 欺骗干扰 干扰检测 变分贝叶斯高斯混合模型
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MULTIPLICITY AND CONCENTRATION BEHAVIOUR OF POSITIVE SOLUTIONS FOR SCHRDINGER-KIRCHHOFF TYPE EQUATIONS INVOLVING THE p-LAPLACIAN IN R^N 被引量:4
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作者 贾慧芳 李工宝 《Acta Mathematica Scientia》 SCIE CSCD 2018年第2期391-418,共28页
In this article, we study the multiplicity and concentration behavior of positive solutions for the p-Laplacian equation of SchrSdinger-Kirchhoff type -εpM(εp-N∫RN|△u|p)△pu+v(x|u|p-2u=f(u)in RN, where ... In this article, we study the multiplicity and concentration behavior of positive solutions for the p-Laplacian equation of SchrSdinger-Kirchhoff type -εpM(εp-N∫RN|△u|p)△pu+v(x|u|p-2u=f(u)in RN, where △p is the p-Laplacian operator, 1 〈 p 〈 N, M : R+ → R+ and V : RN →R+ are continuous functions, ε is a positive parameter, and f is a continuous function with subcritical growth. We assume that V satisfies the local condition introduced by M. del Pino and P. Felmer. By the variational methods, penalization techniques, and Lyusternik- Schnirelmann theory, we prove the existence, multiplicity, and concentration of solutions for the above equation. 展开更多
关键词 SchrSdinger-Kirchhoff type equation variational methods multiple positive solutions concentrating solution penalization method
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POSITIVE SOLUTIONS FOR WEAKLY COUPLED NONLINEAR ELLIPTIC SYSTEMS 被引量:1
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作者 龙静 杨健夫 《Acta Mathematica Scientia》 SCIE CSCD 2010年第5期1577-1592,共16页
In this article, we consider the existence of positive solutions for weakly coupled nonlinear elliptic systems {-△u+u=(1+a(x))|u|P-1u+μ|u|a-2u|v|β+λv in Rn,-△u+u=(1+b(x))|v|p-1v+μ|u|a|... In this article, we consider the existence of positive solutions for weakly coupled nonlinear elliptic systems {-△u+u=(1+a(x))|u|P-1u+μ|u|a-2u|v|β+λv in Rn,-△u+u=(1+b(x))|v|p-1v+μ|u|a|v|β-2v+λu in Rn To find nontrivial solutions, we first investigate autonomous systems. In this case, results of bifurcation from semi-trivial solutions are obtained by the implicit function theorem. Next, the existence of positive solutions of problem (0.1) is obtained by variational methods. 展开更多
关键词 Elliptic system in RN positive solution BIFURCATION variational method
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EXISTENCE OF POSITIVE SOLUTIONS TO QUASI-LINEAR EQUATION INVOLVING CRITICAL SOBOLEV-HARDY EXPONENT
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作者 康东升 《Acta Mathematica Scientia》 SCIE CSCD 2004年第4期639-644,共6页
This paper is concerned with the quasi-linear equation with critical Sobolev-Hardy exponent whereΩ(?)RN(N(?)3)is a smooth bounded domain,0∈Ω,0(?)s<p,1<p<N,p(s):=p(N-s)/N-p is the critical Sobolev-Hardy exp... This paper is concerned with the quasi-linear equation with critical Sobolev-Hardy exponent whereΩ(?)RN(N(?)3)is a smooth bounded domain,0∈Ω,0(?)s<p,1<p<N,p(s):=p(N-s)/N-p is the critical Sobolev-Hardy exponent,λ>0,p(?)r<p,p:=Np/N-p is the critical Sobolev exponent,μ>,0(?)t<p,p(?)q<p(t)=p(N-t)/N-p.The existence of a positive solution is proved by Sobolev-Hardy inequality and variational method. 展开更多
关键词 positive solution quasi-linear equation critical Sobolev-Hardy exponent variational method
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MULTIPLICITY OF POSITIVE SOLUTIONS FOR A CLASS OF CONCAVE-CONVEX ELLIPTIC EQUATIONS WITH CRITICAL GROWTH
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作者 廖家锋 蒲洋 唐春雷 《Acta Mathematica Scientia》 SCIE CSCD 2018年第2期497-518,共22页
In this article, the following concave and convex nonlinearities elliptic equations involving critical growth is considered,{-△u=g(x)|u|2*-2u+λf(x)|u|q-2u,x∈Ω u=0,x∈δΩ where Ω RN(N ≥ 3) is an op... In this article, the following concave and convex nonlinearities elliptic equations involving critical growth is considered,{-△u=g(x)|u|2*-2u+λf(x)|u|q-2u,x∈Ω u=0,x∈δΩ where Ω RN(N ≥ 3) is an open bounded domain with smooth boundary, 1 〈 q 〈 2, λ 〉 0. 2*= 2N/N-2 is the critical Sobolev exponent, f ∈L2*/2N/N-2 is nonzero and nonnegative, and g E (Ω) is a positive function with k local maximum points. By the Nehari method and variational method, k + 1 positive solutions are obtained. Our results complement and optimize the previous work by Lin [MR2870946, Nonlinear Anal. 75(2012) 2660-26711. 展开更多
关键词 Semilinear elliptic equations critical growth positive solutions Nehari method variational method
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Positive Radial Solutions for a Class of Semilinear Elliptic Problems Involving Critical Hardy-Sobolev Exponent and Hardy Terms
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作者 Yong-Yi Lan 《Journal of Applied Mathematics and Physics》 2017年第11期2205-2217,共13页
In this paper, we investigate the solvability of a class of semilinear elliptic equations which are perturbation of the problems involving critical Hardy-Sobolev exponent and Hardy singular terms. The existence of at ... In this paper, we investigate the solvability of a class of semilinear elliptic equations which are perturbation of the problems involving critical Hardy-Sobolev exponent and Hardy singular terms. The existence of at least a positive radial solution is established for a class of semilinear elliptic problems involving critical Hardy-Sobolev exponent and Hardy terms. The main tools are variational method, critical point theory and some analysis techniques. 展开更多
关键词 HARDY SINGULAR TERMS Hardy-Sobolev EXPONENT positive Radial Solution Perturbation Method variationAL Approach
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Existence and Multiplicity of Positive Solutions for a Coupled Fourth-Order System of Kirchhoff Type
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作者 LI Zhen-hui XU Li-ping 《Chinese Quarterly Journal of Mathematics》 2021年第1期49-66,共18页
In this paper,we study a coupled fourth-order system of Kirchhoff type.Under appropriate hypotheses of V_(i)(x)for i=1,2,f and g,we obtained two main existence theorems of weak solutions for the problem by variational... In this paper,we study a coupled fourth-order system of Kirchhoff type.Under appropriate hypotheses of V_(i)(x)for i=1,2,f and g,we obtained two main existence theorems of weak solutions for the problem by variational methods.Some recent results are extended. 展开更多
关键词 A coupled fourth-order system of Kirchhoff type positive solutions Lack of compactness variational methods
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基于后置式投影亮分划系统的零位走动量分析
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作者 杨海金 卞臻臻 +6 位作者 高雪军 司振龙 郝芳 袁玉芬 詹江 高赫 李娜 《应用光学》 北大核心 2025年第1期55-61,共7页
针对后置式投影亮分划光学系统在某型微光镜中应用时出现零位走动量超差问题,通过分析该类微光瞄准镜的零位稳定性机理以及开展冲击试验,发现零位走动量超差的主要原因是射击过程中光学系统组合棱镜发生转动,采取将组合棱镜外形尺寸和... 针对后置式投影亮分划光学系统在某型微光镜中应用时出现零位走动量超差问题,通过分析该类微光瞄准镜的零位稳定性机理以及开展冲击试验,发现零位走动量超差的主要原因是射击过程中光学系统组合棱镜发生转动,采取将组合棱镜外形尺寸和安装尺寸公差优化方法,使二者间隙小于0.02 mm,最终微光镜的零位走动量(Δd)小于0.26 mil,满足系统技术指标规定Δd≤0.7 mil要求。给出了同类瞄准镜在设计和生产中对零位走动量控制的关键点及问题解决方案,为提高瞄准镜零位稳定性提供了有效分析依据。 展开更多
关键词 后置式投影亮分划 零位走动量 冲击试验 微光瞄准镜
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无创产前检测在筛查胎儿染色体拷贝数变异中的应用价值
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作者 鞠爱萍 孟祥荣 +1 位作者 覃燕龄 古玉莹 《实用心电与临床诊疗》 2025年第5期665-671,共7页
目的探讨无创产前检测(non-invasive prenatal testing,NIPT)在筛查胎儿染色体拷贝数变异(copy number variations,CNVs)中的应用价值。方法对196例经NIPT显示高风险的样本进行回顾性分析,比对染色体核型分析或染色体微阵列分析(chromos... 目的探讨无创产前检测(non-invasive prenatal testing,NIPT)在筛查胎儿染色体拷贝数变异(copy number variations,CNVs)中的应用价值。方法对196例经NIPT显示高风险的样本进行回顾性分析,比对染色体核型分析或染色体微阵列分析(chromosomal microarray analysis,CMA)结果。根据NIPT筛查胎儿CNVs的阳性率、阳性预测值(positive predictive value,PPV)等临床数据,评估NIPT对胎儿CNVs的检测价值。结果共检测NIPT样本20378例,在196例高风险样本中,包含54例CNVs,筛查阳性率为0.265%;46例孕妇接受了介入性产前诊断,21例确诊为CNVs,其中13例为致病性变异,3例为可能致病性变异,5例为意义不明变异。NIPT筛查CNVs的PPV为45.65%;NIPT筛查出微缺失CNVs 17例,微重复CNVs 36例,1例微缺失合并微重复CNVs,分别占31.48%(17/54)、66.67%(36/54)和1.85%(1/54),其PPV分别为64.29%、35.48%和100.00%。统计学分析显示,NIPT筛查微缺失CNVs和微重复CNVs的阳性率和PPV间的差异无统计学意义(均P>0.05)。结论NIPT筛查胎儿CNVs具有较高的阳性率和PPV。当NIPT筛查为CNVs高风险时,应进行介入性产前诊断;NIPT与染色体核型分析和CMA联合应用,可为临床提供精准的遗传咨询和指导。 展开更多
关键词 无创产前检测 拷贝数变异 染色体微阵列分析 阳性预测值
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橘园坡位变化对红壤胶体颗粒组成及胶体磷含量的影响 被引量:1
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作者 刘卓玲 王艳玲 +2 位作者 张佳敏 李欢 高磊 《农业环境科学学报》 北大核心 2025年第2期409-419,共11页
为明确坡位变化对红壤胶体颗粒组成及胶体磷含量的影响,本研究以江西鹰潭孙家典型红壤小流域观测站内位于坡顶、坡上、坡中及坡底的橘园红壤为研究对象,基于Stoke′s定律采用水分散-虹吸法依次获得粒级为<0.1、0.1~<0.45、0.45~&l... 为明确坡位变化对红壤胶体颗粒组成及胶体磷含量的影响,本研究以江西鹰潭孙家典型红壤小流域观测站内位于坡顶、坡上、坡中及坡底的橘园红壤为研究对象,基于Stoke′s定律采用水分散-虹吸法依次获得粒级为<0.1、0.1~<0.45、0.45~<1μm及1~5μm的胶体颗粒,对比分析了各坡位橘园红壤中胶体颗粒的分布比例、有机质、非晶质氧化铁(Feo)、非晶质氧化铝(Alo)及胶体颗粒所携带的磷素(Pcoll)的含量变化差异;以坡顶橘园红壤为例,借助于热场发射电子扫描显微镜、X射线能量色散谱仪(SEM-EDS)和X射线衍射仪(XRD)观察了各粒级胶体颗粒的微观形貌及元素富集特征;明确了各粒级胶体颗粒的组成矿物及相对比例。结果表明:不同坡位橘园红壤中1~5、0.45~<1、0.1~<0.45μm胶体颗粒的分布比例分别为20.1%~24.8%、4.1%~6.1%、0.2%~0.6%;且随坡位降低,1~5μm胶体颗粒的分布比例呈先增加后降低的趋势,0.45~<1μm与0.1~<0.45μm胶体颗粒则呈降低-增加-降低的趋势。随橘园坡位的降低,各粒级胶体颗粒内有机质和Alo占比呈先增加后降低的趋势,以坡中和坡上有机质占比分别为最低与最高,而坡顶和坡上Alo的占比分别为最低与最高;Feo占比呈先降低后增加的趋势,以坡上和坡中的占比分别为最低与最高。随胶体颗粒粒级的减小,各粒级胶体颗粒内有机质与Feo占比呈先降低后增加的趋势,Alo占比则呈先增加后降低的趋势。不同坡位橘园红壤中各粒级Pcoll含量为0.66~1.57 g·kg^(-1),且均随坡位降低呈先降低后增加的趋势,坡中各粒级Pcoll含量最低,坡底Pcoll含量最高;且胶体粒径越小,Pcoll含量相对越高。通过SEM-EDS观察到坡顶橘园红壤中0.1~<0.45μm胶体颗粒的结合程度最好,颗粒排列紧实呈团状,<0.1μm胶体颗粒的结合程度最差,颗粒呈分散状,而1~5μm和0.45~<1μm胶体颗粒呈片状散落排布,结合程度相仿;磷主要赋存于1~5μm和0.1~<0.45μm胶体颗粒表面,铁则主要赋存于<0.1μm胶体颗粒表面;各粒级胶体颗粒的主要组成矿物为高岭石与多水高岭石。相关分析表明,橘园红壤中总碳、总氮、全磷、有机质、Alo等指标仅对橘园红壤中0.1~<0.45μm胶体颗粒中的胶体磷含量有显著影响。 展开更多
关键词 橘园红壤 坡位变化 胶体磷 矿物组成 有机-无机胶结物质
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