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Susceptibility-weighted imaging is suitable for evaluating signal strength in different brain regions of a rabbit model of acute hemorrhagic anemia 被引量:2
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作者 Jun Xia Ni Xie +3 位作者 Anyu Yin Guozhao Teng Fan Lin Yi Lei 《Neural Regeneration Research》 SCIE CAS CSCD 2014年第9期990-992,共3页
Acute hemorrhagic anemia can decrease blood flow and oxygen supply to brain, and affect its physiological function. While detecting changes in brain function in patients with acute hemorrhagic anemia is helpful for pr... Acute hemorrhagic anemia can decrease blood flow and oxygen supply to brain, and affect its physiological function. While detecting changes in brain function in patients with acute hemorrhagic anemia is helpful for preventing neurological complications and evaluating therapeutic effects, clinical changes in the nervous systems of these patients have not received much attention. In part, this is because current techniques can only indirectly detect changes in brain function following onset of anemia, which leads to lags between real changes in brain function and their detection. 展开更多
关键词 Susceptibility-weighted imaging is suitable for evaluating signal strength in different brain regions of a rabbit model of acute hemorrhagic anemia Figure
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Feasibility of establishing model of Parkinson disease by injecting 6-hydroxydopamine at different parts of the nigrostriatal pathway in the brain of rats
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作者 Yuefei Shen Xuean Mo Guifang Long 《Neural Regeneration Research》 SCIE CAS CSCD 2006年第2期126-129,共4页
BACKGROUND: Previous researches found that animal models with Parkinson disease (PD) could be established by injecting 6-hydroxydopamine (6-OHDA) into medial forebrain bundle (MFB), substantia nigra compacta (... BACKGROUND: Previous researches found that animal models with Parkinson disease (PD) could be established by injecting 6-hydroxydopamine (6-OHDA) into medial forebrain bundle (MFB), substantia nigra compacta (SNC) and caudate-putamen complex (CPU) of the nigrostriatal pathway. OBJECTIVE : To compare behavioral, biochemica 6-OHDA injections in the areas of MFB, SNC and DESIGN: Controlled observational study and histological properties of these rats undergoing the CPU respectively. SEI-IING: Department of Neurology, First Affiliated Hospital of Guangxi Medical University MATERIALS: A total of 64 adult female SD rats weighing 180-230 g were provided by the Animal Experimental Center of Guangxi Medical University. 6-OHDA (Sigma Company, USA); Brain solid positioner (Standard model 51600, Stoelting Co., IL, USA); rotational monitoring of little animal (type QL-1, USA); high liquid chromatography (HLC, Waters Company). METHOOS: The experiment was carried out in the Medical Experimental Center of Guangxi Medical University from February to December 2005. ① According to digital table, 64 SD rats were divided into MFB group, SNC group, CPU group and control group with 16 in each group. On the basis of the brain atlas of Paxinos, rats in the first three groups were injected with 5 μL 6-OHDA into right MFB (0 mm of line of incisor tooth, A/P 4.4 mm, L/R 1.2 mm, ON -7.8 mm), SNC (line of incisor tooth just equal to horizon, A/P -4.8 mm, L/R 1.6 mm, ON -7.8 mm) and CPU (0 mm of line of incisor tooth, A/P 1.2 mm, L/R 2.7 mm, ON -5.4 mm), respectively. The rats in control group were injected with 5 μL ascorbic acid solution (2 g/L). One week after operation, 0.1 g/L apomorphine (Apo, 0.05 mg/kg) was subcutaneously injected into neck and then rotational behavior induced by Apo was recorded once a week for 8 weeks. The PD models were considered successful only when rotational times more than or equal to 7 times per minute. Eight weeks after operation, micro-perfusion was used to obtain micro-perfusate in bilateral CPU and contents of 3,4-dihydroxyphenylacetic acid (3,4-DOPAC) and homovanillic acid (HVA) were also measured. In addition, amount of tyrosine hydroxylase positive cells (TH*) in SNC was counted with immuno- histochemical staining. MAIN OUTCOME MEASURES : ① Successful rate of PD models; ② contents of dopamine and its metabolite in MFB, SNC and CPU groups and TH* amount. RESULTS: All 64 SD rats were involved in the final analysis. ③ Successful rate and rotational behavior: One week after operation, there were 6 successful models both in SNC and MFB groups; in the 2^nd week, there were 6 both in SNC and MFB groups and 1 in CPU group; in the 3^nd week, there were 1 in MFB group and 3 in CPU group; in the 4^nd week, there were 3 in CPU group. Otherwise, no successful case was found out in the next 3 weeks. Abnormal rotational behavior was not observed in control group. Four weeks after operation, successful rates were 81% (13/16) in MFB group, 75% (12/16) in SNC group and 44% (7/16) in CPU group.② Contents of 3, 4-DOPAC and HVA: Eight weeks after operation, contents in the SNC area of the injured side were lower than those on non-lesion side (P 〈 0.01).③Changes of TH+ amount: Eight weeks after operation, TH+ amount in the SNC area of the lesion side was lower than that on non-lesion side (P 〈 0.01 ). CONCLUSION: Injecting 6-OHDA into MFB, SNC and CPU can damage dopaminergic cells and establish successful PD models. 展开更多
关键词 Feasibility of establishing model of Parkinson disease by injecting 6-hydroxydopamine at different parts of the nigrostriatal pathway in the brain of rats
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Study on the Influence of Lanzhou-Urumqi High-Speed Railway on Regional Accessibility and Economic Development
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作者 Lili Ma Xiaolong Han Miao Gong 《Proceedings of Business and Economic Studies》 2024年第2期22-31,共10页
The Lanzhou-Urumqi high-speed railway is an important part of the railway network connecting Gansu,Qinghai,and Xinjiang,and it is of far-reaching significance in facilitating China’s western development.An accessibil... The Lanzhou-Urumqi high-speed railway is an important part of the railway network connecting Gansu,Qinghai,and Xinjiang,and it is of far-reaching significance in facilitating China’s western development.An accessibility model and a double difference model were built to analyze the impact of the Lanzhou-Urumqi high-speed railway on regional accessibility and economic development of the areas along the line before(2012-2014)and after(2017-2019)its opening.The results show that the regional accessibility remains unchanged before and after the operation of this railway line.However,there is a spatial difference in improvement,that of central cities being better.The opening of the high-speed railway is conducive to driving the overall economic development of the region and promoting the comprehensive and coordinated development of regional economies. 展开更多
关键词 Lanzhou-Urumqi high-speed railway Regional economy Double difference model Accessibility model Empirical analysis
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The time-dependent Ginzburg-Landau equation for the two-velocity difference model
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作者 吴淑贞 程荣军 葛红霞 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第8期130-135,共6页
A thermodynamic theory is formulated to describe the phase transition and critical phenomenon in traffic flow. Based on the two-velocity difference model, the time-dependent Ginzburg-Landau (TDGL) equation under cer... A thermodynamic theory is formulated to describe the phase transition and critical phenomenon in traffic flow. Based on the two-velocity difference model, the time-dependent Ginzburg-Landau (TDGL) equation under certain condition is derived to describe the traffic flow near the critical point through the nonlinear analytical method. The corresponding two solutions, the uniform and the kink solutions, are given. The coexisting curve, spinodal line and critical point are obtained by the first and second derivatives of the thermodynamic potential. The modified Korteweg- de Vries (mKdV) equation around the critical point is derived by using the reductive perturbation method and its kink antikink solution is also obtained. The relation between the TDGL equation and the mKdV equation is shown. The simulation result is consistent with the nonlinear analytical result. 展开更多
关键词 traffic flow two-velocity difference model TDGL equation mKdV equation
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Modeling Dynamic Systems by Using the Nonlinear Difference Equations Based on Genetic Programming
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作者 Liu Mm, Hu Bao-qingSchool of Mathematics and Statistics, Wuhan University, Wuhan 430072, Hubei, China 《Wuhan University Journal of Natural Sciences》 CAS 2003年第S1期243-248,共6页
When acquaintances of a model are little or the model is too complicate to build by using traditional time series methods, it is convenient for us to take advantage of genetic programming (GP) to build the model. Cons... When acquaintances of a model are little or the model is too complicate to build by using traditional time series methods, it is convenient for us to take advantage of genetic programming (GP) to build the model. Considering the complexity of nonlinear dynamic systems, this paper proposes modeling dynamic systems by using the nonlinear difference e-quation based on GP technique. First it gives the method, criteria and evaluation of modeling. Then it describes the modeling algorithm using GP. Finally two typical examples of time series are used to perform the numerical experiments. The result shows that this algorithm can successfully establish the difference equation model of dynamic systems and its predictive result is also satisfactory. 展开更多
关键词 dynamic systems the model of difference equation genetic programming
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Viscoelastic modeling of the diffusion of polymeric pollutants injected into a pipe flow
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作者 T.Chinyoka O.D. Makinde 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2013年第2期166-178,共13页
This study focuses on the transient analysis of nonlinear dispersion of a polymeric pollutant ejected by an external source into a laminar pipe flow of a Newtonian liquid under axi-symmetric conditions.The influence o... This study focuses on the transient analysis of nonlinear dispersion of a polymeric pollutant ejected by an external source into a laminar pipe flow of a Newtonian liquid under axi-symmetric conditions.The influence of density variation with pollutant concentration is approximated according to the Boussinesq approximation and the nonlinear governing equations of momentum,pollutant concentration are obtained together with and Oldroyd-B constitutive model for the polymer stress.The problem is solved numerically using a semi-implicit finite difference method.Solutions are presented in graphical form for various parameter values and given in terms of fluid velocity,pollutant concentration,polymer stress components,skin friction and wall mass transfer rate.The model can be a useful tool in understanding the dynamics of industrial pollution situations arising from improper discharge of hydrocarbon pollutants into,say,water bodies.The model can also be quite useful for available necessary early warning methods for detecting or predicting the scale of pollution and hence help mitigate related damage downstream by earlier instituting relevant decontamination measures. 展开更多
关键词 Axi-symmetric flow·Polymeric pollutant dispersion·Oldroyd-B model Buoyancy forces·Semi-implicit finite difference method
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Performance of real‑time neutron/gamma discrimination methods 被引量:1
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作者 Shi‑Xing Liu Wei Zhang +5 位作者 Zi‑Han Zhang Shuang Lin Hong‑Rui Cao Cheng‑Xin Song Jin‑Long Zhao Guo‑Qiang Zhong 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2023年第1期102-110,共9页
Nuclear security usually requires the simultaneous detection of neutrons and gamma rays.With the development of crystalline materials in recent years,Cs2LiLaBr6(CLLB)dual-readout detectors have attracted extensive att... Nuclear security usually requires the simultaneous detection of neutrons and gamma rays.With the development of crystalline materials in recent years,Cs2LiLaBr6(CLLB)dual-readout detectors have attracted extensive attention from researchers,where real-time neutron/gamma pulse discrimination is the critical factor among detector performance parameters.This study investigated the discrimination performance of the charge comparison,amplitude comparison,time comparison,and pulse gradient_(m)ethods and the effects of a Sallen–Key filter on their performance.Experimental results show that the figure of merit(FOM)of all four methods is improved by proper filtering.Among them,the charge comparison method exhibits excellent noise resistance;moreover,it is the most_(s)uitable method of real-time discrimination for CLLB detectors.However,its discrimination performance depends on the parameters t_(s),t_(m),and t_(e).When t_(s)corresponds to the moment at which the pulse is at 10%of its peak value,t_(e)requires a delay of only 640–740 ns compared to t_(s),at which time the potentially optimal FOM of the charge comparison method at 3.1–3.3 MeV is greater than 1.46.The FOM obtained using the t_(m)value calculated by a proposed maximized discrimination difference model(MDDM)and the potentially optimal FOM differ by less than 3.9%,indicating that the model can provide good guidance for parameter selection in the charge comparison method. 展开更多
关键词 Charge comparison Maximized discrimination difference model Pulse filtering Real time n-γdiscrimination
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A review on different theoretical models of electrocaloric effect for refrigeration
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作者 Cancan SHAO A.A.AMIROV Houbing HUANG 《Frontiers in Energy》 SCIE CSCD 2023年第4期478-503,共26页
The performance parameters for characterizing the electrocaloric effect are isothermal entropy change and the adiabatic temperature change,respectively.This paper reviews the electrocaloric effect of ferroelectric mat... The performance parameters for characterizing the electrocaloric effect are isothermal entropy change and the adiabatic temperature change,respectively.This paper reviews the electrocaloric effect of ferroelectric materials based on different theoretical models.First,it provides four different calculation scales(the first-principle-based effective Hamiltonian,the Landau-Devonshire thermodynamic theory,phase-field simulation,and finite element analysis)to explain the basic theory of calculating the electrocaloric effect.Then,it comprehensively reviews the recent progress of these methods in regulating the electrocaloric effect and the generation mechanism of the electrocaloric effect.Finally,it summarizes and anticipates the exploration of more novel electrocaloric materials based on the framework constructed by the different computational methods. 展开更多
关键词 electrocaloric effect effective Hamiltonian phase-field modeling different theoretical models
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血管生成抑制剂联合分化诱导剂治疗结肠癌肝脏转移的实验研究 被引量:5
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作者 邢会军 崔秀成 +1 位作者 侯雷 刘志满 《河北医学》 CAS 2011年第1期51-54,共4页
目的:实验通过建立人LOVO细胞结肠癌裸鼠肝脏转移瘤模型,研究血管生成抑制剂(TNP-470)联合分化诱导剂(RA)抗结肠癌转移的效应,二者是否具有协同效果。方法:建立人LO-VO细胞结肠癌裸鼠肝脏转移瘤模型,随机分为4组,模型建立后分组治疗,至... 目的:实验通过建立人LOVO细胞结肠癌裸鼠肝脏转移瘤模型,研究血管生成抑制剂(TNP-470)联合分化诱导剂(RA)抗结肠癌转移的效应,二者是否具有协同效果。方法:建立人LO-VO细胞结肠癌裸鼠肝脏转移瘤模型,随机分为4组,模型建立后分组治疗,至治疗结束时处死裸鼠,检测肝脏转移率和肝转移结节数及肝脏转移瘤组织中血管内皮生长因子(VEGF)的表达。结果:结果显示,联合治疗组和TNP-470组与对照组及联合治疗组与RA组比较肝脏转移率均有显著性差异(P<0.05);联合治疗组和RA组与对照组比较,VEGF的表达量明显下降(P<0.05)。结论:血管生成抑制剂TNP-470与分化诱导剂RA联合治疗结肠癌裸鼠肝脏转移瘤比TNP-470或RA单药治疗具有更强的抑瘤作用,TNP-470通过抑制肿瘤血管生成,切断肿瘤细胞的血供和营养供给,抑制结肠癌裸鼠肝脏转移瘤的生长;而RA通过诱导肿瘤细胞凋亡,降低VEGF的表达抑制肿瘤的生长,二者联和应用,抗肿瘤转移效应明显增强。 展开更多
关键词 结肠癌 血管生成抑制剂TNP-470 分化诱导剂RA 裸鼠模型
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血管生成抑制剂联合分化诱导剂治疗结肠癌的实验研究
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作者 邢会军 张学敏 +2 位作者 崔秀成 侯雷 刘志满 《河北医药》 CAS 2010年第21期2972-2974,共3页
目的通过建立人LOVO细胞结肠癌裸鼠皮下移植瘤模型,研究血管生成抑制剂(TNP-470)联合分化诱导剂(RA)抗结肠癌生长的效应,二者是否具有协同效果。方法建立人LOVO细胞结肠癌裸鼠皮下移植瘤模型,模型建立后分组治疗,按治疗方式分为对照组、... 目的通过建立人LOVO细胞结肠癌裸鼠皮下移植瘤模型,研究血管生成抑制剂(TNP-470)联合分化诱导剂(RA)抗结肠癌生长的效应,二者是否具有协同效果。方法建立人LOVO细胞结肠癌裸鼠皮下移植瘤模型,模型建立后分组治疗,按治疗方式分为对照组、TNP-470组、RA组和联合组(TNP-470+RA)至治疗结束时处死裸鼠,测量皮下移植瘤重量,计算抑瘤率;检测肿瘤组织结肠癌细胞凋亡指数(AI)。结果裸鼠皮下移植瘤瘤重、抑瘤率,联合组和对照组及TNP-470组、RA组比较差异均有统计学意义(P<0.05),且TNP-470组、RA组和对照组之间差异亦有统计学意义(P<0.05)。治疗组与对照组癌细胞AI比较,差异有统计学意义(P<0.05);且联合组与RA组和TNP-470组癌细胞的AI比较,差异也有统计学意义(P<0.05)。结论血管生成抑制剂TNP-470与分化诱导剂RA联合治疗结肠癌裸鼠皮下移植瘤比TNP-470或RA单药治疗具有更强的抑瘤作用,TNP-470通过抑制肿瘤血管生成,切断肿瘤细胞的血供和营养供给,抑制结肠癌裸鼠皮下移植瘤的生长;而RA通过诱导肿瘤细胞凋亡,降低VEGF的表达抑制肿瘤的生长,二者联和应用,抗肿瘤效应明显增强。 展开更多
关键词 结肠癌 血管生成抑制剂TNP-470 分化诱导剂RA 裸鼠模型
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Effects of Carbon Sequestration Strategies on Agricultural Production in the North China Plain 被引量:6
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作者 韩健智 邓祥征 战金艳 《Agricultural Science & Technology》 CAS 2009年第5期171-174,共4页
For thousands of years, the North China Plain has been one of the most productive agricultural regions of the country, and the future of this region will be determined in large part by how global climatic change impac... For thousands of years, the North China Plain has been one of the most productive agricultural regions of the country, and the future of this region will be determined in large part by how global climatic change impact regional conditions and by actions taken to mitigate or adapt to impacts of climate change. It is of great importance to estimate the effects of carbon sequestration measures taken to mitigate or adapt to impacts of climate change with proper economic outcome models. This paper aims to measure the effects of the most commonly used carbon sequestration measures, fertilization and irrigation, on agricultural production in the North China Plain. 展开更多
关键词 Cross-sectional data Cross-sectional model First difference model Ricardian model
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具有标准发生率和脉冲干扰的SIRS模型稳定性分析 被引量:1
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作者 马艳丽 李海霞 +1 位作者 褚正清 聂东明 《长春师范大学学报》 2017年第6期1-8,共8页
本文同时考虑脉冲接种和脉冲剔除策略,建立一个具有标准发生率的SIRS传染病模型,从理论分析和数值模拟方面研究了SIRS传染病模型的动力学性质。首先,得到模型无病T周期解的存在性和疾病流行与否的阈值-基本再生数R_0;其次,应用Floquet... 本文同时考虑脉冲接种和脉冲剔除策略,建立一个具有标准发生率的SIRS传染病模型,从理论分析和数值模拟方面研究了SIRS传染病模型的动力学性质。首先,得到模型无病T周期解的存在性和疾病流行与否的阈值-基本再生数R_0;其次,应用Floquet定理证明了无病T周期解是局部渐近稳定的;然后,利用脉冲微分不等式证明了无病T周期解是全局渐近稳定的;最后,进行计算机数值模拟来进一步验证理论结果的正确性。 展开更多
关键词 SIRS模型 标准发生率 基本再生数 全局渐近稳定性 脉冲微分方程
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1995-2020年喀什市植被覆盖度时空动态变化研究 被引量:12
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作者 孙与襄 麦麦提吐逊·麦麦提 +2 位作者 马合木江·艾合买提 陶洪飞 李巧 《中国农村水利水电》 北大核心 2022年第1期71-78,92,共9页
为了揭示和探讨喀什市植被覆盖度空间动态变化规律及驱动力因素。以Landsat系列卫星数据为数据源,基于归一化植被指数(NDVI)和像元二分模型,运用ENVI 5.3和ArcGIS 10.3软件对喀什市植被覆盖度进行估算,研究1995-2020年植被覆盖度的时空... 为了揭示和探讨喀什市植被覆盖度空间动态变化规律及驱动力因素。以Landsat系列卫星数据为数据源,基于归一化植被指数(NDVI)和像元二分模型,运用ENVI 5.3和ArcGIS 10.3软件对喀什市植被覆盖度进行估算,研究1995-2020年植被覆盖度的时空变化格局。研究结果表明:①喀什市整体植被主要以高植被覆盖为主,中与低植被覆盖以相对破碎形式围绕高植被覆盖分布在市中心周围与乡道两侧农田防护林;②1995-2020年期间的喀什市植被覆盖度与覆盖面积均呈增加。2020年比1994年植被覆盖面积增加172.6 km^(2),增幅36.3%;③喀什市植被覆盖度区域性和时段性改善与退化并存。时段上,2010-2015年退化明显,2015-2020年改善面积最大;区域上,城区退化最严重,东部四乡改善最显著,总与高植被覆盖质心向东部四乡分别直线迁移6.39 km与8.69 km,其中在2010-2020年上述两者质心迁移速度显著加快;④喀什市降水量的增加及气温的升高,加之城市化加快及人类活动频繁是近年来植被覆盖度变化的主要原因,其中林地与耕地面积的增加对植被覆盖度贡献最大。研究结果可为喀什市生态环境和可持续发展提供科学参考依据。 展开更多
关键词 喀什市 归一化植被指数 像元二分模型 植被覆盖度 遥感监测 驱动力
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Does Industry-University-Research Cooperation Matter? An Analysis of Its Coupling Effect on Regional Innovation and Economic Development 被引量:5
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作者 CUI Zhizhen LI Erling 《Chinese Geographical Science》 SCIE CSCD 2022年第5期915-930,共16页
The dislocation between regional innovation and economic development directly influences the economic effect of regional innovation. However, no in-depth researches have been made on how to solve this problem. Using d... The dislocation between regional innovation and economic development directly influences the economic effect of regional innovation. However, no in-depth researches have been made on how to solve this problem. Using data from Henan Province, China,employing geographical detector technology, this paper focuses on testing whether the industry-university-research cooperation can contribute to coordinating the relation between regional innovation and economic development. It is shown that: 1) the industry-universityresearch cooperation in Henan Province is increasing gradually, and the network presents a core-edge structure, and the coupling degree between regional innovation and economic development is spatially unbalanced, which is similar to the spatial distribution of the intensity of industry-university-research cooperation;2) as an important approach to effectively connect scientific researches with market demands, the industry-university-research cooperation can help form an interactive, interconnected, coupled and coordinated virtuous relation between regional innovation and economic development. Compared with the cooperation between organizations of the same type and the separate innovation of organizations, the improvement of the industry-university-research cooperation level can better coordinate the relation between regional innovation and economic development;3) the cooperative innovation model between enterprises and universities can better promote the coupling between regional innovation and economic development, compared with many industryuniversity-research cooperation models. For underdeveloped areas lacking local knowledge base, industry-university-research cooperation should be considered as a long-term development strategy, especially using the knowledge sources of external universities and scientific research institutions to enhance innovation capability and achieve economic growth. 展开更多
关键词 industry-university-research cooperation regional innovation capability economic development level coupling relation model difference Henan Province China
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分数阶回归模型解的存在性
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作者 盛红林 《数学理论与应用》 2009年第4期79-81,共3页
考虑一类分数阶回归模型,给出了解的存在唯一性结果,并进一步讨论了模型的离散形式。
关键词 分数微积分 回归模型 存在唯一性
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Adaptive learning rate GMM for moving object detection in outdoor surveillance for sudden illumination changes 被引量:1
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作者 HOCINE Labidi 曹伟 +2 位作者 丁庸 张笈 罗森林 《Journal of Beijing Institute of Technology》 EI CAS 2016年第1期145-151,共7页
A dynamic learning rate Gaussian mixture model(GMM)algorithm is proposed to deal with the problem of slow adaption of GMM in the case of moving object detection in the outdoor surveillance,especially in the presence... A dynamic learning rate Gaussian mixture model(GMM)algorithm is proposed to deal with the problem of slow adaption of GMM in the case of moving object detection in the outdoor surveillance,especially in the presence of sudden illumination changes.The GMM is mostly used for detecting objects in complex scenes for intelligent monitoring systems.To solve this problem,a mixture Gaussian model has been built for each pixel in the video frame,and according to the scene change from the frame difference,the learning rate of GMM can be dynamically adjusted.The experiments show that the proposed method gives good results with an adaptive GMM learning rate when we compare it with GMM method with a fixed learning rate.The method was tested on a certain dataset,and tests in the case of sudden natural light changes show that our method has a better accuracy and lower false alarm rate. 展开更多
关键词 object detection background modeling Gaussian mixture model(GMM) learning rate frame difference
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基于峰值电流与脉冲宽度的微细电极控形研究 被引量:2
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作者 王慧 王元刚 李晓鹏 《现代制造工程》 CSCD 北大核心 2021年第5期1-5,共5页
针对微细电火花孔加工时因微细电极形状损耗难以控制导致的微孔加工精度不高问题,提出利用峰值电流和脉冲宽度两个重要加工参数控制微细电极形状损耗的方法,并运用差分进化(Differental Evolution,DE)算法优化的支持向量机(Support Vect... 针对微细电火花孔加工时因微细电极形状损耗难以控制导致的微孔加工精度不高问题,提出利用峰值电流和脉冲宽度两个重要加工参数控制微细电极形状损耗的方法,并运用差分进化(Differental Evolution,DE)算法优化的支持向量机(Support Vector Machine,SVM)(DE-SVM)方法建立了微细电极形状损耗的分类预测模型。研究表明:该方法是可行的,对于给定的试验数据,相比常用的粒子群(Particle Swarm Optimization,PSO)算法优化的SVM(PSO-SVM)方法和遗传算法(Genetic Algorithm,GA)优化的SVM(GA-SVM)方法,DE-SVM方法能够获得分类准确率高且拟合度合理的分类预测模型;不同微细电极形状损耗形式具有紧密的相关性,在较小的峰值电流(4~20 A)和较大的脉冲宽度(>5μs)条件下易获得底部规整的微孔。研究成果从微细电极形状损耗控制角度出发,为提高微细电火花孔的加工精度提供了一种思路。 展开更多
关键词 微细电火花孔加工 形状损耗 差分进化算法 支持向量机 分类预测模型
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Effect of oxidative stress-associated damage to the lung tissue caused by different body mass index in the rat models
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作者 李筱妍 《China Medical Abstracts(Internal Medicine)》 2017年第1期40-41,共2页
Objective To investigate the influence of different diets on serum protein expression levels of 4-hydroxynonenal(4-HNE),thioredoxin(Trx),thioredoxin reductase(TrxR)and the sctivities of Trx and TrxR,and to explore the... Objective To investigate the influence of different diets on serum protein expression levels of 4-hydroxynonenal(4-HNE),thioredoxin(Trx),thioredoxin reductase(TrxR)and the sctivities of Trx and TrxR,and to explore the effect of damage to the lung tissue and the underlying mechanisms of different body mass index caused by different diets in the rat models.Methods 展开更多
关键词 Effect of oxidative stress-associated damage to the lung tissue caused by different body mass index in the rat models lung body
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A twin-channel difference model for cross-calibration of thermal infrared band 被引量:2
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作者 LI JiaGuo GU XingFa +4 位作者 YU Tao LI XiaoYing GAO HaiLiang LIU Li XU Hui 《Science China(Technological Sciences)》 SCIE EI CAS 2012年第7期2048-2056,共9页
Based on the conduction and transformation of the thermal infrared radiative transfer equation of water target,a twinchannel difference model(DM) was proposed to improve the calibration precision by conquering the lim... Based on the conduction and transformation of the thermal infrared radiative transfer equation of water target,a twinchannel difference model(DM) was proposed to improve the calibration precision by conquering the limitation that the atmospheric condition when image is acquiring cannot be truly obtained in the traditional radiometric simulation calibration method.The analysis of surface,atmosphere and top-of-atmosphere(TOA) radiative energy decomposition demonstrated that the apparent TOA radiance of the uncalibrated channel is the differential combination of two reference channels.The DM avoids impacts from atmospheric temperature and density.The only impact is from water vapor(WV) content.Based on the fitting error analysis of 742 mid-latitude atmospheric profiles(column WV content:0-5×10 3 atm cm) selected from TIGR database,the DM is insensitive to WV content.The maximum error is less than 0.2 K when the view zenith angels(VZAs) of reference channels and uncalibrated channel are less than 30.The error becomes 0.3 K when VZAs range from 30 to 40 and 0.6 K when VZAs are in 40-50.Because the uncertainty increases when VZAs are larger than 50,the best range of VZAs is 30-50.The vicarious calibration results at Lake Qinghai field indicated that the calibration precision of the DM cross-calibration by using MODIS bands 31 and 32 as reference channels to calibrate IRS band 08 is similar to that of vicarious calibration.Therefore,the DM is a reliable alternative tool for sensor on-orbit calibration and validation with high precision and frequency. 展开更多
关键词 remote sensing CROSS-CALIBRATION difference model IRS MODIS
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A FINITE DIFFERENCE METHOD FOR THE MODEL OF WHEEZES 被引量:4
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作者 Lu Bai-nian (Department of Mathematics, Shaanxi Normal University, Xi’an, Shaanxi, China) 《Journal of Computational Mathematics》 SCIE CSCD 1995年第2期123-129,共7页
In this paper, a finite difference scheme for the linear and nonlinear models of wheezes are given. The stability of the finite difference scheme for the linear model is obtained by using of von Neumann method. Moreov... In this paper, a finite difference scheme for the linear and nonlinear models of wheezes are given. The stability of the finite difference scheme for the linear model is obtained by using of von Neumann method. Moreover, the convergence and stability of the finite difference scheme for the nonlinear model are studied by the energy inequalities method. By some numerical computations, the relationships between angular frequency and wall position, fluid speed and amplitude are discussed. Finally, the author shows that the numerical results are coincided with Grotberg's theoretical results. 展开更多
关键词 MATH A FINITE DIFFERENCE METHOD FOR THE model OF WHEEZES
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