期刊文献+
共找到1,979篇文章
< 1 2 99 >
每页显示 20 50 100
基于CNN-BiLSTM-Cross Attention动态集成模型的短期负荷曲线预测方法
1
作者 杨菁 李丹 +1 位作者 王佳秋 张闯 《电工技术》 2026年第2期75-79,共5页
电力市场化改革及经济的快速发展促使发电企业和供电公司更加依赖准确的短期负荷预测来进行有效的市场运作和盈利规划,然而传统模型难以有效提取和表征高维负荷曲线中的关键特征,如负荷特性、气象条件、日期周期性特征等,特别是在处理... 电力市场化改革及经济的快速发展促使发电企业和供电公司更加依赖准确的短期负荷预测来进行有效的市场运作和盈利规划,然而传统模型难以有效提取和表征高维负荷曲线中的关键特征,如负荷特性、气象条件、日期周期性特征等,特别是在处理多变量之间的交互作用时表现不佳。对此,提出一种基于CNN-BiLSTM-Cross Attention的短期负荷预测模型来预测未来几天内的负荷曲线,该模型利用CNN从负荷曲线中提取局部特征后通过BiLSTM捕捉长期依赖关系,并通过交叉注意机制实现负荷特性、气象特征、节假日效应等多模态信息的深度融合。实验结果表明,与传统方法相比,所提模型在预测准确性和计算效率方面均有显著提升,尤其在处理包含可再生能源的动态电力系统时表现优越。 展开更多
关键词 短期负荷曲线预测 CNN-BiLSTM-cross Attention 多模态信息 负荷特性 气象特征 节假日效应
在线阅读 下载PDF
Cross-Linguistic Evidence for Distinguishing between Effected and Affected Objects
2
作者 邵光庆 《海外英语》 2013年第20期295-296,共2页
In today's academic field, the motivation for distinguishing between the effected and the affected objects has received scant attention. This article attempts to probe into this question by citing the related cros... In today's academic field, the motivation for distinguishing between the effected and the affected objects has received scant attention. This article attempts to probe into this question by citing the related cross-linguistic evidence to justify such a distinction. It concludes that some grammatical constructions or linguistic phenomena across languages cannot be well interpreted without the framework of effected-/affected-object dichotomy. Both types of objects show prototypical properties of direct objects, and they are complementary in the realization of direct-objecthood. 展开更多
关键词 cross-LINGUISTIC EVIDENCE effected OBJECTS Affecte
在线阅读 下载PDF
The effect of dynamical screening on helium(e,2e) fully differential cross-sections
3
作者 孙世艳 贾祥富 +4 位作者 苗向阳 张均锋 谢祎 李雄伟 师文强 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第7期2744-2748,共5页
This paper presents the fully differential cross sections (FDCS) for 102eV electron impact single ionization of helium for both the coplanar and perpendicular plane asymmetric geometries within the framework of dyna... This paper presents the fully differential cross sections (FDCS) for 102eV electron impact single ionization of helium for both the coplanar and perpendicular plane asymmetric geometries within the framework of dynamically screened three-Coulomb-wave theory. Comparisons are made with the experimental data and those of the three-Coulomb wave function model and second-order distorted-wave Born method. The angular distribution and relative heights of the present FDCS is found to be in very good agreement with the experimental data in the perpendicular plane geometry. It is shown that dynamical screening effects are significant in this geometry. Three-body coupling is expected to be weak in the coplanar geometry, although the precise absolute value of the cross section is still sensitive to the interaction details. 展开更多
关键词 fully differential cross sections screening effects perpendicular plane geometry
原文传递
Nucleus-Nucleus Effects in Fully Differential Cross Sections for Energetic C6++He Collisions with Small Momentum Transfer
4
作者 陆晨文 安文芳 +1 位作者 孙世艳 贾祥富 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第9期35-38,共4页
The modified Coulomb-Born approximation with and without the internuclear interaction (MCB-NN and MCB) is used to calculate the fully differential cross sections (FDCS) for the single ionization of helium by lOO M... The modified Coulomb-Born approximation with and without the internuclear interaction (MCB-NN and MCB) is used to calculate the fully differential cross sections (FDCS) for the single ionization of helium by lOO MeV/amu C6+ impact. The effects of the internuclear interaction on the FDCS are examined in geometries. The results are compared with experimental data and theoretical predictions from a three-body distorted-wave (3DW) model and a time-dependent close-coupling model. It is shown that the present MCB-NN results are in good agreement with the experiments in the scattering plane and the MCB results qualitatively reproduce the experimental structure outside the scattering plane. In particular, the MCB theory predicts the 'double-peak' structure in the perpendicular plane. 展开更多
关键词 MCB NN Nucleus-Nucleus effects in Fully Differential cross Sections for Energetic C He Collisions with Small Momentum Transfer
原文传递
Effects of walk-off on cross-phase modulation induced modulation instability in an optical fibre with high-order dispersion 被引量:1
5
作者 钟先琼 向安平 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第6期1683-1688,共6页
This paper investigates the effects of walk-off among optical pulses on cross-phase modulation induced modulation instability in the normal dispersion region of an optical fibre with high-order dispersion. The results... This paper investigates the effects of walk-off among optical pulses on cross-phase modulation induced modulation instability in the normal dispersion region of an optical fibre with high-order dispersion. The results indicate that, in the case of high-order dispersion, the walk-off effect takes on new characteristics and will influence considerably the shape, position and especially the number of the spectral regions of the gain spectra of modulation instability. Not only the group-velocity mismatch, but also the difference of the third-order dispersion of two optical waves will alter the gain spectra of modulation instability but in different ways. Depending on the values of the walk-off parameters, the number of the spectral regions may increase from two to at most four, and the spectral shape and position may change too. 展开更多
关键词 modulation instability cross-phase modulation walk-off effect the difference ofthe third-order dispersion
原文传递
Interference effects on the photoionization cross sections between two neighbouring atoms:nitrogen as an example
6
作者 吴建华 袁建民 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第12期5283-5290,共8页
Interference effects on the photoionization cross sections between two neighbouring atoms are considered based on the coherent scattering of the ionized electrons by the two nuclei when their separation is less than o... Interference effects on the photoionization cross sections between two neighbouring atoms are considered based on the coherent scattering of the ionized electrons by the two nuclei when their separation is less than or comparable to the de Broglie wave length of the ionized electrons. As an example, the single atomic nitrogen ionization cross section and the total cross sections of two nitrogen atoms with coherently added photoionization amplitudes are calculated from the threshold to about А (1 А=0.1 nm) of the photon energy. The photoionization cross sections of atomic nitrogen are obtained by using the close-coupling R-matrix method. In the calculation 19 states are included. The ionization energy of the atomic nitrogen and the photoionization cross sections agree well with the experimental results. Based on the R-matrix results of atomic nitrogen, the interference effects between two neighbouring nitrogen atoms are obtained. It is shown that the interference effects are considerable when electrons are ionized just above the threshold, even for the separations between the two atoms are larger than two times of the bond length of N2 molecules. Therefore, in hot and dense samples, effects caused by the coherent interference between the neighbours are expected to be observable for the total photoionization cross sections. 展开更多
关键词 interference effect photoionization cross section nitrogen atom
原文传递
EFFECTS OF SLOPING BOTTOM ON THE DEEPCROSS-EQUATORIAL BOUNDARY CURRENT
7
作者 吴德星 吕红民 +1 位作者 郭群 卢镇 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 1997年第1期65-69,共5页
This paper reports study focusing on the effects of sloping bottom on the deep cross-equatorial boundary current, and discusses model and laboratory experiment results showing that the southward that the southward int... This paper reports study focusing on the effects of sloping bottom on the deep cross-equatorial boundary current, and discusses model and laboratory experiment results showing that the southward that the southward intrusion distance and flow speed of the western boundary current depend on the bottom slope variation rate,the difference between and and are the current thickness at eastward edge and westward edge, respectively), and the net mass transport. 展开更多
关键词 deep cross-equatorial BOUNDARY current effectS of sloping BOTTOM laboratory TURNTABLE experiment
原文传递
Photoemission cross section:A critical parameter in the impurity photovoltaic effect
8
作者 Jiren Yuan Haibin Huang +4 位作者 Xinhua Deng Zhihao Yue Yuping He Naigen Zhou Lang Zhou 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第1期552-556,共5页
A numerical study has been conducted to explore the role of photoemission cross sections in the impurity photovoltaic(IPV) effect for silicon solar cells doped with indium. The photovoltaic parameters(short-circuit... A numerical study has been conducted to explore the role of photoemission cross sections in the impurity photovoltaic(IPV) effect for silicon solar cells doped with indium. The photovoltaic parameters(short-circuit current density, opencircuit voltage, and conversion efficiency) of the IPV solar cell were calculated as functions of variable electron and hole photoemission cross sections. The presented results show that the electron and hole photoemission cross sections play critical roles in the IPV effect. When the electron photoemission cross section is 10^-20cm^2, the conversion efficiencyη of the IPV cell always has a negative gain(△η 0) if the IPV impurity is introduced. A large hole photoemission cross section can adversely impact IPV solar cell performance. The combination of a small hole photoemission cross section and a large electron photoemission cross section can achieve higher conversion efficiency for the IPV solar cell since a large electron photoemission cross section can enhance the necessary electron transition from the impurity level to the conduction band and a small hole photoemission cross section can reduce the needless sub-bandgap absorption. It is concluded that those impurities with small(large) hole photoemission cross section and large(small) electron photoemission cross section,whose energy levels are near the valence(or conduction) band edge, may be suitable for use in IPV solar cells. These results may help in judging whether or not an impurity is appropriate for use in IPV solar cells according to its electron and hole photoemission cross sections. 展开更多
关键词 solar cell impurity photovoltaic effect photoemission cross section conversion efficiency
原文传递
Changes in brain activation patterns according to cross-training effect in serial reaction time task An functional MRI study
9
作者 Yong Hyun Kwon Jung Won Kwon Ji Won Park 《Neural Regeneration Research》 SCIE CAS CSCD 2013年第7期639-646,共8页
Cross-training is a phenomenon related to motor learning, where motor performance of the untrained limb shows improvement in strength and skill execution following unilateral training of the homologous contralateral l... Cross-training is a phenomenon related to motor learning, where motor performance of the untrained limb shows improvement in strength and skill execution following unilateral training of the homologous contralateral limb. We used functional MRI to investigate whether motor performance of the untrained limb could be improved using a serial reaction time task according to motor sequential learning of the trained limb, and whether these skill acquisitions led to changes in brain activation patterns. We recruited 20 right-handed healthy subjects, who were randomly allocated into training and control groups. The training group was trained in performance of a serial reaction time task using their non-dominant left hand, 40 minutes per day, for 10 days, over a period of 2 weeks. The control group did not receive training. Measurements of response time and percentile of response accuracy were performed twice during pre- and post-training, while brain functional MRI was scanned during performance of the serial reaction time task using the untrained right hand. In the training group, prominent changes in response time and percentile of response accuracy were observed in both the untrained right hand and the trained left hand between pre- and post-training. The control group showed no significant changes in the untrained hand between pre- and post-training. In the training group, the activated volume of the cortical areas related to motor function (i.e., primary motor cortex, premotor area, posterior parietal cortex) showed a gradual decrease, and enhanced cerebellar activation of the vermis and the newly activated ipsilateral dentate nucleus were observed during performance of the serial reaction time task using the untrained right hand, accompanied by the cross-motor learning effect. However, no significant changes were observed in the control group. Our findings indicate that motor skills learned over the 2-week training using the trained limb were transferred to the opposite homologous limb, and motor skill acquisition of the untrained limb led to changes in brain activation patterns in the cerebral cortex and cerebellum. 展开更多
关键词 neural regeneration neuroimaging cross-training effects motor skill learning cortical activation cerebellar activation serial reaction time task functional MRI response time response accuracy primary motor cortex dentate nucleus VERMIS grants-supported paper photographs-containingpaper NEUROREGENERATION
暂未订购
A Facile Photo-cross-linking Method for Polymer Gate Dielectrics and Their Applications in Fully Solution Processed Low Voltage Organic Field-effect Transistors on Plastic Substrate 被引量:1
10
作者 Ying Liu Jia-Qing Zhao +4 位作者 Wen-Jian Sun Yu-Kun Huang Su-Jie Chen Xiao-Jun Guo Qing Zhang 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2018年第8期918-924,共7页
A simple and effective photochemical method was developed for cross-linking of polymer gate dielectrics. Laborious synthetic processes for functionalizing polymer dielectrics with photo-cross-linkable groups were avoi... A simple and effective photochemical method was developed for cross-linking of polymer gate dielectrics. Laborious synthetic processes for functionalizing polymer dielectrics with photo-cross-linkable groups were avoided. The photo-cross-linker, BBP-4, was added into host polymers by simple solution blending process, which was capable of abstracting hydrogen atoms from polymers containing active C--H groups upon exposure to ultraviolet (UV) radiation. The cross-linking can be completed with a relatively long wavelength UV light (365 nm). The approach has been applied to methacrylate and styrenic polymers such as commercial poly(methylmethacrylate) (PMMA), poly(iso-butylmethacrylate) (PiBMA) and poly(4-methylstyrene) (PMS). The cross-linked networks enhanced dielectric properties and solvent resistance of the thin films. The bottom-gate organic field-effect transistors (OFETs) through all solution processes on plastic substrate were fabricated. The OFET devices showed low voltage operation and steep subthreshold swing at relatively small gate dielectric capacitance. 展开更多
关键词 Organic field-effect transistors Solution processed Polymer dielectric cross-linking PHOTOCHEMISTRY
原文传递
Nonlinear spectral cleaning effect in cross-polarized wave generation
11
作者 Linpeng Yu Yi Xu +5 位作者 Fenxiang Wu Xiaojun Yang Zongxin Zhang Yuanfeng Wu Yuxin Leng Zhizhan Xu 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第5期281-286,共6页
The underlying mechanism of the spectral cleaning effect of the cross-polarized wave(XPW) generation process was theoretically investigated. This study shows that the spectral noise of an input spectrum can be remov... The underlying mechanism of the spectral cleaning effect of the cross-polarized wave(XPW) generation process was theoretically investigated. This study shows that the spectral noise of an input spectrum can be removed in the XPW generation process and that the spectral cleaning effect depends on the characteristics of the input pulses, such as the chirp and Fourier-transform-limited duration of the initial pulse, and the modulation amplitude and frequency of the spectral noise. Though these factors codetermine the output spectrum of the XPW generation process, the spectral cleaning effect is mainly affected by the initial pulse chirp. The smoothing of the spectrum in the XPW generation process leads to a significant enhancement of the coherent contrast. 展开更多
关键词 nonlinear optics cross-polarized wave generation spectral cleaning effect
原文传递
Selection Effects of Soil Fertility on the Progenies of Soybean Crosses
12
作者 Zou Jijun, Yang Qingkai, Wang Jiming(Northeast Agricultural University, Harbin 150030, PRC) 《Journal of Northeast Agricultural University(English Edition)》 CAS 1996年第2期88-93,共6页
The F2, F3, families and F4 lines of six soybean crosses, were selected successively under high-and low - fertility sites with the relection objective of high yield and the method of pedigree was used. Two best F4 - d... The F2, F3, families and F4 lines of six soybean crosses, were selected successively under high-and low - fertility sites with the relection objective of high yield and the method of pedigree was used. Two best F4 - derived lines were chosen from each of the six crosses under both high-and low-fertility for use in this study. In 1995, the total 24 lines were tested in high, medium and low fertility sites with the same experimental design (CRB) to study the selcctoin effects of high and low - fertility. The results suggested that high- and low-fertility had different selection effects. High fertility was more effective for selecting lines, which had higher yield under high-fertility and lower yield under low-fertility; low-fertility was better for selecting lines, which had higher yield under low-fertility and lower yield under low-fertility, and high fertility was somewhat better than low fertility for selecting lines, which had higher yield under both high and low-fertility. It revealed that the lines selected from high-fertility had superior yield potential. The lines selected from high-fertility had shorter plant height, more nodes on main stem, fewer branches, higher seed-stem ratio. The reverse was true for the lines selected from low-fertility . The lodging-resistance of the lines selected from highfertility was greater than that of the lines from low-fertility. The soil fertility level of breeding nursery should be chosen according to the breeding objective. 展开更多
关键词 progenics or soybean crosses soil fertility selection effects
全文增补中
考虑水下跨接电容效应的水下磁耦合谐振式无线电能传输系统多参数辨识方法
13
作者 刘旭 钟敬 +1 位作者 荣灿灿 夏晨阳 《电工技术学报》 北大核心 2026年第2期374-388,共15页
通过在水下磁耦合谐振式无线电能传输(UMCR-WPT)系统中引入参数辨识技术,可在无任何复杂的原副边通信的情况下,获得互感、跨接电容和负载等关键系统物理参数,从而实现系统的精确控制与状态监测。因此,该文提出一种基于UMCR-WPT系统跨接... 通过在水下磁耦合谐振式无线电能传输(UMCR-WPT)系统中引入参数辨识技术,可在无任何复杂的原副边通信的情况下,获得互感、跨接电容和负载等关键系统物理参数,从而实现系统的精确控制与状态监测。因此,该文提出一种基于UMCR-WPT系统跨接电容效应的多参数联合辨识方法,仅需单次测量UMCR-WPT系统发射端的电压和电流,即可实现系统互感、跨接电容和负载的精确辨识。该文首先依据跨接电容理论,建立精确的UMCR-WPT系统等效电路模型,利用定义推导发射端测量电压和电流与输入阻抗之间的关系,得到互感、跨接电容和负载的参数辨识表达式。然后,通过联合遗传-差分进化算法在保证精度的同时实现互感、跨接电容和负载的在线联合辨识,并阐述了具体辨识流程和步骤。最后,搭建系统实验平台,实验结果表明,在不同线圈耦合和负载工况下,互感、跨接电容、负载电阻的最大辨识误差分别为2.62%、4.10%和4.38%,同时,通过所建立的UMCR-WPT系统理论模型计算得到的输出功率和效率与实验的最大误差为4.451%和5.15%,有效地证明了所提出的UMCR-WPT系统多参数辨识方法的有效性。 展开更多
关键词 水下无线电能传输 跨接电容效应 多参数辨识 遗传-差分进化算法
在线阅读 下载PDF
Water equivalence of some 3D dosimeters:a theoretical study based on the effective atomic number and effective fast neutron removal cross section
14
作者 A.M.El-Khayatt 《Nuclear Science and Techniques》 SCIE CAS CSCD 2017年第12期170-181,共12页
Effective atomic numbers for photon energy absorption(ZPEA_(eff)) and their corresponding electron numbers (NPEA_(eff)), and effective macroscopic removal cross sections of fast neutrons(RR) were calculated for 27 dif... Effective atomic numbers for photon energy absorption(ZPEA_(eff)) and their corresponding electron numbers (NPEA_(eff)), and effective macroscopic removal cross sections of fast neutrons(RR) were calculated for 27 different types of three-dimensional dosimeters, four types of phantom materials, and water. The values of ZPEA_(eff) and NPEA_(eff) were obtained using the direct method for energies ranging from 10 keV to 20 MeV. Results are presented relative to water, for direct comparison over the range of examined energies. The effect of monomers that are used in polymer gel dosimeters on the water equivalence is discussed. The relation between Σ_R and hydrogen content was studied. Micelle gel dosimeters are highly promising because our results demonstrate perfect matching between the effective atomic number, electron density number, and fast neutron attenuation coefficient of water. 展开更多
关键词 3D DOSIMETERS WATER EQUIVALENCE effectIVE atomic number Photon energy absorption REMOVAL cross section Fast neutrons
暂未订购
考虑电感变化的永磁同步电动机MTPA控制方法
15
作者 李峰 宋佳星 《微特电机》 2026年第1期76-81,共6页
现有基于虚拟正弦信号注入(virtual sine signal injection,VSSI)的最大转矩电流比(maximum torque per ampere,MTPA)控制方法以理想永磁同步电动机(permanent magnet synchronous machine,PMSM)数学模型为理论基础,未考虑电感变化带来... 现有基于虚拟正弦信号注入(virtual sine signal injection,VSSI)的最大转矩电流比(maximum torque per ampere,MTPA)控制方法以理想永磁同步电动机(permanent magnet synchronous machine,PMSM)数学模型为理论基础,未考虑电感变化带来的不利影响。为了提升MTPA控制效果,增加考虑磁路交叉耦合效应,提出在线电感辨识方法和改进的MTPA控制方法。基于帕德逼近与变步长神经网络的电感辨识方法,不仅可以解决辨识模型欠秩问题,而且能够在线更新变化的电感参数,结合改进的基于VSSI的MTPA控制,可以有效降低电流矢量角误差,减小定子铜损耗,实现更准确的MTPA控制。通过仿真实验对所提方法的准确性进行了验证。 展开更多
关键词 永磁同步电动机 MTPA控制 虚拟正弦信号注入 交叉耦合效应 电感辨识
在线阅读 下载PDF
Probing the medium effect and isospin dependence of the in-medium nucleon-nucleon cross section in heavy ion collisions
16
作者 刘建业 郭文军 邢永忠 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第11期3305-3311,共7页
Probing in-medium nucleon-nucleon (NN) cross section σ1/NN(α) in heavy ion collisions has been investigated by means of the isospin-dependent quantum molecular dynamics (IQMD) with the isospin- and momentum-de... Probing in-medium nucleon-nucleon (NN) cross section σ1/NN(α) in heavy ion collisions has been investigated by means of the isospin-dependent quantum molecular dynamics (IQMD) with the isospin- and momentum-dependent interaction (IMDI(T)). It is found that there are the very obvious medium effect and the sensitive isospin-dependence of nuclear stopping R on the in-medium NN cross section α1/NN(α) in the nuclear reactions induced by halo-neutron projectile and the same-mass stable projectile. However, R induced by the neutron-halo projectile is obviously lower than that induced by the corresponding stable projectile. In particular, there is a very obvious dependence of R on the medium effect of σ1/NN(α) in the whole beam energy region for the above two kinds of projectiles. Therefore, the comparison between the results of R's in the reactions induced by the neutron-halo projectile and the corresponding same-mass stable projectile is a more favourable probe for extracting the information of σ1/NN(α) because of adding a new judgement. 展开更多
关键词 isospin effect neutron-halo projectile nuclear reaction nucleon-nucleon cross section nuclear stopping
原文传递
正反交效应对玉米子粒蛋白质含量的影响
17
作者 王瑞齐 汤泽洋 +2 位作者 吴金丽 周志强 李新海 《玉米科学》 北大核心 2026年第1期1-7,共7页
在4个不同杂种优势类群中挑选子粒蛋白质含量差异显著的8份自交系,采用Griffing双列杂交III设计配制56个正反交组合,测定亲本、F_(1)和F_(2)蛋白质含量及产量相关性状。通过方差、相关性和一般配合力分析,揭示玉米蛋白质含量的遗传特性... 在4个不同杂种优势类群中挑选子粒蛋白质含量差异显著的8份自交系,采用Griffing双列杂交III设计配制56个正反交组合,测定亲本、F_(1)和F_(2)蛋白质含量及产量相关性状。通过方差、相关性和一般配合力分析,揭示玉米蛋白质含量的遗传特性。结果表明,蛋白质含量受遗传与环境共同影响,F_(1)存在显著母本效应,F_(2)效应减弱。F_(1)蛋白质含量与母本呈极显著正相关,F_(2)与双亲均呈极显著正相关,且F_(1)与F_(2)蛋白质含量也呈极显著相关。F_(2)蛋白质含量与穗行数、行粒数、出籽率及玉米产量呈极显著负相关,与百粒重呈极显著正相关。GCA效应分析显示,承系53、HP434、CA590的蛋白质GCA效应为正,昌7-2、PH6WC、CA590和PH4CV的产量GCA效应为正。组合CA590×PH6WC在蛋白质含量与产量上均表现突出,表明玉米产量与品质性状协同改良具备可行性。 展开更多
关键词 玉米 子粒蛋白质含量 正反交效应 遗传效应 品质改良
原文传递
黏弹性土中横截面异形桩竖向动力响应理论分析
18
作者 周航 汪义圣 李运舟 《岩土工程学报》 北大核心 2026年第2期270-279,共10页
横截面异形桩在工程应用中日益广泛,但该领域的理论研究相对匮乏。基于Hamilton原理和变分运算在直角坐标系下导出异形桩-黏弹性土模型的控制方程。采用COMSOL建立带异形边界的二维土体模型,求解土体的控制方程,该方法克服了异形边界带... 横截面异形桩在工程应用中日益广泛,但该领域的理论研究相对匮乏。基于Hamilton原理和变分运算在直角坐标系下导出异形桩-黏弹性土模型的控制方程。采用COMSOL建立带异形边界的二维土体模型,求解土体的控制方程,该方法克服了异形边界带来的土体位移函数求解困难的问题。运用MATLAB中的边值计算方法求解桩的控制方程,最后在MATLAB中编写迭代程序进行上述方程的耦合计算。建立了一套分析异形桩竖向动力响应的理论模型。将该理论模型的半解析解与现有解析解进行对比,验证了该方法的可靠性。最后,讨论了异形桩的横截面参数、桩-土模量比、桩的长细比等对桩顶复阻抗的影响。结果表明:随着外荷载频率增大,桩的横截面形状对桩顶阻抗的影响也逐渐增大,其中H形桩的异形效应相较于X形桩和矩形桩更为明显。 展开更多
关键词 黏弹性土 横截面异形桩 HAMILTON原理 异形效应 复杂边界条件 动力阻抗
原文传递
恶性肿瘤患者对氢氧气吸入改善抗肿瘤药物治疗不良反应相关知识的认知调查及影响因素分析
19
作者 樊剑 赵家义 +1 位作者 吴明花 商艳 《海军军医大学学报》 北大核心 2026年第1期132-138,共7页
目的了解恶性肿瘤患者对氢氧气改善抗肿瘤药物治疗不良反应相关知识的知晓状况、态度倾向以及相关行为的认知情况,以期为优化肿瘤治疗方案、提升治疗效果及患者生活质量提供理论依据。方法采用简单随机抽样的方法,选取2022-2023年于海... 目的了解恶性肿瘤患者对氢氧气改善抗肿瘤药物治疗不良反应相关知识的知晓状况、态度倾向以及相关行为的认知情况,以期为优化肿瘤治疗方案、提升治疗效果及患者生活质量提供理论依据。方法采用简单随机抽样的方法,选取2022-2023年于海军军医大学第一附属医院接受抗肿瘤药物治疗和氢氧气吸入治疗的恶性肿瘤患者120例作为调查对象。利用自主设计的调查问卷,调查患者对氢氧气治疗作用相关知识的知晓情况、对氢氧气治疗的态度倾向及使用氢氧气治疗时相关行为的认知情况。结果共发放问卷120份,回收问卷114份,有效回收率为95.0%。患者对氢气相关特性和作用的知晓情况较好,但对氢气的安全性认知仍有提升空间;患者对氢氧气治疗的态度整体较为积极;在氢氧气相关正确使用行为方面,认知情况存在偏差。性别、年龄、婚姻状况、受教育程度、家庭平均月收入、居住方式和是否合并慢性病对患者使用氢氧气治疗时相关行为的认知有影响(均P<0.05)。结论恶性肿瘤患者对氢氧气能改善抗肿瘤药物不良反应有一定了解,态度较为积极,但仍需加强氢氧气具有治疗作用的知识普及和正确使用行为的教育引导,以提高患者对氢氧气治疗作用的全面认知和接受程度。 展开更多
关键词 氢氧气 肿瘤 药物治疗 不良反应 现况调查
原文传递
Preparation for Polyvinyl Alcohol Hollow Microsphere and Its Sustained Release Effect on Urea 被引量:4
20
作者 邵兵 邱舒 +3 位作者 张文莉 倪良 邵怿 王超 《Agricultural Science & Technology》 CAS 2008年第5期8-12,18,共6页
[Objective] The aim of this study was to discuss the optimizing preparation conditions of polyvinyl alcohol(PVA)hollow microsphere and its application in the production of slow-release urea fertilizer.[Method]PVA holl... [Objective] The aim of this study was to discuss the optimizing preparation conditions of polyvinyl alcohol(PVA)hollow microsphere and its application in the production of slow-release urea fertilizer.[Method]PVA hollow microsphere was prepared by the emulsion chemical cross-linking method,while its composition,morphology and particle size was analyzed by technologies of FT-IR,SEM and TEM respectively.Thus,factors such as rate of emulsified speed,crosslink temperature and linking agent amount with effects on morphology and particle size of hollow microsphere were also discussed in this study.Furthermore,based on the optimizing preparation conditions,PVA fertilizer carrier microsphere was prepared by coating urea to investigate its sustained release effect on urea.[Result]The optimizing preparation conditions of polyvinyl alcohol(PVA)hollow microsphere were as follows:rate of emulsified speed 6 000 r/min,crosslink temperature 35 ℃ and linking agent amount 25 ml.PVA fertilizer carrier microsphere had significant sustained release effect on urea,and the optimal cross-linking time was 3 hours.[Conclusion]This study provides theoretical basis for the development of new slow-release fertilizer. 展开更多
关键词 Polyvinyl alcohol HOLLOW MICROSPHERE EMULSION chemical cross-linking UREA SUSTAINED release effect
在线阅读 下载PDF
上一页 1 2 99 下一页 到第
使用帮助 返回顶部