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931.
以混凝土结构和钢结构两种不同结构形式,利用有限元分析软件ANSYS分析了该两种结构在六种不同风荷载下的最大层位移、层间位移及层间位移角的变化情况,最后通过分析,验证了两种不同结构形式的各自可行性。 相似文献
932.
Daylight simulators (i.e., D50, D55, D65, and D75 simulators) play an important role for industrial applications, such as surface color industry, recipe formulation, and graphic arts industry. Conventional light sources, including xenon lamps, tungsten‐halogen lamps, and fluorescent lamps, have been used as daylight simulators. In this article, a genetic algorithm is employed to investigate optimized channels for each daylight simulator. It is found that at least six LED channels are required to produce high quality daylight simulators in terms of the CIE Metamerism Indices. Furthermore, it is possible to create a spectrally tunable daylight simulator using six LED channels with wavelengths of 357, 420, 474, 533, 595, and 660 nm. This wavelength combination with appropriate intensity combinations can produce D50, D55, D65, and D75 simulators with good performance, in terms of the CIE Metamerism Indices. The color appearance of various color samples or objects under such a daylight simulator is found to be very similar to those under a corresponding daylight illuminant. © 2016 Wiley Periodicals, Inc. Col Res Appl, 42, 419–423, 2017 相似文献
933.
In this paper, quasi-Monte Carlo combined with multiple linear regression (QMC-MLR) is proposed to solve probabilistic load flow (PLF) calculation. A distinguishing feature of the paper is that PLF is approached by a low-dimensional problem with the concept of the effective dimension, and thus QMC based on low-discrepancy sequences is used to improve the sampling efficiency of the Monte Carlo simulation (MCS). Moreover, according to the relationship between linear correlation and linear regression, the MLR-based correlation control technique is developed to arrange the orders of samples in order to introduce prescribed dependences between variables. The proposed method is tested with the IEEE 118-bus system. Simulation results indicate that the MLR-based technique is robust and efficient in handling correlated non-normal variables and the proposed method shows better performances in PLF calculation compared with other MCS techniques, including simple random sampling (SRS), Latin hypercube sampling (LHS) and Latin supercube sampling (LSS). 相似文献
934.
935.
低温永磁波荡器(Cryogenic Permanent Magnet Undulator,CPMU)利用稀土永磁材料钕铁硼或镨铁硼在低温下的剩磁及内禀矫顽力大幅增大的特性,通过使磁体工作在50-150 K的低温环境,获得相比于常规真空内波荡器(In-vacuum Undulator,IVU)高30%-50%的磁场性能。在磁气隙一定的条件下,CPMU可以在较小的周期长度下获得较大的磁场强度,这对于提升同步辐射光的亮度具有重要意义。本文介绍了上海光源(Shanghai Synchrotron Radiation Facility,SSRF)钕铁硼CPMU磁体冷却技术的研究进展,对CPMU的静态热负载进行了详细的理论分析及实验研究。CPMU静态热负载的理论分析方法在CPMU样件低温冷却实验装置得到了验证,并在完整钕铁硼CPMU样机中得到了应用。 相似文献
936.
《Thin》2014
In this research, softening and ratcheting behaviors of SS316L cantilevered cylindrical shells under cyclic bending load were investigated. Experimental tests were carried out by a Servo-Hydraulic INSTRON 8802 machine. Force-control and displacement-control loadings were applied and the effects of displacement amplitude, mean force, loading history and cutout position were examined. Under displacement-control loading, softening behavior was observed due to growth of ovalization and it was shown that as the displacement amplitude increases, softening rate and density of plastic energy increase. Accumulation of the plastic strain or ratcheting phenomenon occurred under force-control loading with nonzero mean force. Increase of the mean force accompanied with an increase in the accumulation of the plastic deformation and its rate. In loading history, it was seen that prior load with higher force amplitude retards the ratcheting behavior and plastic deformation of subsequent load with smaller force amplitude. In addition, due to sensitivity of cutout to the bending moment, as the position of the cutout changes from the middle of shell towards the cantilevered end, the accumulation of the plastic deformation increases. 相似文献
937.
938.
Medical image interpretation is moving from using 2D- to volumetric images, thereby changing the cognitive and perceptual processes involved. This is expected to affect medical students' experienced cognitive load, while learning image interpretation skills. With two studies this explorative research investigated whether measures inherent to image interpretation, i.e. human-computer interaction and eye tracking, relate to cognitive load. Subsequently, it investigated effects of volumetric image interpretation on second-year medical students' cognitive load. Study 1 measured human-computer interactions of participants during two volumetric image interpretation tasks. Using structural equation modelling, the latent variable ‘volumetric image information’ was identified from the data, which significantly predicted self-reported mental effort as a measure of cognitive load. Study 2 measured participants' eye movements during multiple 2D and volumetric image interpretation tasks. Multilevel analysis showed that time to locate a relevant structure in an image was significantly related to pupil dilation, as a proxy for cognitive load. It is discussed how combining human-computer interaction and eye tracking allows for comprehensive measurement of cognitive load. Combining such measures in a single model would allow for disentangling unique sources of cognitive load, leading to recommendations for implementation of volumetric image interpretation in the medical education curriculum. 相似文献
939.
工程检测领域应用信息化管理已成为一个重要的监管手段,本文试从福建省运用自动采集远程监控系统进行全省基桩静载检测试验监管中遇到的若干问题进行研究,分析影响因素,从技术、制度、管理等方面提出规范基桩检测行为的措施,确保基桩检测数据的真实性和有效性。 相似文献
940.
由于采动荷载和爆破荷载对已有支护锚杆产生影响,因此迫切需要研究锚杆在动荷载作用下的微观力学特性及黏结性变化。从工程实际出发,现场监测锚杆工作状态下轴力变化和爆破荷载作用下锚杆周边围岩振动信息,并开展探索性室内试验。通过室内试验获得锚杆在轴向荷载作用下横向固有频率振动后的振动强度与工作龄期耦合作用下锚杆黏结性衰减规律的拟合计算式。研制了横向简谐荷载作用下端锚黏结式锚杆模型试验装置,采用均匀设计方法,考虑锚杆长度和锚杆直径两个影响因素,通过动态监测系统获得了横向简谐荷载作用下锚杆应力沿锚杆长度的分布规律、锚杆应力分布与拉拔力的关系,以及剪切应力与位移的关系。最终采用大型有限差分软件FLAC3D,建立了锚杆与围岩相互作用的力学模型。 相似文献