763 research outputs found
On ecological City and cultural construction
Eco-city Environment , The is the result of a city's ecological culture showing the mutual constraints and development of various forces . is also eco-city and various resources Configure the results of coordinated symbiosis . Eco-city construction should focus on the ecological environment of cities , Cultural , Smart Feature , also needs to reflect the characteristics of the circular economy , This is an important way to build an environment-friendly and resource-saving society and achieve sustainable development , It is an important way to promote economic growth in the construction of eco-city . at birth Building Energy resource-conserving economic growth mode and consumption pattern in urban environment , Promote the comprehensive and healthy development of ecological city and cultural construction , Eco City constructionResearch hotspots and important topics for . This article analyzes and discusses the
Modeling municipal yields with (and without) bond insurance
YesWe develop an intensity-based model of municipal yields, making simultaneous use of the CDS premiums of the insurers and both insured and uninsured municipal bond transactions. We estimate the model individually for 61 municipal issuers by exploiting the dramatic decline in credit quality of the bond insurers from July 2007 to June 2008, and decompose the municipal yield spread based on the estimated parameters. The decomposition reveals a dominant role of the liquidity component as well as interactions between liquidity and default similar to those modeled by Chen et al. (2016) for corporate bonds. Towards the end of the sample period, our model also reproduces the "yield inversion" phenomenon documented by Bergstresser et al. (2010)
Near-field beamforming performance analysis for acoustic emission source localization
This paper attempts to study the localization performance of a near-field acoustic emission (AE) beamforming by varying parameters such as array types, localization velocity, the maximum diameter of the array and the sensor spacing. To investigate how those parameters affect localization performance, an improved finite element method is established to obtain AE signals which take real propagation characteristics and have high signal to noise ratio. And AE signals of the finite element simulation under different parameters are obtained based on the presented method. Then AE beamforming is used to localize AE sources, and the influences of these parameters on the AE beamforming localization performing are analyzed. The results indicate that the parameters have impact on the localization accuracy clearly. This work can provide a reference for the selection of parameters when the beamforming is used to localize AE sources
Elastokinetics modeling and characteristic analysis of the parallel robot mechanism
This paper focuses a new 4-UPS-RPS five degree of freedom (DOF) spatial parallel robot mechanism with independent intellectual property rights obtained. Based on KED method and together with finite element method, Lagrange equation and substructure modeling method, the elastokinetics analytical model of this parallel robot mechanism is established under the ideal situation. Subsequently, the research results, such as elastokinetics model, stress and frequency characteristic analysis, are obtained. Combined with typical examples, key design parameters which significantly influence the dynamic characteristics of the system, are explicated. The work done in this paper lays a solid foundation for the dynamic optimum design of parallel robot mechanism and the physical prototype development
Effects of Glyphosate-Resistant Genetically Modified Soybean on Blood Biochemical Indexes, Hepatopancreatic Antioxidant Capacity and Tissue Morphology of Cyprinus carpio
The juvenile carps (Cyprinus carpio) were fed diets with four protein sources (15% and 30% glyphosate-resistant genetically modified (GM) named GM 15 and GM 30, respectively, and 15% and 30% non-genetically modified (NGM) soybean named NGM 15 and NGM 30) for 180 days. Results showed that alkaline phosphatase (ALP) activity for the GM30 group was significantly lower than that of the NGM30 group. The activity of glutathione peroxidase (GSH-Px) in the hepatopancreas of carp for the GM30 group was significantly higher than that of the NGM15 group (P0.05). This study indicates that it may aggravate the damage degree of intestinal epithelial cells of carp and more easily cause liver cell damage in the short term when the amount of GM soybean in the feeds was 30%. Therefore, higher glyphosate-resistant GM soybean may have adverse effects on the carp's serum, intestinal, and hepatopancreas and considerably reduce the hepatopancreatic carp's antioxidant capacity
Nonlinear characteristic analysis of high-speed spatial parallel mechanism
In order to grasp the nonlinear characteristic of high-speed spatial parallel mechanism, the analysis of nonlinear characteristics for spatial parallel mechanism is investigated. The nonlinear elastic dynamic equation of 4-UPS-UPU high-speed spatial parallel mechanism is derived by kineto-elastodynamics theory, the dynamic equation is solved by numerical method, the nonlinear characteristic of the parallel mechanism is analyzed by phase diagram. Numerical results show that 4-UPS-UPU high-speed spatial parallel mechanism exhibits typical nonlinear characteristic during exercise, the factors, such as the motion trajectory of parallel mechanism, the material of driving limbs, the diameter of driving limbs and the mass of moving platform, are also have effect on nonlinear characteristics of parallel mechanism. Therefore the reasonable choice of the above factors can weaken the chaos motion. This researches provide important theoretical base of the chaos suppression for spatial parallel mechanism
Adaptive iterative working state prediction based on the double unscented transformation and dynamic functioning for unmanned aerial vehicle lithium-ion batteries.
In lithium-ion batteries, the accuracy of estimation of the state of charge is a core parameter which will determine the power control accuracy and management reliability of the energy storage systems. When using unscented Kalman filtering to estimate the charge of lithium-ion batteries, if the pulse current change rate is too high, the tracking effects of algorithms will not be optimal, with high estimation errors. In this study, the unscented Kalman filtering algorithm is improved to solve the above problems and boost the Kalman gain with dynamic function modules, so as to improve system stability. The closed-circuit voltage of the system is predicted with two non-linear transformations, so as to improve the accuracy of the system. Meanwhile, an adaptive algorithm is developed to predict and correct the system noises and observation noises, thus enhancing the robustness of the system. Experiments show that the maximum estimation error of the second-order Circuit Model is controlled to less than 0.20V. Under various simulation conditions and interference factors, the estimation error of the unscented Kalman filtering is as high as 2%, but that of the improved Kalman filtering algorithm are kept well under 1.00%, with the errors reduced by 0.80%, therefore laying a sound foundation for the follow-up research on the battery management system
MULTI-PORT ELECTROMAGNETIC INTERFERENCE IMPROVEMENT USING HETEROGENEOUS PORTS
Techniques are provided herein for using different profiles on different ports for different radiation directions in multi-port projects. Because the superposition effect is weakened, the maximum radiation of a project is about 3dB smaller than those with uniform ports
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