KDE-Based Rainfall Event Separation and Characterization

Rainfall event separation is mainly based on the selection of the minimum inter-event time (MIET). The traditional approach to determining a suitable MIET for estimating the probability den sity functions is often using the frequency histograms. However, this approach cannot avoid arbi trariness and subjectivity in selecting the histogram parameters. To overcome the above limitations, this study proposes a kernel density estimation (KDE) approach for rainfall event separation and characterization at any specific site where the exponential distributions are suitable for characterizing the rainfall event statistics. Using the standardized procedure provided taking into account the Poisson and Kolmogorov–Smirnov (K-S) statistical tests, the optimal pair of the MIET and rainfall event volume threshold can be determined. Two climatically different cities, Hangzhou and Jinan of China, applying the proposed approach are selected for demonstration purposes. The results show that the optimal MIETs determined are 12 h for Hangzhou and 10 h for Jinan while the optimal event volume threshold values are 3 mm for both Hangzhou and Jinan. The KDE-based approach can facilitate the rainfall statistical representation of the analytical probabilistic models of urban drainage/stormwater control facilitie

Impact of quantum confinement on transport and the electrostatic driven performance of silicon nanowire transistors at the scaling limit

In this work we investigate the impact of quantum mechanical effects on the device performance of n-type silicon nanowire transistors (NWT) for possible future CMOS applications at the scaling limit. For the purpose of this paper, we created Si NWTs with two channel crystallographic orientations <110> and <100> and six different cross-section profiles. In the first part, we study the impact of quantum corrections on the gate capacitance and mobile charge in the channel. The mobile charge to gate capacitance ratio, which is an indicator of the intrinsic performance of the NWTs, is also investigated. The influence of the rotating of the NWTs cross-sectional geometry by 90o on charge distribution in the channel is also studied. We compare the correlation between the charge profile in the channel and cross-sectional dimension for circular transistor with four different cross-sections diameters: 5nm, 6nm, 7nm and 8nm. In the second part of this paper, we expand the computational study by including different gate lengths for some of the Si NWTs. As a result, we establish a correlation between the mobile charge distribution in the channel and the gate capacitance, drain-induced barrier lowering (DIBL) and the subthreshold slope (SS). All calculations are based on a quantum mechanical description of the mobile charge distribution in the channel. This description is based on the solution of the Schrödinger equation in NWT cross sections along the current path, which is mandatory for nanowires with such ultra-scale dimensions

Probing the Charge Separation Process on In2S3/Pt-TiO2 Nanocomposites for Boosted Visible-light Photocatalytic Hydrogen Production

A simple refluxing wet-chemical approach is employed for fabricating In2S3/Pt-TiO2 heterogeneous catalysts for hydrogen generation under visible light irradiation. When the mass ratio between Pt-TiO2 and cubic-phased In2S3 (denoted as In2S3/Pt-TiO2) is two, the composite catalyst shows the highest hydrogen production, which exhibits an 82-fold enhancement over in-situ deposited Pt-In2S3. UV-vis diffuse reflectance and valence band X-ray photoelectron spectra elucidate that the conduction band of In2S3 is 0.3 eV more negative compared to that of TiO2, favoring charge separation in the nanocomposites. Photoelectrochemical transient photo-current measurements and optical pump - terahertz probe spectroscopic studies further corroborate the charge separation in In2S3/Pt-TiO2. The migration of photo-induced electrons from the In2S3 conduction band to the TiO2 conduction band and subsequently into the Pt nanoparticles is found to occur within 5 picoseconds. Based on the experimental evidence, a charge separation process is proposed which accounts for the enhanced activity exhibited by the In2S3/Pt-TiO2 composite catalysts

Simulation study of the impact of quantum confinement on the electrostatically driven oerformance of n-type nanowire transistors

In this paper, we have studied the impact of quantum confinement on the performance of n-type silicon nanowire transistors (NWTs) for application in advanced CMOS technologies. The 3-D drift-diffusion simulations based on the density gradient approach that has been calibrated with respect to the solution of the Schrödinger equation in 2-D cross sections along the direction of the transport are presented. The simulated NWTs have cross sections and dimensional characteristics representative of the transistors expected at a 7-nm CMOS technology. Different gate lengths, cross-sectional shapes, spacer thicknesses, and doping steepness were considered. We have studied the impact of the quantum corrections on the gate capacitance, mobile charge in the channel, drain-induced barrier lowering, and subthreshold slope. The mobile charge to gate capacitance ratio, which is an indicator of the intrinsic speed of the NWTs, is also investigated. We have also estimated the optimal gate length for different NWT design conditions

Driving Factors and Spatial Temporal Heterogeneity of Low-Carbon Coupling Coordination between the Logistics Industry and Manufacturing Industry

The low-carbon coupling coordination of the logistics industry and manufacturing industry is an ecological innovation organization that integrates economic benefits, social benefits, and ecological benefits under strict carbon emission constraints. In order to control or reduce the carbon dioxide emission of the two industries, it is very important to understand the driving factors of emission change and formulate effective carbon policy. The Yangtze River Delta has developed manufacturing clusters and a perfect logistics system. The Yangtze River Delta region is taken as an example. Firstly, the coupling coordination model is used to calculate the low-carbon coupling coordination scheduling of the region. Then, the spatiotemporal geographically time-weighted regression model (GTWR) is used to explore the spatial heterogeneity of driving factors of low-carbon coupling coordination. The empirical results show the following: the low-carbon coupling coordination in the Yangtze River Delta is at a good coordination, and each driving factor has a positive effect on the coupling coordination. From the regional city level and time change level, the regression coefficients of each driving factors are analyzed, and it is found that the impact of driving factors on low-carbon coupling is significantly different between large cities and small and medium-sized cities, and the spatial heterogeneity of driving factors is significant. Specifically, the marginal impact of human capital, technological progress, and urbanization level on the low-carbon coupling between logistics and manufacturing in the Yangtze River Delta is increasing year by year; the marginal impact of international trade, industrial policy, and foreign investment on the Yangtze River Delta is decreasing year by year; and the marginal impact of capital investment and infrastructure on the Yangtze River Delta is relatively stable. Finally, according to the heterogeneity of driving factors in cities of different sizes, the corresponding development suggestions are put forward

The impacts of improvements in the unified economic and environmental efficiency of transportation infrastructure on industrial structure transformation and upgrade from the perspective of resource factors

As an important part of a modern economic system, a modern industrial system is the key to promoting high-quality economic development. China’s modern industrial system construction focuses on industrial restructuring. At present, in order to strengthen the support and leading role of transportation in the modern economic system, China is actively promoting the construction of a competitive transportation power. Therefore, it is necessary to study whether large-scale investment in transportation infrastructure can promote industrial structure transformation and upgrade. This paper takes China as the research background. Firstly, a RAM model was employed to evaluate the unified economic and environmental efficiency of transportation infrastructure that measures the level of transportation infrastructure investment. Secondly, a PVAR model was built to evaluate the dynamic effects of transportation infrastructure investment on industrial structure transformation and upgrade. Finally, from the perspective of rational flow and optimal allocation of resource factors, the paper points out that transportation infrastructure investment can indirectly promote industrial structure transformation and upgrade through three paths, namely expanding market demand, reducing resource misallocation and increasing technological innovation, and the first half of these paths are positively regulated by policies. Then, an empirical test was done with the moderated mediation model. Research findings suggest that: first, improvements in the unified economic and environmental efficiency of transportation infrastructure can only promote industrial structure supererogation in a short time, but have no significant effect on promoting industrial structure rationalization in the short or long term. Second, in actual situation, transportation infrastructure investment can promote industrial structure transformation and upgrade only by expanding market demand and technological innovation, but not by reducing resource misallocation. Third, the first half of these paths through which transportation infrastructure investment promotes industrial structure transformation and upgrade are positively regulated by policies. This paper provided some theoretical reference for promoting industrial structure transformation and upgrade by virtue of the sustainable development of transportation