从《东京制造》到《一点儿北京》——当代城市记录对建筑学的批判与探索

自20世纪中叶开始,建筑学的探索拓展到了城市,建筑师通过对城市的研究,迂回地找寻建筑学的突破。如今,面对越发复杂的、超出传统建筑学范畴的当代城市问题,建筑师们逐渐放弃了以一己之力撼动学科的态度,转向更为具体的城市空间及其问题的研究,并试图从中获得对具体现象的解决策略。本文选取当代具有代表性的城市记录读本《东京制造》和《一点儿北京》为主要研究对象,结合其所在的城市背景,对两个读本的研究方法、研究视角、文本内容进行分析和总结;并探索了从记录到创作之间的关系,以及记录成果对建筑学的批判和启发。     

Modeling of rate-dependent phase transition in bacterial flagellar filament

Recent experiment of Darnton and Berg [34] showed that phase transition of bacterial flagellar filament is loading rate-dependent. The object of this paper is to describe the observed loading rate-dependent phase transition responses of the filament by using time dependent Ginzberg–Landau continuum model. We developed a finite element method (FEM) code to simulate the phase transition under a displacement-controlled loading condition (controlled helix-twist) by using viscosity-type kinetics. Our FEM simulation captures the main features of the rate-dependence: under slow loading (i.e., loading time ? the relaxation time) the filament phase transition is an equilibrium process and each phase grows via interface propagation on the Maxwell line; under rapid loading (i.e., loading time ? the relaxation time), the phase transition does not occur and the response is elastic. Our FEM model provides a tool to study the effects of loading-rate dependent phase transition for bio-filament with viscous kinetics.     

An independent but not identically distributed bit error model for heavy-tailed wireless channels

The error patterns of a wireless channel can be represented by a binary sequence of ones(burst) and zeros(run),which is referred to as a trace.Recent surveys have shown that the run length distribution of a wireless channel is an intrinsically heavy-tailed distribution.Analytical models to characterize such features have to deal with the trade-off between complexity and accuracy.In this paper,we use an independent but not identically distributed(inid) stochastic process to characterize such channel behavior and show how to parameterize the inid bit error model on the basis of a trace.The proposed model has merely two parameters both having intuitive meanings and can be easily figured out from a trace.Compared with chaotic maps,the inid bit error model is simple for practical use but can still be deprived from heavy-tailed distribution in theory.Simulation results demonstrate that the inid model can match the trace,but with fewer parameters.We then propose an improvement on the inid model to capture the ’bursty’ nature of channel errors,described by burst length distribution.Our theoretical analysis is supported by an experimental evaluation.     

Instabilities of Regression Estimates Relating Air Pollution to Mortality

The instability of ordinary least squares estimates of linear regression coefficients is demonstrated for mortality rates regressed around various socioeconomic, weather and pollution variables. A ridge regression technique presented by Hoer1 and Kennard (Technometrics 12 (1970) 69–82) is employed to arrive at “stable” regression coefficients which, in some instances, differ considerably from the ordinary least squares estimates. In addition, two methods of variable elimination are compared—one based on total squared error and the other on a ridge trace analysis.     

Ring shear characteristics of discontinuous plane

Residual shear strength is an essential parameter in evaluating the long-term stability of reactivated landslides in geotechnical engineering. According to previous studies, earthquake-induced landslides may occur on discontinuous planes, such as bedding planes, between weathered and unweathered mudstones having different cementation properties resulting from diagenesis. However, the shear behaviour at the contact surfaces between the cemented and the non-cemented soil layers has not yet been sufficiently investigated. The objective of this study is to elucidate the residual strength characteristics of artificial bedding planes that model the actual behaviour of slip surfaces occurring between two layers with different degrees of cementation. The experimental tests were conducted with a ring shear test apparatus. Additionally, in order to simulate the realistic mechanical behaviour of naturally cemented clay, artificial cementation bonds were created by adding a cementing agent at different ratios to clay slurry. A series of ring shear tests was performed under various conditions on one-layer non-cemented and cemented kaolin samples, respectively, as well as on two-layer specimens composed of one layer each of cemented kaolin and non-cemented kaolin. The test results showed that the residual friction angle of the two-layer combinations of non-cemented and cemented kaolin was approximately 33.6% lower than that of pure kaolin. In contrast, the residual friction angle of cemented kaolin may be as much as 6.2° greater than that of non-cemented kaolin. At cement ratios of up to 2%, the stress ratio of cemented kaolin increased as the shear displacement rate increased. As the cement content was increased beyond 2%, the degree of increase was not significant. These results suggest that the residual strength of cemented kaolin at cement contents greater than 2% is independent of the shear rate.     

A review study on titanium niobium oxide-based composite anodes for Li-ion batteries: Synthesis,structure, and performance

The growing demands for Li-ion batteries (LIBs) in the electrification revolution, require the development of advanced electrode materials. Recently, intercalating titanium niobium oxide (TNO) anode materials with the general formula of TiNb_xO_2+2.5x have received lots of attention as an alternative to graphite and Li₄Ti₅O₁₂ commercial anodes. The desirability of this family of compounds stems from their high theoretical capacities (377–402 mAh/g), high safety, high working voltage, excellent cycling stability, and significant pseudocapacitive behavior. However, the rate performance of TNO-based anodes is poor owing to their low electronic and ionic conductivities. TNO-based composites generally are prepared with two aims of enhancing the conductivity of TNO and achieving a synergic effect between the TNO and the other component of the composite. Compositing with carbon matrices, such as graphene and carbon nanotubes (CNTs) are the most studied strategy for improving the conductivity of TNO and optimizing its high-rate performance. Also, for obtaining anode materials with high capacity and high long-term stability, the composites of TNO with transition metal dichalcogenides (TMDs) materials were proposed in previous literature. In this work, a comprehensive review of the TNO-based composites as the anodes for LIBs is presented which summarizes in detail the main recent literature from their synthesis procedure, optimum synthesis parameters, and the obtained morphology/structure to their electrochemical performance as the LIBs anode. Finally, the research gaps and the future perspective are proposed.     

Depth video spatial and temporal correlation enhancement algorithm based on just noticeable rendering distortion model

Spatial and temporal inconsistency of depth video deteriorates encoding efficiency in three dimensional video systems. A depth video processing algorithm based on human perception is presented. Firstly, a just noticeable rendering distortion (JNRD) model is formulated by combining the analyses of the influence of depth distortion on virtual view rendering with human visual perception characteristics. Then, depth video is processed based on the JNRD model from two aspects, spatial and temporal correlation enhancement. During the process of spatial correlation enhancement, depth video is segmented into edge, foreground, and background regions, and smoothened by Gaussian and mean filters. The operations of the temporal correlation enhancement include temporal–spatial transpose (TST), temporal smoothing filter and inverse TST. Finally, encoding and virtual view rendering experiments are conducted to evaluate the proposed algorithm. Experimental results show that the proposed algorithm can greatly reduce the bit rate while it maintains the quality of virtual view.     

Regulatory and ratemaking approaches to mitigate financial impacts of net-metered PV on utilities and ratepayers

The financial interests of U.S. utilities are poorly aligned with customer-sited solar photovoltaics (PV) under traditional regulation. Customer-sited PV, especially under a net-metering arrangement, may result in revenue erosion and lost earnings opportunities for utility shareholders as well as increases in average retail rates for utility ratepayers. Regulators are considering alternative regulatory and ratemaking approaches to mitigate these financial impacts. We performed a scoping analysis using a financial model to quantify the efficacy of mitigation approaches in reducing financial impacts of customer-sited PV on utility shareholders and ratepayers. We find that impacts can be mitigated through various incremental changes to utility regulatory and business models, though the efficacy varies considerably depending on design and particular utility circumstances. Based on this analysis, we discuss tradeoffs policymakers should consider, which ultimately might need to be resolved within broader policy contexts.     

Piezo-assisted photoelectric catalysis degradation for dyes and antibiotics by Ag dots-modified NaNbO3 powders

NaNbO₃ is explored as a potential candidate for catalysis due to its excellent piezoelectricity. However, its photocatalysis is significantly limited for the inherent characteristics of wide band gap. In this work, NaNbO₃ and Ag dots-modified NaNbO₃ micron-sized powders are prepared and applied in piezo-photocatalysis to explore the coupling effects. The results show that the piezocatalysis degradation efficiency of RhB solution (the initial concentration C₀ = 5 mg/L) reaches 92.3% within 30 min, and the rate constant k is 0.0889 min^?1. The efficiency of piezo-photocatalysis degradation reaches 92.7% in 25 min, and the rate constant k is 0.11 min^?1 for NaNbO₃. The rate constant k of Ag dots-modified NaNbO₃ for piezo-photocatalytic degradation of RhB (C₀ = 5 mg/L) is increased to 0.16314 min^?1. The optical and electrochemical activities of NaNbO₃-0.75hAg are studied to reveal the role of Ag nanoparticles. The band gap of NaNbO₃ is 3.59 eV, which is decreased to 3.36 eV after the modification with Ag dots. The lower band gap means that e^? in the valence band is more easily excited to shift the conduction band, which is beneficial to the photocatalytic reaction process. In addition, NaNbO₃-0.75hAg has a higher photogenerated carrier density, a faster electron-hole pair separation and transfer rate, which are beneficial to the catalytic oxidation process. The work provides a useful means to decease the band gap of NaNbO₃ and achieve outstanding piezo-photocatalysis for degradation of hazardous organic dyes in contaminated water.     

A novel adaptive deadbeat- based control for load frequency control of low inertia system in interconnected zones north and south of Scotland

An adaptive deadbeat (ADB) controller was developed to investigate its capability in providing a fast frequency response to an electrical power system. This controller was developed to meet the requirements of the National Grid System Operability Framework (SOF), which requires frequency to be accelerated in line with a fast rate of change of frequency (RoCoF) when a high rate of nonsynchronous machines are presented. The controller’s parameters were optimized using particle swarm optimization (PSO) to ensure a robust operation and to maintain the proper operation of the power system. The design of the ADB controller was then integrated with the multiarea model of the north and south zones of Scotland. This model was developed in order to conform to the future energy requirements scenario stated by National Grid whereby regional control can be provided in both the north and south of Scotland. In comparison with the standard PI and Fuzzy-PI controllers used in the four highlighted case studies, it was shown that the ADB controller was able to significantly reduce the RoCoF and deviation of frequency when a sudden loss of generation occurred in a low inertia zone. The ADB also showed high robustness against a wide range of operating conditions.