Agglomeration and firm‐level productivity: A Bayesian spatial approach

This paper estimates the impact of industrial agglomeration on firm‐level productivity in Chinese manufacturing sectors. To account for spatial autocorrelation across regions, we formulate a hierarchical spatial model and use a Bayesian instrumental‐variable approach. We find that agglomeration of the same industry (i.e., localization) has a productivity‐boosting effect, but agglomeration of urban population (i.e., urbanization) has no such effect. In addition, the localization effect increases with the educational levels of employees and the share of intermediate inputs in gross output. These results may suggest that agglomeration externalities occur through knowledge spillovers and input sharing among firms producing similar manufactures.     

A structural multisectoral model with new economic geography linkages for Tuscany

This paper describes the Remi‐Irpet macroeconometric multisectoral model. The Remi‐Irpet, based on an input‐output core structure, has its most distinctive feature in the modelling of vertical pecuniary externalities à la Fujita‐Krugman‐Venables which represents the core dynamization mechanism. Our contribution first presents the theoretical background of the model. Second, we present a simulation exercise performed through the model in which we evaluate the structural impact of incoming FDIs for Tuscany. The impact analysis is defined in terms of (i) change in the overall productive capacity and (ii) medium‐term changes in prices and productivity, driven by the changes in the accessibility to labour and intermediate inputs.     

The propagation of uncertainty through travel demand models: An exploratory analysis

The future operations of transportation systems involve a lot of uncertainty – in both inputs and model parameters. This work investigates the stability of contemporary transport demand model outputs by quantifying the variability in model inputs, such as zonal socioeconomic data and trip generation rates, and simulating the propagation of their variation through a series of common demand models over a 25-zone network. The results suggest that uncertainty is likely to compound itself – rather than attenuate – over a series of models. Mispredictions at early stages (e.g., trip generation) in multi-stage models appear to amplify across later stages. While this effect may be counteracted by equilibrium assignment of traffic flows across a network, predicted traffic flows are highly and positively correlated. Received: March 2001/Accepted: August 2001     

基于居民行为需求特征的“15分钟社区生活圈”规划对策研究

“15分钟社区生活圈”是上海未来打造社区生活的基本单元.结合2016年《上海市15分钟社区生活圈规划导则(试行)》的研究制定工作,通过开展上海市居民行为特征的实证调查,挖掘现状社区空间供给与居民未来需求之间的差异和问题,作为打造“15分钟社区生活圈”,提升社区空间品质的切入点.基于实证调查,围绕居住、就业、服务、交通以及休闲五个系统,从开放活力、功能复合、服务精准、步行可达和绿色休闲五个方向提出构建“15分钟社区生活圈”的规划思路和对策,为社区层面规划提供一定参考.     

Is There Something Beyond ‘Outside of the Box’?

Here, architectural and scientific researcher Rachel Armstrong questions whether the definition of ‘experimental’ green design presented here goes far enough. She urges architects to not dwell on evaluation processes, performance and ‘strategies’ and to seek a far more radical solution to sustainability, which abandons the current emphasis on industrial technologies and the existing educational and professional frameworks. In its place, she envisions employing biology as a driver for wholly new living materials and systems. Copyright © 2011 John Wiley & Sons, Ltd.     

Study of superconductors by a.c. susceptibility

An apparatus used for a.c. susceptibility measurements is described and the usefulness of a.c. susceptibility measurements for investigating superconductors is discussed. The importance of carefully studying the real and imaginary parts of a.c. susceptibility is pointed out as illustrated by the results obtained on A15 compounds (V₃Si) and on Nb-Ti samples.     

平炉用硅铝钡合金炉前预脱氧冶炼GCr15钢的工业试验

介绍用硅铝钡合金炉前预脱氧，炉后用高硅铁合金化冶炼ＧＣｒ１５钢的新工艺，生产的ＧＣｒ１５钢，其氧化物、硫化物及钢中氧含量均优于原工艺，钢中氧含量可接近电炉精炼钢水平。     

Computing multiple pitchfork bifurcation points

A point (x*,λ*) is called apitchfork bifurcation point of multiplicityp≥1 of the nonlinear systemF(x, λ)=0,F:ℝⁿ×ℝ¹→ℝⁿ, if rank∂ _xF(x*, λ*)=n−1, and if the Ljapunov-Schmidt reduced equation has the normal formg(ξ, μ)=±ξ ²⁺ p±μξ=0. It is shown that such points satisfy a minimally extended systemG(y)=0,G:ℝ ⁿ⁺²→ℝⁿ⁺² the dimensionn+2 of which is independent ofp. For solving this system, a two-stage Newton-type method is proposed. Some numerical tests show the influence of the starting point and of the bordering vectors used in the definition of the extended system on the behavior of the iteration.     

沉淀硬化PH15-7Mo不锈钢采用电渣重熔工艺时Al含量的控制研究

研究了PHl5-7Mo钢的真空(VIM)母材采用电渣重熔(ESR)工艺时,合金元素的变化和不同的重熔工艺对重熔子材Al含量的影响,总结出根据母材Al含量的不同,在电渣重熔时调整Al含量的规律,使电渣重熔子材的Al含量满足要求,为该钢的生产提供了控制成份的依据.     

中小型落地箱五虎将

随着音响音乐爱好者的聆听空间变宽变大,有条件选用一些中小型的落地箱。当前市场上的落地箱不少,品质有高有低,售价不一,向大家介绍5款不同厂家的名牌中小型落地箱,它们都是当前市场上同等价位中较出色的产品。AE AELITE3性能指标:3路4单元倒相式设计;承受功率175W;频率响应40~24?kHz(±3?dB);灵敏度89?dB;阻抗8?Ω;重量18?kg;体积(W×D×H)230?mm×920?mm×297?mm;外观为黑色或樱桃木皮;参考价格9?750元/对。来自英国AE公司AELITE3相对便宜。AE在1987年成立于伦敦西部,自成功地开发出第一个用铝镁振膜的书架箱AE1后,在专业音响…