南北高架环行立交拥堵原因与对策探讨

一、前言 上海近年来为了解决日益突出的交通问题,投入了不少资金兴建高架道路,获得了通过能力大、快捷方便的效果。但同时也产生了一些问题,如高架道路容量不足、进出口受阻,等等。尤其是高架中的环行立交,建成使用以来,议论更多一些。环行立交作为一种立交型式,它的适用性如何?目前高架、立交受阻,症结何在?有无改善的对策措施?笔者参加了南北高架道路的设计,愿发表点看法,以供讨论。

三维流形不变量的等价表示

设M是由S3中通过标架环链(L,f)做手术得到的三维流形,对于标架环链(L,f)可以得到保持同痕及K+和K-变换的环链不变量,进而得到三维流形M的不变量,从而三维流形不变量可以由L的Kauffman括号的有限线性组合给出,当取变量为第4r个复单位根时,利用括号多项式、Temperly-Lieb代数、Jones-Kauffman模、线性束理论等给出了不同的三维流形不变量的表示.证明了这些三维流形不变量的表示是等价的,同时给出了三维流形不变量的一个新表示.

One-pot synthesis of a hierarchical microporous-mesoporous phosphotungstic acid-HKUST-1 catalyst and its application in the selective oxidation of cyclopentene to glutaraldehyde

A hierarchical microporous-mesoporous metal-organic framework of HKUST-l（Cu）-encapsulated phosphotungstic acid （HPW） material, referred to as HPWs@Meso-HKUST-1, is prepared by a one-pot synthesis method using cetyltrimethylammonium bromide as the supramolecular template. The addition of HPWs to the synthesis mixture of hierarchical porous HKUST-1 results in the direct encapsulation of HPWs inside the mesopores of the HKUST-1 structure, with a homogeneous distribution over the HKUST-1 crystals, which is confirmed by XRD, FT-IR, N2 adsorption, UV-Vis DRS, and TEM. FT-IR-CO adsorption experiments indicated that additional Lewis acid sites were present in the HPWs@Meso-HKUST-1 sample. The novel heterogeneous catalyst demonstrates excellent catalytic performance for the selective oxidation of cyclopentene （CPE） to glutaraldehyde CGA） using tert-butyl hydroperoxide and acetonitrile （MeCN） as the oxidant and solvent, respectively. The high activity of the catalyst is attributed to the mesostructure of the catalyst and the nature and appropriate abundance of the HPWs--being highly dispersed with the addition of Lewis sites. After a reaction for 36 h, the 30% wt% HPWs@Meso-HKUST-1 catalyst exhibits a CPE conversion of 92.5% and a high GA yield of 73%. Furthermore, the HPWs@Meso-HKUST-1 material is sufficiently stable to prevent the leaching of HPWs, and behaves as a true heterogeneous catalyst that can be repeatedly recycled without sustaining a loss of activity and selectivity in the selective oxidation of CPE.

A SYNTHETIC ENVIRONMENT FOR SYSTEM EVOLUTION

Due to the immaturity of practice and the increasing complexity of system of system (SoS). It is necessary to develop systematic methodologies that enable evolution of such systems. This paper presents a prototype design for a synthetic system evolution environment (SEE). It outlines the purpose of the environment, describes its concept of operations, details its main functions and processes in utilizing the system architecture knowledge for systems evolution, and introduces its initial high level architecture design.In addition, it also documents the approach for developing the environment.

Sedimentary Environment Analysis of Ancient Sand Ridges from Zk23 Hole in the East China Sea

Abstract： Based on the analysis of core samples from the hole of Zk23 in the East China Sea Continental Shelf and by means of sedimentary stratigraphy, biostratigraphy and chronostratigraphy, the authors consider that the fine-sand deposition in borehole was part of buried ancient estuary sand ridges of the Yangtze River. The deposition history of study area around the hole before and after the glacial period as well as postglacial period is made clear after our research： （1） the estuarine sublayer -undersea delta facies strata was deposited under the fast sea level rise about 15 kaB.P; （2） sand ridges mostly consisting of fine-sand, were formed when the sea level was the fluctuant range of 60 - 80 m of isoba during the deglacial period around 15 - 12 kaB.P; （3） first silty clay and clay silt strata above the sand ridges were deposited during the period when the sea level rose fast from 12 to 7 kaB.P, and then it keeps stable to the present.

PHOTOP ROJECTS来拍吧!

从五彩各异的门板到绽放的烟花,10种新鲜的拍摄题材供你尝试。如何拍摄清晰的图像对于摇拍来说,使用独脚架可以帮助你很多。将长焦镜头的脚架环安装到脚架上,而不是相机。然后将镜头的防抖模式设置为追随拍摄模式。面对拍摄对象飞来的方向站立,然后保持镜头始终对准飞鸟,跟随拍摄。[PROJECT1]定格空中的飞鸟拍摄飞行中的鸟类能够检验你的摇拍技术是否过关。想要给自己找个有挑战性的拍摄题材?试试拍摄飞行中的鸟类吧!这张照片是专业野生动物摄影师Ben

Security integrated framework for semantic web based on social intelligence

An integrated security framework for a semantic web is proposed based on the social intelligence of an individual＇s avoiding harm and preserving transaction logic-integrity. The framework extends the semantic web model and controls the dynamic security of semantic web services, such as trust, logic and reasoning. It includes four layers, that is, a trust entrance layer, a social intelligence layer, a transaction layer, and a TCP/IP security protocols layer. The trust entrance layer deals with trustable features from users. Social intelligence layer is responsible for logical questions for a semantic web. The transaction layer carries out transaction reasoning. And the TCP/IP security protocols layer ensures security communication. These layers can cooperate to build closed-security-ring with different security grades. The integrated security framework provides an integrated security method for semantic web flow so that it is universal for various semantic web technologies.

Persistent toxic substances in urban highway runoff in Shanghai

Urban highway runoff samples from seventeen rainfall events were collected in Shanghai in 2011. The concentrations of ten heavy metals and sixteen polycyclic aromatic hydrocarbons PAHs are analyzed. The results show that the heavy metal concentrations range within 0.50 to 51.80 As 0 to 20.80 Se 13.67 to 445.80 Zn 0 to 44.20 Pb 0 to 15.80 Ni 39.58 to 264.20 Fe 0 to 253.00 Mn 0 to 8.20 Cr 0 to 124.20 Cu and 159.83 to 536.40 μg/L Al . Se Pb Mn and Al concentrations in most samples exceed their corresponding criterion continuous concentrations CCCs while Zn and Cu concentrations exceed their criterion maximum concentrations CMCs .The concentrations ofΣPAHs range within 37.25 to 114.57 ng/L and concentrations of PAHs are all below their corresponding CCCs.Cu Zn and ΣPAHs show the first flush phenomenon. Analysis results of the modified Nemerow index method NIM indicate that runoff from eight rainfall events may have very strong biological toxicity effects four have strong effects three have moderate effects and only two have insignificant effects.Therefore it is concluded that urban highway runoff is a significant pollution source to aquatic ecosystems and needs immediate purification.

Environmental Effects on Rural-to-Urban Migration in China

Abstract： Migration process has become increasingly important in recent research on population and the environment. A majority of the existing migration and environment literature has focused on the environmental causes and determinants of migration. With the largest rural-to-urban migration flow in world history, and growing concerns about the environmental problems accompanying its fast economic development, China provides a particularly important case for migration and environment research. This paper reviews major migration theories and recent research on environmental effects on migration, with specific attention to the influences of en- vironmental factors on rural-to-urban labor migration in China. A comprehensive multilevel conceptual framework is developed for studying the environmental causes of rural-to-urban migration in China. The effects of land resources on household labor migration decisions in rural China are explored to illustrate the application of this framework.

Ionic covalent organic frameworks for highly effective catalysis

As an emerging class of crystalline porous materials, covalent organic frameworks（COFs） have been widely used as catalysts or catalyst supports. Flexible regulation of the pores and easy introduction of functional active sites onto the skeleton of COFs make them promising platforms for many catalysis applications. However, only a single function is generally observed in these COFs. Herein, we synthesized a negatively charged ionic COF（I-COF） and successfully incorporated functionalized counter ions, that is, metallic Mn2＋ and a coordination complex of manganese（Ⅱ） bipyridine complexes（[Mn（bpy）2]2＋）, via a simple ion exchange process. The resulting I-COFs can act as effective heterogeneous catalysts for epoxidation reactions. We envisage that with this type of ionic architecture, a variety of other functional cations could be exchanged into the frameworks, thus making the COF a versatile platform for different applications.

Solvothermal synthesis of Co-substituted phosphomolybdate acid encapsulated in the UiO-66 framework for catalytic application in olefin epoxidation

Hybrid composites of phosphomolybdic acid@UiO-66(PMo12@UiO-66)and Co-substituted phosphomolybdic acid@UiO-66(PMo11Co@UiO-66)were synthesized using the direct solvothermal method.A variety of characterization results demonstrated that phosphomolybdic acid(PMo12)or Co-substituted phosphomolybdate acid(PMo11Co)clusters are uniformly dispersed in the cages of Zr-based metal-organic UiO-66 frameworks.The catalytic properties of these hybrid composites were investigated by applying the epoxidation of olefins with tert-butyl hydroperoxide as the oxidant.Compared to PMo12@UiO-66,PMo11Co@UiO-66 showed a much higher catalytic activity and was simply recovered by filtration and reused for at least ten runs without significant loss of catalytic activity.Particularly,PMo11Co@UiO-66 can efficiently convert cyclic olefins like limonenes to epoxides,and its selectivity to 1,2-limonene oxide reached 91%in the presence of a radical inhibitor such as hydroquinone.The excellent catalytic activity and stability of the hybrid composite PMo11Co@UiO-66 are mainly attributed to the uniform distribution of highly active PMo11Co units within the smaller cages of UiO-66,to the suitable surface polarity of the hybrid composite for facilitating the access of reagents and solvent,and to the strong interface-interactions between the polyoxometalate and the UiO-66 framework.

Soft-sensing Design Based on Semiclosed-loop Framework

Soft-sensing is widely used in industrial applications. The traditional soft-sensing structure is open-loop without correction mechanism. If the working condition is changed or there is unknown disturbance, the forecast result of soft-sensing model may be incorrect. In order to obtain accurate values, it is necessary to carry out online correction. In this paper, a semiclosed-loop framework (SLF) is proposed to establish a soft-sensing approach, which estimates the input variables in the next moment by a prediction model and calibrates the output variables by a compensation model. The experimental results show that the proposed method has better prediction accuracy and robustness than other open-loop models.

Key technologies of precision demolition blasting of ultra-long urban viaduct in complicated surroundings

The key technologies of precision blasting were put forward based on the characteristics of urban via- duct blasting demolition in complicated surroundings. Initial bending instability mechanics model of reinforcing steel bar frame of blasting fragmented pier and sequenced collapsed dynamic model were established for quanti- tative blasting design. Technologies of water pressure blasting were applied in multi-cell box girder fragmenta- tion. The detonating network of non-electric duplication crossover was adopted for the safety and reliability of ultra-long delay. The rationality of blasting scheme and parameters were validated by physical model test. Harm- ful effects were forecasted and controlled by integrated protective technologies. Specialization, cooperation, pre- cision, execution （SCPE） project management method was put forward for precision management. The key tech- nologies of precision demolition blasting can provide reference for similar proiects.

An Open Architecture for Converged Internet of Things

An open architecture for converged Internet of Things (IoT) is proposed in this paper.By using this model,the various and huge amount of data can be converted into converged data and then encapsulated as service packages.Moreover,a Representational State Transfer (REST) platform has been implemented in the lab environment.The merit of this architecture is the enhancement of data efficiency.Experimental results are provided to show the benefits of the proposed architecture.

Ionization of a covalent organic framework for catalyzing the cycloaddition reaction between epoxides and carbon dioxide

Covalent organic frameworks(COFs),with two dimensional(2D-)or three dimensional(3D-)structures,have accessible open channels or nanopores,with uniform sizes ranging from angstroms to nanometers and have emerged as an excellent and promising platform for designing catalysts or catalyst carriers.Herein,a 2 D-COF grafted with a 1-alkyl-3-methylimidazolium-based ionic liquid(AMIMBr@H2 P-DHPh COF)on the channel walls was synthesized and utilized as a highly efficient heterogeneous catalyst for the chemical fixation of CO2 via a reaction with epoxides under solvent-free and co-catalyst-free conditions.The as-synthesized AMIMBr@H2 P-DHPh COF shows excellent catalytic activity in promoting the cycloaddition reactions between epoxide and CO2;the excellent catalytic activity was maintained for up to five cycles.Advantages like high porosity,functional versatility,easy modification of COFs,and high catalytic activity of ionic liquids,have been realized in a single material.

7G＇s Environmental Initiative through the Lens of the Technology-Organization-Environment （TOE） Framework

This qualitative research study addresses the research question of how the environmental sustainability initiative of 7G （Seventh Generation）, a product design, marketing, and distribution company in the household and personal care products, could be understood within its supply chain context using Tornatzky and Fleischer＇s TOE （Technology-Organization-Environment） framework. Content analysis, a research technique for making valid inferences from text following a set of procedures, was used and applied to secondary data materials on 7G. The findings reveal that the environmental, organizational, and technological contexts, which are key elements of the TOE framework, are useful in analyzing and comprehending the business practices and business processes adopted by 7G to pursue its sustainability initiative. Of particular interest are those business processes that were included by 7G＇s EMS （Environment Management System） and enabled by green IS （Information Systems）. Both the strengths and weaknesses of 7G＇s efforts are discussed and suggestions are presented for modifying certain phases of the systems development life cycle methodology when implementing green IS.

Reliability Prediction for Internetware Applications:A Research Framework and Its Practical Use

The open and dynamic environment of Internet computing demands new software reliability technologies.How to efficiently and effectively build highly reliable Internet applications becomes a critical research problem.This paper proposes a research framework for predicting reliability of individual software entities as well as the whole Internet application.Characteristics of the Internet environment are comprehensively analyzed and several reliability prediction approaches are proposed.A prototype is implemented and practical use of the proposed framework is also demonstrated.

Lightweight SOA-Based Twin-Engine Architecture for Enterprise Systems in Fixed and Mobile Environments

Mobile devices as a popular computing platform for enterprise systems have enabled certain tasks to be executed out of office.However,the work may be interrupted due to the server shutdown or network disconnection when employees access traditional single-engine Business Process Management System.To overcome this defect,we present a lightweight twin-engine architecture based on Service Oriented Architecture(SOA).In this paper,we discuss in detail the design and implementation of the architecture,and present a trigger mechanism to activate engines according to the states of hybrid environments since it is critical for the two types of engines to cooperate closely in hybrid environments with fixed and mobile computing resources.The experimental results validate the usability of the architecture.

A Web Service Framework for Environmental and Carbon Footprint Monitoring in Construction Supply Chains

With the growing environmental concerns, green supply chain management （GSCM） is gaining significant attention in the construction industry. Tracking and monitoring the environmental effects brought forth by the participating members along a supply chain is important to GSCM. The GreenSCOR model developed by the Supply Chain Council provides a generic framework for measuring the total carbon footprint and environmental footprint in a supply chain. The model is based on the Supply Chain Operations Reference （SCOR） model, which represents a supply chain network in a hierarchically structured manner. This paper describes the GreenSCOR framework and its potential application to the construction industry. This paper also presents a web services approach to incorporate the GreenSCOR model to the implementation of collaborative information systems. Each process element in the SCOR model is represented and delivered as individual web service units, which can be reused and integrated using standard web services technologies. The service units are combined and managed in a prototype web service collaborative framework, called SC Collaborator, which is designed and developed for supporting construction supply chain management. An illustrative example is presented to demonstrate the implementation of the GreenSCOR-based SC Collaborator framework.

Environmental Impact Optimization of Reinforced Concrete Slab Frame Bridges

The main objective of this research is to integrate environmental impact optimization in the structural design of reinforced concrete slab frame bridges in order to determine the most environment-friendly design. The case study bridge used in this work was also investigated in a previous paper focusing on the optimization of the investment cost, while the present study focuses on environmental impact optimization and comparing the results of both these studies. Optimization technique based on the pattern search method was implemented. Moreover, a comprehensive LCA （life cycle assessment） methodology of ReCiPe and two monetary weighting systems were used to convert environmental impacts into monetary costs. The analysis showed that both monetary weighting systems led to the same results. Furthermore, optimization based on environmental impact generated models with thinner construction elements yet of a higher concrete class, while cost optimization by considering extra constructability factors provided thicker sections and easier to construct. This dissimilarity in the results highlights the importance of combining environmental impact （and its associated environmental cost） and investment cost to find more material-efficient, economical, sustainable and time-effective bridge solutions.