长江三角洲区域政策强度的定量化及其演变过程——以区域开放开发政策为例

区域政策强度是政府投入影响区域经济格局的政策变量值的大小。区域政策强度的影响因素可分为政策自身内容和政策背景属性两类,前者主要考察政策工具体系,后者则主要考察区域政策的影响范围和政策实施保障能力。在此基础上提出区域政策强度定量化的指标体系,据此定量考察区域政策强度值的时空演变规律与特征。以改革开放以来长江三角洲实施的区域开放开发政策作为实证研究样本,经过区域政策强度的定量化分析发现:区域开放开发政策强度具有能级上的差异,不同类型区域政策的强度值变化特征不同,并在时间上呈阶段性和周期性,在空间上由等级梯度向扁平化转变。     

中国古代砖砌体力学性能研究综述

古代砖砌体建筑由于材料劣化、环境影响,材料特性及力学性能均受到不同程度的影响和损伤,为了保护历史文化的载体,结合古建筑材料获取原始且必要的数据,系统总结了古砖、传统灰浆的制备工艺和材料性能,简要归纳了古砖、传统灰浆和古砖砌体基本力学性能及其测试方法,对比分析了单砖和砌体抗压强度的差异以及古建筑砌体材料力学性能研究现状。并对今后古砌体如弹性模量等力学性能、古砌体材料及结构的损伤机理等的研究提出了展望或建议,可为砖石古建筑的修缮保护提供参考依据。     

微生物诱导碳酸钙修复汉白玉石梁裂缝试验研究

石质文物劣化后产生裂缝等病害,需要恰当的修复方法。本研究应用微生物诱导碳酸钙沉积技术修复汉白玉石梁裂缝,模拟石质文物裂缝修复。研究对象为带V型槽的非贯通和贯通裂缝的汉白玉石梁(尺寸为40 mm×40 mm×160 mm),修复方法为先注浆后自由下渗。通过对比石梁修复前后破坏荷载和强度的变化以及CT扫描技术可视化非贯通裂缝修复过程来评价修复效果。结果显示:修复后石梁裂缝表面致密光滑,颜色与母材相近,整体美观性好;非贯通裂缝修复后破坏荷载均有所增加,贯通裂缝修复后的抗折强度能恢复到原有强度的35.12%,均值为3.684 MPa,最高能达到5.234 MPa;CT扫描结果定性和定量均表明胶凝体密度随修复进行而增加,接触面修复质量弱于其他位置。     

Determination of Shear Strength of Masonry Panels Through Different Tests

This study addresses the problem of evaluation of strength of masonry walls. In-plane behavior of masonry panels has been studied under monotonic diagonal-compression and shear-compression loading in quasi-static test facility. The results of 35 laboratory and in situ tests are analyzed to show that in the case of the diagonal compression test results are lower than the strength of masonry walls evaluated trough the shear-compression test, highlighting the problem of choosing the test which best simulates to the real behavior of the masonry when stressed by lateral loads. A presentation is also given of the results of a F.E. investigation for shear strength evaluation of masonry walls. F.E. modeling non-linear procedure was used for the representation of masonry panels. The numerical simulations are compared with experimental results and the reliability of the different finite element models is discussed, thus confirming the different shear strength values measured in the experimental campaign.     

热老化模式对纸张性能的影响

为研究连续热老化与非连续热老化对不同纸张的pH值、机械性能和聚合度的影响,观察脱酸前后的纸张性能与老化方式的相关性,采用非连续热老化,老化8h后间隔16h继续老化,与连续热老化,研究酸性纸张与碱性纸张pH值、抗张强度和聚合度随时间变化情况,并用纤维断裂率计算各老化情况下纸张纤维断裂速率常数.实验结果表明,在非连续热老化方式下,纸张的pH值、抗张强度和聚合度下降均比连续热老化方式快;且各纸张在不同老化方式下的纤维断裂速率分别为KA=10.75×10-3,KB=16.78×10-3,Kc =3.75 ×10-3,KD =8.36×10-3.从而说明温度的波动对纸张老化具有一定的促进作用,图书保存中应注意环境条件的恒定.同时也进一步证实了碱残留对于降低纸张纤维降解速度具有非常重要的作用.     

抗钻强度在文物加固保护中的应用

抗钻强度测试是一种极微小破坏性的强度测试方法,特别适合于物保护中加固强度及加固剂渗透深度的测定。通过用有机氟材料对几种不同材质物(石质、砖或陶质、土质)在实验室和现场加固强度及渗透深度的测试,并与抗压强度进行比较,结果表明抗钻强度是一种有效的加固强度表征方法,特别适合于物的现场保护应用。     

A SUMMARY OF RESULTS OF SIMULATED SEISMIC LOAD TESTS ON REINFORCED CONCRETE BEAM-COLUMN JOINTS,BEAMS AND COLUMNS WITH SUBSTANDARD REINFORCING DETAILS

The results of some simulated seismic load tests on reinforced concrete one-way interior and exterior beam-column joints with substandard reinforcing details typical of buildings constructed in New Zealand before the 1970s are described. The tests were conducted using both deformed and plain round longitudinal reinforcement. The interior beam-column joint cores lacked transverse reinforcement and the longitudinal bars passing through the joint core were poorly anchored. The exterior beam-column joint units contained very little transverse reinforcement in the members and in the joint core. In one exterior beam-column joint unit the beam bar hooks were not bent into the joint core. That is, the hooks at the ends of the top bars were bent up and the hooks at the ends of the bottom bars were bent down. This anchorage detail was common in many older buildings constructed before the 1970s. In the other exterior beam-column joint unit the hooks at the ends of the bars were bent into the joint core as in current practice. The improvement in performance of the joint with beam bars anchored according to current practice is demonstrated. In addition, tests were conducted on interior joints with lap splices in the beam longitudinal reinforcement bars near the column face. The tests were conducted using both deformed and plain round longitudinal reinforcement. Tests were also conducted on columns with plain round bar longitudinal reinforcement and inadequate transverse reinforcement.

The reinforcing details were close to identical to those in an existing seven storey reinforced concrete building that was designed and built in New Zealand in the late 1950s.

The test results give an indication of the performance of beam-column joints and members with the above now out-of-date reinforcing details.

The test results reported are a summary of results reported in a number of publications written since 1994.     

SEISMIC DESIGN OF BASE-ISOLATED STRUCTURES USING CONSTANT STRENGTH SPECTRA

This paper presents the concept of constant strength design spectra for the design of base-isolated structures; particularly those structures using isolators with a bilinear hys-teretic behaviour when subjected to dynamic loading. The constant strength design spectra relate peak accelerations, velocities, displacements and effective isolated natural periods for bilinear systems with a given yield strength and post yield stiffness. Constant strength design spectra could be useful for the design of base isolators with bilinear hysteretic behaviour, as these devices can be designed for fixed yield strength and post yield stiffness. The concept of constant strength design spectra and its application for the design of base isolated structures is illustrated with case studies of specific structures.     

RESPONSE OF UNREINFORCED MASONRY BUILDINGS

Abstract

A summary of dynamic measurements are presented that illustrate relations between linear seismic demand and true nonlinear response of unreinforced masonry buildings with flexible diaphragms and rocking piers subjected to a series of simulated earthquake motions.     

新型防霉剂CM1在丝织品保护中的应用研究

为探讨新型防霉剂CM-1在丝织品保护中的效果,通过抑菌活性和模拟环境加速老化实验,检验了其用于丝织品保护中的生物活性,皿内抑菌实验表明防霉剂有很好的生物活性,且具广谱性。结合多种仪器分析,通过热老化、光老化、酸碱水解老化等方法验证防霉剂对丝织品后期安全性影响。结果表明,防霉剂能有效抑制丝织品褪色,红外光谱显示样品的化学结构没有变化,扫描电镜结果说明防霉剂可使样品对抗热老化,对样品表面有保护作用,拉力试验和X-射线衍射论证了防霉剂对丝织品的拉力强度和结晶度均没有影响。