泰顺廊桥-文兴桥结构残损分析及修缮探讨

泰顺廊桥是中国传统木构建筑中的特有形式,文兴桥是其中著名的一座木拱廊桥。文兴桥木材构件的性能退化、强外力的作用、环境及人为因素的作用加速了桥体的损伤。通过对当地匠人的寻访,分析造桥工艺及细部构造,在准确测绘的基础上,建立了损坏前和损坏后的有限元模型,综合分析桥体的残损原因,提出了适用于文兴桥修缮加固的建议。     

SMA 增强含损伤智能结构的失效研究

从细观角度出发, 运用变分原理着重对形状记忆合金(Shape Memory Alloy, SMA) 增强含损伤智能结构的热、力学行为进行了分析, 给出了含损伤典型单元体的细观位移场、应力应变场的数学描述, 建立了SMA增强智能结构界面的失效判据, 并通过算例对失效判据进行了直观的几何描述。本文的结果为进一步研究智能结构的完整性提供了相应的理论支持。     

Pain and suffering costs of persons in construction accidents: Hong Kong experience

Direct financial costs of accidents are the tip of the iceberg when compared to the indirect costs. Notwithstanding the difficulties involved, it is very important to estimate the indirect costs borne by society, and the non‐material losses due to pain, suffering and loss of enjoyment of life undergone by the victim. This study investigates the pain and suffering costs (non‐material losses) of the victims of construction accidents in Hong Kong based on relevant High Court personal injury case judgements in the years 1999–2003. The 54 non‐fatal accident cases and 14 fatal accident cases analysed indicate that the average percentage of compensation awarded for non‐material damages (pain, suffering and loss of enjoyment of life) to that for material damages (loss of earnings, medical and travelling expenses, etc.) during those years is about 30%. This result enables estimating the pain and suffering costs of the society for a particular year if the total material losses of all construction accidents in that year are known. Based on previous research in which the material losses in Hong Kong were evaluated for the years 1999, 2000 and 2001, the corresponding pain and suffering costs could be estimated as 219 million, 150 million and 107 million Hong Kong dollars, respectively (US$1.00?=?HK$7.80).     

建设工程合同中承担违约责任的方式分析

在工程项目的建设过程中，需要形成各类建设工程合同加以调整不同主体之问的权利和义务，其中违约责任条款是建设工程合同中一项十分重要的条款。违约责任条款是指合同当事人因违反有效合同义务按合同约定所应承担的责任，对合同当事人双方的利益都十分重大，因此合同对此应给予明确。本文主要论述了承担违约责任的三种方式——定金、违约金、损害赔偿的概念与特点，重点分析了三种方式之间的联系与区别。最后结合建设工程合同的特点，分析阐述了建筑工程合同中承担违约责任的方式的具体特征和应用特点。     

Ultrasonic C-Scan and shearography NDI techniques evaluation of impact defects identification

The new all-composite wing for semi-aerobatic sport and training aircraft is being developed in the Czech aircraft industry. The typical outer composite structure of this wing is sandwich with carbon skins in combination with honeycomb. This new composite structure is designed in accordance with CS-23 airworthiness requirements. The NDI techniques for reliable detecting of manufacture or in-service defects (disbonding, defects from impact, etc.) are therefore, necessary. This paper compares the results of visual, ultrasonic C-Scan and laser shearography impact damage assessment and determination of sandwich panels, which were cut out from sandwich skins of this developmental wing. Considering the reliability, simplicity and rapidity of each technique and with the digital indicator measurement as a base, the laser shearography is evaluated as the most suitable method for that purpose.     

New positive-type photosensitive polyimide: poly(hydroxyimide) with diazonaphthoquinone

A positive working photosensitive polyimide based on polyhydroxyimide (PHI) and 2,3,4-tris[1-oxo-2-diazonaphthoquinone-4-sulfonyloxy] benzophenone (D4SB) as a photoreactive compound has been developed. The PHI was prepared by the ring-opening polyaddition of 4,4′-hexafluoroisopropylidenebis(phthalic anhydride) (6FDA), 4,4′-diamino-4″-hydroxytriphenylmethane (DHTM), and 4,4′-oxydianiline (ODA), followed by thermal cyclization in refluxing xylene. The PHI film showed excellent transparency to UV light. The photosensitive polyimide containing 30 wt% of D4SB showed a sensitivity of 250 mJ/cm² and a contrast of 5.2 when it was exposed to 436 nm light followed by developing with a 1% aqueous tetramethylammonium hydroxide (TMAH) solution at 35°C.     

离子束刻蚀光导HgCdTe探测器芯片的温度限制

利用离子对束对光导ＨｇＣｄＴｅ芯片阳极氧化膜，Ｃｒ－Ａｕ电极和ＨｇＣｄＴｅ芯片的成形进行刻蚀，要求ＨｇＣｄＴｅ芯片表面温度不能超过８０℃。     

间接耦合光探测器分析

分析了有关间接耦合光探测器的论述中对耦合系数的两种不同定义的物理意义，指出其中存在的问题。分析了间接耦合光探测器的实验数据与产品性能，提出结果上的商榷意见。     

Synthesis,z-scan and degenerate four wave mixing characterization of certain functionalized photosensitive polyesters containing ortho-hydroxyazo chromophores

The preparation and NLO characterization of photosensitive polyesters containing azoaromatic residues in the molecular backbone, functionalized with orthohydroxy chromophores is presented. Samples were studied for its UV–vis absorption, FT-IR and intensity dependent nonlinear absorption properties. Nonlinear characterization was carried out with z-scan using frequency doubled, Q-switched Nd:YAG laser operating at 532 nm. The closed aperture z-scan spectra reveal the self defocusing effects of the samples with negative nonlinearity coefficient (n₂) showing values as high as −1.28 × 10⁻¹⁰ (esu) for certain samples and the corresponding third order susceptibility coefficient of the order of 29.9 × 10⁻¹² (esu). Degenerate four wave mixing technique was employed to substantiate the findings. The numerical fits show that the molecules exhibit reverse saturable absorption. A study of beam fluence dependence of nonlinear absorption coefficient (β_eff) has been presented. All phenomena indicate that molecules are reverse saturable absorbers whose optical limiting property gets enhanced with increasing conjugation length.     

Condition assessment of building façades based on hazard to people

Abstract

To make periodic inspections of the buildings is useful to quantify the extent to which deficiencies are severe or not, in order to facilitate decision making and prioritize interventions. In previous works by the authors is proposed a scale of gravity of damages in buildings, with the aim of being of widespread and of common use among professionals. This scale is applied through the direct assignment (DA) methodology, based on the generic definitions of each degree. It is demonstrated and characterized the existence of certain level of variability among technicians, when assigning gravity values using DA methodology, due to the fuzzy condition of the attribute to be evaluated. The main goal of this paper is to propose a methodology to assign values of gravity, based on hazard for people of detachments from the façade, by using measurable parameters and mathematical functions. The final objective is to reduce the level of variability among inspectors when assessing the condition state of a building façade. The proposed methodology is named system of evaluation of façades (SEF). The methodology can be also extended to the assessment of other building systems as structures or roofs and other type of infrastructures.