“长江口二号”沉船出水青花瓷中的污染物研究

位于长江入海口的“长江口二号”清代沉船是中国目前发现的保存最为完整的古代木制沉船之一，已于2022年11月完成整体打捞。在进行水下考古调查时，沉船出水的部分青花瓷出现的病害现象引起了考古工作者的关注，特别是裂纹中黑色污染物及表面铁锈状污染物对文物的外观产生了很大影响。本工作选取了三件具有典型被污染特征的青花瓷标本作为代表，使用能量色散X射线荧光分析(EDXRF)、光学显微镜(OM)、X射线衍射分析(XRD)、拉曼光谱分析(Raman)和扫描电子显微镜-能谱分析(SEM-EDS)等方法，对污染物进行了研究，探讨了其形成原因以及环境的影响作用，并对其潜在危害进行了分析。研究表明，污染物主要以方解石、菱铁矿等碳酸盐以及铁的氧化物、氢氧化物和硫化物为主。长期处于河口淤泥中的还原性环境是导致菱铁矿和亚稳的铁硫化物形成的原因，船体中铁质构件腐蚀对局部环境的污染是重要的影响因素，这也反映出被污染的青花瓷所处位置和环境的特殊性。出水的部分青花瓷釉中裂纹的形态表明其形成是由物理撞击造成，而釉中硅灰石晶体的选择性腐蚀会导致腐蚀坑的形成，裂纹和腐蚀坑均为外部污染物进入釉层内部提供了通道，导致瓷器劣化。出水后...     

吴昌硕篆书对联保留原裱绫的修复

在现今的书画修复案例中,保留具有古旧气息的优秀原装裱,将其与残破的画心一起修复的方式正日益增多。本案例为宜兴博物馆馆藏的一件《吴昌硕篆书八言联》需要保留原民国装裱进行修复。画心与原装裱皆有严重折痕、断痕,甚至断裂,天头处有缺损,包首与覆背老化酥脆。通过对材质、病害状况、原装裱特点的分析研究,为达到最佳修复效果,采用分离画心与装裱,分别进行修复再组合的方法,并在组合还原时对原装裱的不佳之处进行改进与微调,使其既恢复原有面貌,保留典雅的时代气韵,又有利于今后的收藏与保护。     

Predicting Ductile Crack Initiation of Steel Bridge Structures Due to Extremely Low-Cycle Fatigue Using Local and Non-Local Models

The strain-based prediction model combining the Miner's rule and Manson-Coffin's relationship provides a local parameter for evaluating the ductile crack initiation of steel structures, and some modified models based on it were proposed to evaluate extremely low-cycle fatigue (ELCF) behaviors of steel structures. Previous research has confirmed these local models to be an accurate index for ductile crack initiation in steel bridge piers, however it is found to quite depend on the mesh size of the numerical model used. In this study, a non local damage parameter is presented and successfully applied to ductile crack initiation life assessment of steel bridge piers subjected to earthquake-type cyclic loading. The non local damage parameter is based on averaging the strains over the effective plane using a weight function in the exponential form, and introduces the non local damage parameter to replace the local state variable. Finite element analysis with three different mesh sizes is employed. Comparisons of the local and non local solutions with those of experiments indicate that the non local prediction model can predict the ductile crack initiation of steel bridge piers with good accuracy regardless of the specimen geometries and loading histories, meanwhile the mesh independent nature of the non local model is also demonstrated.     

文物裂隙趋势预测模型研究

露天不可移动文物常年遭受风化侵蚀和人为破坏,保存环境十分恶劣,掌握文物健康状况并进行趋势预测,是"预防性"文物保护工作的重要内容。文物健康监测数据具有不确定性和贫信息性,传统概率统计方法和模糊数学方法不能满足预测要求。针对文物裂隙数据的特点,以陕西唐顺陵天禄石刻为研究对象,提出了采用灰色系统理论来预测文物裂隙发展趋势,建立了裂隙GM((1,1)模型和Verhulst模型,分别确定了灰色模型的灰色作用量和发展系数,并且对唐顺陵石刻文物的裂隙进行了预测。实验用前12个月的裂隙月均值,对随后的7个月的裂隙进行了定量预测,发现天禄石刻的裂隙有缓慢增大的趋势。与同期真实裂隙监测值相比,GM((1,1)模型和Verhulst模型预测值的平均相对误差满足裂隙预测精度要求。研究结果为文物健康趋势研究提供了定量分析的理论依据。     

论继续解放思想与破解发展难题

党的十八大报告深刻指出:"解放思想、实事求是、与时俱进、求真务实,是科学发展观最鲜明的精神实质","着力把握发展规律、创新发展理念、破解发展难题"。马克思主义中国化是中国特色社会主义理论的形成和发展的基础,中国的事业要取得更大的新发展就要积极推进马克思主义中国化以及继续解放思想。改革开放以来发展史雄辩地证明,只有继续解放思想,才能推进中国特色社会主义不断前进,才能破解发展难题。     

Experimental Study on Damage Behavior of Reinforced Concrete Shear Walls Subjected to Cyclic Loads

Previous experimental research on shear walls has mainly focused on load carrying capacity, deformation, or hysteretic characteristics, with relatively little attention paid to individual damage states and their corresponding responses during the entire loading process until failure. The damage behavior of seven reinforced concrete shear wall specimens subjected to cyclic loading is presented in this study. The effects of the axial load ratio, transverse reinforcement ratio of confining boundary elements, and cross-section shape on damage characteristics, ductility, shear deformation, and crack width of the specimens were analyzed comprehensively.     

海上丝绸之路窑址裂隙充填灌浆材料比选室内试验研究

对裂隙进行充填灌浆,可以有效防止裂隙的进一步发展和雨水的渗漏,使遗址得以更好地保存。为比选出适宜于潮湿环境下窑址裂隙充填灌浆材料,采用烧料礓石、烧阿嘎土、砺灰三种传统石灰材料分别对浙江和福建四处"海上丝绸之路"遗址点的遗址土进行改性研究。测试改性后浆体材料不同龄期的抗压、抗折强度、收缩率,以及温湿度循环、冻融循环、水稳定性、安定性、耐碱性试验后试样的力学性能变化。试验结果表明,三种石灰类材料均具有良好的耐候性,但砺灰试样的耐冻融特性稍差、龄期强度低、收缩变形较大。烧料礓石改性试样具有较高的龄期强度、较低的收缩率、良好的耐候性。因此,建议将烧料礓石作为主剂应用于四处窑址的灌浆材料中。相关研究成果对窑址裂隙灌浆材料的选取具有实际指导意义。     

Seismic Assessment of a Monumental Building through Nonlinear Analyses of a 3D Solid Model

ABSTRACT

The paper analyzes the static behavior and the seismic vulnerability of the “San Francesco ad Alto” building in Ancona (Italy), which is currently used as a Regional Headquarter of the Marche Region by the Italian Army and was formerly a monastery. The global static structural behavior and the dynamic properties have been evaluated using the Finite Element modeling technique, in which the nonlinear behavior of masonry has been taken into account by proper constitutive laws. The concepts of homogenized material and smeared cracking are used to evaluate the capacity of the monastery to withstand lateral loads together with the expected demands resulting from seismic actions (N2 method), using a nonlinear static analysis (pushover). The comparison of seismic demand and capacity confirms the susceptibility of these types of buildings to extensive damage and collapse, as frequently observed in similar buildings. This paper aims to point out that advanced numerical analyses can offer significant information on the understanding of the actual structural behavior of historical buildings. It is believed that the methodology and the overall conclusions of this case study are valid for many historical monasteries in Europe.