清至民国山东东部玉米、番薯的分布——兼论新进作物与原作物的竞争

本文提出了玉米、番薯集中产区和一般产区的数量标准,探讨了清代至民国时期山东东部地区玉米、番薯的分布特征,阐明了玉米、番薯以竞争的方式取得优势地位的过程,以及南方和北方的玉米、番薯不同的发展模式。研究表明,与南方的玉米、番薯发展模式不同,在北方,两种美洲作物以竞争的方式排挤了原有作物,并导致作物结构由多样性渐趋向于简单化。     

Seismic Performance and Modeling of a Half-Scale Base-Isolated Wood Frame Building

The concept of base isolation is a century old, but application to civil engineering structures has only occurred over the last several decades. Application to light-frame wood buildings in North America has been virtually non existent with one notable exception. This article quantitatively examines issues associated with application of base isolation in light-frame wood building systems including: (1) constructability issues related to ensuring sufficient in-plane floor diaphragm stiffness to transfer shear from the superstructure to the isolation system; (2) evaluation of experimental seismic performance of a half-scale base-isolated light-frame wood building; and (3) development of a displacement–based seismic design method and numerical model and their comparison with experimental results. The results of the study demonstrate that friction pendulum system (FPS) bearings offer a technically viable passive seismic protection system for light-frame wood buildings in high seismic zones. Specifically, the amount and method of stiffening the floor diaphragm is not unreasonable, given that the inter-story drift and accelerations at the upper level of the tested building were very low, thus resulting in the expectation of virtually no structural, non structural, or contents damage in low-rise wood frame buildings. The nonlinear dynamic model was able to replicate both the isolation layer and superstructure movement with good accuracy. The displacement-based design method was proven to be a viable tool to estimate the inter-story drift of the superstructure. These tools further underscore the potential of applying base isolation systems for application to North America's largest building type.     

Application of an Extended Bouc-Wen Model in Seismic Response Prediction of Unbonded Fiber-Reinforced Isolators

The focus of this article is on seismic-response prediction of Stable Unbonded-Fiber Reinforced Elastomeric Isolators (SU-FREIs). The lateral load-displacement of a SU-FREI can be characterized with a gradual softening that is followed by stiffening. An extended Bouc-Wen Model is developed to simulate the response behavior of SU-FREIs under seismic events. To examine the accuracy of model, the response of a base isolated structure to different input earthquakes were simulated and compared with the results of a previous shake table study. Results of this study indicate that the proposed Bouc-Wen Model is robust and reasonably accurate in seismic analysis of SU-FREIs.     

Effects of Base and Lift Joints on the Dynamic Response of Concrete Gravity Dams to Pulse-Like Excitations

Near-fault earthquakes with forward-directivity effects produce pulse-like excitations. This article studies the dynamic response of monolithic and cracked sections of gravity dam under symmetric and anti-symmetric pulse-like excitations. The pulses are generated by the modified Gabor Wavelet transform. Two main characteristics of the pulses are pulse period and amplitude. The prescribed cracks are located along the base and two distinct lift joints through the dam body. The dam is modeled along with its reservoir using finite element method. The effects of base and lift joints, pulses shape, period, and amplitude, and reservoir height on the dam dynamic response are studied.     

New insights about the construction and use of shell mounds from the geochemical analysis of mollusks: an example from the greater San Francisco Bay

A new method developed by Schweikhardt et al. (2011) for the geochemical analysis of bay mussels is applicable (when combined with radiocarbon assessments) for examining the seasonal construction patterns and growth cycles of coastal mound sites over time. Ideally suited for the analysis of mollusk fragments in museum collections, this method allows archaeologists to evaluate divergent models about the functions of mound sites, as well as the mobility practices and social organizations of the mound builders. In this case study, the method is employed to examine two adjacent mounds (Ellis Landing, Brooks Island) in the San Francisco Bay Area, California to assess whether their occupants may have participated in a broader multi-site community dating to the Late Period (1100–250 BP).     

太行抗日根据地女性婚姻家庭待遇及其冲突

抗战全面爆发之后,随着太行抗日根据地建立、巩固与发展,边区政府颁布了一系列新婚姻法规及其支持性政策,从而使得农村女性婚姻家庭与两性关系呈现出与以往不同的样貌。男女平等思想的倡导提高了妇女在婚姻家庭中的地位、婚姻自由政策的推行解除了妇女在婚姻问题上的痛苦,而频仍发生的家庭纠纷与日益增多的解约离婚案件亦造成了根据地各级政府在婚姻家庭管理上的混乱。尽管新婚姻法令的目标在于根除社会陋习并建立符合新民主主义革命诉求的新型男女关系和婚姻家庭关系,但中共对根据地的婚姻管理不得不立足于法制与现实的平衡之中。     

实践中的转变：抗日根据地减租减息运动中的减息政策研究

在抗日根据地的减租减息运动中,减息政策的变化受多种因素的影响,但借贷利率的限制无疑是其中最重要的因素。由于规定的利率过低,造成农村金融借贷停滞,给农民的生产和生活造成很大困难,放开对借贷利率的限制成为唯一的选择。减息政策经历了从严格的利率限制到完全放开的转变,这是在实践中根据实际情况作出的政策改变,但从实际效果来看,放开对借贷利率的限制并没有起到预期的恢复农村借贷的效果,借贷困难的局面一直持续下去。     

国计与民生:抗战时期川康区食糖专卖中的蔗糖定价之争

抗战时期食糖专卖政策的实施打破了川康区原有的蔗糖价格生成机制。由于蔗糖价格不仅与战时经济统制、国家税收休戚相关,也同蔗农、制糖商切身利益紧密相连,蔗糖定价机制的转变最终导致蔗农、制糖商与食糖专卖局之间发生利益纠葛,甚至演变为"官民"纷争。经过多次博弈与角力,在地方政府居中协调下方使各方之矛盾暂时得以缓和。此一纷争,在很大程度上体现了抗战特殊时期协调国计与民生内在关系的紧张与矛盾。     

民国时期江南地区疫灾地理研究

疫灾自古以来就是人类健康和生命安全的巨大威胁。本文通过编制疫灾序列,采用历史文献分析、数理统计分析和GIS空间分析等方法,对民国时期江南地区的疫灾时空变迁进行研究,结果发现: 一、 民国时期江南地区无年不疫,疫灾季发率高达94.70%,秋、夏、春三季疫灾多发,集中了全年近九成的疫灾县数,秋、夏季尤甚,集中了全年四分之三的疫灾县数;逐年的疫灾广度总体呈上升趋势,但波动特征明显;在明初至民国末年的582年间,江南地区疫灾的波动周期越来越短,年均发生疫灾的县数越来越多,说明随着时间的推移,疫灾越来越频繁,民国时期是江南地区历史上疫灾最频繁最严重的时期。二、 民国时期江南地区的疫灾主要分布于大运河、宁沪杭铁路沿线及其以东的地区,苏州—无锡一带和环上海地区为疫灾热点区,江苏溧阳地区和浙西山丘地区为疫灾冷点区;疫灾分布重心始终位于苏州境内。三、 民国时期江南地区疫灾分布的一般规律是: 交通沿线城市都是疫灾高发点,人口稠密区多为疫灾频发区,水旱灾害严重区也是疫灾严重区,平原地区的疫灾多于山丘地区的疫灾。     

三峡地区砖(石)室墓建筑研究

在三峡地区墓葬建筑中,砖(石)室墓是最重要的建筑形制,它开始流行于两汉时期,所蕴含的文化信息相当丰富,是古代厚葬风俗的一种重要表现形式,对研究中国古代风俗史和建筑史提供了大量有价值的材料。