保存液Ph值和钙离子浓度对古尸骨组织脱钙的影响

为了检测保存液pH值和Ca2 浓度对古尸骨组织脱钙的影响,本实验于2002年检测了古尸保存液的pH值和微量元素含量,然后分两步调整了马王堆古尸保存液的pH值和Ca2 浓度,并分别于2004年、2006年进行了相同检测。结果发现适当上调保存液的pH值和Ca2 浓度能明显延缓古尸保存液中Ca2 浓度的增加:而保持适当的pH值、适当降低Ca2 浓度明显加速了古尸保存液中Ca2 浓度的增加。这些表明保存液pH值和Ca2 浓度的适当提高有利于防止古尸骨组织的脱钙。     

北京万泉寺遗址金代白瓷胎釉配方的锶同位素特征研究

北京丰台万泉寺遗址位于金中都遗址内,遗址出土金代白瓷样品在形制上符合金代定窑白瓷特征。白瓷胎体成分和锶同位素比值综合研究确定了三种制胎原料,其中:高铝黏土原料的锶同位素比值在0.73左右;白云岩化石灰岩原料的锶同位素比值在0.72左右且钙含量较高;草木灰原料的锶同位素比值在0.71左右,且锶含量在1 000 μg/g左右。通过釉层的成分分析及胎釉成分的对比研究,发现釉层主要使用高硅原料与白云岩化石灰岩配制而成,并受到了部分熔融胎体的强烈影响,根据与草木灰关联性较强的P₂O₅含量推断,釉层中可能也含有一定量草木灰。万泉寺遗址白瓷的研究丰富了有关金代定窑白瓷胎釉配方的认识,确认了白云岩化石灰岩为胎釉的主要钙质助熔剂,揭示了草木灰类助熔剂在胎和釉中可能存在各自独立的来源。     

孙中山与护国运动

在反对袁世凯的护国运动期间,孙中山主张以北方地区为重点,与袁世凯进行坚决的军事斗争;他主张护国运动应以建立巩固的民主制度为最终目标,而不应仅仅满足于推翻袁世凯;他主张各派反袁势力团结一致,即使发生矛盾也应和平解决,不应诉诸武力。在护国运动期间,孙中山对各地革命党武装的反袁军事行动进行了指导,帮助各地革命党武装筹措经费,动员各界人士参加反袁斗争,为反袁斗争进行了舆论宣传。许多革命党人在孙中山的派遣和指导下参加反袁斗争并作出重大贡献;孙中山对一些护国运动领导人的反袁活动起到了推动作用,对当时的社会舆论也产生了一定影响。     

Experimental Study on Self-Centering Concrete Wall with Distributed Friction Devices

A self-centering concrete wall with distributed friction devices is proposed to achieve seismic resilient building structures. Unbonded post-tensioned tendons, running vertically through wall panels, provide a restoring force that pulls the structure back toward its undeformed plumb position after earthquake. Two steel jackets are installed at wall toes to prevent concrete spalling and crushing. Friction devices are distributed between the wall and its adjacent gravity columns to achieve controllable energy dissipation, and these devices are readily replaceable. Desirable self-centering and energy dissipation capacities were observed in low-cyclic loading tests, and influences of various parameters on the hysteretic behavior were investigated.     

Numerical Simulation and Seismic Fragility Analysis of a Self-Centering Steel MRF with Web Friction Devices

This article presents the seismic fragility analysis of a self-centering steel moment-resisting frame (SC-MRF) with web friction devices. A detailed numerical model of the SC frame was developed using the Open System for Earthquake Engineering Simulation (OpenSees) and the elastoplastic responses of the SC-MRF were studied, including the strength degradation under cyclic loading, tendon rupture, beam buckling, bolt bearing and friction loss, etc. The proposed simulation approach is validated by comparing the simulated results with those in existing hybrid-simulation tests, quasi-static pushover test and low cyclic tests, where good agreement is observed. In addition to the well-established performance limit states (i.e., immediate occupancy, collapse prevention and global dynamic instability), two unique performance limit states (i.e., the recentering and repairable limit states) are defined for the SC-MRF. Finally, incremental dynamic analyses are conducted to evaluate the seismic fragilities regarding the five performance limit states.     

城市公园视觉景观质量的影响因素分析——以北京市紫竹院公园为例

本文将主客观评价法相结合,对北京市紫竹院公园视觉景观质量影响因素进行分析。课题组实地评价并拍摄照片,室内请评判者给照片打分评出美景度分值,请专家对主观性因子评价,与实地评价结果做一致性检验;对两种方式获取的数据进行方差分析、相关分析,并建立线型回归模型。结果表明:主观性因子的实地评价和室内问卷评价结果具有一致性;专业背景不同不影响评判者对景观美景度的评判结果;美景度与区内因子呈正相关,与区外因子呈负相关;区内的3个因子更能影响对景观的评判,其中,自然景观所占比例影响最为显著。     

Chasing Tibetan Antel Across Changtang Grassland

n the beginning of Winter, we drove along a zigzagging road across Ithe grassland of north Tibet. Music played incessantly from the vehicle while the extensive landscape stole our breath away. Above the black mountain range; golden clouds and the remaining starswere still hanging in the blue sky. Sporadic groups of antelopes, each consisting of about three to five antelopes, were rtmning beside the road.     

满铁与日本的中国东北移民

满铁作为日本“国策会社”,在日本向中国东北移民过程中,通过设置调查机关,投资成立移民执行机构,建立具有自身特色的移民组织等活动,大力支持并积极参与日本移民侵略。由于满铁与日本军方特殊的密切关系,也必然决定了其在日本对中国东北移民活动中,扮演着策划者和执行者的重要角色。     

Regional Coverage Maximization: Alternative Geographical Space Abstraction and Modeling

Analysis results are often found to vary with the way we abstract geographical space. When continuous geographic phenomena are abstracted, processed, and stored in a digital environment, some level of discretization is often employed. Information loss in a discretization process brings about uncertainty/error, and as a result research findings may be highly dependent on the particular discretization method used. This article examines one spatial problem concerning how to achieve the maximal regional coverage given a limited number of service facilities. Two widely used geographical space abstraction approaches are examined, the point‐based representation and the area‐based representation, and issues associated with each representation scheme are analyzed. To accommodate the limitations of the existing representation schemes, a mixed representation strategy is proposed along with a new maximal covering model. Experiments are conducted to site warning sirens in Dublin, Ohio. Results demonstrate the effectiveness of the mixed representation scheme in finding high‐quality solutions when the regional coverage level is medium or high.