壳聚糖对天冬酰胺的吸附性能研究

采用壳聚糖对水溶液中天冬酰胺的吸附性能进行初步研究。采用粒内扩散模型、准一级动力学模型和准二级动力学模型对壳聚糖吸附天冬酰胺的动力学数据进行拟合,并采用Langmuir等温方程和Freundlich等温方程对其吸附等温线数据进行结果拟合。试验表明,当天冬酰胺的初始浓度分别为50、100、150 mg/L时,壳聚糖对天冬酰胺的吸附过程均符合准二级动力学方程(R^2=0.985 7～0.993 2)。壳聚糖对天冬酰胺的吸附等温线符合Langmuir等温吸附模型(R^2=0.978 8),其饱和吸附量为87.72 mg/g。壳聚糖对天冬酰胺具有一定的吸附能力。

A Review on Researches of Active Tectonics—History,Progress and Suggestions

This paper reviews the history and progress of research on active tectonics in China and overseas.By giving a brief introduction on the history of active tectonic research in China and other countries,the paper sums up the process and development of quantitative investigation of active tectonics since the 1980s.The focus is on the main efforts and progress made in China on certain aspects of research,such as basic surveys and applied investigation of active tectonics,the study of theories related to regional active tectonics and their kinematics and geodynamics,surveys on coupling relations between deep and shallow structures,active fault surveys and prospecting and seismic hazard assessment in urban areas,as well as the efforts made using Quaternary geochronology.Furthermore,the paper looks back on Chinese quantitative investigation of active tectonics in China and sums up cognitions derived from studies on the determination of several basic and measurable parameters of active tectonics.These parameters include the length of fault and fault segmentation,coseismic slip and cumulative slip,fault slip rate,the sequence of paleoearthquake events and the time elapsed since the most recent event.At the same time,efforts and progress made in China on assessing the long-term seismic potential for active faults and evaluating the risk from potential active fault movement have been reviewed by summarizing research on developing theories,models,methods and the application of time-dependent seismic potential to probabilistic assessment,magnitude estimation for potential earthquakes on active faults,and the forecast of potential risk caused by active fault movement.Finally,in consideration of the realities and problems in the research of active tectonics in China,the authors put forward several suggestions for issues worthy of more attention for further investigation in the future.

Learning and Progressing Through Scientific Practices—Commemorating the 90th Anniversary of the Haiyuan Earthquake and Working to Improve the Ability of Earthquake Prediction and Seismic Hazard Reduction

The great Haiyuan earthquake occurred at 20:06:09 on December 16,1920 in the south of Ningxia Hui Autonomous Region.The magnitude of this earthquake is 8.5,listed as one of the three greatest earthquakes to ever occur in Chinese continent.This devastating earthquake killed about 230,000 people according to previous reports.Recent studies show that total casualties may have reached 270,000.The study of this earthquake using modern scientific and technological methods is the first in the history of earthquake research in China.Significant breakthroughs took place in the middle of last century.The earthquake surface rupture,with 200km in length and prominent left-lateral strike-slip displacement,was discovered.The first monograph on the Haiyuan earthquake was published.In the 1980s,innovative large-scale geological mapping technology for active faults was developed during studies on the Haiyuan earthquake surface ruptures,with the publication of the first large-scale map of the Haiyuan active fault.Quantitative studies were carried out on the fine structure and geometry of the fault zone,Holocene slip rate,co-seismic displacement,paleoearthquake and recurrence intervals and future earthquake risk assessment.The innovative studies also included rupture propagation along the strike-slip fault,evolution of pull-apart basins,determination of total displacement of the strike-slip fault,transition equilibrium between strike-slip displacement along its major strand and crustal shortening at the end of the strike-slip fault,and the mechanism of deformation on Liupan Mountain.On the occasion of the 90th anniversary of the Haiyuan earthquake,careful retrospect of scientific progress achieved during the recent 20 years would be helpful in providing further direction in the study of active faults and earthquake hazard reduction.While taking this occasion to remember those lost by the Haiyuan earthquake,we aim to make greater contributions to earthquake prediction and seismic hazard reduction.

A New Upsurge in Global Seismicity

This paper studies the temporal and spatial distribution of great global earthquakes （Mw i〉 8.0） since 1900. We compare the two periods of upsurges of great earthquakes occurring in the middle of last century and beginning of this century. The former period took place between 1950 and 1965 during which 13 great earthquakes （Mw I〉 8.0） occurred, including three events with moment magnitude greater than 9. 0. The largest magnitude in this period reached 9.6. The latter period starts from the beginning of this century. In less than 12 years, 15 great earthquakes have attacked the world with the largest magnitude being Mw 9. 1. On the basis of comparison between these two upsurges of global earthquake activity, we infer that the ongoing high level of earthquake activity may continue for another five years or so. Numerous great earthquakes （Mw I〉8. 0） and many large earthquakes （Mw6.0 ~ 7. 0） will occur globally in these five years. In addition, this paper also discusses the relationships between earthquake activity along the Sumatra segment of the Indian-Australia plate boundary and that in the Bayankala block in the middle of Qinghai-Tibetan plateau as well as in the blocks of the southern plateau. The results indicate that the Qinghai-Tibetan plateau, in particular its middle and southern parts, is a likely place for future earthquakes of magnitude over 7.0.

Remarks on Urban Active Fault Exploration and Assessment of Fault Activity

to the practice of urban active fault exploration and associated fault activity assessment conducted in recent years, this paper summarizes the problems encountered in geological, geomorphological, geochemical and geophysical surveys, and proposes the following means and suggestions to solve these problems. To determine the most recent faults or fault zones, emphasis should be placed on identifying the youngest active faults and offset geomorphology. To understand the history of faulting and to discover the latest offset event, it is suggested that geophysical prospecting, drilling and trenching be conducted on one pro/de. Because of significant uncertainties in late Quaternary dating, we advise systematic sampling and the use of multiple dating methods. Shallow seismic reflection has been proven to be the most useful method in urban active fault exploration. However, there is a pressing need to increase the quality of data acquisition and processing to obtain high resolution images so as to enhance our ability to identify active faults. The combination of seismic P-wave reflection and S-wave reflection methods is proved to be a powerful means to investigate the tectonic environments of the deep crust.

Discussion of rupture mechanisms on the seismogenic fault of the 2008 M_s8.0 Wenchuan earthquake

The May 12, 2008, Ms8.0 Wenchuan earthquake was the outcome of a recent movement of an active intra-continental thrust fault zone. The seismogenic fault of this earthquake underwent oblique-slip faulting along the central fault and pure thrust faulting along the range-front fault of the Longmenshan fault zone. The former had a steep dip and large vertical displacement, and the latter had a gentle dip and little vertical displacement. The fault zone consisted of compressive double fault ramps rup turing with right-lateral strike-slip components resulting from strain partitioning of a deep oblique slip fault in the brittle zone of the upper crust. The kinematic pattern and rupture mechanisms are complex for the seismogenic fault, as indicated by the geometric pattern of its surface ruptures, the coseismic displacement distribution and focal mechanisms of the main shock and aftershocks. As a tear fault, the NW-trending, left-lateral, strike-slip Xiaoyudong fault zone has accommodated NE-trending displacements with different shortening amounts. However, because of intense compression on the southwestern segment of the seismogenic fault, the left-lateral, strike-slip Xiaoyudong fault also carries a clear compression component. Normal faulting with a strike-slip component controls the formation of a fault-trough along the central fault, which is characterized by thrusting with a strike-slip component and strike-slip with thrusting. The fault-troughs are the product of the interaction of slip and grav ity on the seismogenic fault under specific geological and geomorphic conditions. Gravitational force exaggerated the vertical component of fault displacement, which by no means represents the actual maximum vertical displacement of the seismogenic fault.