Large scale production of carbon nanotube arrays on the sphere surface from liquefied petroleum gas at low cost

Liquefied petroleum gas (LPG), a cheap industrial material, is used as carbon source to produce carbon nanotube (CNT) arrays on ceramic spherical surface on a large scale in the floating catalyst process. The ceramic spheres provide huge surface area and good mobility, leading to the mass production of CNT arrays continuously. The arrays obtained from the surface are of good alignment, and the purity is as high as 97.5%. With the decrease of the growth temperature, CNTs in the array form with small-diameter of about 13 nm can be obtained. Therefore, with the industrial fuel as carbon source and the ceramic sphere as substrate, CNT arrays can easily be produced on large scale at low cost.     

基于OPC和IMC的先进控制及其应用

工业生产装置的常规PID控制,由于它的简单实用,具有一定的鲁棒性,至今仍被广泛采用采用。但它的PID参数几乎都是凭经验设定的,很难达到最佳效果,使控制质量不理想,造成装置自控率、平稳率低,装置产量不高和产品质量差等状况,针对上述问题,本文提出了一种基于OPC的数据采集技术和内模控制原理相结合的方法,从生产装置获取数据辨识对象模型,然后以辨识后的对象模型为基础对装置实施IMC-PID先进控制。实际应用结果表明,该方法操作简洁实用,效果明显,显著提高了装置的平稳率和自控率。该方法为类似苯乙烯装置的复杂化工控制系统的优化和先进控制提供了一种新的解决方案。     

加氢裂化分馏过程的模拟与分析

针对某炼油厂加氢裂化段第二分馏塔分馏所得产品航空煤油与柴油不符合要求的问题,使用流程模拟软件UniSim Design,数值模拟了加氢裂化段第二分馏塔分馏过程,通过调节工艺的主要影响因素柴油抽出量与尾油抽出量,产品达到了航空煤油的干点为300℃、柴油干点为360℃的要求,提高了航空煤油的产量。     

High-resolution climate change in mid-late Holocene on Tianchi Lake,Liupan Mountain in the Loess Plateau in central China and its significance

According to a core from Tianchi Lake, Liupan Mountain in Loess Plateau sediment, fossil pollen assemblages, magnetic suscep-tibility (MS) and color scale were measured based on reliable Abies leaf macrofossils radiocarbon chronology. We recovered a very good high-resolution mid-late Holocene climate change achieve for the transition area of the East Asia monsoon region and northwest arid region. The results show that the basic climate background was in agreement with the records from cave records in monsoon regions in eastern China. Besides, it shows more detailed records in abrupt climate change.     

Evolution of prehistoric agriculture in central Gansu Province,China: A case study in Qin’an and Li County

This study, based on environmental archaeological studies focused on Qin’an County and Li County in Gansu Province, China, shows that during 8–7.3 ka BP few cultivated crop seeds were found. After 6.4 ka BP, during the Banpo period, many crop seeds appeared, indicating the development of agriculture. Millet agriculture in this area appeared and flourished a little later than in the Central Plain of China. Climate change is an important factor that influenced the development of agriculture in this area. The rapid expansion of agriculture during late Yangshao and Changshan benefited from the humid and warm climate in the mid-Holocene, especially the emergence of rice. After 4 ka BP, climate became drier, and agriculture began to decline. So Siwa Culture is char-acterized by pastoral economy, until the Eastern Zhou period, agriculture began to recover, when wheat and barley appeared in Li County, indicating diversification of agriculture of this time.     

A deep-bodied ginglymodian fish from the Middle Triassic of eastern Yunnan Province, China, and the phylogeny of lower neopterygians

The Ginglymodi are a group of ray-finned fishes that make up one of three major subdivisions of the infraclass Neopterygii.Ex- tant ginglymodians are represented by gars,which inhabit freshwater environments of North and Central America and Cuba.Here, we report the discovery of well-preserved fossils of a new ginglymodian,Kyphosichthys grandei gen.et sp.nov.,from the Middle Triassic(Anisian)marine deposits(Guanling Formation)in Luoping,eastern Yunnan Province,China.The discovery documents the first known fossil record of highly deep-bodied ginglymodians,adding new information on the early morphological diversity of this group.The studies of functional morphology of extant deep-bodied fishes indicate that Kyphosichthys is not a fast swim- mer but has a good performance in precise maneuvering,representing a morphological adaptation to structurally complex habitats (e.g.thick macrophyte beds,rocky areas,or coral reefs),which differs from the other members of this group.A cladistic analysis with the new fish taxon included supports the hypothesis that the Ginglymodi are more closely related to the Halecomorphi than to the Teleostei.Represented by Felberia,Kyphosichthys,and Dapedium,a highly deep and short fish body type has inde- pendently evolved at least three times in the stem-group neopterygians,ginglymodians,and basal teleosts within the lower neop- terygians of the Triassic.     

XML技术在软件测试框架中的应用

对国内外软件测试工具的系统框架进行研究，在此基础上提出一种扩展性更好的系统框架设计方案。在本文提出的系统框架中，源程序信息使用XML格式的文件表示，根据具体应用，系统使用不同的信息提取模板文件（XSLT格式）对应用关心的程序信息进行提取。随着应用的增加，系统只需要扩充相应的信息提取模板文件，而不用改变源程序信息文件。     

Occurrence of perfluoroalkyl acids in precipitation from Shenyang, China

Perfluorosulfonates （PFSAs） and perfluorocarboxylates （PFCAs） in precipitation collected from Shenyang, China were determined. Snow samples were collected in the snow event on March 4, 2007 from 34 sites involving both the urban and suburban areas in Shenyang. The snowmelt was preconcentrated by solid phase extraction and analyzed using LC-MS method. Measurable amounts of perfluoroalkyl acids （PFAS） were found in precipitation samples from Shenyang, demonstrating that wet deposition is one possible pathway for the removing of the selected PFAS chemicals from atmosphere. Major PFAS detected were PFOS （〈0.38-51 ng/L）, PFOA （0.82-13 ng/L） and PFHpA （0.76-11 ng/L）, with their mean concentration of 5.4, 3.3 and 2.9 ng/L, respectively. Other PFSAs and PFCAs were detected at much lower frequency or below the limit of detection in all the samples. The work presented here offers some basis for the investigation on the environmental behavior and the evaluation of human exposure to PFAS.