Imaging bacteriorhodopsinlike molecules of claretmembranes from Tibet halobacteria xz515 by atomic force microscope

HalobacteriaH.sp.xz 515 was isolated from a salt lake in Tibet. Although proton release-and-uptake across claret membrane is in reverse order compared to bacteriorhodopsin in purple membrane fromHalobacterium Salinarum, and its efficiency of proton pump is much lower, AFM image shows that the molecules are still arranged in a two-dimensional hexagonal lattice of trimers. Primary structure of Cto G-helix of the archaerhodopsin shows that it has only 56% homology with bacteriorhodopsin. But the interactive amino acid residues at the interface between B and D-helixes are conserved. These amino acid residues are believed to play a significant role in the stability of protein oligomers.     

Geochemical identification of coal-sourced oils and interbedded shale-sourced oils as revealed by compound specific carbon isotopic analysis

To date, questions remain as to how to differentiate between coaland interbedded shale-sourced oils in coal measures. Based on the hypothesis that δ¹³C value of sedimentary organic matter is controlled by the depositional environment and productivities of biota grown in such depositional setting, this note examines compound specific carbon isotopic profiles from coal and interbedded shale extracts using the gas chromatography-isotope ratio mass spectrometry technique (GC/IRMS). The results show that compound specific carbon isotope values from coal extracts are enriched in¹³C relative to that of interbedded shale extracts, and provide useful information in characterizing coal- and interbedded shale-sourced oils in coal measures. An example for its successful application from the Turpan Basin, Northwestern China is presented.     

Exponentially adaptive synchronization of an uncertain delayed dynamical network

Over the past decades, complex networks have been prosperous greatly in various fields of sciences and engineering. Much attention has been given to investigate the synchronization of complex networks in recent years. However, few work has done for the networks with uncertain parameters and unknown topology. In this paper, to further reveal the dynamical mechanism in complex networks with time delays, an uncertain general complex dynamical network with delayed nodes is studied. By constructing a drive network and a suitable slave network, several novel criteria for the networks consisting of the identical nodes and different nodes have been obtained based on the adaptive feedback method. Particularly, the hypotheses and the proposed adaptive laws for network synchronization are simple and can be readily applied in practical applications. Finally, numerical simulations are provided to illustrate the effectiveness of the proposed synchronization criteria.     

基于Adaboost方法的车载嵌入式疲劳驾驶预警系统

提出一种基于Adaboost的实时算法, 并应用于车载嵌入式系统。用红外光源和红外摄像头获取驾驶员的视频图像, 对其疲劳状态进行监控。首先通过人脸检测定位驾驶员的人脸, 然后提取人眼区域并对人眼闭合状态进行判断, 基于PERCLOS标准制定了相应的预警机制, 对潜在的疲劳驾驶进行判断并预警。该算法从PC移植到嵌入式平台并根据实验进行了优化, 先后制作了多个车载嵌入式装置进行实车测试, 达到了大于92%的准确率和少于1.5 s的判断响应时间。实验装置稳定可靠, 可实际应用于营运车辆。     

一款工作于2.4 GHz频段的带有源负载的高性能双平衡有源混频器

对带有源负载的CMOS双平衡Gilbert有源混频器的1/f噪声、线性度与转换增益进行深入分析。这款采用PMOSFETs做负载的混频器工作于2.4 GHz频段。为降低混频器的1/f噪声, 利用双阱工艺中的寄生垂直NPN晶体管作为开关, 同时在PMOSFETs处并联最低噪声的分流电路作为负载。运用在PMOSFETs处的高性能运算放大器, 不仅为零中频输出提供了合适的直流偏置电压, 以避免下级电路的饱和, 并能够为混频器提供足够高的转换增益。同时, 在输入跨导(G_m)级电路中采用电容交叉耦合电路能够将转换增益进一步提高。为了增加混频器的线性度, 采用共栅放大器作为输入跨导级电路。这款混频器采用TSMC 0.18m 1-Poly 6-Metal RF CMOS工艺, 在1.5 V电源电压、3 mA的电流消耗下获得了17.78 dB的转换增益、13.24 dB的噪声因子和4.45 dBm输入三阶交调点的高性能。     

Rayleigh light scattering and its applications to biochemical analysis

The recent applications of light scattering technique in biochemical analysis have been reviewed. The mechanic theories of resonance light scattering and Rayleigh light scattering (RLS), the relationships and differences between them, their applications and the interference factors in biochemistry analysis have been covered. By contrasting Rayleigh light scattering with double scattering and anti-scattering, the advantages of RLS have been pointed out. Finally, some prospects for the future application of this technique have been given.     

Analysis of carbon isotope in phytoliths from C3 and C4 plants and modern soils

The analysis of carbon isotope in phytoliths from modern plants and surface soils in China shows that the values of carbon isotope are consistent with those from C3 and C4 plants,and the processes of photosynthesis of the original plants can be clearly identified by carbon isotope in phytoliths.The value of carbon isotope varied from -23.8‰ to -28‰,with the maximum distributed in the latitude zone from 34° N to 40° N in North China and East China areas,and the minimum in the Northeast China and South China regions.The values of carbon of phytoliths tend to increase from low to high and then reduce to low value again as the latitude increases.In the same latitude zone,the carbon isotope in phytoliths from grassland soil under the trees is obviously lower than that from grassland soil without any trees with the difference of 1‰-2‰.     

Evolution of drainage systems and its developing trend in connection with tectonic uplift of Eastern Kunlun Mt.

The Eastern Kunlun Mt. had been subjected to uplift together with the Qinghai-Xizang (Tibet) Plateau before the Early Pleistocene, and yet the Mt, did not protrude out of the Plateau surface. During that period lakes spread all over the studied region, with the drainage systems being all short rivers flowing into the lakes. At the end of the Early Pleistocene, intensive tectonic uplift led to the rising of the Eastern Kunlun Mt. and made the Mt. protrude onto the Plateau surface. As a result, a fault depression valley formed extending nearly from west to east along the fault belt of the Southern Kunlun Mt. Lakes in this region died out, surface runoffs joined into the valley of the Southern Kunlun Mt. resulting in a large river streaming nearly from west to east. Around 150 kaBP, because of the strong differential movement, rivers, such as the Jialu River and the Golmud River, retrogressively eroded seriously, cutting through the Burhan Budai Mt. Then they pirated the large river and divided it into four portions. Owing to the uplift of the Eastern Kunlun Mt., strongly retrogressive erosion of the upper reaches of the Jialu River has made the watershed of the Buqingshan Mt. migrate 6–10 km southward since Holocene. At present, it remains a stronger trend of retrogressive erosion developing upward to the basin of the Yellow River Source and it seems that the Jialu River is scrambling for the streamhead of the Yellow River.     

日语时间表达式识别与日汉翻译研究

基于自定义知识库, 提出一种知识库强化规则集以及与统计模型相结合的日语时间表达式识别方法,旨在不断提高时间表达式的识别精准度。按照Timex2标准对时间表现的细化分类, 结合日语时间词的特点, 渐进地扩展重构日语时间表达式知识库, 实现基于知识库获取的规则集的优化更新。同时, 融合条件随机场CRF统计模型, 提高日语时间表达式识别的泛化能力。通过考察基于短语的翻译模型翻译时间词的精度, 提出统计机器翻译(SMT)结合规则翻译日语时间词的必要性。实验结果显示, 日语时间表达式识别的开放测试F1值达到0.8987, 基于《日汉时间词平行字典》与规则的翻译精度和召回率都略高于基于统计机器翻译模型。     

基于隐主题马尔科夫模型的多特征自动文摘

基于隐主题马尔科夫模型, 消除LDA主题模型的主题独立假设, 使得文摘生成过程中充分利用文章的结构信息, 并结合基于内容的多特征方法提高文摘质量。提出在不破坏文章结构的前提下, 从单文档扩展到多文档的自动文摘策略, 最终搭建完善的自动文摘系统。在DUC2007标准数据集上的实验证明了隐主题马尔科夫模型和文档特征的优越性, 所实现的自动文摘系统ROUGE值有明显提高。