Deactivations during the numerical processing

Deactivation has been encountered frequently in functional brain imaging researches. However, the deactivations during the numerical processing have not been reported yet. In this study, the functional magnetic resonance imaging (fMRI) was employed to investigate the pattern of the deactivation in the brain of 15 healthy subjects during the numerical addition task. Analyses revealed significant deactivations in several brain regions, including the posterior cingulate, precuneus, anterior cingulate and prefrontal cortex. Especially, we found notable deactivation in bilateral insula. Accounting for the cognitive functions of these regions participating in a combinated way, we discuss their contributions in sustaining the brain activity during conscious resting state, and indicate that the insula is an important area of gathering auditory information from the external world.     

Highly Zn, Mn-rich calcite in calcareous tufa from the Qixiashan Pb-Zn Mine, Nanjing: a possible candidate for Zn-Mn removal from mining impacted waters

The exploitation of metallic mines may cause serious environmental problems. The removal of the heavy metals from the contaminated mining environments has become an urgent issue. In this paper, the occurrence and distribution of heavy metals in the calcareous tufa collected from the mining laneway of the Qixiashan Pb-Zn Mine in Nanjing were investigated by using multiple mineralogical techniques. Examination by X-ray diffraction spectrum (XRD) shows that calcite is the major component of the calcareous tufa. Several heavy metals such as Mn, Zn, Mg, Fe and Pb are detected in calcite by means of electron microprobe analysis. Although the heavy metal contents in the hostrock and the formation water are significantly low, the contents of Mn, Zn, Mg, Fe and Pb in the tufa calcite are as high as 23.65 wt%, 9.6 wt%, 0.76 wt%, 4.44 wt% and 0.66 wt%, respectively. The back-scattered electron image shows complex compositional zoning texture in the tufa, which is linked directly to variations in heavy metals, particularly in Mn and Zn. In addition, we also observed floccule and helical precipitations, which may be derived from the metabolism of the microbe. It is deduced that the occurrence and high concentration of heavy metals in tufa may be controlled by the activities of microbes. The results presented in this work suggest that calcite will be an important candidate for the remediation of the heavy metal contamination in mining areas. Supported by National Basic Research Program of China (Grant No. 2007CB815603), National Natural Science Foundation of China (Grant No. 40573001) and the Ph.D. Programs Foundation of Ministry of Education of China (Grant No. 20050284044)     

Decay of geometry for unimodal maps: The C2 case

We prove that a C2 unimodal interval map with critical order not greater than 2 has the decay of geometry property, by showing that all the cross-ratio estimates needed in the previous proof for the C3 case remain true.     

Study on the specific interaction between angiogenin and aptamer by atomic force microscopy （AFM）

The specific interaction between angiogenin and aptamer has been investigated by using AFM. The specificity of the interaction is revealed by comparing the binding probability of aptamer to other elements in a series of control experiments. The results have shown that there is specific interaction force between angiogenin and aptamer. Moreover, the single molecular pull-off force between angiogenin and aptamer has also been determined using the Poisson statistical method to be 133.7±11.7 pN. These findings obtained are helpful to the better revelation of recognition mechanism between angiogenin and aptamer, which provided basis for further understanding the inhibition of the aptamer to angiogenic activity.     

EEG-based asynchronous BCI control of a car in 3D virtual reality environments

Brain computer interface (BCI) aims at creating new communication channels without depending on brain’s normal output channels of peripheral nerves and muscles. However, natural and sophisticated interactions manner between brain and computer still remain challenging. In this paper, we investigate how the duration of event-related desynchronization/synchronization (ERD/ERS) caused by motor imagery (MI) can be modulated and used as an additional control parameter beyond simple binary decisions. Furthermore, using the non-time-locked properties of sustained (de)synchronization, we have developed an asynchronous BCI system for driving a car in 3D virtual reality environment (VRE) based on cumulative incremental control strategy. The extensive real time experiments confirmed that our new approach is able to drive smoothly a virtual car within challenging VRE only by the MI tasks without involving any muscular activities. Supported by the National High-Tech Research Program of China (Grant No. 2006AA01Z125) and the National Basic Research Program of China (Grant No. 2005CB724301)     

Chinese semantic processing cerebral areas

This study has identified the active cerebral areas of normal Chinese that are associated with Chinese semantic processing using functional brain imaging. According to the traditional cognitive theory, semantic processing is not particularly associated with or affected by input modality. The functional brain imaging experiments were conducted to identify the common active areas of two modalities when subjects perform Chinese semantic tasks through reading and listening respectively. The result has shown that the common active areas include left inferior frontal gyrus (BA 44/45), left posterior inferior temporal gyrus (BA37); the joint area of inferior parietal Iobules (BA40) and superior temporal gyrus, the ventral occipital areas and cerebella of both hemispheres. It gives important clue to further discerning the roles of different cerebral areas in Chinese semantic processing.     

图形创造性思维脑部机制的功能磁共振研究

采用现代认知神经科学手段研究创造性思维背后的神经机制已成为新的热点.大量疾病状态的研究提示正常人在从事创造性活动时可能存在一个左侧半球对右侧的抑制机制,对其去抑制可以导致图形创造力突然增加,然而这一假说尚无直接证据.对26名健康志愿者(15名女性,11名男性,平均年龄22岁)进行了磁共振扫描,在他们做图形想象任务时观察其脑部活动,研究发现:相对于非创造性图形想象,创造性任务激活了左侧前额叶(ROI分析,p=0.037),但与此同时右侧前额叶(ROI分析,p=0.007)及后部皮层区域(FWE校正,p<0.05)大量去激活.结果提示在图形创造性活动中,左侧前额叶可能抑制了右侧半球的活动,这一抑制的解除可以使右侧功能得以自由发挥而提高图形创造力.     

Stable dislocation configuration in the surface layer of metals

The stable dislocation configuration in the surface layer of metals was calculated according to dislo-cation energy theory. It was shown that the stable dislocation configuration was only influenced by Burger's vector, while dislocation line could fluctuate closely around the direction vertical to free sur-face in a limited range.     

Ultrahigh resolution optical coherence tomography with femtosecond Ti:sapphire laser and photonic crystal fiber

Optical coherence tomography （OCT） with ultrahigh axial resolution was achieved by the super-continuum generated by coupling femtosecond pulses from a commercial Ti：sapphire laser into an air-silica microstructure fiber. The visible spectrum of the super-continuum from 450 to 700 nm centered at 540 nm can be generated. A free-space axial OCT resolution of 0.64 pm was achieved. The sensitivity of OCT system was 108 dB with incident light power 3 mW at sample, only 7dB below the theoretical limit. Subcellular OCT imaging was also demonstrated, showing great potential for biomedical application.     

Microstructure and structural color in wing scales of butterfly Thaumantis diores

The butterfly Thaumantis diores is a species in the Northeast of China. There are two kinds of scales on its wings, which overlap like roof tiles and completely cover the membrane. The SEM results showed that only Type-I scales play a key role in forming the blue structural color. Type-II scales have black chemical color. The cross section micro-configuration of scales is achieved by using the transmission electron microscopy (TEM). The brilliant blue generated through the multilayer microstructure is explained by the photonic crystal reason. The multilayer microstructure of the ridges is optimized to 1D Bragg stack for simulation. The reflectivity of the wing is measured by a spectrometer, and the experimental graph accord with the simulation curves basically. When this species fly, the wing’s color and brightness can change because of the transform between structural color and chemical color. The bionic color-changing design and the significance of this effect in video stealth or other fields are discussed at the end of the paper. Supported by Fok Ying Tong Education Foundation (Grant No. 101020), the Natural Science Foundation of China (Grant No. 30570235, 50635030), National Basic Research of China (Grant No. 2007CB616913) and Key Project of the Ministry of Education (Grant No. 105059)     

Arbitrarily long distance quantum communication using inspection and power insertion

The biggest obstacle for long distance quantum communication is the channel loss and the channel noise on photons. In this paper, a method to solve this problem was analyzed using inspection and power insertion (IPI). It is proved that quantum communication may be established over arbitrarily long distance using this technology. The amount of resources required is a polynomial function of the distance. IPI is proposed as a general technique to prolong quantum secure direct communication where secret messages are transmitted directly over a quantum channel. Supported by the National Basic Research Program of China (Grant No. 2006CB921106), National Natural Science Foundation of China (Grant No. 10325521) and Key Project of Ministry of Education of China (Grant No. 306020)     

The fluorescence quenching and resonance Rayleigh scattering enhancement of ET-CPM system

In pH 4.4 BR buffer medium, erythrosine (ET) and Chlorphenamine Maleate (CPM) could form ion-association complex, which led to the quenching of fluorescence and synchronous fluorescence, and the significant enhancement of resonance Rayleigh scattering(RRS) of erythrosine. Furthermore, a new RRS spectrum would appear, and the maximum RRS wavelength was located at about 578 nm. The quenched fluorescence and enhanced RRS intensity was directly proportional to the concentration of CPM in the ranges of 0.24―8.0 ...     

脑疲劳状态下脑功能网络研究与分析

旨在研究连续长时间脑力活动引发的脑疲劳对大脑连接性的影响,探索大脑疲劳评价的客观指标.通过持续认知任务实验诱发脑疲劳,选用互相关方法对采集到的脑电信号进行了不同导联间时域关联特性分析,构建并比较分析了正常态和脑疲劳态的脑功能网络.最后基于复杂网络理论对脑功能网络的特征参数进行了统计分析.结果表明,持续认知任务后,主观感觉疲劳程度显著增加,脑功能网络的平均度、平均聚类系数和网络密度与正常态相比均显著降低,而平均路径长度显著增大.脑功能网络参数可以很好地反映脑疲劳后大脑的连接性变化情况.     

Effect of the contact distance on transport properties of an orsanic molecular device

Using a spatially symmetric phenyldithiolate molecule sandwiched between two gold electrodes as model system and through shifting one electrode from symmetric contact site to form asymmetric contact, we investigated the properties of electronic transport in such a device by the first-principles. It was found that the/（G ）-V characteristics of a device show significant asymmetry and the magnitudes of current and conductance depend remarkably on the variation of molecule-metal distance at one of the two contacts. Namely, an asymmetric contact would lead to the weak rectifying effects on the current-voltage characteristics of a molecular device. The analysis shows that the HOMO is responsible for the resonant tunneling and its shift due to the charging of the device while the bias voltage is the intrinsic origin of asymmetric/（G）- Vcharacteristics.     

Design and demonstration of a 0.22 THz gyrotron oscillator

Gyrotrons are the most powerful terahertz sources and have potential applications in many areas. A terahertz gyrotron oscillator with a pulsed solenoid producing up to an 8 T magnetic field has been designed, constructed and tested. In a 7.96 T magnetic field, 3 kW output power radiations at 0.22 THz frequency have been generated. Supported by the State Key Development Program of Basic Research of China (Grant No. 2007CB310400) and National Natural Science Foundation of China (Grant No. 1067611)     

Pollen assemblage characteristics of lakes in the monsoon fringe area of China

This paper presents the pollen assemblages from 108 surface sediment samples from 4 lakes （the Lake Daihai, Lake Hongjiannao, Lake Hulunnao and Lake Duikounao） in the monsoon fringe area of China. The herb pollen taxa Artemisia, Chenopodiaceae, Poaceae and Compositae are the major components of pollen assemblages of the 4 lakes and Pinus, Betula, Quercus, Ulmus, Populus, Ostryopsis and Elaeagnaceae are frequently presented, which reflect regional and local vegetation well. The mean similarity coefficients for samples from the Lake Daihai, Lake Hongjiannao, Lake Hulunnao and Lake Duikounao are 0.66±0.17, 0.71±0.11,0.73±0.12 and 0.67±0.12 respectively, so pollen assemblages are relatively consistent in each lake, which shows that focusing and mixing effects have occurred before and after pollen deposition. However, pollen assemblages do differ between sampling sites in each lake. The largest difference is seen in the Lake Daihai, followed by the Lake Duikounao, Lake Hulunnao and Lake Hongjiannao （The mean Euclidean distance is 20.09 ± 11.11, 11.22 ± 3.64, 10.67 ± 4.03 and 8.44 ± 4.51 respectively）. These differences are possibly caused by the differences of focusing and mixing effects, pollen source areas, drainage areas and regional vegetation compositions. The Lake Daihai and Lake Hongjiannao have water deeper than 5 m and strong re-suspension, focusing and mixing effects occur in the lakeshore and shallow water areas, where pollen concentrations are lower than in deeper lake areas. In the Lake Hulunnao and Lake Duikounao, with depths less than 5 m, re-suspension and mixing effects are obvious across the whole lake area, so pollen assemblages and pollen concentrations are more consistent among sampling sites in each lake. Comparison between the lake samples and samples from the inflowing river reveals that wind is primary pollen transportation force in the Lake Hongjiannao, where the consistency of pollen assemblage is conspicuous, while there is greater variation in lakes where pollen input is do     

Structural dependences of the <Emphasis Type="Italic">η</Emphasis><Superscript>6</Superscript> complexes of 3-amino-9-ethylcarbazole with chromium tricarbonyl fragment on third-order optical nonlinearities

Degenerate four-wave mixing measurements, using the 35 ps pulses at 532 nm, have been employed to investigate the third-order nonlinear optical parameters of two chromium tricarbonyl complexes η6-bonded to 3-amino-9-ethylcarbazole at either the NH2-substituted aryl ring （1） or the unsubstituted ring （2） and their precursor 3-amino-9-ethylcarbazole （AECz）. The second-order hyperpolarizability y of the compounds 1 and 2 were found to be 42.9×10^-31 and 35.9×10^-31 esu, respectively, approximately one order of magnitude greater than AECz. The relation between the molecular structure and second-order hyperpolarizability of the compounds I and 2 was explored in detail based on the three-level model and the density functional theory （DFT） calculation. The theoretical results indicate that the spatial distribution of electron density has the profound role in the third-order nonlinear optical properties.     

Preparation of nano-compounded polyolefin materials through in situ polymerization technique: status quo and future prospects

Nano-compounding of polyolefins, an economical yet very effective route to high-performance polyolefin materials, has received considerable attention in recent years. Unlike most of the other polymers, polyolefins are chemically inert, which dictates that nano-compounding of polyolefins has to be conducted via in situ polymerization. In this review, a technological progress of the nano-compounding of polyolefins via in situ polymerization technique was summarized thoroughly, with emphasis laid on the current research status of polyolefin/montmorillonite (MMT) nanocomposites. A clear perspective for future researches on this specific family of materials was envisaged. Supported by National Natural Science Foundation of China (Grant No. 50373048) and State Key Development Program of Basic Research Program of Ministry of Science and Technology of China (Grant No. G2003CB615600)     

Preparation of monolayer-assembled fluorescent film and its sensing performances to hidden nitroaromatic explosives

Pyrene was chemically assembled on a glass plate surface in a monolayer manner via spacers containing triethylenetetramine （TETA） subunits. It has been demonstrated that the fluorescence emission of the film is sensitive to the presence of trace amount of nitroaromatic compound （NAC） vapors. As discovered in the present work, the response selectivity of the pyrene-functionalized film depends on the length of the spacer, the vapor pressure of a given NAC, and the quencher size. The film shows faster response to those quenchers which have higher vapor pressure and smaller size. Compared to the film with shorter spacers, the present film with longer flexible spacers shows a slower response to the NACs, but higher selectivity to the quencher size. Additionally, the detection limits to common ex- plosives in vapor phase, 2,4,6-trinitrotoluene （TNT） and 2,4-dinitrotoluene （DNT）, are 7.14×10^-12 and 5.49×10^-11 g·mL^-1, respectively. Further examinations indicated that the sensing process is fully reversible, and the vapors of those common interference such as benzene, toluene, ethanol, and perfume have little effect upon the sensing performances of the film.