Types and biotic successions of Ordovician reefs in China

Ordovician reefs are located in the South China,Tarim,and North China blocks,in low-latitude epicontinental marine regions and mostly consist of large-scale carbonate platforms.During the Paleozoic,faunal radiation reef biota diverged and thrived in diverse paleogeographic settings.Algal reefs of the Early Ordovician,Calathium-lithistid sponge-algal reefs of the late Early Ordovician to early Middle Ordovician,and coral-stromatoporoid-algal reefs of the early Late Ordovician,indicate change from Cambrian to Paleozoic biota.Coral-stromatoporoid-algal reefs were the basic communities after 100 Ma.The macroevolution of biotic struc-tures generally shows increased complexity;the evolution of China’s reef biota parallels that worldwide.Important aspects are:(1) The Calathium-algal reefs from the early Tremadocian Nantzinkuan Formation,Zhangjiajie,western Hunan are the pioneer reefs,and the Darriwillian Yijianfang Formation,Bachu are the relic reefs.(2) The bryozoan-dominated reefs of the late Tremadocian Fenhsiang Formation,Middle Yangtze Platform are unique.(3) The early coral-stromatoporoid-algal reefs are highly restricted in China.(4) The algal reefs from the latest Katian on the western margin of the Yangtze Platform,represent an abnormal reef-building environment during the initial stages of Gondwanan glaciations.     

An efficient scheme for multi-party quantum state sharing via non-maximally entangled states

We present a new scheme for investigating the usefulness of non-maximally entangled states for multi-party quantum state shar-ing in a simple and elegant manner.In our scheme,the sender,Alice shares n various probabilistic channels composed of non-maximally entangled states with n agents in a network.Our protocol involves only Bell-basis measurements,single qubit measurements,and a two-qubit unitary transformation operated by free optional agents.Our scheme is a more convenient realiza-tion because no other multipartite joint measurements are needed.Furthermore,in our scheme various probabilistic channels lessen the requirement for quantum channels,which makes it more practical for physical implementation.     

Comparison of different triolein-based composite semipermeable membranes for passive sampling of organochlorine pesticides

Passive sampling methods have been widely used for more than 20 years because they can provide information on time-weighted average concentrations(CTWA) of hydrophobic organic contaminants in water.Many factors affect the efficiency and applicability of a passive sampling process.Among others,selection of the sampler design and choice of the supporting membrane material are important factors that determine the performance of passive samplers.In this work,the influences of some critical properties of membranes,such as membrane density,hydrophilicity of the membrane surface,and chemical and mechanical resistances,on the uptake of organic chlorinated pesticides(OCPs) were evaluated.Four membrane materials,namely cellulose acetate(CA),cellulose acetate butyrate(CAB),a cellulose acetate-cellulose triacetate blend(CA-CTA),and cellulose triacetate(CTA),and their triolein-embedded samplers were selected for the study.The four membranes are all hydrophilic;CAB has the highest contact angle and CA has the lowest.CTA is chemically and mechanically resistant,and has better tensile strength than the other membranes have.CAB does not have good chemical resistance and dissolves in hexane/dichloromethane solvent.CA and CTA alone showed lower uptake rates for the selected OCPs than with triolein-embedded passive samplers,indicating that triolein increased the accumulation capacity.Triolein-embedded CA(TECAM),CA-CTA(TECA-CTA),CTA(TECTA),and CAB(TECAB) as passive samplers showed similar uptake patterns;TECTA showed the highest uptake rates and TECAB showed the poorest accumulation.In summary,TECTA gave the best performance among all the tested composite semipermeable membranes.     

<Emphasis Type="Italic">In situ</Emphasis> measurement of PM<Subscript>1</Subscript> organic aerosol in Beijing winter using a high-resolution aerosol mass spectrometer

Organic aerosol (OA) is a crucial component of atmospheric fine particles. To achieve a better understanding of the chemical characteristics and sources of OA in Beijing, the size-resolved chemical composition of submicron aerosols were measured in-situ using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer in the winter of 2010, with a high time resolution of 5 min. During this study, the mean OA mass concentration was 20.9±25.3 μg/m3, varying between 1.9 and 284.6 μg/m3. Elemental analysis showed that the average H/C, O/C and N/C (molar ratio) were 1.70, 0.17, and 0.005, respectively, corresponding to an OM/OC ratio (mass ratio of organic matter to organic carbon) of 1.37. The average mass-based size distributions of OA present a promi- nent accumulation mode peaking at approximately 450 nm. The prominent presence of ultrafine particles (Dva < 100 nm) was mainly from the fresh emissions of combustion sources. A Positive Matrix Factorisation (PMF) analysis of the organic mass spectral dataset differentiated the OA into three components, including hydrocarbon-like (HOA), cooking-related (COA), and oxygenated (OOA) organic aerosols, which, on average, accounted for 26.9%, 49.7% and 23.4%, respectively, of the total organic mass. The HOA and COA likely corresponded to primary organic aerosol (POA) associated with combustion-related and cooking emissions, respectively, and the OOA components corresponded to aged secondary organic aerosol (SOA).     

Determination of trace heavy metals in milk using an ionic liquid and bismuth oxide nanoparticles modified carbon paste electrode

A novel carbon composite electrode modified with bismuth oxide nanoparticles and the ionic liquid n-octylpyridinium hexafluorophosphate was fabricated and used to simultaneously determine cadmium and lead levels using square wave anodic stripping voltammetry.This electrode combines the unique advantages of nanomaterials and ionic liquid with the low cost and easy fabrication of the carbon composite electrode.Compared with the traditional binder based composite electrode,our electrode exhibited well-defined and separate stripping voltammetric peaks for cadmium and lead.Furthermore,the antifouling capacity of the bismuth film electrode was significantly improved by the ionic liquid.Under optimized conditions,the linear range of the composite electrode was from 3.0 to 30.0 μg L-1 for both metal ions with a detection limit of 0.15 μg L-1 for cadmium and 0.21 μg L-1 for lead.Trial milk sample analyses showed that the modified electrode was sensitive,reliable and effective for the determination of trace heavy metals,holding great promise for routine analysis applications.     

Modern human behaviors during the late stage of the MIS3 and the broad spectrum revolution: Evidence from a Shuidonggou Late Paleolithic site

The last glacial period was vital for the distribution and evolution of early modern humans in Asia. The Shuidonggou Late Paleolithic site, dated at 30-20 ka BP, accumulated cultural remains during the important late stage of MIS 3 period in the last glacial. These remains represent characteristics of typical Late Paleolithic conditions in North China:high degree of standardization and morphological variability of tool types, exploitation of bone materials, systematic use of body decorations, extensive use of earth-pit hearths, distinct functional spatial organization within habitations, and conversion of subsistence patterns. These characteristics illustrate early modern human behaviors during the late MIS3 period, and provide clues and perspectives for the analysis of early modern human origins in China. At the same time, the conversion of subsistence patterns is considered to be a combination of multiple early modern human behaviors, as well as the result of the Broad Spectrum Revolution. In this paper, we argue for the dynamic mechanism of Broad Spectrum Revolution from a human behavioral and ecological perspective.     

Aerodynamic optimization and evaluation for the three-dimensional afterbody/nozzle integrated configuration of hypersonic vehicles

The optimization of 2D expansion lines and key parameters of three-dimensional configurations was carried out under simulated conditions of Mach 6.5 and a flight altitude of 25 km for an integrated configuration of the afterbody/nozzle of a hypersonic vehicle.First,the cubic B-spline method was applied to parameterize the expansion lines of the upper expansion ramp.The optimization procedure was established based on computational fluid dynamics and the sequential quadratic programming method.The local mesh reconstruction technique was applied to improve computational efficiency.A three-dimensional integrated configuration afterbody/nozzle was designed based on the two-dimensional optimized expansion lines.The influence rules incorporated certain key design parameters affecting the lift and thrust performance of the configuration,such as the ratio of the lengths of the lower expansion ramp to the afterbody (l/L),the dip angle of the lower expansion ramp ω,and the ratio of exit height to the length of afterbody (H/L).Under these conditions,we found that the integrated configuration has optimal performance when l/L=1/6,H/L=0.35 and =10°.We also showed that the presence of a side-board promotes lift and thrust performance,and effectively prevents the leakage of high pressure gas.     

Improved zero-sum distinguisher for full round <Emphasis Type="Italic">Keccak-f</Emphasis> permutation

Keccak is one of the five hash functions selected for the final round of the SHA-3 competition,and its inner primitive is a permutation called Keccak-f.In this paper,we observe that for the inverse of the only nonlinear transformation in Keccak-f,the algebraic degree of any output coordinate and the one of the product of any two output coordinates are both 3,which is 2 less than its size of 5.Combining this observation with a proposition on the upper bound of the degree of iterated permutations,we improve the zero-sum distinguisher for the Keccak-f permutation with full 24 rounds by lowering the size of the zero-sum partition from 21590 to 21575.     

Investigation of the interfacial water structure on poly[2-（dimethylamino）ethyl methacrylate] at the air/water interface by sum frequency generation vibrational spectroscopy

The effect of pH on the conformation of surface alkyl groups and the structure of interfacial water molecules on poly[2-(dime-thylamino)ethyl methacrylate](PDEM) at the air/water interface were investigated with sum frequency generation vibrational spectroscopy(SFG-VS).At pH 4.1,the hydrogen bonding SFG spectra were similar to that of the air/pure water interface.As the pH increased from 5.4 to 9.6,the SFG intensities of both highly ordered hydrogen bonding(3200 cm-1 band) and less-ordered hydrogen bonding(3400 cm-1 band) were enhanced because of the charge-induced effect of deprotonated PDEM.The free OH peak disappeared completely because it was replaced by interfacial PDEM molecules.At pH 11.5,a new spectral band appeared at about 3580 cm-1 in the ppp and sps spectra,and this could be assigned to the C2v asymmetric stretching mode of the water molecules through molecular symmetry simulation.These hydrogen bonding structures are fully consistent with the conformational change of PDEM alkyl groups,and PDEM molecules act as a Hofmeister solvent.PDEM molecules are kosmotropic when they are charged and become more chaotropic as the pH increases.