Synthesis and self-assembly of amphiphilic ABA type triblock copolymer with well-defined glycopolymer segments

A novel amphiphilic ABA type triblock copolymer with well-defined glycopolymer segments was successfully synthesized via the atom transfer radical polymerization （ATRP） technique, using a bromo-terminated difunctional polysulfone as macroinitiator. The difunctional polysulfone macroinitiator was prepared by esterifying the phenolic end groups of polysulfone to aaloesters. This macroinitiator was then used to initiate the polymerization of a glucose-carrying monomer, 3-O-methacryloyl-1,2：5,6-di-O-isopropylidene-D-glucofuranose （MAIpG）, resulting an ABA type triblock copolymer. After acidolysis treatment, the isopropylidenyl groups of the protected sugar residues were removed, thus the amphiphilic ABA type triblock copolymer with well-defined glycopolymer segments was obtained. The polymers obtained were identified by FT-IR, ^1H-NMR, GPC, and TGA. The self-assembly behavior of the amphiphilic glycopolymer in selective solvent （e.g. DMF/H2O） system was also preliminarily explored. The resultant amphiphilic glycopolymer shows potential applications in the fields of controlled release and delivery of drugs, micro-reactors, nano-materials, medical devices, and SO on.     

On-line catalytic upgrading of biomass fast pyrolysis products

Pyrolysis-gas chromatography/mass spectrometry （Py-GC/MS） was employed to achieve fast pyrolysis of biomass and on-line analysis of the pyrolysis vapors. Four biomass materials （poplar wood, fir wood, cotton straw and rice husk） were pyrolyzed to reveal the difference among their products. Moreover, catalytic cracking of the pyrolysis vapors from cotton straw was performed by using five catalysts, including two microporous zeolites （HZSM-5 and HY） and three mesoporous catalysts （ZrO2＆TiO2, SBA-15 and AI/SBA-15）. The results showed that the distribution of the pyrolytic products from the four materials differed a little from each other, while catalytic cracking could significantly alter the pyrolytic products. Those important primary pyrolytic products such as levoglucosan, hydroxyacetaldehyde and 1-hydroxy-2-propanone were decreased greatly after catalysis. The two microporous zeolites were ef- fective to generate high yields of hydrocarbons, while the three mesoporous materials favored the formation of furan, furfural and other furan compounds, as well as acetic acid.     

十八胺/羟丙基-β-环糊精包合物的制备与分析

以羟丙基-β-环糊精（HP-β-CD）为主体,十八胺（ODA）为客体,采用研磨法制备了具有超分子结构的ODA/HP-β-CD包合物。考察了研磨时间、主客体物质的量比及包合温度对包合率的影响,确定了包合物的最佳制备工艺：研磨时间15min,主客体物质的量比2:1,热处理温度75℃。1H NMR和XRD衍射结果表明,ODA成功包合入HP-β-CD空腔中。通过相溶解度法研究了HP-β-CD在水中对ODA的增溶作用,结果表明HP-β-CD在水中对ODA增溶效果显著;经计算确定其包合常数为7877.69L/mol,形成的包合物结构稳定。     

Pulping performance of transgenic poplar with depressed Caffeoyl-CoA O-methyltransferase

This paper evaluated pulping performance of 3-year-old field-grown transgenic poplar （Populus tremula × Populus alba）. The transgenic poplar with anti-sense CCoAOMT had an about 13% decreased lignin content, in which a slight increment was found in S/G ratio. Chemical analysis showed that the transgenic poplar had significantly less benezene-ethanol extractive than that of control wood, but no significant differences were found in contents of ash, cold water extractive, hot water extractive, 1% NaOH extractive, holocellulose, pentosans and cellulose. Fiber assay demonstrated that down-regulation of CCoAOMT expression improved the fiber quality in transgenic poplar. Kraft pulping showed that lower lignin in transgenic poplar led to remarkable improved pulp quality and increased pulp yield.     

蒸汽凝结水中十八胺超分子缓蚀剂对碳钢的保护研究

分别采用分子动力学与半经验量子化学法,对羟丙基-β-环糊精(HP-β-CD)与十八胺(ODA)超分子包合体系的稳定构象进行了研究。以旋转挂片实验得到的碳钢腐蚀速率为基础,通过Arrhenius方程和过渡态理论,分析了该包合物在蒸汽凝结水中对碳钢的防腐蚀机理。热力学计算及俄歇电子能谱(AES)的结果显示,包合物中的ODA分子会克服其与HP-β-CD分子间非共价键作用,以吸附的形式在碳钢表面形成保护膜,且吸附过程符合Langmuir等温式;在流动的凝结水中,包合物中的 ODA分子以一定倾斜角度在碳钢表面吸附。     

酸性沸石催化葡萄糖制备5-羟甲基糠醛研究

以酸性沸石为催化剂,催化葡萄糖脱水制备5-羟甲基糠醛(5-HMF).沸石催化剂采用固载磷钨酸(PW)和脱铝两种方法制备,固载PW方法用3种类型沸石:HY、MCM-41和HMOR,脱铝方法用HY型沸石,共制得产物PW/MCM-41、PW/HMOR、PW/HY、HY-D0.2和HY-D1.0,考察沸石结构、反应温度、葡萄糖与水质量比、催化剂与葡萄糖质量比对制备5-HMF的影响.结果表明,沸石固载PW后5-HMF的产率均有所提高,其中,以Y型沸石(HY)固载PW后(PW/HY)作为催化剂时5-HMF产率最高,为27.9％;HY特殊的结构对提高5-HMF的产率具有重要的作用.另外,提高反应温度有利于加快5-HMF的生成;葡萄糖与水质量比为3.0∶100时5-HMF产率最高,反应2.5h时达到30.4％,说明适当的葡萄糖与水质量比有利于5-HMF的制备.     

硫化促进剂在5A分子筛上的动态行为研究

文中以程序升温脱附(TPD)和原位红外-程序升温脱附(IR-TPD)为主要实验手段,对5A分子筛的表面酸性特征及硫化促进剂在5A分子筛上的动态行为进行研究。结果表明:5A分子筛表面对胺类化合物表现出吸附能量高低不等的B酸、混合B酸和L酸、L酸及弱化学吸附位。对于吸附型缓释交联剂而言。有效的表面吸附部位为弱化学吸附位,且带有氢键吸附的特征。动力学计算结果表明:对于有效部位而言,不同的硫化促进剂由5A分子筛内孔表面脱出时,其动力学特征不同,但均与晶内扩散有关,其表观脱附活化能分别为75.4kJ/mol(二乙胺),63.6kJ/mol(环己胺)和69.9kJ/mol(乙二胺)。     

正已烷在酸性沸石催化剂上的蒸汽裂解反应

利用蒸汽热裂装置考察ＨＭ，ＨＺＳＭ－５型沸石型上ｎ－Ｃ６的蒸汽热裂反应性能，并用ＴＰＤ，ＩＲ及异丙醇分解反应测定其酸碱性，发现酸性Ｐｅｎｔａｓｉｌ型沸的蒸汽热裂反应活性高，烯烃特别是乙烯收率较高，其中以ＳｉＯ２／Ａｌ２Ｏ３比为６０的ＨＺＳＭ－５沸石为最佳。     

Effects of ultraviolet radiation B （UV-B） on photosynthesis of natural phytoplankton assemblages in a marine bay in Southern China

Solar ultraviolet radiation B (UVB) is known to have inhibitive effects on phytoplankton photosynthesis. UVB light decreases rapidly with increasing depth in the water column and exerts different degrees of UVB inhibitive effects on phytoplankton photosynthesis. In this study, the objectives were to quantify effects of UVB on phytoplankton photosynthesis and quantum yield, and to examine UVB effects on phytoplankton photosynthesis when light varies. The insitu experiments were conducted in Da Ya Bay, which is a semienclosed area in the subtropical South China. The results showed a significant reduction of photosynthetic rates and quantum yield in the presence of UVB. Maximum photosynthetic rates (Pmax) and maximum quantum yield (Φmax) were 11%-22% and 17%-49% less under solar radiation with UVB than without UVB. A simplified model was developed to describe the UVB biologically effective fluence rate (E*inh) as an exponential decay function of depth. Light-shift experiments, in which water samples from the surface and at depth of 4 m were divided into several subsamples, and each subsamples were then incubated at different depths with and without UVB in the water column, showed that phytoplankton from the deeper water (4 m) had more inhibitive rates by UVB than that from the surface when exposed to the same light condition.     

Evolution of the serum resistance-associated SRA gene in African trypanosomes

Serum resistance-associated (SRA) protein, a protein unique for Trypanosoma brucei rhodesiense, is responsible for resistance of this parasite to the lysis by normal human serum (NHS) and is a vital molecular marker to distinguish this species from other African trypanosomes. We cloned and sequenced the SRA basic copy (SRAbc) gene from T. b. rhodesiense and related species and found that this gene is confined to the subgenus Trypanozoon. The average 82% identity among the sequenced SRAbc genes indicates that they may have a common origin and are highly conserved. Since SRAbc coexists in the T. b. rhodesiense genome with SRA, we propose that SRAbc might be the ‘donor VSG’, which after duplication became inserted into the expression site by recombination. Under natural selection, SRAbc could reform into SRA following mosaic formation. Supported by National Natural Science Foundation of China (Grant Nos. 30570245, 30670275), Changjiang Scholars and Innovative Research Team in University (Grant No. DPCKSCU/IRT0447), International Foundation for Science of Sweden (Grant No. B/4318-1), Grant Agency of the Czech Republic (Grant No. Z60220518) and Education Foundation of the Czech Republic (Grant No. 2B06129)     

Near-infrared spectroscopy-based quantification of substrate and aqueous products in wastewater anaerobic fermentation processes

In this study, a Fourier transform near-infrared （FT-NIR） technique was used for process monitoring of anaerobic fermentation. Orthogonal signal correction （OSC） method was used as NIR spectral pre- processing options. Calibration models were established and the validation of the method was per- formed with the sucrose, ethanol and volatile fatty acids （VFAs） contents determined by the anthrone and gas chromatography methods, respectively. Spectral range and the number of internal latent variables were optimized for the best correlation coefficient. Test set validation of sucrose resulted in excellent measurement of prediction performance and the correlation coefficient of determination is 0.930. Similar prediction statistics for individual VFA and total VFA contents were obtained. These re- sults proved that the NIR spectroscopy technology is able to quantify the contents of both volatile fatty acids and sucrose in wastewater anaerobic fermentation process.     

The role of sediment resuspension duration in release of PAHs

Polycyclic aromatic hydrocarbons （PAHs） are ubiquitous environmental pollutants. Due to their low water solubility and high hydrophobicity, PAHs are rapidly sorbed onto particles and subsequently deposit in sediments once introduced into aquatic environment. In such a way, sediments become a huge sink for PAHs. During sediment resuspension, the potential exists for PAHs to be released from sediments into water. Sediment resuspension plays an important role in the transportation and fate of PAHs in the aquatic environment. In this study, release behavior of PAHs on Yangtze River sediment during resuspension was investigated using a particle entrainment simulator （PES）. The role of resuspension duration on release of 16 PAHs was measured by resuspending sediment for 12 h at 0.2 and 0.5N/m^2, respectively. Results indicated that PAH concentrations in TSS increase over time with more increase of phenanthrene and 4-ring PAHs. Comparing with 0.2 N/m2 （30%）, TPAHs concentrations in TSS demonstrated remarkable increase during 0.5 N/m2 resuspension （37%）. Dissolved PAH concentrations increased throughout the duration with more increase of 2-3 ring PAHs （50%-88%）. Dissolved PAH concentrations showed remarkable increase during 0.5 N/m^2 resuspension （50%）. Moreover, PAH concentrations in overlying water throughout the duration of resuspension were higher than toxic effects threshold values in drinking water developed by WHO, which may cause toxic effect on ecosystem.     

Effects of the dispersed droplet sizes on the critical behavior of pseudobinary microemulsion

The critical behavior of pseudobinary microemulsion systems{water/sodium di(2-ethylhexyl)sulfo- succinate(AOT)/n-decane}with various droplet sizes was studied by measurements of refractive index. It was found that the critical exponentsβfor all systems approach 0.327 in a region sufficiently close to the critical temperature,which is consistent with 3D-Ising universality class.The critical temperatures linearly decrease as the dispersed droplet sizes increase.The critical amplitude almost linearly in- creases with increasing the dispersed droplet sizes.     

Preparation and characterization of three-dimensionally ordered macroporous polystyrene <Emphasis Type="Italic">via</Emphasis> atom-transfer radical polymerization

Three-dimensionally ordered macroporous polystyrene （3DOM PS） with pore size of 350 nm was fab- ricated using Cp2Co/Ethyl 2-bromoisobutyrate （EBiB） catalytic system by ATRP. The resulting polymers were detected by FT-IR, 1H-NMR, SEM, and GPC. The microstructure of 3DOM PS was confirmed by FT-IR and 1H-NMR. SEM micrographs show that both silica spheres within the templates and pores in the 3DOM polystyrene are arranged in highly ordered fashion, and the shrinkage of the pores in the 3DOM PS is 24%. GPC curves show that the 3DOM PS possesses slightly lower Mn and narrow MWD compared with bulk one. This result indicats that living polymerization is different from non-living polymerizationin in the confined space.     

Scenario simulation and forecast of land use/cover in northern China

Modeling land use/cover scenario changes and its potential impacts on structure and functions of ecosystem in typical regions are helpful to understanding the interactive mechanism between land use/cover system and ecosystem. Based on the analysis of the existing land use/cover simulation and forecast models, a land use/cover scenario dynamics model by the integration of System Dynamics （SD） model, Back Propagation Neural Network （BPNN） and Cellular Automata （CA） model is developed with land use/cover scenario changes in northern China in the next 30 years and simulated in this paper. The model is to simulate the land use/cover scenario demands by using a SD model at first, and then allocating the land use scenario patterns at the local scale with the considerations of land use/cover suitability, inheritance ability and neighborhood effect by using BPNN-CA model to satisfy the balance between land use/cover scenario demands and supplies. It integrates the advantages of SD, BPNN and CA. Macro-driving factors and the micro-spatial pattern are also fully taken into account. The BPNN simplifies the identification of the factors＇ weights used in CA model and improves the reliability of the simulation results. The simulation accuracy of the model developed in this paper was found to be about 74%. It suggests that the model has the ability to reflect the complexity of land use/cover system at different scales to some extent and it is a useful tool for assessing the potential impacts of land use system on ecosystem. The simulated results also indicate that the urban land, water area and forest will increase significantly, and farmland and unable land will decrease gradually. Obvious land use/cover changes will take place in the farming-pastoral zone and the southeast area of northern China.     

On the development of the GRAPES——A new generation of the national operational NWP system in China

Numerical weather prediction （NWP） has become one of the most important means for weather forecasts in the world. It also mirrors a nation＇s comprehensive strength in meteorology. In 2000, China Meteorological Administration （CMA） established the National Innovative Base for Meteorological Numerical Prediction in the Chinese Academy of Meteorological Sciences （CAMS）, to work on developing a new generation of the national operational NWP system-Global/Regional Assimilation and PrEdiction System （GRAPES）, to enhance meteorological services in China in the new century. In recent years, the GRAPES has witnessed a fast development. The GRAPES has been set up as an integration of the model framework, data assimilation, regional and global NWP system, which can be commonly used for both operation and research. In this paper, a brief review is made for illustrating the GRAPES system, including the advanced designs of the GRAPES, its diverse applications in multi-fields, and efficiencies of the regional and global GRAPES in operational applications based on hindcast results.     

Measuring radial Young’s modulus of DNA by tapping mode AFM

Based on tapping mode AFM imaging, a method was demonstrated to evaluate compression elasticity of single double-stranded DNA （dsDNA） molecules in the force region. With images under ambient conditions, Young＇s moduli of dsDNA in compression were calculated. Results demonstrated that Young＇s moduli of dsDNA can be simply deduced according to the proposed model. The method can also be used to evaluate the compression elasticity of similar soft nanomaterials.     

Mesoproterozoic age for Xiamaling Formation in North China Plate indicated by zircon SHRIMP dating

Zircon grains of magmatic origin from tuffite layers in the Xiamaling Formation at Zhaojiashan Village, Xuanhua area, Hebei Province, were used for zircon dating with a Sensitive High-Resolution Ion Microprobe （SHRIMP Ⅱ）, which gives a weighted mean ^207Pb/^206Pb age of 1366±9 Ma. It shows a very similar age （1368±12 Ma） as the zircon dating from the Xiamaling Formation in Western Hill, Beijing. This age proposes that the Xiamaling Formation in the North China plate should be of Mesoproterozoic, instead of Neoproterozoic based on K-Ar, Ar-Ar dating. The new zircon age also indicates the development of macrofossils algae from the Mesoproterozoic age.     

Tunable multiple-channel filters based on photonic heterostructures using single-negative materials

We studied the multiple-channel filters based on photonic heterostructures consisting of single-negative permittivity and single-negative permeability media. The results showed that the number of resonance modes inside the zero-φeff gap increases as the number of heterogenous interface M increases. The number of resonance modes inside the zero-φeff, gap is equal to that of heterogenous interface M, and it can be used as M channels filter. This result provides a feasible method to adjust the channel number of multiple-channel filters. When losses are involved, the results showed that the electric fields of the resonance modes decay largely with the increase of the number of heterogenous interface and damping factors. Besides, the relationship between the quality factor of multiple-channel filters and the number of heterogenous interface M is linear, and the quality factor of multiple-channel filters decreases with the increase of the damping factor. These results provide feasible methods to adjust the quality factor of multiple-channel filters.     

取心工具用大尺寸疏水吸油海绵的制备与吸油性能研究

海绵取心工具（取心衬筒）中一种关键材料是高吸油海绵，为了满足钻井取心的使用需求，需要制备大尺寸、超疏水的吸油海绵。利用多巴胺（DA）氧化自聚（以NaIO₄为氧化剂）以及聚多巴胺（PDA）与疏水剂（十八胺，ODA）的反应，采用一步和两步浸涂法对小尺寸（30 mm×30 mm×10 mm）和大尺寸（910 mm×400 mm×10 mm）商用三聚氰胺海绵进行疏水改性；利用扫描电子显微镜（SEM）观察改性海绵的表面形貌，并测定其水接触角和吸油性能。结果表明：改性海绵表面形成了PDA粒子，两步法所得改性海绵的表面粒子细密、均匀；增大DA的质量浓度和提高氧化剂含量，海绵表面PDA粒子增多。确定了海绵改性的最优条件：DA质量浓度为4~6 mg/mL，DA与NaIO₄的质量比为1：1，海绵在ODA溶液中的浸泡时间为2~4 h。在小尺寸样品研究结果的基础上，将大尺寸海绵在DA溶液中浸泡1 min，在空气中放置2 h，然后与ODA溶液反应4 h进行改性，所得大尺寸改性海绵的表面水接触角为152.6°，10 s时吸油量达90 g/g，并且多次吸油、析油后仍保持较高的吸油量和解析率，可以满足取心衬筒的使用要求。