NiY分子筛选择性吸附脱硫性能及作用机理

用液相离子交换法制备了NiY分子筛,并用XRD、TEM、ICP、N2吸附和吡啶吸附原位红外技术等表征手段对其进行了表征. 利用固定床、气相色谱-硫发光检测器（GC-SCD）及傅里叶红外光谱（FT-IR）等方法系统研究了NiY分子筛对噻吩、2-甲基噻吩、3-甲基噻吩、四氢噻吩、苯并噻吩、二苯并噻吩、4-甲基二苯并噻吩、4,6-二甲基二苯并噻吩8种有机硫化物的选择性吸附脱硫性能和吸附机理. 结果表明,NiY分子筛对硫化物的穿透吸附硫容量顺序为四氢噻吩﹥苯并噻吩≈二苯并噻吩≈4,6-二甲基二苯并噻吩﹥4-甲基二苯并噻吩﹥2-甲基噻吩≈3-甲基噻吩﹥噻吩,说明有机硫化物的空间位阻效应不是其在NiY分子筛上吸附的决定因素. 红外结果表明,不同硫化物与NiY分子筛的作用机理并不相同,但主要以硫原子与金属离子配位作用（S-M作用）为主. 噻吩及其烷基取代物在NiY吸附剂上表面酸性作用下发生催化反应,噻吩环的共轭体系遭到破坏形成硫化物大分子或聚合物,导致分子筛孔道的堵塞,严重影响吸附剂的吸附脱硫能力. NiY的选择性吸附脱硫性能是硫化物与吸附中心的作用模式及吸附剂表面酸性综合作用的结果.     

PS-b-P (DMS-stat-VMS)嵌段聚合物的制备及性能

采用活性阴离子聚合方法,以仲丁基锂为引发剂,以苯乙烯、六甲基环三硅氧烷（D3）和2,4,6-三乙烯基-2,4,6-三甲基环三硅氧烷（V3）为反应单体,分步聚合制备了聚苯乙烯-b-聚（二甲基硅氧烷-stat-乙烯基甲基硅氧烷）[PS-b-P（DMS-stat-VMS）]嵌段聚合物.采用傅里叶变换红外光谱、氢核磁共振谱及凝胶渗透色谱对共聚物的化学结构、分子量及分子量分布进行了表征,并通过扫描电子显微镜、原子力显微镜及接触角等测试方法研究了共聚物各链段组分对共聚物形貌及表面亲疏水/油性的影响.结果表明,所制备的共聚物分子量分布较窄,由于各组分性能的差异而呈现出微相分离结构,同时该共聚物保留了PS-b-PDMS原有的表面性质,为设计结构多样性及性能优异的聚硅氧烷共聚物提供了新思路.     

Passively Q-Switched Tm,Ho：YVO4 Laser with Cr：ZnS Saturable Absorber at 2 μm

A stable diode-pumped passively Q-switched Tm,Ho：YVO4 laser with Cr：ZnS saturable absorber is reported. The shortest pulse duration of -500 ns with the central wavelength of 2041 nm is obtained at the pump power of 7.4 W, corresponding to the pulse energy of 3.5 μd at repetition rate of 65 kHz.     

A Diode-Pumped 1617 nm Single Longitudinal Mode Er：YAG Laser with Intra-Cavity Etalons

We demonstrate the continuous wave p-polarized single longitudinal mode （SLM） operation of an Er：YAG laser at 1617.6nm pumped by a diode-laser with three inserted Fabry-Perot （FP） etalons at room temperature. The Brewster angle inserted FP is applied to obtain the p-polarized laser. For free running, the maximum output power is 570 m W with a pump power of 12.5 W. An incident pump power of 12.5 W is used to generate the maximum p-polarized single longitudinal mode output power of 78.5 m W, corresponding to a slope efficiency of 1.6% and an optical-to-optical efficiency of 0.61%. The beam quality M2 is measured to be 1.15 at the highest SLM output power. This stable polarized SLM oscillation is encouraging due to its application for an injection-locked system used as a master laser.     

Predicting the growth of new links by new preferential attachment similarity indices

By revisiting the preferential attachment (PA) mechanism for generating a classical scale-free network, we propose a class of novel preferential attachment similarity indices for predicting future links in evolving networks. Extensive experiments on 14 real-life networks show that these new indices can provide more accurate prediction than the traditional one. Due to the improved prediction accuracy and low computational complexity, these proposed preferential attachment indices can be helpful for providing both instructions for mining unknown links and new insights to understand the underlying mechanisms that drive the network evolution.     

氮肥管理对夏玉米土壤CH4和N2O排放的影响

通过设置四个不同的氮肥管理措施, 即氮肥施用量300 kg N/ha (N300)和250 kg N/ha (N250)、改进的施肥模式(Optimized)以及施用缓释肥(SRU), 研究华北平原夏玉米生长季土壤与大气之间CH₄和N₂O的交换通量及相应措施的减排潜力. 结果表明, 在2008年整个夏玉米生长季, 土壤都是大气CH₄的净吸收库和N₂O的排放源. 夏玉米生长季土壤氧化吸收的CH₄总量从大到小依次为Optimized > N250 > SRU > N300, 对应的吸收总量依次为624.16、590.07、487.89以及316.02 g CH₄-C/ha, 各处理间氧化吸收的CH₄总量无显著差异. 与N300和N250这两个处理相比, 依据夏玉米对氮肥的需肥规律以及玉米根层土壤速效氮的供给能力而确定氮肥施用量, 同时再平衡施用磷肥和钾肥的改进施肥模式能够显著降低夏玉米生长季N₂O的排放. 施用聚乙烯包膜的尿素也能够显著降低夏玉米季N₂O的排放. 夏玉米生长季土壤排放的N₂O总量从大到小依次为N300 > N250 > Optimized > SRU, 对应的排放总量依次为3462.18、2340.07、1680.00以及911.91 g N2O-N/ha, 相应的N₂O排放系数分别为1.15%、0.94%、0.91%以及0.30%.     

紫外光引发剂907及其反应中间体的气相色谱测定

建立了光引发剂907合成工艺控制中反应原料、中间体及产物的气相色谱分析方法。采用SE-54石英毛细管柱,程序升温进行分离,氢火焰离子化检测器(FID)进行检测。结果表明,原料苯甲硫醚,反应中间体807A、807B、907C和产物907线性范围分别为0.2～14.0μg/mL、0.4～20.0μg/mL、0.5～22.0μg/mL和0.6～19.0μg/mL,线性相关系数R均大于0.999,相对标准偏差小于2.5%,回收率为93.6%～106.8%。产物结构通过红外光谱进行表征。该方法线性关系、准确度和精密度良好,适用于光引发剂907合成工艺的快速监控及产品定量分析。     

Theoretical Studies on the Proton Transfer Mechanism in Four-water Hydrated Glycine Complexes

The mp2/6-31++g**//b3lyp/6-31++g** method has been employed to study the proton transfer mechanism in 4H2O-glycine complexes(4W-G).Compared with bare glycine the four-water hydrated neutral glycine complexes(4W-GN) can turn into the corresponding zwitterionic glycine(4W-GZ) through proton transfer.The most stable conformation of 4W-GZ has a "double water-chain" structure and is more stable than its corresponding precursor 4W-GN by 0.97 KJ/mol though it is less stable than the most stable 4W-GN by 7.80 KJ/mol.It is a spontaneous reaction to form the most stable conformation of 4W-GZ,and the potential barrier is only 1.97 KJ/mol,so the probability of this reaction is very high and the most stable 4W-GZ may be detected in experiment or in the early stage of experiment.     

碎裂结构边坡变形机理及治理对策研究

碎裂结构边坡稳定性受多组相交结构面控制,且受降雨、地震等多因素影响强烈,具有一定的特殊性。本文以某花岗岩碎裂结构边坡为例,在边坡的地质条件和岩体结构研究的基础上,结合施工及监测反馈信息,深入分析了边坡变形破坏模式,并根据稳定性计算结果,提出锚索、钢筋桩与排水相结合的支护方案。研究结果表明：坡体内部陡倾卸荷裂缝发育形成后缘切割面,中下部滑面追踪陡缓两组结构面发展;支护措施实施后,边坡经历“5•12”地震及雨季,多点位移计监测结果表明,地震和降雨对边坡稳定性影响较大,支护措施较好地控制了边坡变形。