横泉水库坝基渗漏分析与评价

文中利用野外工程地质勘察及大量水文地质试验后所取得的水文地质参数，对横泉水库第四系松散层和基岩强风化层的渗透性及渗漏量给出了分析与评价。     

Quadratic Optical Nonlinearities of N‐Methyl and N‐Aryl Pyridinium Salts

Four series of dyes with dimethylamino electron donor groups and N‐R‐pyridinium (R = methyl Me, phenyl Ph, 2,4‐dinitrophenyl 2,4‐DNPh, or 2‐pyrimidyl 2‐Pym) electron acceptors are studied as their hexafluorophosphate salts. The intramolecular charge‐transfer (ICT) energies (E_max) of these compounds decrease within each of the series in the order R = Me > Ph > 2,4‐DNPh > 2‐Pym, as the electron‐accepting ability of the pyridinium ring increases. Hyper‐Rayleigh scattering with femtosecond 1300 or 800 nm lasers yields fluorescence‐free first hyperpolarizabilities β, and static first hyperpolarizabilities β₀[H] are obtained via the two‐state model. Dipole moment changes Δμ₁₂ for the ICT transitions obtained from Stark spectroscopy afford β₀[S] values by using β₀ = 3Δμ₁₂(μ₁₂)²/2(E_max)² (μ₁₂ = transition dipole moment). The β₀[S] data show that the combination of pyridyl N‐arylation with conjugation extension affords large increases in β₀. The β₀[H] data generally agree with this conclusion, but resonance effects may explain some apparent anomalies. X‐ray structural studies on various salts reveal that the use of tosylate anions is not a generally applicable approach to engineering noncentrosymmetric structures of pyridinium salts. However, trans‐N‐phenyl‐4‐(4‐dimethylaminophenyl‐4‐buta‐1,3‐dienyl)pyridinium hexafluorophosphate adopts the polar space group Cc, and shows a very large powder second harmonic generation efficiency from a 1907 nm laser, which is similar to that of the well‐studied material trans‐4′‐(dimethylamino)‐N‐methyl‐4‐stilbazolium tosylate (DAST).     

ICP-AES法测定陶瓷UO_2芯块粉末标准物质中Al、Ba、Co、Ta、Ti和V

采用２３７季铵萃淋树脂和萃取色谱分离技术，在６．５ｍｏｌ／ＬＨＮＯ３介质中定量分离陶瓷ＵＯ２芯块粉末标准物质中铀与待测杂质元素。用ＩＣＰ直读光谱仪同时测定流出液中Ａｌ、Ｂａ、Ｃｏ、Ｔａ、Ｔｉ和Ｖ。分析结果均在标准值的置信区间内，相对标准偏差ｓｒ＜７．５％。取样３００ｍｇ时，测定下限为（０．０１６—０．２５０）×１０－６。     

Electrochemical reduction of silicon chloride in a non-aqueous solvent

The electrodeposition of silicon was engaged in propylene carbonate containing SiCl₄ and tetrabutylammonium chloride. Cyclic voltammograms showed the possibility of electrodeposition of Si at −3.6 V versus Pt quasi-R.E. Potentiostatic electrolysis yielded a porous and white deposit with the thickness of 50 μm at −3.6 V for 1 h. Raman spectroscopic analysis of the deposit immersed in pure propylene carbonate soon after the electrolysis confirmed that the electrodeposit was amorphous silicon. Moreover, EDX and XPS results indicated that the electrodeposited Si was so active that it was oxidized immediately in the air. Finally, the electrodeposition process of Si film is discussed based on chronopotentiometry and chronoamperometry.     

Improved and Practical Synthesis of [2,4,5‐Tris(trimethylsilyl)‐ phenyl](phenyl)iodonium Triflate and Utilization as a 1,4‐Benzdiyne Synthon

An efficient and improved method for preparing [2,4,5‐tris(trimethylsilyl)phenyl](phenyl)iodonium triflate as a 1,4‐benzdiyne synthon was developed by using phenyiodonium diacetate/boron triflouride⋅diethyl etherate [PhI(OAc)₂/BF₃⋅OEt₂] reagent. The iodonium triflate generated 3,4‐bis(trimethylsilyl)benzyne quantitatively to give cycloadducts with tetraphenylcyclopentadienone, furan and anthracene in high yields. These cycloadducts bearing two trimethylsilyl groups were transformed into the corresponding aryne precursors, which underwent subsequent cycloaddition reactions to afford polycyclic aromatic compounds such as 1,4‐dihydro‐1,4‐epoxyanthracene, naphthotriazole, triptycene, and anthratriazole derivatives in good to high yields. The total reactions are formally considered as double cycloaddition reactions of 1,4‐benzdiyne. This practical and useful formal benzdiyne strategy is described.

     

米曲霉A100-8种曲的培养工艺的研究

米曲霉A100-8菌种,是经离子注入诱变育种后,是以沪酿3．042为对照筛选得到的其特点为蛋白酶、糖化酶以及纤维素酶活力均有明显提高,且以偏酸性蛋白酶活力为主。因此,本文着重研究了A100-8种曲的培养条件。通过对原料的加水量、培养时间及有关无机盐的添加等的有效试验,最终由正交试验确立米曲霉A100-8的最佳培养工艺为,原料的加水量为120％;硫酸锰的添加量为0．04％、氯化钙为0．4％、磷酸盐为O．2％;培养时间为72h。成曲孢子数可达192亿／g左右;出芽率为95％以上（均以干基计）,较优化前均提高30％以上。     

无机盐对丙烯腈与N-乙烯基吡咯烷酮共聚物溶液黏度的影响

引　言黏度是碳纤维前驱体聚丙烯腈原丝纺丝工艺过程中重要的控制指标之一 .为得到高性能的原丝 ,一般采用提高共聚物的分子量、增加纺丝原液中共聚物的浓度或改变共聚单体等方法 ,结果使得纺丝原液黏度急剧上升 ,纺丝压力过大 ,不便于输送 ,易出现危险 .增加共聚单体的含量可降低原液黏度 ,但共聚单体的含量也有极限值[1,2 ] .少量文献曾提到过无机盐对聚丙烯腈溶液黏度是有影响的[3 ,4] ,指出某些无机盐的加入可使得丙烯腈共聚物溶液黏度下降[5] ,这对于原丝生产具有重要意义 ,但对于原液中常出现的离子Na 、Zn2 、Fe3 、Cu2 、K 、…     

筛选具有抑制引起腹泻致病菌黏附功能的益生菌

筛选能够抑制引起腹泻致病菌黏附的益生菌,并且对其适应肠道环境:耐酸、耐胆盐和黏附性能进行评价。从中国西部地区传统发酵食品以及人类粪便样品中分离的14株益生菌作为筛选菌株。对这14株益生菌进行抑制致病菌黏附的筛选,最终筛选出7株使致病菌黏附数量降低到1.5×104CFU/m L的益生菌进行耐受肠道环境能力评价。实验结果显示这7株益生菌在p H2的条件下处理90min后存活的益生菌依然能够达到107CFU/m L左右,在0.3%的胆盐环境中处理2h后菌数降低到原来的百分之一,单层细胞上黏附的益生菌数J5、G15和F0533能够达到106CFU/m L,显示出了较强的黏附能力。经过综合分析筛选出F0533、IN4125、G15、J5和M7益生菌,经16S r DNA基因技术鉴定分别为Lactobacillus rhamnosus、Lactobacillus rhamnosus、Lactobacillus paracasei、Lactobacillus casei和Lactobacillus paracasei。      

3,5‐Bis(n‐perfluorooctyl)benzyltriethylammonium Bromide (F‐TEBA): An Efficient,Easily Recoverable Fluorous Catalyst for Solid‐Liquid PTC Reactions

A readily available 3,5‐bis(perfluorooctyl)benzyl bromide and triethylamine were reacted under mild conditions to give 3,5‐bis(n‐perfluorooctyl)benzyltriethylammonium bromide ( F‐TEBA ), an analogue of the versatile phase‐transfer catalyst, benzyltriethylammonium chloride (TEBA), containing two fluorous ponytails. This perfluoroalkylated quaternary ammonium salt was successfully employed as a catalyst in a variety of reactions run under solid‐liquid phase‐transfer catalysis (SL‐PTC) conditions. Thus, being both hydrophobic and lipophobic, F‐TEBA could be quickly recovered in quantitative yields, and reused without loss of activity over several reaction cycles.