金沙江下咱日堆积体的成因和稳定性初步分析

下咱日堆积体的稳定性对拟建的梨园水电站大坝和附近的水力设施有着重要的意义。利用下咱日堆积体的勘察资料,本文分析后认为下咱日堆积体经历了中更新世的金江冰期和晚更新世的丽江冰期两次冰期的作用,是由冰碛物、河流沉积物、湖相沉积物及崩积物组成的复杂成因堆积体;稳定性初步分析认为,下咱日堆积体局部有坍塌,但是整体稳定,以后稳定与否的关键是堆积体中湖相沉积层及坡脚的松散砾石层的稳定性。     

Spectral Differences of the Molecule-ion Adducts of β-Cyclodextrin and Lithium Carbonate

A small shielding effect on the hydrogen atoms of chiral carbons of β-cyclodextrin (β-CD) was detected by ¹H nuclear magnetic resonance, but a large environmental change of the chiral carbon atoms at high concentration ratios of lithium carbonate (Li₂CO₃) to β-CD was observed by polarimetry in aqueous solution. These findings urged us to investigate whether different formation conditions of the molecule-ion system between Li₂CO₃ and β-CD in solid state were involved in different spectral performances. To answer the question, we prepared three adducts of Li₂CO₃ to β-CD, i.e., samples 1, 2, and 3, by magnetic stirring, solvothermal and grinding conditions, respectively. Powder X-ray diffraction and Fourier transformation infrared spectroscopy provided the information of formation of the three molecule-ion adducts. Besides, scanning electron microscope images provided different surface information of the three adducts. Further, significant spectral differences in thermal behavior of these adducts were found by thermogravimetry and derivative thermogravimetry.     

川藏公路茶树山滑坡特征及成因机制分析

通过对川藏公路茶树山滑坡地质环境条件的系统调查研究,分析了滑坡岩土体结构、边界条件、变形特征、影响因素,并结合3DEC数值模拟,对其变形破坏机制进行了深入的探讨。综合分析表明,滑坡位于活动断裂带内,后缘斜坡陡峭,岩体破碎,同时前缘为较厚的松散堆积体斜坡,在地震活动、降雨等影响因素的诱发作用下,滑坡成因机制主要表现为以下3个阶段:(1)倾倒拉裂阶段,滑坡受后缘地形及岩体结构控制作用较为明显,在坡体浅表层一定深度范围内出现较为强烈的倾倒拉裂变形带,产生倾倒-拉裂滑动; (2)蠕滑变形阶段,前缘松散堆积体在强大的自重推力作用下发生蠕滑变形; (3)前部"锁骨段"剪断,整体失稳阶段,滑坡前部锁骨段在自重推力及断层活动的持续影响下,发生剪断,控制后缘倾倒拉裂体稳定性的潜在滑面与前缘松散堆积体体内的剪切滑动面贯通,滑坡整体失稳。     

Electrochemical DNA biosensor for the determination of benzo[a]pyrene–DNA adducts

The metabolites of the environmental pollutant, benzo[a]pyrene (BaP) are carcinogenic and mutagenic agents. Thus, the determination of additional products (adducts) of the interaction between DNA and BaP, attracts great interest in cancer research.

In this study, the determination of interaction between BaP and calf thymus double-stranded DNA (dsDNA) was performed by using differential pulse voltammetry (DPV) and constant current chronopotentiometric stripping analysis (PSA) in connection with carbon paste electrode (CPE) or glassy carbon electrode (GCE). As a result of interaction of BaP with dsDNA, the signal obtained from the oxidation of guanine decreased and a new adduct signal at a more positive potential appeared. This new peak is attributed to the formation of an adduct from the interaction of guanine with BaP. The chemically prepared anti-7,8,9,10-tetrahydrobenzo[a]pyrene-7,8-diol-9,10-epoxide (BPDE) adduct by using iodine oxidation was analyzed and the electrochemical signal of the adduct was observed. When the dsDNA modified GCE was immersed into various concentrations of BaP solution, the oxidation peak of guanine decreased and the adduct peak increased with the increasing BaP concentration. The partition coefficient was also obtained from the peak of BaP with dsDNA. The results revealed that the formation of adducts could be determined by using electrochemical DNA biosensors, which are fast, simple and cost-effective devices. Furthermore, this study promises that the analysis of other important adducts would benefit from the introduction of electrochemical methods.     

氯柱硼镁石在硼酸溶液中溶解转化的Raman光谱

利用Raman光谱对氯柱硼镁石在30 ℃时,4.5%的硼酸水溶液中溶解相转化过程进行了研究。研究结果表明相转化产物为库水硼镁石(2MgO·3B₂O₃·15H₂O)。根据Raman光谱位移对溶液中各种聚硼酸根B(OH)-₄,B₂O(OH)2-₆,B₃O₃(OH)-₄等阴离子的Raman峰进行了归属以及它们间的相互作用分别进行了讨论分析。提出了溶液中硼氧配阴离子的存在形式及其相互作用机理和我国青藏高原盐湖区库水硼镁石形成的地球化学成盐条件和机理。     

Formation Enthalpy Calculation of Oxygen Vacancy Defect in Doped Lithium Niobate Crystals

The relationship between temperature and oxygen vacancy concentration is deduced in this paper. Based on the data of thermal weight-loss experiment, the formation enthalpies of congruent and several doped LN crystals have been calculated. It was found that the formation enthalpy of oxygen vacancies can be decreased evidently by doping valence-changeable ions. The experimental results were discussed and a new reduction process of the photorefractive LN crystal at a relatively low temperature was proposed, and the reduced crystals showed a good effect in practical use.     

KDP晶体中点缺陷Na取代K的电子结构研究

 对磷酸二氢钾(KDP)晶体中Na取代K点缺陷的几何结构及电子结构进行了第一性研究。计算的形成能约为0.46 eV,因此在KDP晶体中此类缺陷比较容易形成。Na取代K以后没有在带隙中形成缺陷态,但在价带中引入两个占据态。它们分别位于费米面以下49 eV和21.5 eV处,这两个占据态分别由Na原子的s和p轨道形成。相对于K来说,由于它们位于价带深处,具有很低的能量,因此Na在KDP中比K稳定。Na在KDP晶体中与周围氧原子的重叠布居仅为0.09, 故它不与主体原子发生共价作用,仅以静电库仑力影响周围原子,此缺陷周围晶格仅发生微小畸变。     

Study of Nd-nitrato complexes in aqueous-methanol solutions

The stability constantsK ₁=3.6 andK ₂=1 of Nd(MeOH) _x NO ₃ ²⁺ and Nd(MeOH) _x (NO₃) ₂ ⁺ complexes were determined spectrophotometrically. On the basis of an analysis of the stepwise stability constants ratio it was found that these are inner sphere complexes.

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Untersuchungen zon Nd-Nitratokomplexen in wäßrig-methanolischen Lösungen

Zusammenfassung Es wurden die StabilitätskonstantenK ₁=3.6 undK ₂=1 der Komplexe Nd(MeOH) _x NO ₃ ²⁺ und Nd(MeOH) _x (NO₃) ₂ ⁺ spektrophotometrisch bestimmt. Basierend auf einer Analyse der stufenweisen Stabilitätskonstanten wurde festgestellt, daß es sich um Komplexe der inneren Sphäre handelt.

     

Molecular associations of [2.2]paracyclophanearylhydrazones with organic acceptors,VIII

Summary Molecular complexes of mono and disubstituted [2.2]paracyclophanehydrazones with organic acceptors have been studied by means of thermodynamic and spectroscopic properties. Furthermore, the enhancement of the donor strength, induced by the hydrazono group, is viewed in the light of substituent as well as transannular effects.

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Molekulare Assoziation von [2.2]Paracyclophanarylhydrazonen mit organischen Akzeptoren, 8. Mitt.

Zusammenfassung Es wurden Molekülkomplexe von mono- und disubstituierten [2.2]Paracyclophanarylhydrazonen mit organischen Akzeptoren mittels thermodynamischer und spektroskopischer Methoden untersucht. Zusätzlich wird der Anstieg in der Donorstärke, der von der Hydrazonogruppe induziert wird, im Hinblick auf Substituenten- und auch transannulare Effekte diskutiert.

     

Formation and structural characterization of novel polynuclear palladium selenolato complexes [Pd3Se(SePh)3(PPh3)3]Cl and [Pd6Cl2Se4(SePh)2(PPh3)6]

In addition to well-known dinuclear phenylselenolato palladium complexes, the reaction of [PdCl₂(PPh₃)₂] and NaSePh affords small amounts of novel trinuclear and hexanuclear complexes [Pd₃Se(SePh)₃(PPh₃)₃]Cl (1) and [Pd₆Cl₂Se₄(SePh)₂(PPh₃)₆] (2). Complex 1 is triclinic, P1?, a=13.6310(2), b=16.2596(2), c=16.9899(3) Å, α=83.1738(5), β=78.9882(5), γ=78.7635(5)°. Complex 2 is monoclinic, C2/c, a=25.7165(9), b=17.6426(8), c=27.9151(14) Å, β=110.513(2)°. There are no structural forerunners for 1, but the hexanuclear complex 2 is isostructural with [Pd₆Cl₂Te₄(TeR)₂(PPh₃)₆] (R=Ph, C₄H₃S) that have been observed as one of the products in the oxidative addition of R₂Te₂ to [Pd(PPh₃)₄]. Mononuclear palladium complexes may play a significant role as building blocks in the formation of the polynuclear complexes.