Divisors on Generic Complete Intersections in Projective Space

Let be a generic complete intersection of hypersurfaces of degree in -dimensional projective space. We study the question when a divisor on is nonrational or of general type, and give an alternative proof of a result of Ein. We also give some improvement of Ein's result in the case .

     

Adsorption enthalpy and desorption enthalpy during displacement of adsorbate to solvent in a liquid-solid system

The adsorption heat of the stoichiometric displacement process for the adsorption of a solute in a liquid-solid system was investigated. On the basis of the SDM-A and the rule of the additivity of energy, an expression which describes the dependence of the adsorption enthalpy on the nature and concentration of the solute, and on the solvent and adsorbent, was derived. The adsorption heat determined for the solute with the traditional method can be divided into two independent fractions, relating to the adsorption of the solute and to the desorption of the solvent. Experimental data on both isotherms from the literatures and precise calorimetry were used to test the adsorption heat and its fractions computed quantitatively via the equations presented in this study, and a satisfactory degree of conformity between them was obtained. Supported by the Natural Science Foundation of Shaanxi Province in China.     

铽与苯乙酮酸、2,2''''-联吡啶、1,10-菲口罗啉、三苯基氧膦铽三元配合物的合成、结构表征及荧光性能的研究

以硝酸铽、苯乙酮酸（HL）, 2, 2＇-联吡啶（dipy）、 1, 10-菲啰啉（phen）和三苯基氧膦（TPPO）合成了TbL3dipy（H2O）2, TbL3phen（H2O）2和TbL2（TPPO）2NO3 3种新型固态配合物. 用元素分析、电导率、红外光谱和核磁共振谱对其进行了表征, 确定了配合物的组成. IR表明, 配合物中羧酸根可能以单齿方式配位. 1HNMR显示, 苯乙酮酸根配位后苯环上5个氢原子的化学位移移向高场. 室温下测定了配合物的荧光激发光谱, TbL3dipy（H2O）2, TbL3phen（H2O）2和TbL2（TPPO）2NO3最佳激发波长分别为361.0, 359.0和367.0 nm;分别以最佳激发波长测定了配合物的发射光谱, 配合物TbL3dipy（H2O）2, TbL3phen（H2O）2 和TbL2（TPPO）2NO3显示Tb3＋离子的特征发射光谱, TbL3dipy（H2O）2和TbL3phen（H2O）2均产生四条谱带, 分别归属于^5D4-^7Fj（j= 6, 5,4,3）能级跃迁（TbL3dipy（H2O）2： 489.0, 545.0, 584.0, 620.0 nm;TbL3phen（H2O）2： 490.0, 544.0, 583.0, 620.0 nm）;但在相同测定条件下, TbL2（TPPO）2NO3仅显示5D4-7F5（544.0 nm）能级跃迁光谱. 3种配合物中TbL3dipy（H2O）2发光强度最高.     

Isolation and purification of honokiol and magnolol from cortex Magnoliae officinalis by high-speed counter-current chromatography

High-speed counter-current chromatography was used to isolate and purify honokiol and magnolol from cortex Magnoliae Officinalis (Magnolia officinalis Rehd. et Wils.), a plant used in the traditional Chinese medicine. A crude sample, 150 mg, was successfully separated with a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (1:0.4:1:0.4, v/v), and the fractions were analyzed by high-performance liquid chromatography. The separation produced 80 and 45 mg of honokiol and magnolol with purities of 99.2 and 98.2%, respectively, in 2.5 h.     

Synthesis and Magnetism of 2-Hydroxy-1,3-propylene-bis(oxamato)-bridged Co~ⅡCu~ⅡCo~Ⅱ Complexes

ＳｙｎｔｈｅｓｉｓａｎｄＭａｇｎｅｔｉｓｍｏｆ２┐Ｈｙｄｒｏｘｙ┐１，３┐ｐｒｏｐｙｌｅｎｅ┐ｂｉｓ（ｏｘａｍａｔｏ）┐ｂｒｉｄｇｅｄＣｏⅡＣｕⅡＣｏⅡＣｏｍｐｌｅｘｅｓＭＩＡＯＭｉｎｇ－ｍｉｎｇ，ＣＨＥＮＧＰｅｎｇ，ＬＩＡＯＤａｉ－ｚｈｅｎｇＪＩＡ...     

偶合反应化学发光法测定痕量银的研究

本将Ａｇ（Ⅰ）催化Ｓ２Ｏ＾２－８氧化Ｍｎ（Ⅱ）生成ＭｎＯ＾－４的催化反应与ＬｕｍｉｎｏｌＭｎＯ＾－４－ＯＨ＾－的化学发光反应相偶合，建立起一种新的灵敏测定痕量银的化学发光分析法，在所研究的优化条件下，该法测定银的选择性较好，检测限达到３．２×１０＾－１２ｇ／ｍＬＡｇ线性浓度范围为１．０×１０＾－１１－１．０×１０＾－５ｇ／ｍＬＡｇ，用于水样分析，结果较为满意。     

Atomic radical—molecule reactions F + CH<Subscript>3</Subscript>C≡CH: mechanistic study

The reaction of atomic radical F with propyne has been studied theoretically using ab initio quantum chemistry methods and transition state theory. The potential energy surface was calculated at the CCSD(T)/aug-cc-pVDZ (single-point) level using the UMP2/6-311++G(d,p) optimized structures. Two reaction mechanisms including the addition–isomerization–elimination reaction mechanism and the directed hydrogen abstraction reaction mechanism are considered. For the hydrogen abstraction reactions, i.e., the most probable evolution pathway in the title reaction, the HF formation occurs via direct abstraction mechanism dominantly and the H atom picked up by the atomic radical F should come mostly from the methyl group of normal propyne. On the other hand, for the addition–isomerization–elimination mechanism, the most feasible pathway should be the atomic radical F attacking on the C≡C triple bond in propyne (CH₃C≡CH) to form a weakly-bound adduct A1 with no barrier, followed by F addition to the C≡C triple bond to form the low-lying intermediate isomer 5. Subsequently, isomer 5 directly dissociates to P3 H₂CCCHF + H via transition state TS₅/P3. The other reaction pathways on the doublet PES are less competitive due to thermodynamical or kinetic factors. Furthermore, based on the analysis of the kinetics of all channels through which the addition and abstraction reaction proceed, we expect that the competitive power of reaction channels may vary with experimental conditions for the title reaction. The present work will provide useful information for understanding the processes of atomic radical F reaction with other unsaturated hydrocarbons. This material is available from author via E-mail.