不同二氧化碳浓度条件下红松和长白赤松土壤生化特性研究

以连续 5年在生长季以不同浓度CO2 (70 0和 5 0 0 μmol·mol-1)处理的长白赤松和红松幼苗为研究对象 ,进行了土壤微生物生物量C、纤维素分解月动态以及过氧化氢酶活性动态研究 .结果表明 ,在秋季 ,红松和长白赤松土壤微生物生物量C在不同浓度CO2 处理箱的大小顺序均为 :对照箱 >5 0 0 μmol·mol-1箱 >70 0 μmol·mol-1箱 ;红松和长白赤松土壤 5和 10cm层在不同浓度CO2 处理下 ,其纤维素分解强度的月动态均表现出一定的规律性 ,且各处理之间在每个月份中也表现出一定的规律性 ;在生长季 ,红松和长白赤松土壤纤维素分解强度在 5和 10cm层均表现为 5 0 0 μmol·mol-1CO2 处理下较 70 0 μmol·mol-1CO2 处理下高 ;红松和长白赤松土壤过氧化氢酶活性在不同浓度CO2 处理之间均表现出一定的规律性 ,且各处理的月动态变化也呈现出一定的规律性 .

Preparation and characterization of long methacrylate monolithic column for capillary liquid chromatography

Long methacrylate monolithic columns (100 cm x 320 mum i.d.) were prepared from silanized fused-silica capillaries of 320 mum i.d. by in situ copolymerization of butyl methacrylate (BMA) with ethylene dimethacrylate (EDMA) in the presence of a suitable porogen. The separation performance and selectivity of the column were evaluated and compared with a 25 cm x 320 mum i.d. column prepared in the same way by capillary high-performance liquid chromatography (mu-HPLC) The results showed that the 1 m long monolithic column can generate 33 x 10(3) plate number and exhibited good permeability, higher sample loadability, and separation capability. (C) 2004 Elsevier B.V. All rights reserved.

不同施肥黑土微生物量氮变化特征及相关因素

研究长期施用两种不同量有机肥 (M2 、M4)和化肥 (NPK)的黑土微生物量N在作物生长季的变化特征 .结果表明 ,施用有机肥黑土微生物量N显著高于施用化肥 (NPK)和不施肥 (CK) ,微生物量N季节波动小 .微生物量N为M42 5 5 2～ 2 39 12mg·kg-1,M2 10 4 0～ 94 31mg·kg-1,NPK 6 2 7～ 87 0 4mg·kg-1,CK 9 15～ 6 9 81mg·kg-1,同一处理最大值与最小值相差 7～ 14倍 .M2 、NPK处理微生物量N最大值出现在抽雄吐丝期 ,M4处理最大值出现在拔节期 ,CK处理最大值出现在播种期 ;不同处理微生物量N的差异并未因季节变化及玉米生育时期影响而明显改变 .微生物量N的动态变化与极少数黑土生物、理化特性指标动态变化显著相关 ;微生物量N与黑土生物、理化特性 ,植物氮、磷、钾有极显著的正相关关系 ,与土壤含水量、籽粒粗蛋白含量呈显著正相关关系 .

不同水分管理方式对稻田土壤生物学特性的影响

在下辽河平原单季稻地区研究了常规浅湿干灌溉 (CK)、浅湿干灌溉薄膜阻渗 (IC)、湿润灌溉薄膜阻渗 (MC)、淹水灌溉薄膜阻渗 (FC) 4种不同水分管理方式下土壤线虫及土壤微生物量的动态变化。结果表明 ,耙耕前 ,CK、FC处理食细菌线虫数量显著高于MC、IC处理 ;薄膜阻渗在黄熟期显著降低了土壤食细菌线虫的数量 ,在耙耕前显著降低了食真菌线虫数量。潮棕壤稻田食真菌线虫与食细菌线虫相比数量较低。在耙耕前不同水分管理方式下土壤微生物量C显著低于对照。不同水分管理方式在水稻分蘖期、抽穗期对食细菌线虫数量、食真菌线虫数量、微生物量C和微生物量N没有影响。土壤食细菌线虫、食真菌线虫数量与土壤微生物量C、N没有达到显著相关。

彩绒革盖菌固体发酵生产木质素酶工艺优化研究

采用均匀设计U15( 5 8)和双温度培养法进行彩绒革盖菌固体发酵生产木质素酶 ,对漆酶、愈创木酚酶、多酚氧化酶的活力进行回归分析。结果表明 :应用双温度培养法进行彩绒革盖菌固体发酵生产木质素酶时 ,在自然补给氧气 ,培养基pH自然 (约 6 5 ) ,并保持环境湿度约 60 %的条件下 ,2 0d是适宜的发酵周期 ;玉米浆、麸皮、 (NH4 ) 2 SO4 、水分适宜作为固体培养基的成分 ;少量的Tween 80有利于木质素酶的生产。

A study of shear viscosity of interfacial films containing alkyl metal phosphates

Experimental data are presented to show the influence of alkyl metal phosphates, Shengli resin fraction, and NaCl, on the shear viscosity of interfacial films and the stability of emulsions. It was found that the alkyl metal phosphates and the Shengli resin fraction could enhance the shear viscosity of interfacial films and the stability of emulsions. NaCl (0.01-0.03 mol L-1) could change the shear viscosity of interfacial films containing alkyl metal phosphates and the Shengli resin fraction. The shear viscosity of interfacial films containing ethyl iron phosphate and the Shengli resin fraction decreased with the increase of the concentration of NaCl. On the other hand, NaCl could decrease the stability of the emulsions. (C) 2004 Elsevier B.V. All rights reserved.

长白山5种主要森林群落细根现存生物量研究

通过对长白山5种主要森林群落类型细根现存生物量的研究发现:不同森林群落细根生物量有较大差别.其中,阔叶红松林细根生物量最高,达到5.9677t/hm2,其次为云冷杉林(4.6305t/hm2)、岳桦林(4.3724t/hm2)、白桦林(4.0008t/hm2)、山杨林(2.8699t/hm2);不同森林群落死活细根的比率也不同,云冷杉林死细根含量所占比例最高,达40%以上,而其他群落类型相对较低,死细根所占比率都在20%以下;从不同土壤层次中细根所占的比例看,红松阔叶林在0～10cm土壤中细根含量占总根量的60%以下,其他则都在70%以上,其中白桦林最高,达到80%以上.

Heat capacity and enthalpy of fusion of pyrimethanil laurate (C24H37N3O2)

Low-temperature heat capacities of pyrimethanil laurate (C24H37N3O2) were precisely measured with an automated adiabatic calorimeter over the temperature range between T = 78 K and T = 340 K. The sample was observed to melt at (321.52 +/- 0.04) K. The molar enthalpy and entropy of fusion as well as the chemical purity of the compound were determined to be (67244 +/- 11) J (.) mol(-1), (209.28 +/- 0.02) J (.) mol(-1) (.) K-1, (0.9943 +/- 0.0004) mass fraction, respectively. The extrapolated melting temperature for the absolutely pure compound obtained from fractional melting experiments was (322.264 +/- 0.006) K. (C) 2004 Elsevier Ltd. All rights reserved.

长白山北坡岳桦种群结构及动态分析

以“空间代时间”的方法 ,以种群径级结构代替年龄结构 ,采用静态生命表、生存分析和空间格局分析方法 ,探讨了长白山北坡不同海拔分布的岳桦种群的结构和动态规律。结果表明 ,在海拔 180 0、190 0和 2 0 0 0m ,随海拔升高 ,岳桦种群密度增大 ,径级分布范围减小 ,种群存活曲线由DeeveyⅡ型过渡到DeeveyⅠ型 ,种群由稳定型过渡为增长型 ,说明岳桦种群由低海拔向高海拔 ,群落处于不同的演替和发展阶段。而且随着岳桦径级的增大 ,其分布格局由集群分布过渡到随机分布。

长白山北坡植被垂直带群落交错区的定量判定

以海拔梯度上的群落重要值和二元数据为指标 ,采用游动分割窗技术辨析了长白山北坡各植被带群落交错区的位置和宽度 .结果表明 ,采用平方欧氏距离 (SED)和Bray Curtis距离函数 (PD)计算的游动分割窗的峰值和峰宽有较好的重合性 ,其中基于灌木和草本物种重要值的平方欧氏距离更能准确地反映交错带植被的变异 .依据游动分割窗的分析 ,判定阔叶红松林和暗针叶林的交错区为渐变类型 ,位于海拔 112 0m ,宽度为 2 0 0m ,暗针叶林和岳桦交错区为急变类型 ,位于海拔 1790m ,宽度为 5 0m ,林线为急变类型 ,位于海拔 2 0 0 0m ,宽度为 4 0m .

Structure and acidity of Mo/H-MCM-22 catalysts studied by NMR spectroscopy

A comprehensive study on physical and chemical properties of Mo/MCM-22 bifunctional catalysts has been made by using combined analytic and spectroscopic techniques, such as adsorption, elemental analysis, and Xe-129 and P-31 NMR of adsorbed trialkylphosphine oxide probe molecules. Samples prepared by the impregnation method with Mo loadings ranging from 2-10 wt.% have been examined and the results are compared with that obtained from samples prepared by mechanical mixing using MoO3 or Mo2C as agents. Sample calcination treatment is essential in achieving a well-dispersed metal species in Mo/MCM-22. It was found that, upon initial incorporation, the Mo species tend to inactivate both Bronsted and Lewis sites locate predominantly in the supercages rather than the 10-membered ring channels of MCM-22. However, as the Mo loading exceeds 6 wt.%, the excessive Mo species tend to migrate toward extracrystalline surfaces of the catalyst. A consistent decrease in concentrations of acid sites with increasing Mo loading < 6 wt.% was found, especially for those with higher acid strengths. Upon loading of Mo > 6 wt.%, further decreases in both Bronsted and Lewis acidities were observed. These results provide crucial supports for interpreting the peculiar behaviors previously observed during the conversion of methane to benzene over Mo/MCM-22 catalyst under non-oxidative conditions, in which an optimal performance was achieved with a Mo loading of 6 wt.%. The effects of Mo incorporation on porosity and acidity features of the catalyst are discussed. (C) 2004 Published by Elsevier B.V.

Double proton transfer and one-electron oxidation behaviors in double H-bonded glycinamide-formamidine complex and comparison with biological base pair

The behaviors of double proton transfer (DPT) occurring in a representative glycinamide-formamidine complex have been investigated employing the B3LYP/6-311++G** level of theory. Computational results suggest that the participation of a formamidine molecule favors the proceeding of the proton transfer (PT) for glycinamide compared with that without mediator-assisted case. The DPT process proceeds with a concerted mechanism rather than a stepwise one since no zwitterionic complexes have been located during the DPT process. The barrier heights are 14.4 and 3.9 kcal/mol for the forward and reverse directions, respectively. However, both of them have been reduced by 3.1 and 2.9 kcal/mol to 11.3 and 1.0 kcal/mol with further inclusion of zero-point vibrational energy (ZPVE) corrections, where the lower reverse barrier height implies that the reverse reaction should proceed easily at any temperature of biological importance. Additionally, the one-electron oxidation process for the double H-bonded glycinamide-formamidine complex has also been investigated. The oxidated product is characterized by a distonic radical cation due to the fact that one-electron oxidation takes place on glycinamide fragment and a proton has been transferred from glycinamide to formamidine fragment spontaneously. As a result, the vertical and adiabatic ionization potentials for the neutral double H-bonded complex have been determined to be about 8.46 and 7.73 eV, respectively, where both of them have been reduced by about 0.79 and 0.87 eV relative to those of isolated glycinamide due to the formation of the intermolecular H-bond with formamidine. Finally, the differences between model system and adenine-thymine base pair have been discussed briefly.