耕作技术在黄土高原地区的实践研究

针对耕作技术在特殊的自然条件和社会条件下为了良化农田生态环境和持续增产所采取的一整套用地与养地相结合的技术体系 ,着重分析了培肥地力、轮作倒茬、化学技术、选育品种、节水、立体种植、地膜覆盖、水土保持耕作法等八种技术充分利用光、热、水、气、土、肥资源而取得明显的社会效益、经济效益和生态效益 ,剖析了旱作技术在农业持续、稳定、健康发展中的作用和改善农业生态环境的显著地位 ,供同类地区的决策者和研究者借鉴

三江平原白浆土不同土地利用类型Fe~(2+)分布特征

土壤铁元素由高价态转化为低价态(二价铁),是土壤中铁元素移动的主要途径。为了探讨三江平原不同土地利用类型Fe2+分布情况及影响因素,文章通过在三江平原典型白浆土区采取水田、旱田、草地、林地4种不同土地利用类型样点,对其Fe2+含量及其影响因子进行对比研究分析。结果表明:土壤表层(0～10cm)Fe2+含量高低顺序为水田>草地>旱田>林地,主要影响因子为水分状况和pH值(r=0.851,r=0.909,p<0.01),其中水田Fe2+含量(305.5mg·kg-1)明显高于林地和旱田(30～40mg·kg-1),是其含量的8～10倍;草地除表层(0～20cm)Fe2+含量低于水田外,以下各层含量均高于其它土地利用类型;草地、旱田、林地Fe2+含量垂直分布规律相似:表层(0～10cm)及白浆层(30～40cm)含量略高,40cm以下Fe2+含量持续缓慢递减,相关分析表明旱田、草地主要影响因子为土壤pH值(r=-0.871,r=0.795,p<0.05),林地影响因子相关性均不显著;水田垂直变化趋势与其它3种类型相比有所不同,表层最高达305.5mg·kg-1,至40cm深处急剧递减至35.2mg·kg-1,以下无明显变化,主要影响因子为水分状况和TOC(r=0.962,r=0.991,p<0.01)。

沙地云杉新种的鉴定及其对我国北方生态环境建设意义

在浩瀚无垠的小腾格里沙地东部边缘，生态环境非常脆弱地区、分布着大面积的原始云杉天然林，是世界上非常罕见特殊的森林生态系统类型．但是长期以来，这种云杉究竞是哪一种？在我国植物分类学上一直是个争论性问题．我国著名树木分类学家郑万钧教授在《中国植物志》第七...

Green synthesis of 1-2 nm gold nanoparticles stabilized by amine-terminated ionic liquid and their electrocatalytic activity in oxygen reduction

Stable gold nanoparticles with average size 1.7 nm synthesized by an amine-terminated ionic liquid showed enhanced electrocatalytic activity and high stability.

间同1,2-聚丁二烯的结构和结晶动力学研究

间同1,2-聚丁二烯(s-PB)由丁二烯用Fe(2-EHA)3/Al(i-Bu)3/DEP作催化剂,在己烷溶剂中50℃下聚合制备.用13C NMR谱方法测定的1,2-结构含量为89.3%,间同结构为86.5%;X射线测得聚合物的结晶度约为68%.非等温结晶动力学研究采用DSC方法,改进的Avrami方程可以很好地分析s-PB非等温结晶过程的主期结晶,表明其结晶过程是自成核,三维球形生长.Ozawa方程不适合分析s-PB非等温结晶动力学;Avrami和Ozawa方程结合的方法可以很好地描述s-PB非等温结晶过程,指数a为1.138,F(θ)随着结晶度的提高而增大;并计算了s-PB的结晶活化能.

Synthesis, characterization, crystal structure and magnetic property of asymmetrical double Schiff base heterotrinuclear complex: Cu(II)-Co(II)-Cu(II)

An asymmetrical double Schiff-base Cu(II) mononuclear complex, HCuLp (H(3)Lp is N-3-carboxylsalicylidene-N'-5-chlorosalicylaldehyde-1,3-diaminopropane) and a heterometal trinuclear complex with double molecular structure (CuLp)(2)Co center dot 5H(2)O have been synthesized and characterized by means of elemental analyses, IR and electronic spectra. The crystal structure of the heterotrinucler complex was determined by X-ray analysis. Each asymmetric unit within the unit cell of the complex contains two heterotrinuclear neutral molecules (a) [CuLpCoCuLp], (b) [(CuLpH(2)O) CoCuLp] and four uncoordinated water molecules. In the two neutral molecules, the central Co2+ ions are located at the site of O-6 with a distorted octahedral geometry, one terminal Cu2+ ion (Cu(3)) at the square-pyramidal environment of N2O3, and the other three at the square planar coordination geometry with N2O2 donor atoms. Magnetic properties of the heterotrinucler complex have been determined in the temperature range 5-300 K, indicating that the interaction between the central Co2+ ion and the outer Co2+ ions is antiferromagnetic.

芳香环状低聚物组分分布与单体结构关系的研究

根据Jacoson-Stockmayer(J-S)环化理论,应用基质辅助激光解吸离子化飞行时间质谱(MAIDL-TOFMS),对一系列芳香环状低聚物组分分布进行分析,研究了芳香环状低聚物的组分分布与单体结构的关系,结果表明,在芳香聚酯、聚膦酸酯及芳香聚醚环状低聚物系列中,Inc_n与Inn呈良好的线性关系,符合J-S理论分布,在环状聚酯及聚膦酸酯系列中,低聚物的组分分布受双酚单体的中心键角影响,单体的中心键角在100°～120°之间,其中心键角愈小,γ值愈大,而在聚醚系列中,在固定一种单体的前提下,环化物的组分分布受另一单体键角的影响与环状聚酯和聚膦酸酯相一致。

Direct decomposition of NO over the mixed oxide catalysts Nd_(2-)Sr_xNiO_(4±λ)

The nitrogen oxides (NO_x) are serious pollutants in earth's atmosphere in the sensethat they are one of the main sources to cause the acid rain. The removal of NO_x is oneof the key research topics in the protection of environmen.

碱土金属复合氟化物体系中钐离子的价态及光谱

一定条件下钐离子、铕离子、镱离子等都具有明显的变价特性。钐离子通常以+3价形式存在,Sm~(3+)电子构型为[Xe]4f~5,基态光谱项为~6H_(5/2),4f能级最低激发态为~4G_(5/2)。Sm~(2+)在溶液中很不稳定,极易被氧化,但在某些固态化合物中Sm~(2+)能够比较稳定存在。通过适当的还原方法可以制得+2价钐的化合物。Sm~(2+)电子构型为[Xe]4f~6,基态光谱项为~7F_0,4f能级最低激发态光谱项为~5D_0。通常~5D_0能级位置较其4f~5d激发态能级下限位置低,因此室温

ANESTHETIC LIDOCAINE AND DICAINE TRANSFER ACROSS LIQUID LIQUID INTERFACES

Lidocaine transfer across the water/1,2-dichloroethane and the water/nitrobenzene interfaces has been investigated by chronopotentiometry with linear current scanning and cyclic voltammetry. The irreversible hydrolysis occurring in the phase transfer of dicaine at the water/nitrobenzene interface is discussed.

2,3,5-triphenyl-2H-tetrazolium chloride and 2,4,6-tri(2-pyridyl)-s-triazine on the corrosion of mild steel in HCl

Electrochemical measurement, quantum chemical method, and scanning electron microscopy (SEM) were performed to investigate the inhibitive effect of 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) and 2,4,6-tri(2-pyridyl)-s-triazine(TPT) on the corrosion of mild steel in 1mol.L-1 HCl at room temperature. Impedance spectroscopy measurement showed that the polarization resistance increased and that double layer capacitance decreased with the increase in the inhibitive concentration, and the results of potentiodynamic polarization showed that the inhibitors suppressed both cathodic and anodic processes of steel corrosion without change in the mechanism. Higher the orbital density distribution strength of the lowest unoccupied molecular orbital, higher is the molecule dipole, and lower energy gap between the energy of the highest occupied molecular orbital and the energy of the lowest unoccupied molecular orbital resulted in higher inhibitory efficiency. The results of SEM analysis showed that the metal was protected from aggressive corrosion by the addition of TTC and TPT.

青藏高原正常有机土与草毡寒冻雏形土地温观测的比较研究

在海拔高度相同、距离相近的纤维正常有机土与草毡寒冻雏形土地区，虽然区域气候一致，但二者地温具有显著的分布差异。从不同类型土壤４０～８０ｃｍ层次地温分布特征来看，草毡寒冻雏形土区域地温年平均3.0℃，变化剧烈，年较差大，０℃等值线可延伸至很深处。纤维正常有机土地温年平均1.4℃，变化较为平稳，０℃等值线只延至８０～９０ｃｍ左右。二类型地区地温随深度变化也有很大的不一致性。

塔里木南缘元古代变质基性火山岩地球化学特征—古塔里木板块中元古代裂解的证据

超大陆裂解是当今地学研究最前沿课题。通过研究塔里木南缘铁克里克构造带前寒武纪变质火山岩的岩石化学特征、微量元素特征、稀土元素特征及Sm-Nd同位素特征，探讨古塔里木板块的中元古代大陆裂解构造事件。该套变质火山岩组合下部以变质酸性火山岩（流纹岩夹部分晶屑凝灰岩）为主，夹少量玄武岩，上部为玄武岩夹少量条带状大理岩。基性火山岩ω(SiO2)为42.34%-49.55%,ω（Na2O+K2O)为2.63%-8.81%。下部玄武岩ω(Na2O)/ω(K2O)值为0.54-1.5，为钾玄岩系列，稀土总量高，且轻稀土富集，平均ω（La)n/ω(Yb)n值为3.45,δ(Eu)为0.69-0.91，具弱至中等的Eu负异常，微量元素具有碱性板内玄武岩特征；上部玄武岩ω（Na2O)/ω(K2O)为5.11-17.89，为拉斑系列，轻重稀土没有明显分异，δ(Eu)在0.81-1.13之间，基本没有Eu异常，ω(La)n/ω(Yb)n平均为1.69,配分曲线与大洋拉斑玄武岩一致，微量元素显示LILE（如Rb、Ba、Th)富集，HFSE与大洋拉斑玄武岩一致。岩石地球化学反映从早到晚由碱性－钙碱系列逐渐向拉斑系列演化。在上部玄武岩中获得（1200±82.3)Ma的Sm-Nd等时线年龄。认为该套变质火山岩记录了古塔里木反块在中元古代大陆裂解的构造过程。