Effect of nutrient level on phytoplankton community structure in different water bodies

Increasing levels of pollution within water bodies can cause eutrophication and an associated rapid growth in and reproduction of phytoplankton. Although most frequently occurring in bodies of water such as lakes and dams, in recent years an increasing number of river systems in China have suffered serious algal blooms. The community structure of phytoplankton may differ, however, dependent on the hydrodynamic conditions and nutrient levels within the water body. The field investigation results obtained from a stagnant river in Suzhou City and Taihu Lake, China, showed that in water with higher concentrations of nitrogen and phosphorus, Chlorophyta became the predominant species and in water with lower concentrations of nitrogen and phosphorus, Cyanobacteria became the predominant species. Growth experiments with competitive species, Microcystis aeruginosa Kutz and Scenedesmus quadricauda （Turp.）, were conducted at three different nutrient levels. The biomass of algae in pure and mixed cultures was measured under conditions of different N/P ratios at oligotrophic, eutrophic and hypertrophic nutrient levels. The results indicated that the most suitable state for the growth and reproduction of M. aeruginosa and S. quadricauda were eutrophic conditions in both pure and mixed cultures. Under competition, however, the lower medium nutrient levels favoured M. aeruginosa, while the higher medium nutrient levels better suited S. quadricauda. Under similar hydrodynamic conditions, the community structure of phytoplankton in the water body was determined by the dominant species in competition for nutrients.

P-wave velocity structure in the crust and the uppermost mantle of Chao Lake region of the Tan-Lu Fault inferred from teleseismic arrival time tomography

Chao Lake is a Geoheritage site on the active Tan-Lu Fault between the Yangtze craton,the North China craton,and the Dabie orogenic belt in the southeast.This segment of the fault is not well constrained at depth partly due to the overprinting of the fault zone by intrusive materials and its relatively low seismic activity and sparse seismic station coverage.This study took advantage of a dense seismic array deployed around Chao Lake to delineate the P-wave velocity variations in the crust and uppermost mantle using teleseismic earthquake arrival time tomography.The station-pair double-difference with waveform crosscorrelation technique was employed.We used a multiscale resolution 3-D initial model derived from the combination of highresolution 3-D v S models within the region of interest to account for the lateral heterogeneity in the upper crust.The results revealed that the velocity of the upper crust is segmented with structures trending in the direction of the strike of the fault.Sedimentary basins are delineated on both sides of the fault with slow velocities,while the fault zone is characterized by high velocity in the crust and uppermost mantle.The high-velocity structure in the fault zone shows characteristics of magma intrusion that may be connected to the Mesozoic magmatism in and around the Middle and Lower Yangtze River Metallogenic Belt(MLYMB),implying that the Tan-Lu fault might have formed a channel for magma intrusion.Magmatic material in Chao Lake is likely connected to the partial melting,assimilation,storage,and homogenization of the uppermost mantle and the lower crustal rocks.The intrusions,however,seem to have suffered severe regional extension along the Tan-Lu fault driven by the eastward Paleo-Pacific plate subduction,thereby losing its deep trail due to extensional erosion.

适用于光导开关触发的V/N气体开关设计与验证

为了满足多路精确同步触发开关要求,将光导开关(PCSS)与V/N气体开关结合,可充分发挥PCSS低触发阈值、低抖动和光电隔离以及V/N气体开关工作电压高、带载能力强等优势。两种开关结合的核心是V/N气体开关结构参数与PCSS触发回路的参数匹配。分析计算了V/N气体开关的结构电容、触发回路振荡参数、开关电场分布等,研究了V/N气体开关的结构电容与PCSS、串联电感等构成的振荡回路的匹配关系,通过实验获得了V/N气体开关自击穿电压曲线、导通延迟时间以及不同欠压比下的延迟时间抖动等,初步验证了适用于PCSS触发的V/N气体开关设计。

SYNTHESIS AND STRUCTURE OF A LINEAR TRIVANADIUM COMPOUND(Ph_4P)[V_3(OC_6H_4S-o)_6]-SIMULATION OF THE VANADIUM SITE OF ALTERNATIVE NITROGENASE

Compound(Ph_4P)[V_3MP_6](MPH_2=o-HOC_6H_4SH)was obtained by reaction of VCl_3 and Na_2MP in ethanol in the presence of Ph_4PBr.It is triclinic and crystallizes in space group P1,fw=1237.3,a=14.127(4), b=14.342(4),c=15.878(4);α=65.08(2),β=73.09(2),T=78.68(2)°;V=2781.3~3, Z=2,d_c=1.48 g/cm^3.Final R factor is 0.063.The three vanadium atoms are linearly arranged and bridged by the oxygen atoms and terminally chelated by the thiolato-atoms of the six MP^2-ligands in pseudo-S_6 symmetry.

基于语义功能语法的“V着个N/NP”结构句法语义特点研究

“V着个N/NP”结构首见于宋代,是在“V个N/NP”结构中增加持续体标记“着”形成的,语义功能为表达动作或状态的持续。本文一是分析状态动词所在“V着个N/NP”结构的句法语义特点,旨在呈现状态动词作为动词中较为特殊的一类,其语义特征对此结构句法语义特点的影响;二是通过分析此结构中“个”的语义特点,提出“个”具有指称总量以及标记贬义的语义功能,进而阐释“V着个N/NP”结构具有不对称性和主观性的原因。

Synthesis, Crystal Structure and Kinetic Mechanism of Thermal Decomposition of a Zinc(II) Complex with N-Salicylidene-p-toluidine

The title complex, Zn（C24H13NO）2Cl21, has been synthesized by the reaction of zinc chloride with Schiff base ligand N-salicylidene-p-toluidine and its structure was determined by single-crystal X-ray diffraction. The crystal is of monoclinic, space group Cc with a = 14.896（3）, b = 12.506（2）, c = 15.352（3） A,β = 114.711 （4）°, V = 2598.0（8） A^3, C28H26ZnCl2N2O2, Mr = 558.80, Z = 4, Dc = 1 .429 g/cm^3,μ = 1.179 mm^-1, Flack parameter = 0.027（19）, F（000） = 1152, R = 0.0709 and wR = 0.1041 for 3117 observed reflections （Ⅰ 〉 2σ（Ⅰ））. In complex 1, the center Zn ion is four-coordinated by two O atoms from two Schiff base ligands and two Cl atoms in a distorted tetrahedral geometry. Additionally, the thermal decomposition of complex 1 as well as its kinetic mechanisms and equations is studied under the non-isothermal integral and differential methods in air by TG-DTG curves.

Syntheses,Structures and Luminescent Property of Two Supramolecular Complexes Containing N-P-Acetamidobenzenesulfonyl-glycine Acid Ligand

Making use of N-P-acetamidobenzenesulfonyl-glycine acid （abbreviated as abglyH2）,two transitional metal complexes [Zn（abglyH）（phen）2]ClO4·H2O （1） and Co（abglyH）2（bipy）2（H2O）2 （2） （phen = 1,10-phenanthroline,bipy = 4,4＇-bipyridine） have been synthesized under mild conditions and characterized by IR,elemental analysis and X-ray diffraction analysis. Complex 1 is a monomeric compound which is further assembled by intermolecular hydrogen bonds and π-π interaction into a 2-D supramolecular network. Complex 2 is also a monomeric compound and further connected by intermolecular hydrogen bonds to form a 2-D supramolecular network. Fluorescent analysis shows that complex 1 has an emissive maximum at 364 nm in the solution state at room temperature.

Effects of N-doping concentration on the electronic structure and optical properties of N-doped β-Ga_2O_3

The electronic structures and the optical properties of N-doped β-Ga2O3 with different N-doping concentrations are studied using the first-principles method.We find that the N substituting O（1） atom is the most stable structure for the smallest formation energy.After N-doping,the charge density distribution significantly changes,and the acceptor impurity level is introduced above the valence band and intersects with the Fermi level.The impurity absorption edges appear to shift toward longer wavelengths with an increase in N-doping concentration.The complex refractive index shows metallic characteristics in the N-doped β-Ga2O3.

Syntheses and crystal structures of rare earth (Nd, Gd) 1-D chain com-plexes with N-p-tolylsulfonyl-β-alanine

Two rare earth complexes of Ts-β-AlaH with the formula of [Ln2（H2O）4（Ts-β-AlaH）6]n·4nH2O （where Ln = Nd（1）, Gd（2）; Ts-β-AlaH = N-p-tolylsulfonyl-β-Alanine） have been synthesized and characterized by elemental analysis, IR and X-ray diffraction. The results show that the two complexes are isostructural. They crystallize in a monoclinic system with P21/n space group. Crystal data for 1： a = 0.95149（19） nm, b = 1.9012（4） nm, c = 2.2863（5） nm, β= 100.37（3）°, Z= 4, De= 1.509 mg/cm^3, F（000） = 1880, R1= 0.0560, wR2= 0.1564 [I 〉 2σ（/）]; for 2： a = 0.9495（2） nm, b = 1.9037（4） nm, c = 2.2987（5） nm, β= 99.87（3）°, Z = 4, Dc= 1.541 mg/cm^3, F（000） = 1916, R1= 0.0515, wR2= 0.1566 [I〉2σ（I）]. The two complexes are one-dimensional chains and the coordination number of the Nd^3＋ or Gd^3＋ ion is nine.

Synthesis and Crystal Structure of N,N',N''-Tris-(2-aminophenyltriphenylphosphium)-benzene-1,3,5-tricarboxamide

A new tripodal P,N ligand （C63H48N3O3P3） was prepared and characterized by elemental analysis, IR and single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/c with a = 13.013（3）, b = 28.406（6）, c = 14.911（3） A^°, β= 111.04（3）°, V= 5144.6（18） A^°^3 Z = 4, Dc = 1.276 g/cm^3, Mr = 987.95, λ（MoKa） = 0.71073 A^°,μ = 0.17 mm^-1, F（000） = 2064, R = 0.0786 and wR = 0.1545. A total of 43260 unique reflections were collected, of which 5112 with I 〉 2σ（I） were observed. The title compound has a central benzene ring, which is linked by -NH-CO- bonds to three 2-aminophenyltriphenylphosphium moieties, of which two with P（1） and P（2） centers are pointing to the same face of the central aryl ring, while the third one directs oppositely, forming a pseudo-propeller. In the crystal structure, there exist face-to-face π-π stacking interactions which increase the stability of the crystal structure.

Synthesis and Crystal Structure of Mo(CO)_4(NNP) (NNP=2-(N-Cyclohexyl-N-diphenylphosphinomethyl)aminopyridine)

The crystal structure of the title complex, Mo(CO)4(NNP), (NNP=2-(N-cyclohexyl- N-diphenylphosphinomethyl)aminopyridine) has been determined, and its crystallographic data are as follows: triclinic, space group P , a = 9.135(1), b = 9.772(1), c = 17.000(2) , a = 76.377(2), b = 78.333(2), g = 67.243(2)? Mr = 582.44, V = 1349.7(3) 3, Z = 2, Dc = 1.433 g/cm3, m(MoKa) = 0.581 mm-1 and F(000) = 596. A total of 5614 reflections were collected in the range of 2.30< q < 25.03? of which 4721 were independent (Rint = 0.0176) and 4159 observed reflections (I ≥ 2s(I)) were used in the refinement. R = 0.0326 and wR = 0.0867. The Mo centre is six-coordinated by four carbonyls (MoC 1.938(4), 2.003(4), 2.019(4), 2.035(4) ) and P, N atoms from the ligand (MoP 2.4812(8), MoN 2.349(3) ?. The coordination geometry of the complex can be described as an octahedron.

Synthesis and Crystal Structure of a 1-D Chain Zinc(Ⅱ) Coordinated Polymer with N-p-Tolysulfonyl-glutamine

A novel coordination polymer {[Zn（ts-gln）（bipy）].3H2O}n （ts-glnH2 = N-p-tolysulfonyl-glutamine, bipy = 2,2′-bipyridine） has been prepared and structurally characterized by X-ray diffraction method. It crystallizes in orthorhombic, space group P212121 with a = 8.2622（5）, b =16.6244（10）, c = 18.2807（10） A, V = 2510.9（3） A^3, C22H2N4O8SZn, Mr = 573.91, Z = 4, Dc = 1.518 g/cm^3, μ（MoKα） = 1.115 mm^-1, F（000） = 1192, the final R = 0.0262 and wR = 0.0662 for 5691 independent reflections with Rint = 0.0240. The zinc（Ⅱ） atom is coordinated by N（3） and N（4） atoms of a bipy molecule, two carboxylate O（1） and O（2A） and amino N（ 1 ） atoms of ts-gln ligands, resulting in a square-pyramidal geometry. The title complex consists of an infinite zigzag chain of zinc（Ⅱ） ions linked by the carboxylate of N-p-tolysulfonyl-glutamine.

Synthesis and Crystal Structure of 〔Na(N-(p-chlorophenyl)aza-15-crown-5)-(Et_2O)〕_2 (Na_2W_(0.5)Mo_(7.5)O_(26))

[Na (N- (p-chlorophenyl ) aza-15--crown--5 ) (Et2O )]2 (Na2W0.5 Mo7.5 O26), Mr= 2119. 4, monoclinic, space group P21/c, a= 17. 803(4), b= 13. 674 (3), c= 14. 610(3), β= 112. 33(3)°, V=3290(1) A3, Z= 2, Dc= 2. 139 g/cm3, μ= 1.704 mm-1, F (000) = 2079, R = 0. 026, Rw= 0. 030. The supermolecular complexconsists of one [Na2W0.5Mo7.5O28)2- anion in which only two Mo atoms are replaced byW in 25% (M= l/4W+3/4Mo) and the two Na+ are linked symmetrically to neighbouring [W0.5Mo7.5O26]4- units on the right and the left respectively and two complexcanons in which each Na+ deviates from the plane of the four ether oxygens and is coordinated to every hetero--atom in the crownether ring, and is also coordinated to the Oatom of Et2O.

Synthesis and Crystal Structure of Tris(N-p-methylphenyl-3-hydroxy-2-ethyl-4-pyridinonato)iron(III)

The complex [Fe(C14H14NO2)3]2H2O has been prepared by reaction of N-p-methylphenyl-3-hydroxy-2-ethyl-4-pyridinone with FeCl36H2O. A single-crystal X-ray study shows that the iron atoms lie in a trigonally distorted octahedral environment coordinated to the hydroxy and ketone oxygen atoms of three ligands in the mer configuration Mr=773.57(C42H46N3O8Fe). The crystal is hexagonal with space group P31c; a=15.943(2), c=17.612(4)? V=3877.0(12)?, Z=4, Dc=1.325g/cm3, m=0.445mm-1, F(000)=1634, R=0.0446, wR= 0.1154 for 3085 reflections with I >2s(I). The bond lengths from iron to oxygens are 1.980(1)?for the ketone oxygens and 2.071(1)?for the hydroxy oxygens. The molecule exhibits the expected propeller shape, and the angle of the trigonal twist is 48.37. The dihedral angles are 0.5(2)?between chelate ring plane and pyridine ring plane and 71.31(7)?between pyridine ring plane and benzene ring plane. The solvent H2O(O(3) and O(4)) molecules are linked with O(2) and O(1) by hydrogen bonds with bond lengths 2.900(1) and 2.999(1)? respectively.

C-V法测量pn结杂质浓度分布的基本原理及应用

全面地介绍了pn结C-V测量法的基本原理、测试设备及条件。利用pn结反向偏压时的电容特性推导了有效杂质浓度随深度分布的计算公式及突变结和线性缓变结的1/(C2)-V和1/(C3)-V关系图。应用该原理计算、分析了IN5401整流二极管pn结的特性及杂质浓度的纵向分布。

Keggin型P-V-Mo-W四元杂多酸催化合成乙酸正丁酯

采用正交试验设计研究了Keggin型P-V-Mo-W四元系列杂多酸H4PVMoxW11-xO40·nH2O(x=1,2,3,4)催化冰乙酸和正丁醇合成乙酸正丁酯的反应,得出最佳反应条件如下:正丁醇与冰乙酸的物质量比为1.2∶1,催化剂的用量为冰乙酸质量的0.5%,反应时间为40 min,酯化率达到88.52%。该系列杂多酸的酯化率随钨原子数的增加而提高。

从“X于”结构来看“V+P+N”结构的发展趋势

"V+P+N"是一类常用的结构,性质比较复杂。本文首先综述对"V+P+N"结构研究的几种观点;然后根据原型理论,通过对"X于"结构的考察来预测"V+P+N"结构的发展趋势;最后用方言材料来为我们的观点提供佐证。

Keggin型P-V-Mo-W四元杂多酸催化合成肉桂酸正丁酯的研究

利用正交实验设计研究了Keggin型P-V-Mo-W四元系列杂多酸H4PVMoxW11-xO40·nH2O(x=1,2,3,4)催化肉桂酸和正丁醇合成肉桂酸正丁酯的反应.结果表明,最佳反应条件为:正丁醇与肉桂酸的物质的量比为1.2∶1,催化剂的用量为肉桂酸质量的0.5%,反应时间为1.5h.该系列杂多酸随着钼、钨原子比例的增加,酯化率提高.

论“V+P+N”中P由前加成分向后加成分的转变

由于汉语韵律的原因,现代汉语“V+P+N”结构中有的P由“P+N”结构中的前加成分变成了“V+P”的后加成分。前附后的P呈现出动态的变化趋势,有的变成了语法成分———助词,有的变成了构词成分———词缀,有的还游移于助词和词缀之间。

基于OpenMV的无接触温度测量与身份识别装置

由于疫情原因影响,现在无接触测温装置需求量迅速提高。本文基于OpenMV设计了一款无接触温度测量与身份识别装置.本产品以STC89C52RC单片机作为主控,实现了体温测量和人脸识别功能。本产品的主要特点有便携式、成本较低,实现了非接触式体温测量、口罩佩戴检测、人脸识别等功能。