南美白对虾高位池沉积物理化性质和细菌状况的研究

在南美白对虾4个月的养殖期内,对虾养殖池每平方米水面积积累沉积物平均湿重8.69 kg,干重2.29 kg,含水率73.2%.沉积物在虾池中的水平分布,养殖前期分布比较均一;养殖后期则分布不均,主要集中在虾池的中心.沉积物数量的月变化随着养殖时间的延长而逐渐增多.沉积物间隙水的pH值变化在6.21～7.67之间,平均为6.55.沉积物的有机物含量(平均为17.6%)和耗氧速率(平均为1.81 g/m2·d)较高,二者存在显著的正相关关系(r=0.7704).沉积物中含有丰富的氮、磷、钾等生物营养元素.沉积物中细菌总数变化在136.1×107～782.3×107 cells/g之间,平均为352.9×107cells/g.沉积物中细菌总数与有机物含量之间存在正相关关系(r=0.606 7).

滇中地区土壤有效磷含量对植物理化性质的影响

以滇中地区昆明、玉溪和曲靖3市所属12个县(市、区)的云南松、矮杨梅、牛尾蒿等32种主要森林植物为研究对象,共采集了32种346批次叶(茎)、17种43批次枝及对应植物根部土壤为实验样品,测定了其抽提物含量、灰分含量、热值和土壤有效磷含量,分析了土壤有效磷含量对植物理化性质的影响,进而研究了土壤有效磷含量对植物燃烧性的影响。结果表明:(1)土壤有效磷在一定程度上增加叶的抽提物含量和热值,降低叶灰分含量,但枝理化性质对土壤有效磷含量的响应不及叶明显;(2)滇青冈、华山松、黄茅、南烛、牛尾蒿、野八角、银荆、云南樟的叶理化性质对土壤有效磷含量响应较灵敏,云南油杉和云南樟的枝理化性质对土壤有效磷含量响应较灵敏,土壤有效磷也能相对明显地增加云南松、华山松、地盘松、牛尾蒿、紫茎泽兰等滇中地区常见植物枝、叶(茎)的抽提物含量和热值,降低他们的灰分含量;(3)在生境相似的条件下,土壤有效磷含量与抽提物含量、热值呈显著正相关关系。土壤有效磷能够在一定程度上增加植物的粗脂肪含量和热值,降低其灰分含量。这种变化趋势有利于植物燃烧性的提升。并就加强滇中地区森林火灾风险治理提出相应的措施与建议。

借助Multiwfn实现物理化学性质描述符的可视化:以单环B5N5为例

借助化学软件实现物理化学性质描述符的可视化能够极大地丰富课堂教学的内容,展现化学中的美。本文基于分子轨道绘制了仅由π电子贡献的定域化轨道定位函数(LOL-π)填色图、电子定域化函数(ELF)和扫描隧道显微镜(STM)图像,用表面静电势、平均局部离子化能(ALIE)、局部电子亲合能(LEA)可视化了分子表面反应位点,并用相互作用区域指示函数(IRI)和非键作用(NCI)函数分析揭示了B5N5单环的成键情况和弱相互作用,是把科研成果应用于课堂教学的典型范例。

冀北山地典型林分地表可燃物抗火性研究

以冀北山地塞罕坝林区典型林分白桦林(Betula platyphylla)、樟子松林(Pinus sylvestris)、华北落叶松林(Larix principis-rupprechtii)的地表可燃物为研究对象,分析可燃物载量、燃点、热值、平衡含水率和时滞等特征,并用熵权法对3个典型林分的抗火性进行评价。结果表明:(1)3种典型林分可燃物的载量基本呈现华北落叶松林(47.52 t/hm 2)>樟子松林(42.75 t/hm 2)>白桦林(24.28 t/hm 2)的变化规律,不同可燃物类别呈现腐殖质>枯落物1(d<0.6 cm的小枝、叶和杂草)>枯落物2(0.6 cm≤d<2.5 cm的小枝)>枯落物3(2.5 cm≤d<7.62 cm的枝条)的变化规律。(2)3种典型林分中,白桦林分地表可燃物燃点最低,热值最高,时滞最长,表现为更易燃烧,释放热量最大,潜在林火蔓延时间较长。(3)熵权法综合评定3种典型林分的地表可燃物综合抗火性表现为:樟子松林>华北落叶松>白桦林。

不同类型樟子松人工固沙林土壤质量研究

从土壤微生物、土壤持水性、土壤物理、化学性质方面探讨了不同类型樟子松人工固沙林土壤质量状况,得出针阔混交林比针叶纯林土壤质量高的结论.松杨混交林、松枫混交林林下微生物细菌、真茵数量分别比樟子松纯林高1～3倍,表层枯枝落叶量比纯林高8.54%～10.02%,0～20 cm最大持水量提高了4%～5%.不同林分类型间土壤差异不大,混交林有降低趋势;养分状况表层有较明显差异,但深层土壤中除速效N之外,其他各项养分含量差异不明显。

Influence of functionalized graphene on the bacterial and fungal diversity of Vicia faba rhizosphere soil

The effect of functionalized graphene on the growth and development of Vicia faba L.was investigated by analyzing its impact on the composition and diversity of the microbial community in rhizosphere peat soil.Seedlings of V.faba planted in this peat soil were treated with either distilled water(CK)or 25 mg·L^(−1)(G25)of functionalized graphene solution.Results showed that the height and root length of V.faba seedlings in the G25 group were significantly larger than those in CK group.The microbial com-munity was analyzed by amplifying and sequencing the 16S rRNA gene V_(3)-V_(4) region of bacteria and internal transcribed spacer re-gion of fungi in rhizosphere soil using Illumina MiSeq technology.Alpha and beta diversity analysis indicated that functionalized graphene increased the richness and diversity of bacteria and fungi in the V.faba rhizosphere peat soil.The abundances of three ni-trogen cycling-related bacteria,Hydrogenophaga,Sphingomonas and Nitrosomonadaceae,were also altered after treatment with the functionalized graphene.The relative abundance of Basilicum,related to soil phosphorus solubilization,decreased in the fungal com-munity,while the relative abundance of Clonostachys and Dimorphospora,which exhibited strong biological control over numerous fungal plant pathogens,nematodes and insects,increased in the soil after functionalized graphene treatment.Redundancy analysis re-vealed that the potential of hydrogen(pH),organic matter,and total phosphorus contributed the most to the changes in bacterial and fungal community composition in the rhizosphere soil.Overall,our findings suggested that the addition of functionalized graphene altered the relative abundances of nitrogen and phosphorus cycling-related microorganisms in peat soil,promoting changes in the physicochemical properties of the soil and ultimately leading to the improved growth of V.faba plants.

滇中3种阔叶燃烧性与土壤有效磷含量的关系

为探究滇中地区土壤有效磷含量与植物叶片理化性质以及燃烧性的关系,以银荆、蓝桉、滇青冈3种滇中地区常见常绿阔叶树种为研究对象,统计随着土壤有效磷含量升高,植物叶片粗脂肪含量升高、灰分含量降低、热值增大的样品批次所占比例,并计算植物叶片的燃烧性综合指数,分析叶片燃烧性综合指数与土壤有效磷含量的关系,研究土壤有效磷含量对植物燃烧性的影响。结果表明:随土壤有效磷含量升高,银荆和滇青冈叶片的粗脂肪含量升高、灰分含量降低、热值增大的批次比例均在50%以上。蓝桉叶片除粗脂肪含量升高的批次比例超过50%外,灰分含量降低与热值增大的批次比例均未达到50%。土壤有效磷含量升高,3种植物叶片的粗脂肪含量升高,但其对灰分含量和热值的影响在不同树种之间有所差别。土壤有效磷含量升高能够提升植物叶片的燃烧性,对滇青冈的提升效果最显著。

Chemical Constituents from Starfish Asterias rollestoni

Aim To investigate novel bioactive and structural metabolites from marineorganisms. Methods Column chromatography in association with semi-preparative HPLC were used for theisolation of compounds. 1D and 2D NMR, IR, UV, and MS were employed for structure elucidation.Results From the butanol fraction of the 95% EtOH extract of the starfish Asterias rollestoni, a newcompound N^7 -2'-deoxypseudoxanthosine (1), along with sixteen known compounds, 2'-0-methyl-inosine(2), 2'-deoxyinosine (3), 2'-0-methylguanosine (4), inosine (5); thymine (6), uracil (7), thymidine(8), deoxyuridine (9), 2'-0-methyluridine (10), ( ― )-(1S, 3S)-1-methyl-1, 2, 3,4-terrahydro-β-carboline-3-carboxyl-ic acid (11), ( ― )-(1R, 3S)-1-methyl-1, 2, 3,4-tetrahydro-β-carboline-3-carboxylic acid (12) , ( ― )-(3S)- 1, 2, 3,4-tetrahydro-β-carboline-3-carboxylic acid (13), L-tryptophan (14), L-phenylalanine (15), 3-carboxyindole (16), and p-hydroxybenzoic acid (17) , have been isolated. Conclusion Compound 1 is a newnatural product, and compounds 8, 9 and 10 are isolated from natural sources for the first time, andthe known compounds except 14 and 15 are first reported from starfish Asterias rollestoni.

A first-principle calculation of structural,mechanical and electronic properties of titanium borides

The first-principle calculations are performed to investigate the structural,mechanical and electronic properties of titanium borides （Ti2B,TiB and TiB2）.Those calculated lattice parameters are in good agreement with the experimental data and previous theoretical values.All these borides are found to be mechanically stable at ambient pressure.Compared with parent metal Ti （120 GPa）,the larger bulk modulus of these borides increase successively with the increase of the boron content in three borides,which may be due to direction bonding introduced by the boron atoms in the lattice and the strong covalent Ti-B bonds.Additionally,TiB can be regarded as a candidate of incompressible and hard material besides TiB2.Furthermore,the elastic anisotropy and Debye temperatures are also discussed by investigating the elastic constants and moduli.Electronic density of states and atomic Mulliken charges analysis show that chemical bonding in these titanium borides is a complex mixture of covalent,ionic,and metallic characters.

韶关小坑林场5种阔叶林对土壤特性的影响

对杉木林林分改造树种山杜英、樟树、黎蒴、红锥和火力楠形成的5种纯林的土壤理化性质、凋落物储量和养分进行研究,结果表明山杜英、樟树、藜蒴、红椎和火力楠的土壤容重分别为1.30、1.19、1.24、1.29和1.16·gcm^(-3),山杜英和红椎的土壤容重显著大于樟树和火力楠,土壤毛管持水量、总孔隙度、毛管孔隙度、非毛管孔隙度和通气孔隙度相反。5种林地的土壤p H值在4.3~5.1范围,属强酸性土壤。山杜英和樟树林的土壤有机质和全氮含量较高,火力楠中等,藜蒴和红椎较低,土壤全磷含量排序为火力楠>樟树>藜蒴>红椎>山杜英,土壤全钾含量为红椎>山杜英>樟树>火力楠>藜蒴。土壤碱解氮含量为樟树>火力楠>山杜英=藜蒴>红椎,土壤有效磷含量为红椎>樟树>山杜英=藜蒴=火力楠,土壤速效钾含量为樟树>火力楠>藜蒴>红椎>山杜英。

Effects of Biochar with Organic Materials on Substratum for Raising Rice Seedlings

[Objective] With a rice variety ＂Long Rice 11＂ as a test cultivar,an experiment of raising rice seedlings with the new substrata prepared from biochar,and maize stalks,rice husks,organic fertilizer,turf,zeolite,fine river sand and arable layer soil by mixing according to certain volume proportions was caried out,in order to investigate the physical and chemical properties of different organic-material seedling-raising substrata and the effects of these substrata on seedling growth.[Method] The experiment raised seedlings in greenhouses and adopted randomized block arrangement.[Result] The substratum of biochar mixed with maize stalks and rice husks could increase the maximum water-holding capacity of the substratum,reduce the volume weight of the substratum and improve the buffering effect of the substratum.It also had great effects on the contents of alkali-hydrolyzale nitrogen and rapidly available potassium in the substratum,and could improve the root number and substantial degree of rice seedlings.[Conclusion] Biochar with maize stalks and rice husks（the treament HC） is the optimal substratum in this study.

Evaluation of Soil Fertility Under Different Cupressus chengiana Forests Using Multivariate Approach

The distribution and growing conditions of Cupressus chengiana forests along with the physical and chemical properties of soils in Northwest Sichuan were studied in 2002 to investigate the conditions and characteristics of soil fertility of C. chengiana and to compare and investigate differences of soil fertility for six C. chengiana populations and their relationships with vegetation, climate and disturbance. The results of the study at 0-20 cm soil depth showed that 1) significant differences (P < 0.05) existed among populations for soil bulk density, soil total porosity, capillary porosity, maximum water-holding capacity, capillary water-holding capacity and topsoil natural water content; 2) chemical characteristics of soil organic matter, total N, total P, alkali-hydrolyzable N, available P, available K and cation exchange capacity were significantly different among the populations; and 3) based on the significant effect of soil fertility factors on forest growth, soil physical and chemical characteristics could be selected as an integrated fertility index (IFI) for evaluation of different C. chengiana populations. Principal component and cluster analyses showed significant differences probably due to the difference of vegetation conditions, management measurements, human-induced disturbances and environmental factors. In order to protect the soil ecological functions in fragile ecological regions, C. chengiana could be used in programs enclosing the hill for natural afforestation, natural forest protection programs, and programs replacing agriculture with afforestation measures.

Effects of surface physicochemical properties on NH_3-SCR activity of MnO_2 catalysts with different crystal structures

α‐,β‐,δ‐,andγ‐MnO2nanocrystals are successfully prepared.We then evaluated the NH3selective catalytic reduction(SCR)performance of the MnO2catalysts with different phases.The NOx conversion efficiency decreased in the order:γ‐MnO2>α‐MnO2>δ‐MnO2>β‐MnO2.The NOx conversion with the use ofγ‐MnO2andα‐MnO2catalysts reached90%in the temperature range of140–200°C,while that based onβ‐MnO2reached only40%at200°C.Theγ‐MnO2andα‐MnO2nanowire crystal morphologies enabled good dispersion of the catalysts and resulted in a relatively high specific surface area.We found thatγ‐MnO2andα‐MnO2possessed stronger reducing abilities and more and stronger acidic sites than the other catalysts.In addition,more chemisorbed oxygen existed on the surface of theγ‐MnO2andα‐MnO2catalysts.Theγ‐MnO2andα‐MnO2catalysts showed excellent performance in the low‐temperature SCR of NO to N2with NH3.

Property changes of anchor grout calcined ginger nuts admixed with fly ash and quartz sand after accelerated ageing tests

Calcined ginger nuts admixed by fly ash and quartz sand (CGN-(F+S)) has been validated to be basically compatible to earthen sites as an anchor grout. Accelerated ageing tests including water stability test, temperature and humidity cycling test, soundness test and alkali resistance test are conducted with the objective to further research the property changes of CGN-(F+S) grout. Density, surface hardness, water penetration capacity, water permeability capacity, soluble salt, scanning electron microscopy (SEM) images and energy dispersive spectrometry (EDS) spectrum of these samples have been tested after accelerated ageing tests. The results show that densities of samples decrease, surface hardness, water penetration capacity and water permeability capacity of samples increase generally. Besides, soluble salt analysis, SEM and EDS results well corroborate the changes. Based on the results it can be concluded that property changes are most serious after temperature and humidity cycling test, followed by water stability, soundness and alkali resistance test in sequence. But in general, CGN-(F+S) still has good durability.

Stndy on Soil Magnetic Effect

A study on the effect of applied magnetic field was performed with six types of soils collected fromnortheastern China. Magnetic field was found to cause changes of soil physicc-chemical properties and soilenzyme activities. An appropriate applied magnetic field could cut down soil zeta-potential, soil specificsurface, soil water potential and soil swelling capacity; raise the charge density on soil colloids and theactivities of invertase, hydrogen peroxidase and amylase in the soils; enhance soil aggregation and improvesoil structural status and soil water-releasing capability.

Physicochemical properties of DMI-LiNO_(3) solvated ionic liquid and its application in electrodeposition of neodymium at room temperature

The density,conductivity,and viscosity of the 1,3-dimethyl-2-imidazolinone and lithium nitrate(DMILiNO_(3))solvated ionic liquid were measured as a function of temperature.Additionally,the electrochemical mechanism and electrodeposition of neodymium from the DMI-LiNO_(3) solvated ionic liquid were investigated.Cyclic voltammetry results indicate that the electrochemical reduction of Nd(Ⅲ)is irreversible and proceeds via one-step with three-electron transfer,which is controlled by diffusion with a diffusion coefficient of 5.08×10^(-8) cm^(2)/s.Energydispersive X-ray spectrometry and X-ray photoelectron spectroscopy data confirm that the electrodeposit obtained after electrodeposition at-4 V(vs Ag)using the DMI-LiNO_(3)-Nd(CF_(3)SO_(3))_(3) solvated ionic liquid contains metallic neodymium.

Physicochemical properties of 1,3-dimethyl-2-imidazolinone−ZnCl_(2)solvated ionic liquid and its application in zinc electrodeposition

Zinc chloride(ZnCl_(2))was dissolved in the 1,3-dimethyl-2-imidazolinone(DMI)solvent,and the metallic zinc coatings were obtained by electrodeposition in room-temperature ambient air.The conductivity(σ),viscosity(η),and density(ρ)of the DMI−ZnCl_(2)solvated ionic liquid at various temperatures(T)were measured and fitted.Furthermore,cyclic voltammetry was used to study the electrochemical behavior of Zn(II)in the DMI−ZnCl_(2)solvated ionic liquid,indicating that the reduction of Zn(II)on the tungsten electrode was a one-step two-electron transfer irreversible process.XRD and SEM−EDS analysis of the cathode product confirmed that the deposited coating was metallic zinc.Finally,the effects of deposition potential,temperature and duration on the morphology of zinc coatings were investigated.The results showed that a dense and uniform zinc coating was obtained by potentiostatic electrodeposition at−2 V(vs Pt)and 353 K for 1 h.

Cemented backfill technology based on phosphorous gypsum

Physical-chemical properties of phosphorous gypsum, proportion and cemented mechanism of slurry with gypsum as aggregate were studied to remove the harms of gypsum pile, combining with difficult problems of excessive mined-out gobs, enormous ore body under roadway and low recovery ratio of Yongshaba Mine, Kaiyang Phosphor Mine Group, Guizhou Province, China. An appropriate backfill system and craflwork were designed, using shattering milling method to crush gypsum, double-axles mixing and strong activation mixing way to mix slurry, cemented slurry and mullock backfill alternately process. The results show that gypsum is fit for backfilling afterwards by adding fly ash, though it is not an ideal aggregate for fine granule and coagulate retardation. The suggested dosage （the mass ratio of cement to fly ash to gypsum） is 1：1：6-1：1：8 with mass fraction of solid materials 60%-63%. Slurry is transported in suspend state with non-plastic strength, and then in concretion state after backfilling. The application to mine shows the technology is feasible, and gypsum utilization ratio is up to 100%. Transportation and backfill effect is very good for paste-like slurry and drenching cemented slurry into mullock, and the compressive strength and recovery ratio are 2.0 MPa and 82.6%, respectively, with the maximum subsidence of surface only 1.307 mm. Furthermore, the investment of system is about 7 × 10^6 yuan （RMB）, only 1/10 of that of traditional paste backfill system.

Physico-Chemical Properties and Enzyme Activities of the Arable Soils in Lhasa,Tibet,China

An understanding of the physical,chemical,and biological properties of a soil provides a basis for soil use and management.This paper reports the major physico-chemical properties and enzyme activities of the soils of Lhasa's main arable lands and the factors that influence these soil properties.Composite and core samples were taken from the three main arable soil types(alluvial soil,subalpine arable steppe soil,and subalpine arable meadow soil) and were analysed using standard methods.The bulk density and the ventilation porosity ratio of the soils were close to the recommended values for arable lands,and the dominant soil texture was sandy.The soil moisture release rates were arable steppe soil > alluvial soil > arable meadow soil.Soil organic matter content,Cation-Exchange Capacity(CEC),total and available nitrogen content,and catalase activity of the arable meadow soil were higher than those of the alluvial and the arable steppe soils,while soil pH in the arable meadow was lower.Most of the measured properties did not show a significant variance among these three soils.However,the measured indices(apart from the total potassium) indicate that there are notable differences among the three types of soil.The results implied that the utilisation patterns of the arable soil or human activities,such as tillage practices and fertiliser applications,have a substantialeffect on the soil properties in this region.Our results suggest that the cultivation practices in the region have apparently positive impact on the soil organic matter,nutrient contents and bulk density probably due to the sound fertiliser management such as the applications of farmyard manure and chemical fertilisers.However,intense cultivation practices lowered the activity of most soil enzymes.The results demonstrate that the choice of soil management strategy had a significant impact on the soil physicochemical and biological properties in the region studied.

Synthesis and physico-chemical properties of new green electrolyte 1-butyl-3-methylimidazolium perchlorate

1-butyl-3-methylimidazolium perchlorate([BMIM]ClO4) was synthesized by two steps with N-methylimidazolium.Some physico-chemical properties,such as density,surface tension,viscosity,electrical conductivity as well as electrochemical window,were investigated and solvent performance was also studied.The results show that this kind of ionic liquid is an excellent electrolyte with low viscosity,high electrical conductivity and wide electrochemical window.In addition,[BMIM]ClO4 is soluble in most conventional solvents and some metal oxides have high solubility in it,which lays the foundation of direct electrolysis of metal oxides in this ionic liquid.