Determining the Zn Content of Cherry in Field Using VNIR Spectroscopy

Visible and near-infrared(VNIR)spectroscopy is an eco-friendly method used for estimating plant nutrient deficiencies.The aim of this study was to investigate the possibility of using VNIR method for estimating Zn content in cherry orchard leaves under field conditions.The study was conducted in 3different locations in Isparta region of Turkey.Fifteen cherry orchards containing normal and Zn deficient plants were chosen,and 60 leaf samples were collected from each location.The reflectance spectra of the leaves were measured with an ASD FieldSpec HandHeld spectroradiometer and a plant probe.The Zn contents of leaf samples were predicted through laboratory analysis.The spectral reflectance measurements were used to estimate the Zn levels using stepwise multiple linear regression analysis method.Prediction models were created using the highest coefficient of determination value.The results show that Zn content of cherry trees can be estimated using the VNIR spectroscopic method(87.5相似文献   

Construction Theory of Function on Local Fields

We establish the construction theory of function based upon a local field K p as underlying space. By virture of the concept of pseudo-differential operator, we introduce "fractal calculus"(or, p-type calculus, or, Gibbs-Butzer calculus). Then, show the Jackson direct approximation theorems, Bermstein inverse approximation theorems and the equivalent approximation theorems for compact group D( Kp) and locally compact group K+p(= Kp), so that the foundation of construction theory of function on local fields is established. Moreover, the Jackson type, Bernstein type,and equivalent approximation theorems on the H ?lder-type space Cσ(Kp), σ 0, are proved; then the equivalent approximation theorem on Sobolev-type space Wrσ(Kp),σ≥ 0, 1 ≤ r +∞, is shown.     

Influence of external load on friction coefficient of Fe-polytetrafluoroethylene

A coarse-grained molecular dynamics simulation model was developed in this study to investigate the friction process occurring between Fe and polytetrafluoroethylene(PTFE).We investigated the effect of an external load on the friction coefficient of Fe–PTFE using the molecular dynamics simulations and experimental methods.The simulation results show that the friction coefficient decreases with the external load increasing,which is in a good agreement with the experimental results.The high external load could result in a larger contact area between the Fe and PTFE layers,severer springback as a consequence of the deformed PTFE molecules,and faster motion of the PTFE molecules,thereby affecting the friction force and normal force during friction and consequently varying the friction coefficient.     

稀有气体二聚体基准集NgD×15构建及其对DFT方法的评价

基准集是训练和评价量子化学计算方法的重要工具,稀有气体二聚体Ng_2作为重要的弱色散体系,目前为止仍没有一个较为完整、精确的基准集,最近Head Gordon研究组发表MGCD84数据库时,其RG10基准集仍沿用了Tang-Toennies经验势.本文首先以He_2为例,证明了在CCSD(T)水平,使用中点键函数{6s6p6d3f2g1h}的aug-cc-pV5Z基组收敛性;并在CCSD(T)/aug-cc-pV5Z-{6s6p6d3f2g1h}水平下,经BSSE均衡校正后,获得了He_2至Rn_2全部同核稀有气体二聚体的15点相互作用势,构建了NgD×15基准集.并以此为标准,重新评价了目前常用的DFT的非局域和色散校正方法.总体上,非局域校正的精度较D3色散校正高,ωB97X-V及ωB97X-rV两种方法是该体系最优性价比的DFT-NL方法.     

Crystallization of Poly(ethylene adipate) within γ-Phase Poly(vinylidene fluoride) Matrix

The effects of PEA on the γ-phase PVDF crystal structure and the crystallization of PEA within the pre-existing γ-phase PVDF spherulites have been investigated by optical microscopy(OM), infrared spectroscopy(IR) and scanning electron microscopy(SEM). The results demonstrate that the γ-phase PVDF spherulites consist of the lamellae exhibiting a highly curved scroll-like morphology and develop preferentially in PEA-rich blend. With increasing PEA concentration, the scroll diameter increases and the scrolls are better separated from each other. PEA crystallizes first in the interspherulitic region and transcrystalline layer develops. Subsequently, the transcrystalline layer of PEA continues to grow within the γ-phase PVDF spherulites, e.g., in the region between the scrolls, until impinging on other PEA transcrystalline layers or spherulites. The crystallization kinetics results indicate that the growth rate of PEA crystals in the intraspherulitic region of γ-phase PVDF shows a positive correlation with content of PEA, but a negative one with the crystallization temperature of γ-phase PVDF.     

Mass and isotopic concentrations of water-insoluble refractory carbon in total suspended particulates at Mt.Waliguan Observatory(China)

Mass concentration and isotopic values δ¹³C and ¹⁴C are presented for the water-insoluble refractory carbon（WIRC） component of total suspended particulates（TSP）,collected weekly during 2003,as well as from October 2005 to May 2006 at the WMO-GAW Mt.Waliguan（WLG） site.The overall average WIRC mass concentration was（1183±120）ng/m³（n = 79）,while seasonal averages were 2081 ±1707（spring）,454±205（summer）,650±411（autumn）,and 1019±703（winter） ng/m3.Seasonal variations in WIRC mass concentrations were consistent with black carbon measurements from an aethalometer,although WIRC concentrations were typically higher,especially in winter and spring.The δ¹³C PDB value（-25.3 ± 0.8）%.determined for WIRC suggests that its sources are C₃ biomass or fossil fuel combustion.No seasonal change in δ¹³C PDB was evident.The average percent Modern Carbon（pMC） for ¹⁴C in WIRC for winter and spring was（67.2 ± 7.7）%（n = 29）.Lower pMC values were associated with air masses transported from the area east of WLG,while higher pMC values were associated with air masses from the Tibetan Plateau,southwest of WLG.Elevated pMC values with abnormally high mass concentrations of TSP and WIRC were measured during a dust storm event.     

一类具非光滑位势p(x)-Laplace方程解的存在性

在非光滑临界点理论的基础上,利用带非光滑(PS)条件的山路引理,结合嵌入定理和Lebourg中值定理,获得了一类具非光滑位势p(x)-Laplace方程解的存在性.     

L-fuzzy层双保序算子空间中的(ω_α,υ_α)-仿紧性

首先在层双保序算子空间中引进了两种(ω_α,υ_α)-仿紧性,证明了它们都是好的推广.其次,给出了它们的若干刻画与性质,并指出了它们保持若干拓扑不变性质.最后,讨论了(ω_α,υ_α)-仿紧性、(ω_α,υ_α)-分离性以及(ω_α,υ_α)-紧性之间的关系.     

DMF体系中Cu2O球晶的制备及形貌分析

以N,N-二甲基甲酰胺(DMF)为溶剂,通过改变铜源和表面活性剂,调控反应参数,溶剂热条件下制备了三维十字形、空心及实心的Cu₂O球晶。利用XRD、SEM等表征手段,分析探讨了工艺条件变化对Cu₂O球晶形貌的影响。研究表明,随着DMF浓度的增大,体系的还原能力增强,Cu⁺增多,溶液的过饱和度增大,Cu₂O晶体集合体形态由晶体结构控制的各向异性与对称性的球晶逐渐向各向同性球晶演变。十二烷基硫酸钠(SDS)、十六烷基三甲基溴化铵(CTAB)、聚乙烯吡咯烷酮(PVP)等表面活性剂有助于降低溶液的过饱和度,增加结晶质的表面扩散能力,有利于规则形态Cu₂O晶粒的形成。反应体系中,Cu(Ac)₂·H₂O水解生成的羧基与DMF中的甲酰基在高温下发生脱羧反应产生CO₂气体以及SDS发泡作用产生的气体是形成空心Cu₂O球晶的重要原因。     

基于5-磺基水杨酸的单、双核铜(Ⅱ)三元混配配合物的合成及晶体结构

以5-磺基水杨酸和咪唑衍生物为配体合成了单核、双核结构的三元混配Cu(Ⅱ)配合物:[Cu(H₂biim)(Hssal)(H₂O)₂]·H₂O(1)和{[Cu(MeHbiim)(Hssal)(H₂O)]·0.5H₂O}₂(2)(H₃ssal=5-磺基水杨酸,H₂biim=2,2’-联咪唑,MeHbiim=N-甲基-2,2’-联咪唑),并利用元素分析、红外光谱、紫外-可见光谱、X-射线单晶衍射及热重分析等技术手段对其结构进行了表征。单晶结构解析表明配合物1属于单斜晶系,P2₁／C 空间群,Cu(Ⅱ)离子与1个5-磺基水杨酸根、2个水分子以及1个联咪唑分子形成五配位四角锥构型的单核配合物结构。配合物2属于正交晶系,P2(1)2(1)2(1)空间群,双核Cu(II)离子分别处于五配位四角锥和四配位平面四边形的几何构型的配位环境中,与配合物1不同,5-磺基水杨酸采取μ₂双-单齿配位模式。荧光光谱分析表明配合物2具有较强的荧光性。