A novel model to evaluate spatial structure in thinned conifer-broadleaved mixed natural forests

In order to ensure the effective analysis and reconstruction of forests,it is key to ensure the quantitative description of their spatial structure.In this paper,a distance model for the optimal stand spatial structure based on weighted Voronoi diagrams is proposed.In particular,we provide a novel methodological model for the comprehensive evaluation of the spatial structure of forest stands in natural mixed conifer-broadleaved forests and the formulation of management decision plans.The applicability of the rank evaluation and the optimal solution distance model are compared and assessed for different standard sample plots of natural mixed conifer-broadleaved forests.The effect of crown width on the spatial structure unit of the trees is observed to be higher than that of the diameter at breast height.Moreover,the influence of crown length is greater than that of tree height.There are nine possible spatial structure units determined by the weighted Voronoi diagram for the number of neighboring trees in the central tree,with an average intersection of neighboring crowns reaching 80%.The rank rating of natural forest sample plots is correlated with the optimal solution distance model,and their results are generally consistent for natural forests.However,the rank rating is not able to provide a quantitative assessment.The optimal solution distance model is observed to be more comprehensive than traditional methods for the evaluation of the spatial structure of forest stands.It can effectively reflect the trends in realistic stand spatial structure factors close to or far from the ideal structure point,and accurately assesses the forest spatial structure.The proposed optimal solution distance model improves the integrated evaluation of the spatial structure of forest stands and provides solid theoretical and technical support for sustainable forest management.

HRTEM Study of Three New Regularly Mixed-layer Structures of B_8S_6 Type in Ca-RE Fluorocarbonate Minerals

ＨＲＴＥＭＳｔｕｄｙｏｆＴｈｒｅＮｅｗＲｅｇｕｌａｒｌｙＭｉｘｅｄｌａｙｅｒＳｔｒｕｃｔｕｒｅｓｏｆＢ８Ｓ６ＴｙｐｅｉｎＣａＲＥＦｌｕｏｒｏｃａｒｂｏｎａｔｅＭｉｎｅｒａｌｓＭｅｎｇＤａｗｅｉ（孟大维），ＷｕＸｉｕｌｉｎｇ（吴秀玲），ＰａｎＺｈ...

Syntheses and Crystal Structures of Mono-and Binuclear Copper(Ⅱ) Mixed-ligand Complexes Involving Schiff Base

The mononuclear copper(II) complex [Cu(L)(2-AP)] 1 and binuclear copper(II) complex [Cu(L)(py)]2 2 (L = C10H11O5NS, taurine o-vanillin, py = prydine, 2-AP = 2-aminopyridine) with mixed ligand have been synthesized and characterized by Χ-ray diffraction method. Crystal data for 1: orthorhombic, space group Pbca with a = 11.921(4), b = 15.816(6), c = 17.076(6) ?, V = 3219.7(19) ?3, C15H17CuN3O5S, Z = 8, Mr = 414.92, Dc = 1.712 g/cm3, μ(MoKα) = 1.520 mm–1, F(000) = 1704, the final R = 0.0300 and wR = 0.0705 for 2840 observed reflections with I > 2σ(I); and crystal data for 2: monoclinic, space group P21/c with a = 7.929(3), b = 17.038(5), c = 11.734(4) ?, β = 98.162(6)o, V = 1569.1(9) ?3, C15H16CuN2O5S, Z = 4, Mr = 399.90, Dc = 1.693 g/cm3, F(000) = 820, μ(MoKα) = 1.554 mm–1, the final R = 0.0351 and wR = 0.0848 for 2767 observed reflections (I > 2σ(I)). The molecular structure of complex 1 consists of one tetra-coordinated Cu(II) atom generating a slightly distorted square plane, and a one-dimensional chain structure is formed by intermolecular hydrogen bonds. Complex 2 consists of a diphenolic hydroxyl O-bridged binuclear copper(II) structure. The crystal structures of complexes 1 and 2 reveal that the coordinate copper centers are bound to both nitrogen and oxygen atom donors. The usual N,O-trans arrangement of ligands is observed in both cases.

Syntheses, Crystal Structures and IR Spectra of Two Mixed Metal Complexes:〔Cr_nFe_(3-n)(μ_3-O)-(μ-O_2CC_2H_5)_6 Py_3〕Cl(n=1,2)

Two mixed metal complexes [Cr2Fe(μ3-O) (μ-O2CC2H5)6Py3]Cl (A)and [CrFe2 (μ3-O) (μ-O2CC2H5 )6Py3] Cl (B) have been prepared in non-aqueous sol-vents. Crystal (A) is monoclinic, space group C2/c, with a= 13. 782(3), b= 18. 381(4), c= 16. 643(2) A, β= 92. 84(5)°, V=4211. 1 (4) A3, Z=4, Mr= 887. 03, Dc= 1. 40 g/cm3, μ= 5. 0 cm-1, F(000) = 1836 and R(Rw) = 0. 057(0. 062) for 2134 unique reflections with I> 3δ(I). Crystal (B) is also monoclinic, space group C2/c ,with a= 13. 793(4), b= 18. 401 (6), c= 16. 657(5) A’, β= 93. 18(3)°, V=4221. 3(5) A3, Z= 4, Mr=890. 88, Dc= 1. 40 g/cm3, μ= 10. 5 cm-1, F(000) = 1844 and R(Rw) = 0. 067 (0. 069) for 2131 unique reflections with I>3δ(I). Both (A) and (B)have been characterized by IR spectra. Besides, the relations between the structuresand IR are discussed.

Syntheses,Structures and Properties of Lanthanide Coordination Polymers Constructed from Mixed Acid

Two new coordination polymers,[Ln(oba)(ox)0.5(H2O)2]n(Ln = Ho(1),Eu(2);H2oba = 4,4?-oxybis(benzoic acid),H2ox = oxalic acid) have been synthesized under hydrothermal conditions.According to single-crystal X-ray diffraction analyses,complex 1 crystallizes in the monoclinic system,space group P21/c with a = 13.783(2),b =10.0120(15),c = 12.1974(18) ,β = 105.217(2)°,V = 1624.2(4) 3,C15H12O9Ho,Mr = 501.18,Z = 4,Dc = 2.050 g/cm3,F(000) = 964,μ = 4.919 mm-1,λ(MoKα) = 0.71073 ?,GOOF = 1.124,the final R = 0.0239 and wR = 0.0570 for 3310 independent reflections with Rint = 0.0298.Complexes 2 and 1 are isostructural.Oba and ox ligands bridge the Ln(III) ions into 2D layers with(4,4) topology,which are further interlinked into a 3D supramolecular network by hydrogen bonds.TG curves of the two complexes are studied to examine their thermal stabilities.Additionally,complex 2 shows red fluorescence in the solid state at room temperature.

WAVELET ANALYSIS OF COHERENT STRUCTURES IN A THREE-DIMENSIONAL MIXING LAYER

Wavelet analysis is applied to the results obtained by the direct nu-merical simulation of a three-dimensional (3D) mixing layer in order to investigatecoherent structures in dimension of scale. First, 3D orthonormal wavelet bases areconstructed, and the corresponding decomposition algorithm is developed. Then theNavier-Stokes equations are transformed into the wavelet space and the architecturefor multi-scale analysis is established. From this architecture, the coarse field imagesin different scales are obtained and some local statistical quantities are calculated.The results show that, with the development of a mixing layer, the energy spectrumdensities for different wavenumbers increase and the energy is transferred from theaverage flow to vortex structures in different scales. Due to the non-linear interactionsbetween different scales, cascade processes of energy are very complex. Because vor-tices always roll and pair at special areas, for a definite scale, the energy is obtainedfrom other scales at some areas while it is transferred to other scales at other areas.In addition, energy dissipation and transfer always occur where an intense interactionbetween vortices exists.

Prediction of tree crown width in natural mixed forests using deep learning algorithm

Crown width(CW)is one of the most important tree metrics,but obtaining CW data is laborious and timeconsuming,particularly in natural forests.The Deep Learning(DL)algorithm has been proposed as an alternative to traditional regression,but its performance in predicting CW in natural mixed forests is unclear.The aims of this study were to develop DL models for predicting tree CW of natural spruce-fir-broadleaf mixed forests in northeastern China,to analyse the contribution of tree size,tree species,site quality,stand structure,and competition to tree CW prediction,and to compare DL models with nonlinear mixed effects(NLME)models for their reliability.An amount of total 10,086 individual trees in 192 subplots were employed in this study.The results indicated that all deep neural network(DNN)models were free of overfitting and statistically stable within 10-fold cross-validation,and the best DNN model could explain 69%of the CW variation with no significant heteroskedasticity.In addition to diameter at breast height,stand structure,tree species,and competition showed significant effects on CW.The NLME model(R^(2)=0.63)outperformed the DNN model(R^(2)=0.54)in predicting CW when the six input variables were consistent,but the results were the opposite when the DNN model(R^(2)=0.69)included all 22 input variables.These results demonstrated the great potential of DL in tree CW prediction.

Mixed-field effect at the hyperfine level of^(127)I^(79)Br in its rovibronic ground state:Toward field manipulation of cold molecules

The mixed-field effect at the hyperfine level of the rovibronic ground state of the^(127)I^(79)Br(X^(1)Σ,v=0,J=0)molecule is computed on the J-I uncoupled basis of|JM_(J)I_(1)M_(1)I_(2)M_(2)>,where J is the molecular total angular momentum excluding nuclear spin,M_J is the projection number of J,I_(1) and I_(2) are the nuclear spins of the iodine and bromine atoms,and M_(1) and M_(2) are the projection numbers of I_(1) and I_(2),respectively.When the two applied electric and magnetic fields are parallel,the perturbations are rare and only one perturbation is observed in a relatively large field regime in our computation range.However,when the two fields are off-parallel,the perturbations increase significantly and some sublevels show the Feshbach-like resonance phenomenon.Therefore,such sublevels transit between weak-field seeking and strong-field seeking repeatedly,which can be utilized to enhance or suppress cold molecular collision and chemical reaction rates.Such behavior of the molecular hyperfine structure in the mixed off-parallel fields may also be utilized to construct an electric-field-assisted anti-Helmholtz magnetic trap for cold molecules and to realize evaporative cooling of cold molecules(sub-mK)into the ultracold regime(μK).

Enhanced nitrogen removal at low temperature with mixed anoxic/oxic process

Different hydraulic retention times(HRTs)were tested in a mixed anoxic/oxic(A/O)system at 5C and 10C to investigate the effects of HRT and carrier on nitrogen removal in wastewater at low temperatures.The results showed that the addition of the fillers improved the treatment effect of each index in the system.With an optimal HRT of 7.5 h at 5C,the removal efficiencies of NHþ4-N and total nitrogen(TN)reached 91.2%and 75.6%,respectively.With an HRT of 6 h at 10C,the removal efficiencies of NHþ4-N and TN were 96.7%and 82.9%,respectively.The results of high-throughput sequencing showed that the addition of the suspended carriers in the aerobic zone could improve the treatment efficiency of nitrogen at low temperatures.The microbial analysis indicated that the addition of the suspended carriers enhanced the enrichment of nitrogen removal bacteria.Nitrospira,Nitrotoga,and Nitrosomonas were found to be the bacteria responsible for nitrification,and their relative concentrations on the biofilm at 5C and 10C accounted for 98.11%,92.79%,and 69.98%of all biological samples,respectively.

Floristic Composition, Structure and Soil Properties of Mixed Deciduous Forest and Deciduous Dipterocarp Forest: Case Study in Madan Watershed, Myanmar

Patterns of woody regeneration in terms of species composition and diversity were studied in mixed deciduous forest (MDF) and deciduous dipterocarp forest (DDF) in Minbyin reserved forest of Lewe Township. A total of 57 plant species of MDF belonging to 28 families and 342 individuals and 25 plant species of DDF consist of 15 families and 285 individuals were identified. Plant species diversity was quantitatively higher in the MDF (H' = 3.68) compared to the DDF (H' = 2.39). Tectona grandis showed the highest density (30), dominance (4.40 m2) and IVI (27.01) of MDF and Dipterocarpus tuberculatus also composed the highest density (109), dominance (9.02 m2) and IVI (81.87) in DDF. The smallest diameter class (10 - 20 cm) comprised with 29 species, 103 individuals in MDF and 18 species, 85 individuals in DDF. The size class distribution displayed a reverse J-shaped pattern. The largest numbers of species were concentrated in the smallest height class in both investigated forests because of height and diameter distribution is closely related. The total densities of seedlings and saplings were 1219 and 531 ha-1 in MDF and 988 and 444 ha-1 in DDF respectively. Although soil texture of (40 - 50 cm) and (90 - 100 cm) were sandy clay loam in mixed deciduous forest, the other layers of both investigated forests were sandy loam.

Synthesis, Structure and Luminescent Property of a 2D Cd(Ⅱ) Coordination Polymer Based on Mixed-ligands of 1,3-Bis(imidazol)propane and Pyridine-3,5-dicarboxylic Acid

A new Cd(Ⅱ) coordination polymer, namely, [Cd(1,3-bip)(3,5-pdc)]n(1,3-bip =1,3-bis(imidazol)propane and 3,5-pdc = pyridine-3,5-dicarboxylic acid) has been synthesized under hydrothermal conditions. Compound 1 was characterized by infrared spectrum, elemental analysis,powder X-ray diffraction(PXRD) and single-crystal X-ray diffraction analysis. It crystallizes in monoclinic, space group P21/c with a = 1.40178(7), b = 1.72502(12), c = 1.41635(6) nm, β =92.653(4)o, V = 3.4212(3) nm3, Z = 4, C316H15 Cd N5O4, Mr = 453.73, Dc = 1.762 g/cm, F(000) =1808, μ = 1.310 mm-1, R = 0.0899 and w R = 0.1945. In compound 1, each 3,5-pdc ligand links three Cd(Ⅱ) ions and each Cd(Ⅱ) attaches to bip ligands to form a complicated 2D double-layer structure. In addition, the thermal stability and luminescent property of 1 have been studied in the solid state at room temperature.

A Zinc(Ⅱ) Coordination Framework Based on Terpyridine and 5-Nitroisophthalic Acid Mixed Ligands: Synthesis, Crystal Structure and Fluorescence Property

A new coordination framework, {[Zn(L1)(5-nipc)]·H2O}n(1, L1 = 4ˊ-(4-pyridyl)-4,2ˊ:6ˊ,4ˊˊ-terpyridine, 5-nipc = 5-nitroisophthalic acid), has been prepared under hydrothermal conditions, and determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR and powder X-ray diffraction. Complex 1 crystallizes in monoclinic, space group C2/c with a = 29.983(9), b = 13.709(3), c = 14.391(3)A, β = 114.93(4)°, V = 5364(2) A3, Dc = 1.493 g/cm3, C28H19N5O7 Zn, Mr = 602.85, F(000) = 2464, μ(Mo Kα) = 0.972 mm-1, Z = 8, R = 0.0935 and w R = 0.1509 for 4724 observed reflections(I > 2σ(I)). The structure of 1 exhibits a three-dimensional(3D) network with a layer-pillar structure. The fluorescence property of 1 is also investigated.

Analysis of forest structural complexity using airborne LiDAR data and aerial photography in a mixed conifer–broadleaf forest in northern Japan

Determining forest structural complexity,i.e.,a measure of the number of different attributes of a forest and the relative abundance of each attribute,is important for forest management and conservation.In this study,we examined the structural complexity of mixed conifer–broadleaf forests by integrating multiple forest structural attributes derived from airborne Li DAR data and aerial photography.We sampled 76 plots from an unmanaged mixed conifer–broadleaf forest reserve in northern Japan.Plot-level metrics were computed for all plots using both field and remote sensing data to assess their ability to capture the vertical and horizontal variations of forest structure.A multivariate set of forest structural attributes that included three Li DAR metrics(95 th percentile canopy height,canopy density and surface area ratio) and one image metric(proportion of broadleaf cover),was used to classify forest structure into structural complexity classes.Our results revealed significant correlation between field and remote sensing metrics,indicating that these two sets of measurements captured similar patterns of structure in mixed conifer–broadleaf forests.Further,cluster analysis identified six forest structural complexity classes includingtwo low-complexity classes and four high-complexity classes that were distributed in different elevation ranges.In this study,we could reliably analyze the structural complexity of mixed conifer–broadleaf forests using a simple and easy to calculate set of forest structural attributes derived from airborne Li DAR data and high-resolution aerial photography.This study provides a good example of the use of airborne Li DAR data sets for wider purposes in forest ecology as well as in forest management.

Determining structural variation in a managed mixed stand in an old-growth forest, northern Iran

Numerous approaches have been developed to quantify forest structure modules.A variety has measured each as part of stand attributes.This study was carried out in managed mixed stands in northern Iran.The objective was to quantify stand structure and its variation before and after tree marking through the Gini index and structural triangle method.A full sampling inventory was taken in 2004 and 2014 at the beginning and end of a period,before and after tree marking operations in five stands.The results indicate that the Gini index was 39.5,62.2,43.0,82.0 and 74.0%forⅠ,Ⅱ,Ⅲ,ⅣandⅤstands respectively.Furthermore,approximate structural diameters were determined as a large category forⅠ,Ⅱ,ⅢandⅤstands while standⅡhad an intermediate-large class pre-tree marking to an intermediate-small class post-tree marking.The paired t-test results were not significant for tree numbers and growing stock changes for all species,and for beech,hornbeam,and velvet maple before and after tree harvesting in the whole stand.Therefore,the Gini index and the structural triangle method can be used for natural stand modeling,structural diversity designation,and for management practices in nature-oriented forestry strategies.

A Novel Mixed-valence and Capped-keggin Structural Polyoxometal Complex:{[Co(dien)]_4-[(PO_4)Mo_8~Ⅴ(W_(0.56)^(Ⅵ)Mo_(0.44)^(Ⅵ))_4O_(33)(OH)_3 ]}·nH_2O(n≈1)

A novel inorganic-organic hybrid compound,{[Co(dien)]4[(PO4)MoV8(WVI0.56MoVI0.44)4-O33(OH)3]}·nH2O(1,n≈1,dien=diethylenetriamine),has been synthesized hydrothermally and characterized by single-crystal X-ray diffraction.Compound 1 crystallizes in the triclinic system with a=11.927(2),b=13.328(3),c=19.306(4),α=93.76(3),β=94.14(3),γ=109.99(3)o,V=2863.2(12)3,space group P1 and Z=2 at 173 K.The final full-matrix least-squares refinement converged to R=0.049 for 9621 observed reflections with I>2σ(I)and wR=0.139 for all data(9871)and S=1.073.Crystal structure analysis shows that 1 contains a kind of the first reported mixed-valence and molybdenum-tungsten mixed-distributedε-Keggin structural polyanion capped by four Co(dien)fragments with the main group element P occupying the center site.These results were further confirmed by energy-dispersive X-ray spectroscopy(EDS),X-ray powder diffraction(XRD),Fourier transform infrared spectroscopy(FTIR),Raman spectroscopy,Thermogravimetry(TG)and X-ray photoelectron spectroscopy(XPS)analyses.

RESEARCH ON COHERENT STRUCTURES IN A MIXING LAYER OF THE FENE-P POLYMER SOLUTION

The evolution of the coherent structures in a two_dimensional time_developing mixing layer of the FENE_P fluids is examined numerically. By the means of an appropriate filtering for the polymer stress, some characteristics of the coherent structures at high b were obtained, which Azaiez and Homsy did not address. The results indicate that adding polymer to the Newtonian fluids will cause stronger vorticity diffusion, accompanied with weaker fundamental and subharmonical perturbations and slower rotational motion of neighboring vortices during pairing. This effect decreases with the Weissenberg number, but increases with b. In addition, the time when the consecutive rollers are completely coalesced into one delays in the viscoelastic mixing layer compared with the Newtonian one of the same total viscosity.

Synthesis and Crystal Structure of Quaternary Mixed Anion Complexes of Lanthanide Containing 1,10-Phenanthroline

Ｔｈｅｔｅｒｎａｒｙｃｏｍｐｌｅｘｅｓｏｆｌａｎｔｈａｎｉｄｅｃｏｎｔａｉｎｉｎｇｂｉｄｅｎｔａｔｅｈｅｔｅｒｏｃｙｃｌｅａｍｉｎｅｓｈａｖｅｂｅｎｓｔｕｄｉｅｄｓｉｎｃｅ１９６０．Ｂｕｔｆｅｗｑｕａｔｅｒｎａｒｙｍｉｘｅｄａｎｉｏｎｃｏｍｐｌｅ...

Synthesis Crystal Structureof Quaternary Mixed AnionComplex of Lanthanides[Ln(CCl_3COO)_2 (CH_3COO)(phen) (H_2O)]_2

Three new quaternary mixed anion complexes of lanthanides were prepared from thewater-ethanol solution under slightacidity condition and characterizedby elemental analysis, IR, UVspectrum and single crystal X-raydiffraction analysis. The crystal ofLa(CCl3COO)2 (CH3COO) (phen)(H2O)·DMF]2 belongs to tricliniccrystal system, space group P1with a=1 .2510 (4) nm, b=1.3460(5) nm, c=1.0343 (3)nm, α=102.47(3)°, β=102.34(2)°, γ=113.82 (2)°, μ(MoKa) = 20.47 cm-1, Z= 1, Dc=1. 800 g·cm-3, F (000) =780. 00. The acetate tends to coordinate with the center ion as abridge and trichloroacetate has fourkinds of coordination modes, somany coordination modes were observed in their co-ligand system.

ON THE EVOLUTION OF LARGE SCALE STRUCTURES IN THREE-DIMENSIONAL MIXING LAYERS

In this paper, several mathematical models for the large scale struc-tures in some special kinds of mixing layers, which might be practically useful forenhancing the mixing, are proposed. First, the linear growth rate of the large scalestructures in the mixing layers was calculated. Then, using the much improved weaklynon-linear theory, combined with the energy method, the non-linear evolution of largescale structures in two special mixing layer configurations is calculated. One of themixing layers has equal magnitudes of the upstream velocity vectors, while the an-gles between the velocity vectors and the trailing edge were π/2 - φ and π/2 + φrespectively. The other mixing layer was generated by a splitter-plate with a 45-degree-sweep trailing edge.

Synthesis and Structure of Propionate—bridged Mixed—metal Cluster Comp

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