MODELING HARVEST SCHEDULING IN MULTIFUNCTIONAL PLANNING OF FORESTS FOR LONGTERM WATER YIELD OPTIMIZATION

In this study, wood production and hydrologic functions of forests were accommodated within a planning procedure for separate working circles (areas dedicated to certain forest functions) that were delineated according to an Ecosystem‐Based Functional Planning approach. Mixed integer goal programming was used as the optimization technique. The timing and scheduling of a maintenance cutting (partial harvest) was the decision variable in the modeling effort, and an original formulation was developed as a multiobjective planning procedure. Four sample planning strategies were developed and model outputs were evaluated according to these strategies. Spatial characteristics of stands were considered, and used to prohibit the regeneration of adjacent stands during the same time period. Because of the positive relationship between qualified water production and standing timber volume in the forest, the model attempts to maximize qualified water production levels by increasing standing volume stocks in the forest through the delay of regeneration activities.     

Invariants de Maslov équivariants

We construct two cohomological invariants associated to pairs of Lagrangian sub-bundles of a symplectic bundle on a compact manifold upon which a compact Lie group is acting. The first invariant, which we call the classical equivariant Maslov H-invariant, provides an obstruction to Lagrangian transversality and lives in the Borel cohomology. The second invariant, which we call the equivariant Maslov U-invariant, generalises the author's results in K-Theory 13 (1998), 347–361 to the equivariant context and provides a necessary and sufficient condition for equivariant Lagrangian transversality, up to homotopic stability, and lives in the U-theory (intermediate between the real complex K-theories). As an application, we show that two Lagrangian sub-bundles of a symplectic bundle on a homogeneous space are always stably transverse.     

Ho2(Co,Si)17化合物的结构与磁晶各向异性

用三弧Czochralski法和真空电弧熔炼法制备了Ho2Co17-xSix化合物.通过X射线衍射和磁性测量手段研究了化合物的结构与内禀磁性.重点讨论了磁晶各向异性和自旋重取向转变.实验结果表明,Ho2Co17为Th2Ni17型六角结构,在0.5≤x≤3的化合物均为Th2Zn17型菱方结构,能够获得单相2:17型化合物的最大Si含量是x=3.在x≤2的浓度范围,化合物的易磁化方向垂直于c轴.随Si含量增加,化合物的居里温度和Co原子平均磁矩单调减少.根据Ho2Co17-xSix化合物的居里温度和自旋重取向温度,获得了磁相图.根据热磁曲线,确定了温度补偿点.在Ho2Co17化合物中观察到了在1005 K发生自旋重取向转变.     

Multifrequency acoustical volume backscattering patterns in the Arabian Sea--265 kHz to 3 MHz

High-frequency acoustical volume backscattering was examined during three periods of the annual cycle of winds in the Arabian Sea-the Winter Northeast (NE) Monsoon, the Summer Southwest (SW) Monsoon, and the Fall Intermonsoon-using a multifrequency acoustic profiling system deployed on an undulating towed body. This system measured acoustical volume backscattering strengths at six frequencies ranging from 265 kHz to 3.0 MHz. Measurements were made from near the surface to 250 m depth along a ship track that paralleled the coast of Oman, then proceeded away from the coast towards the middle of the Arabian Sea. At all frequencies, volume backscattering strength was highest near the surface, decreasing with increasing depth. Contrary to expectation, backscattering was generally lower during the Summer SW Monsoon than during the Winter NE Monsoon. Also contrary to expectation, backscattering was not appreciably higher near the coast than it was offshore during the Summer SW Monsoon, although it was higher near the coast during the Winter NE Monsoon. Generally speaking, regional and seasonal differences were smaller than expected, and much smaller than the fine-scale spatial and temporal variability, particularly at frequencies below 1 MHz. There was a daily pattern of increased nighttime backscattering in the upper 100 m at 265 and 420 kHz. This pattern was less evident at 1.1 MHz and above.     

ELLIPSOMETRY OF BLACK LIPID MEMBRANES OF EGG LECITHIN AND CHLOROPLAST EXTRACTS

Abstract— Ellipsometric angles and reflectivity of black lipid membranes containing either egg lecithin or chloroplast extracts were measured at a wavelength of 6328 Å. Evidence was found for positive uniaxial anisotropy in membranes of lecithin. If the thickness of those films is assumed to be 62 Å, the refractive index normal to the film surface is 1.471 ± 0.004, and the refractive index parallel to the film surface is 1.454 ± 0.003. The results for membranes of chloroplast extracts also indicate a positive anisotropy in the indices of absorption.     

Synthesis and mesomorphic properties of perfluorinated rod-like liquid crystals with sulphur-containing spacers

In order to determine the influence of 'sulphur-containing' spacers on the formation of mesophases in low molecular mass compounds, we have examined the mesomorphic behaviour of molecules which consists of a 4-biphenyl unit linked to an unbranched fluorinated chain via a short spacer including at least a sulphur atom. The synthesis of these compounds has been carried out from 2-F-butylethyl iodide or from the 2-F-alkylethyl mercaptans in the case of the F-hexyl and F-octyl tails. The mesomorphic properties have been characterized by polarized light microscopy and by differential thermal analysis showing the peculiar contribution of each of the spacers. The influence of the fluorinated chain and the shape of the connector on the stability of the mesophases has been investigated. The compounds with a thioether or a hemithioacetal spacer showed no mesomorphic properties, whereas the structures with a thioester spacer showed a very interesting enantiotropic behaviour of the smectic A type over a wide temperature range. Furthermore from the series exhibiting liquid crystalline behaviour, increasing the number of fluoromethylene units simultaneously increases both the melting and the clearing temperature. These mesomorphic properties within the fluorinated series are compared with those of their monocatenar hydrocarbon homologues.     

非磁性替代原子对Ce2Co17居里温度和饱和磁化强度的影响

用真空电弧熔炼法制备了Ｃｅ２Ｃｏ１７－ｘＭｘ（Ｍ＝Ｇａ,Ａｌ和Ｓｉ）化合物。通过Ｘ射线衍射和磁性测量手段,研究了非磁性替代原子Ｇａ,Ａｌ和Ｓｉ的加入对Ｃｅ２Ｃｏ１７化合物的剧里温度和饱和磁化强度的影响,其中Ｓｉ在Ｃｅ２Ｃｏ１７化合物中的固溶度最小,并使居里温度和饱和磁化强度下降幅度最大。     

X—射线荧光光谱法分析保护渣中元素

保护渣元素的定量分析一般采用传统的湿法化学分析 ,化学分析虽然准确度好 ,但难以做到快速且劳动量大。利用 X-射线荧光光谱法分析保护渣中各元素含量是一种快速、准确的分析方法 ,在国外已得到广泛应用。本文从现场分析的实际出发 ,选择融样条件、最佳仪器参数 ,用基准物质合成标准样品 ,绘制标准工作曲线 ,曲线线性良好 ,用化学分析法对荧光分析值进行验证 ,结果符合化学允许差。1　试验部分1 .1　仪器设备、试剂及工作条件MXF2 1 0 0 - X-射线荧光光谱仪TR- AUTO- BEAD- 1 0 0 0 S/W熔融炉混合熔剂 :4g四硼酸钠 +4g四硼酸锂 +0 .…     

A Hyland-Bernstein approach to the digital control of Pritchard-Salamon systems

In this paper we consider the fixed finite-order digital linear-quadraticcontrol of Pritchard-Salamon infinite-dimensional systems withunbounded input and output operators under gaussian disturbances.A set of necessary conditions is given in terms of the solvabilityof a discrete-time Hyland-Bernstein system of equations (twomodified Riccati equations and two modified Lyapunov equationscoupled by an projection operator).