苏打碱化土壤盐分离子与相关性分析

选取典型苏打碱化土壤剖面,分析了0～200cm深度主要盐分离子(Ca2 、Mg2 、Na 、K 、CO32-、HCO3-、Cl-和SO42-)的垂直分布规律。对各离子之间的相关性进行了统计分析。结果表明,测试土样离子以Na 和HCO3-离子为主,其剖面分布规律是表层含量较低,在80cm左右逐渐增至最大值,其后离子含量随深度而降低,至160cm以下则又随深度而增加,即在整个土壤剖面上大致呈倒"S"曲线分布。CO32-、HCO3-、Cl-与Na ,CO32-、HCO3-与Cl-之间均是相关系数大于0.80的极显著相关;除K 离子外,其它7个离子间均具有显著相关性,这表明该苏打碱化土壤盐分离子组成具有复杂性的特点。     

黑龙江省西部草地苏打盐渍土无机磷的转化及其对有效磷的影响

本文通过相关分析和通径分析研究了无机磷各组分间的转化关系及其对有效磷的影响 ,结果表明 :苏打碱土的Ca2 -P、Ca8-P、Al-P和Fe -P对有效磷贡献量较大 ,O -P对有效磷表现为负贡献 ,Ca10 -P对有效磷几乎无影响。草甸碱土的Ca2 -P和Fe -P主要通过直接作用影响有效磷 ,Ca8-P和Al -P主要通过间接作用影响有效磷 ;碱化草甸土的Ca2 -P对有效磷的影响主要表现为直接作用 ,Ca8-P、Al-P和Fe -P对有效磷的影响主要表现为间接作用。在苏打盐渍土的磷素循环系统中 ,无机磷各形态间存在一定的转化关系 ,Ca2 -P、Ca8-P和Al-P易于相互转化 ,Fe -P和O -P易于相互转化     

应用吸附等温曲线判断水稻土供硅能力Ⅱ吸附等温曲线方程参数与水稻土理化性质的关系

选取低浓度系列平衡液进行等温吸附试验,研究了不同pH水稻土对硅的吸附等温曲线方程参数与土壤理化性质之间的关系。结果表明:土壤吸附硅的缓冲容量(PBCSi)与土壤粘粒含量呈线性正相关关系(r=0.7745**,n=12),与土壤pH呈对数正相关关系(r=0.8660**,n=12);土壤吸附硅的零位浓度(ZACSi)与土壤游离氧化铁含量呈对数正相关关系(r=0.5801*,n=12),与土壤pH呈指数负相关关系(r=0.8661**,n=12);评价土壤供硅能力指标的参数与土壤氧化铁活化度呈指数负相关关系(r=0.6026*,n=12),与氧化铁晶胶比呈幂函数正相关关系(r=0.5950*,n=12)。     

松嫩平原大安古河道强度盐渍土种稻脱盐试验

松嫩平原中、西部地区土壤盐渍化非常严重,盐渍土改良对于土地资源利用和生态环境改善具有重大意义。在大安古河道苏打草甸盐化土、碱化盐土和草甸碱土复区选择试验田,通过种植水稻,借助周期性的灌水、排水过程,溶洗土壤中的盐分,达到改良盐渍土的目的。经过连续4年的试验,土壤平均含盐量由试验前的0.45%降至第4个试验年的0.15%。从第1试验年到第4试验年,水稻产量由绝收逐渐增至4250 kg hm-2。试验结果表明,充分利用地表水资源,通过种稻改良强度盐渍土是可行的,同时也可为松嫩平原中、西部更大范围利用强度盐渍土壤资源、恢复生态环境提供科学指导。     

黑龙江省西部草地土壤无机磷的形态

本文通过牧场试验,探讨了黑龙江省西部草地土壤无机磷形态,结果表明,四种草地土壤均以Ｃａ－Ｐ为主,约占无机磷总量的６０％左右,Ｏ－Ｐ含量少于Ｆｅ－Ｐ和Ａｌ－Ｐ．草甸黑钙土无机磷总量最高,Ｃａ２－Ｐ、Ｃａ８－Ｐ和Ａｌ－Ｐ都是草甸黑钙土重要的贮磷库;草甸风沙土无机磷总量最低,但Ｃａ８－Ｐ含量相对较高;草甸碱土无机磷总量、Ｃａ２－Ｐ和Ａｌ－Ｐ含量显著高于碱化草甸土．向草甸碱土和碱化草甸土施磷酸二铵能显著增加土壤无机磷的总量,尤其显著提高土壤中Ｃａ８－Ｐ和Ａｌ－Ｐ含量．     

地面覆盖对苏打草甸碱土盐分及牧草生物量的影响

试验区设在黑龙江省肇州县火车头村,土壤类型苏打草甸碱土。本试验随机选取碱斑,直接在碱斑上进行地膜覆盖、草帘覆盖及稻壳覆盖。结果表明,草帘覆盖控盐效果及对于植被的恢复能力明显优于稻壳覆盖与地膜覆盖。     

一种新的简缩极化SAR图像H/α特征空间

现有简缩极化(Compact Polarimetry)SAR图像H/α经验特征空间存在两个问题:一是没有考虑简缩极化模式下的散射熵普遍高于全极化模式;二是在散射机制重叠区域,简缩极化H/α空间的分类能力较弱,尤其是多次散射。针对以上问题首先定量分析了DCP模式简缩极化SAR的散射角与全极化SAR数据散射角之间的关系,且在对7组不同传感器的SAR数据分析的基础上,提出了散射熵的替代参数ED,基于Monte Carlo模拟实验得到了H/α分解的各参数(熵H、平均散射角α和替代参数ED)分解的稳态条件;然后通过统计各散射机制在ED/α分布的密度空间,提出了一种新的简缩极化SAR图像ED/α特征空间。实验结果表明:替代参数ED与全极化熵具有良好相关性,而且ED/α特征空间提高了散射机制分类的精度。     

双峰海浪谱的SAR图像交叉谱仿真研究

由6参数双峰频谱和cos-2s型分布函数得到了双峰海浪方向谱的波数谱形式,并利用海浪谱到合成孔径雷达(Synthetic Aperture Radar,SAR)图像交叉谱的非线性转换关系,对双峰海浪谱的SAR图像交叉谱进行了仿真,分析了不同海浪参数和SAR平台参数对SAR图像交叉谱的影响,并与SAR图像谱进行了比较。     

应用硅素释放动力学方程评价水稻土供硅能力Ⅰ硅素释放动力学方程参数与水稻相对产量的关系

在淹水培养条件下,进行了12种不同pH水稻土硅素累积释放试验,结合田间试验的效果,研究了土壤有效硅、水稻土硅的累积释放特征及其与硅肥肥效之间的关系。结果表明:1mol L-1HAc-NaAc(pH=4)缓冲液法不能直接判断碱性水稻土供硅能力。不同pH水稻土中硅素的释放过程可以用方程y=kxm来描述。土壤硅素120日累积释放量、硅素释放初始速率km与水稻相对产量具有显著的线性正相关关系。因此,应用土壤硅素释放动力学方程参数能够评价不同pH水稻土的供硅能力。     

合成孔径雷达的系统性能研究

雷达方程是雷达系统性能的重要体现,文章首先在基本雷达方程的基础上,考虑SAR系统天线性能、发射机性能和RCS的影响,详细推导出了适用于合成孔径雷达(SAR)的基本方程,并对方程中各参数的物理意义作了详细说明,最后给出了一个性能算例,说明SAR方程对系统设计中参数选择的指导意义.     

滨海土壤I-69杨根际无机磷形态分布及有效性研究

对滨海脱盐土壤或轻度盐渍土壤上不同林龄I -69杨根际、非根际无机磷存在形态、数量和有效性进行了研究 ,结果表明 :I -69杨根系活动能明显提高根际土壤供磷能力 ,3、5、11年生I -69杨根际有效磷明显富集 ,富集量分别为3 .87、4.3 2、4.3 5mg/kg ;Ca2 -P在不同林龄I -69杨根际含量明显高于非根际土 ,差异都达到极显著水平 ,R/S随林龄增大分别是 2 .15、2 .5 9、5 .5 4;Ca8-P在 5、11年生I -69杨根际明显富集 ,而Ca10 -P明显亏缺 ;不同林龄I -69杨根际、非根际土Al-P、Fe -P和O -P含量无明显差异 ,盐渍土壤中它们的生物有效性较低。     

基于Bayes定理和mGA的结构损伤识别方法研究

提出了一种基于幽ycs定理和沐从(微种群遗传算法)的方法,用于识别结构中损伤的位置和程度等参数并分析其不确定性。该方法在获得测量信息后,结合损伤模型,根据Bayes定理更新获得损伤模型参数的后验概率密度函数,以实现在不确定性情况下对损伤的识别。为最大化损伤模型参数的后验概率密度函数,采用mGA搜索获得描述损伤的全局最优参数。将该方法应用于板结构损伤识别,并进行了数值仿真研究以验证所提方法的有效性。     

一种基于秘密分享的高质量(k,n)可视加密算法

(k,n)可视加密算法是一种重要的信息隐藏算法。应用Shamir秘密分享的概念,将一幅二进制秘密图像隐藏在n幅分享图像中,通过在分享过程中增加随机性控制,保证生成的分享图像是接近噪声图像的无意义图像。从n幅无意义分享图像中,任意选取k幅分享图像,使用拉格朗日插值可提取秘密图像。该算法应用Shamir秘密分享来实现(k,n)可视加密,不需要码书,不会造成无限制的像素扩展。实验结果显示,该算法能实现(k,n)可视加密,提取秘密图像的提取正确率能保证100%。     

A transverse local feedback linearization approach to human head movement control

In the mid-nineteenth century, Donders had proposed that for every human head rotating away from the primary pointing direction, the rotational vectors in the direction of the corresponding axes of rotation, is restricted to lie on a surface. Donders'' intuition was that under such a restriction, the head orientation would be a function of its pointing direction. In this paper, we revisit Donders'' Law and show that indeed the proposed intuition is true for a restricted class of head-orientations satisfying a class of quadratic Donders'' surfaces, if the head points to a suitable neighborhood of the frontal pointing direction. Moreover, on a suitably chosen subspace of the 3D rotation group ${\rm SO}(3)$, we describe a head movement dynamical system with input control signals that are the three external torques on the head provided by muscles. Three output signals are also suitably chosen as follows. Two of the output signals are coordinates of the frontal pointing direction. The third signal measures deviation of the state vector from the Donders'' surface. We claim that the square system is locally feedback linearizable on the subspace chosen, and the linear dynamics is decomposed into parts, transverse and tangential to the Donders'' surface. We demonstrate our approach by synthesizing a tracking and path-following controller. Additionally, for different choices of the Donders'' surface parameters, head gaits are visualized by simulating different movement patterns of the head-top vector, as the head-pointing vector rotates around a circle.     

基于模糊信息分配的水环境质量评价

将模糊信息分配方法应用到水环境质量评价中，以西安市水环境质量评价为例进行了检验计算，结果表明：评价结果能较准确地反映水环境质量的实际情况，最后对其进行了合理的分级，具有一定的应用价值，为水环境保护和管理提供依据。     

HUYGENS' PRINCIPLE,PHYSICS AND COMPUTERS

We discuss the emergence of topology from a consideration of set extensions in General Systems Theory. Boundaries arise in a natural way, separating independent elements or regions of the system. Our aim is a unification of Etter theory, Kron's method of Tearing and Jessel's formulation of Huygens' Principle. This should make explicit the equivalence between the objective, structural, holographic and the subjective, relative definitions of information, sought in Bowden (1994b), reprinted in this Special Issue. It connects the abstract generalisations of Schrodinger's equation and Bom's rule derived in probabilistic Etter theory with the real world of electrical and other physical phenomena in General Physical Systems Theory. This paper can be considered as a continuation of Bowden (1990; 1994a) and as a response to Bowden (1994b), reprinted in this issue.

We review the ideas behind Kron's Method of Tearing and Jessel's Principle of Secondary sources (both special cases of the above theory) and their equivalence. We follow Hiley's argument in Hiley (1996) to show how Schrodinger's equation can be thought of as specifying the evolution of (a series of) tearings in continuous space. These can be shown on a commutative diagram as a series of similarity transforms. We compare this with Etter's derivation (Etter, 1998). We describe briefly a recently published derivation of Maxwell's equations from a non-commutative algebra and show how they fit onto a related commutative diagram. Finally we make some comments on applications of the general theory to computer systems. This paper is a series of vignettes of work in progress. It is designed to point the direction of work to come in Constructive Physics.     

辽宁冬麦北移研究进展

本文总结了辽宁省冬麦北移的成就。建国以来,辽宁省有３次大规模的冬麦北移,将冬小麦种植边界从大连南部北移至沈阳铁岭一带大约５００公里。第三次冬麦北移是从１９９１年开始的,８年间共筛选出８个冬小麦品种,１９９８年种植面积 ８ ０００ｈｍ~２。冬麦北移的技术特点是：因地制宜进行冬麦北移,选用合适的品种,建立合理的群体结构,旱种小麦要特别强调镇压保墒。     

一类改进混沌Lur′e系统的滞后同步判据

本文研究了混沌Lur′e系统的滞后同步问题.通过合理构造增广Lyapunov-Krasovskii泛函,使得增广向量不仅包括单积分项以及双积分项,而且加入了增广的三重积分项.在估计Lyapunov-Krasovskii泛函导数表达式的基础上,通过零等式引入自由矩阵,同时利用积分不等式,求得以线性矩阵不等式形式表达下的混沌Lur′e系统滞后同步的判据,即充分条件.最后,通过数值计算表明本文理论研究的有效性.     

直曲增强型负泊松比超材料的力学性能与减振研究

负泊松比超材料结构作为一种新型智能材料与结构,精确计算超材料结构在大应变下的非线性力学性能对其在工程中的潜在应用具有重要意义.本文在弧形内凹负泊松比结构中加入直杆,设计了一类直杆增强型直曲耦合内凹超材料结构;利用能量法推导出了曲边内凹蜂窝结构的横/纵向等效泊松比与等效弹性模量的解析表达式,讨论结构各参数对结构等效泊松比与等效弹性模量的影响.考虑几何非线性大变形,建立了曲边内凹负泊松比结构的有限元模型,并与线性模拟结果对比,验证了解析表达式的正确性.结果表明,等效泊松比与等效弹性模量均随变形增大而变化,且变形越大差异越明显,大变形下须考虑几何非线性;利用谐响应分析计算结构的加速度级和加速度振级落差,凸显所设计超材料结构的减振性能;分析结构整体减振性能,发现其随层数增加逐渐增大;不随频率变化,在低频范围内对激励产生的响应能够起到抑制作用.因此,合理的设计超材料微结构对结构的低频振动具有很好的抑制作用,对负泊松比超材料减振结构设计具有一定的参考意义.     

Digital collaborative learning in elementary and middle schools as a function of individualistic and collectivistic culture: The role of ICT coordinators' leadership experience,students' collaboration skills,and sustainability

The purpose of this study was to examine the influence of online collaborative learning experiences on students' digital collaboration skills and on the sustainability of e-collaboration in schools' culture—comparing individualistic versus collectivistic cultures. In addition, we explored how the leadership experience of schools' ICT coordinators was predicted by their sense of professionalism and cognitive, emotional and social aspects of perceived learning (PL), while leading the collaborative projects. The participants were ICT coordinators from 513 Israeli schools; 214 of whom were Hebrew-speakers, and 299 Arabic-speakers. The participants were asked to complete an online questionnaire, which included multiple-choice and open-ended questions. The results showed significant differences between a variety of the coordinator-related variables as a function of learning culture (more individualistic vs.more collectivistic). Coordinators' leadership experience was a powerful predictor of students' digital collaboration skills, but did not predict the sustainability of e-collaboration. Coordinators' emotional PL predicted the sustainability of collaboration in both schools with more individualistic and with more collectivistic learning cultures. The implications of the findings for educational theory and practise are discussed.