几个含源守恒律方程的精确孤波解

从KdV方程、MKdV方程的孤波解出发,获得了带非均匀项的KdV方程和带非均匀项的MKdV方程的精确孤波解。     

Optical Spatial Solitons and Their Interactions: Universality and Diversity

Spatial solitons, beams that do not spread owing to diffraction when they propagate, have been demonstrated to exist by virtue of a variety of nonlinear self-trapping mechanisms. Despite the diversity of these mechanisms, many of the features of soliton interactions and collisions are universal. Spatial solitons exhibit a richness of phenomena not found with temporal solitons in fibers, including effects such as fusion, fission, annihilation, and stable orbiting in three dimensions. Here the current state of knowledge on spatial soliton interactions is reviewed.     

Sine-Gordon方程的周期孤立波解

运用双孤子法和一般的广田方法,得到了双周期解和周期孤子解,并研究了解的奇性．     

一类可积的非线性常微分方程

研究某类非线性方程的可解性问题,给出了一类可积的一阶非线性常微分方程的可积性证明。这类方程可应用于物理学、力学和推导孤立子方程及寻求孤立子解。     

Formation of a matter-wave bright soliton

We report the production of matter-wave solitons in an ultracold lithium-7 gas. The effective interaction between atoms in a Bose-Einstein condensate is tuned with a Feshbach resonance from repulsive to attractive before release in a one-dimensional optical waveguide. Propagation of the soliton without dispersion over a macroscopic distance of 1.1 millimeter is observed. A simple theoretical model explains the stability region of the soliton. These matter-wave solitons open possibilities for future applications in coherent atom optics, atom interferometry, and atom transport.     

Observation of the inverse Doppler effect

We report experimental observation of an inverse Doppler shift, in which the frequency of a wave is increased on reflection from a receding boundary. This counterintuitive effect has been produced by reflecting a wave from a moving discontinuity in an electrical transmission line. Doppler shifts produced by this system can be varied in a reproducible manner by electronic control of the transmission line and are typically five orders of magnitude greater than those produced by solid objects with kinematic velocities. Potential applications include the development of tunable and multifrequency radiation sources.     

(1+1)维呼吸子的可视化

呼吸子是局域在空间的一种特殊的孤立子.用可视化方法研究了它的两种（1＋1）维呼吸.     

推广的KdV方程的孤立波解

本文首次正确地给出了推广的KdV方程的孤立波的三阶近似解析解。     

Mercury: observations of the 3.4-millimeter radio emission

Observations of the 3.4-millimeter radio emission from Mercury during 1965 and 1966 yielded the following relationship between average brightness temperature T(B) of the disk and the planetocentric phase angle i: T(B) = 277 (+/- 12) + 97 (+/- 17) cos [i + 29 deg (+/- 10 deg)] degrees K The errors are statistical standard; the phase shift corresponds to a phase lag-that is, the maximum and minimum of insolation lag the maximum and minimum of planetary radiation.     

Compression of Ice to 210 Gigapascals: Infrared Evidence for a Symmetric Hydrogen-Bonded Phase

Protonated and deuterated ices (H2O and D2O) compressed to a maximum pressure of 210 gigapascals at 85 to 300 kelvin exhibit a phase transition at 60 gigapascals in H2O ice (70 gigapascals in D2O ice) on the basis of their infrared reflectance spectra determined with synchrotron radiation. The transition is characterized by soft-mode behavior of the nu3 O-H or O-D stretch below the transition, followed by a hardening (positive pressure shift) above it. This behavior is interpreted as the transformation of ice phase VII to a structure with symmetric hydrogen bonds. The spectroscopic features of the phase persisted to the maximum pressures (210 gigapascals) of the measurements, although changes in vibrational mode coupling were observed at 150 to 160 gigapascals.     

The simplest double slit: interference and entanglement in double photoionization of H2

The wave nature of particles is rarely observed, in part because of their very short de Broglie wavelengths in most situations. However, even with wavelengths close to the size of their surroundings, the particles couple to their environment (for example, by gravity, Coulomb interaction, or thermal radiation). These couplings shift the wave phases, often in an uncontrolled way, and the resulting decoherence, or loss of phase integrity, is thought to be a main cause of the transition from quantum to classical behavior. How much interaction is needed to induce this transition? Here we show that a photoelectron and two protons form a minimum particle/slit system and that a single additional electron constitutes a minimum environment. Interference fringes observed in the angular distribution of a single electron are lost through its Coulomb interaction with a second electron, though the correlated momenta of the entangled electron pair continue to exhibit quantum interference.     

几个守恒律方程的精确解

利用守恒律方程等价的概念和求精确解的方法求出了几个守恒律方程的精确解。这些方程分别等价于ＫｄＶ方程、ＭＫｄＶ方程、ＫｄＶ－Ｂｕｒｇｅｒｓ方程等。广义ＫｄＶ方程的一个新的孤波解也被获得。     

基于最大熵模型的不同尺度物种分布概率优化热点分析: 以红色木莲为例

探究东亚特有属——天女花属(Oyama)的分布格局及其变迁。

基于温度、降雨、土壤和紫外线辐射共58个环境变量,结合分布点数据,在MaxEnt中分别基于属和种水平对天女花属的生态位进行模拟,并推测其过去(末次冰盛期和全新世中期)及未来(2050年和2070年) 4个时期的潜在分布区。

自过去到未来,天女花属植物有向高纬度和高海拔迁移的趋势,但末次冰盛期到当前时期的分布区面积均减少,当前时期到未来的面积变化有增加也有减少。在不同时期,基于种水平的模拟在环境异质性高的西南地区更精确且适生区面积更大,而在东北地区不存在显著差异。基于不同水平模拟的不同时期分布区变化有不同的趋势。

在未来对东亚特有属分布格局变迁模拟的研究中,需要注意不同水平模拟产生的差异并选择适合的方法。

     

西双版纳热带季节雨林辐射长期变化特征

[目的]太阳辐射是森林生态系统最主要的能量来源,同时是影响森林生态系统区域气候与环境的最重要因素之一.探讨森林辐射长期变化特征,以期为气候变化、热带地区森林生产力、辐射能量平衡的研究以及辐射模型的建立和验证等建立研究基础.[方法]利用西双版纳热带季节雨林14年(2003-2016)辐射实测数据,对不同时间尺度的辐射各分...     

1961-2020年华北平原冬小麦-夏玉米生长季内光能资源时空变化特征

利用华北平原具有1961-2020年完整时间序列逐日气象资料的55个常规气象站点及11个辐射观测站点的逐日地面观测资料,建立华北平原冬小麦-夏玉米生长季的太阳总辐射的经验公式,从年代际尺度和年际尺度分析冬小麦-夏玉米周年、生长季和关键生育期辐射资源(总辐射、直接辐射、散射辐射和光合有效辐射)的变化特征.结果表明:华北平...     

Resistance shifts accompanying the evoked cortical response in the cat

Clicks and flashes that evoke an electrical response from the auditory or visual cortex also evoke a resistance shift in the tissue. The resistance shift, a drop followed by a rise in resistance, closely follows the temporal pattern of the electrical response recorded simultaneously through the same electrodes. While several experimental manipulations produce corresponding changes in the amplitudes of both electrical response and resistance shift, the resistance shift is more sensitive to alterations in cortical temperature and anesthetic level. The two responses behave distinctly differently as a function of the depth of the electrode in the cortex.     

大气辐射在臭氧反演中的应用

阐述了大气臭氧含量的量度方法,然后在综合分析国内外大量相关文献的基础上,总结归纳了利用太阳透射辐射、太阳紫外散射、红外辐射及微波辐射等大气辐射进行大气臭氧反演的方法、特点及应用,最后总结了利用大气辐射进行臭氧反演的现状及在臭氧探测中应该注意的问题。     

增强UV-B辐射和干旱对不同品种春小麦生长、产量和生物量的影响

 【目的】通过研究增强UV-B辐射和干旱胁迫对不同品种春小麦生长、产量和生物量的影响,为筛选高产、抗旱、抗UV-B辐射春小麦新品种提供依据。【方法】设置干旱、增强UV-B辐射以及二者复合处理处理西北干旱区三个不同的主栽春小麦品种,检测和分析旗叶面积、叶片厚度、叶面积指数、生物量、根冠比、产量和收获指数等生理指标。【结果】增强UV-B辐射可抑制春小麦分蘖,而适度干旱胁迫可促进春小麦分蘖;增强UV-B辐射和干旱胁迫条件下,定西-24、陇春-8139、和尚头生物量分别降低22%,21%和15%,,平均降低20%;复合作用对产量和生物量的影响与增强UV-B辐射和干旱胁迫分别处理相比,没有明显的减少;干旱胁迫较增强UV-B辐射和二者的复合作用对收获指数和产量的负面影响稍小;干旱胁迫使和尚头和定西-24收获指数增加10%,陇春-8139增加23%;而增强UV-B辐射下和尚头的收获指数下降10%,定西-24和陇春-8139的收获指数均提高10%。说明不同品种春小麦在干旱胁迫、增强UV-B辐射以及二者复合作用下,光合产物向生殖器官的分配比例不同。【结论】春小麦对干旱和增强UV-B辐射胁迫的响应存在品种间的差异性;3个品种对干旱胁迫和增强UV-B辐射的响应趋势基本一致; 干旱胁迫和增强UV-B辐射对3个品种生长都具有抑制效应,但品种间存在一定的敏感性差异。在干旱胁迫和增强UV-B辐射作用下,陇春-8139较定西-24、和尚头分蘖少,但千粒重、收获指数和产量最高。因此,陇春-8139在抗旱、抗UV-B辐射和增产方面比其他2个品种具有更大的优势。     

清初岭南佛门的清规戒律与禅宗中兴——佛教戒律与道风建设初探

针对短波天线辐射效率难以现场监测的问题,研究一种基于外场场强测量的短波天线辐射效率监测方法。该方法结合天线仿真与测量技术,通过域变换法解析介质半空间位型并矢格林函数,采用RWG矩量法(RWG-MoM)离散平面分层介质C类混合位电场积分方程（MPIE）,得到天线辐射功率的相对分布。测量天线外场场强,得到场点电磁功率面密度作为样本估计天线辐射功率,由辐射功率与输入功率的比值计算得到天线辐射效率。以短波双极天线为例,基于现有的飞艇场强测量平台,进行室外远场场强的测量,实验得到的归一化场强方向图与仿真结果吻合较好,通过该方法计算得到的天线辐射效率与公开文献一致性较好,实现了短波天线辐射效率的监测。     

1980～2010年青藏高原柴达木盆地太阳辐射变化特征研究

利用1980～2010年格尔木辐射观测站的太阳总辐射、日照时数、水汽压、能见度和云量等月气象资料,建立了适用于柴达木盆地太阳总辐射的多元回归方程,利用方程计算了柴达木盆地的太阳总辐射,进而分析了柴达木盆地太阳能资源变化特征和分布状况。结果表明,柴达木盆地太阳总辐射年变化曲线呈双峰态,从1月份开始增加,2～4月增长最快,至5月出现最大,5～7月变化平缓,8月份以后开始下降,最小值出现在12月份;柴达木地区年太阳总辐射呈明显下降趋势,平均减幅为78.5 MJ/(m2.10a),平均下降幅度为11.3%/10a;夏秋季太阳辐射均呈显著下降趋势,春冬季变化不明显;年太阳总辐射的减少主要是由于夏季太阳总辐射的减少造成的。区域内各气象站年和四季的太阳总辐射变化趋势与整个区域的气候变化趋势不完全同步;柴达木盆地是我国辐射资源最为丰富的地区,开发利用潜力大;空间分布趋势是西北高东南低。春、夏、秋和冬季分别占全年太阳总辐射的30.0、32.4、22.0和15.6%。