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21.
于220℃水热晶化下制备了高结晶度的γ-ZrP,合成了3种γ-苄基膦酸-磷酸锆层状化合物Zr(PO4).(H2PO4)0.15(C6H5CH2PO3H)0.85·0.4H2O(1,d=1.86nm),Zr(PO4)(H2PO4)0.30(C6H5CH2PO3H)0.70·0.6H2O(2,d=1.78nm)和Zr(PO4)(H2PO4)0.50(C6H5CH2PO3H)0.50·0.7H2O(3,d=1.66nm).用X射线粉末衍射和31P固态核磁共振等手段表征其结构,并研究了其与α-苯乙胺的插层性能. 相似文献
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二维或三维金属膦酸盐聚合物作为功能材料在催化、离子交换和纳米材料等研究领域受到广泛关注 .最初的研究主要集中在四价金属盐 ,后来陆续报道了对于其它价态金属盐的研究 [1~ 3] ,但关于单一碱金属的研究报道较少 . 2 0 0 0年 ,Aranda等[4 ] 报道了首例 Na2 [( HO3PCH2 ) 3NH ]· 1 .5 H2 O( Na PP- 1 )晶体结构 .与其它膦酸盐的明显差别是 ,碱金属双膦酸盐是治疗骨质疏松症的药物 [5] .本文从重要的医药原料哌嗪 [6 ]出发 ,制备并测定了一种具有超分子特征的 α-氨基双膦酸钠Na2 [( HO3PCH2 ) NC4 H8N( CH2 PO3H) ]( H2 O)… 相似文献
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Guang-Mei Wei Yi-Tian Gao Wei Hu Chun-Yi Zhang 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,53(3):343-350
There has been considerable interest in the study on the
variable-coefficient nonlinear evolution equations in recent
years, since they can describe the real situations in many fields
of physical and engineering sciences. In this paper, a generalized
variable-coefficient KdV (GvcKdV) equation with the external-force
and perturbed/dissipative terms is investigated, which can
describe the various real situations, including large-amplitude
internal waves, blood vessels, Bose-Einstein condensates, rods
and positons. The Painlevé analysis leads to the explicit
constraint on the variable coefficients for such a equation to
pass the Painlevé test. An auto-B?cklund transformation is
provided by use of the truncated Painlevé expansion and
symbolic computation. Via the given auto-B?cklund
transformation, three families of analytic solutions are obtained,
including the solitonic and periodic solutions. 相似文献
25.
In the study of many problems of mechanical and physical sciences, various versions of the Benjamin-Bona-Mahony (BBM) equation
or the regularized-long-wave equation have been proposed. In this paper, we obtain the solitary-wave solutions to the general
form of the BBM equation, which fully cover the variety of the BBM solitary waves previously reported.
This work has been supported by the China Talent Fund, by the Cheung Kong Scholars Programme of China, by the Cheung-Kong-Scholar
Research Concerted Fund of Beijing University of Aeronautics and Astronautics, and by the Doctoral Education Fund in Basic
Sciences of Beijing University of Aeronautics and Astronautics. 相似文献
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G. Cini Castagnoli G. Bonino E. Callegari C. Taricco Guang-Mei Zhu 《Il Nuovo Cimento C》1993,16(6):807-811
Summary We have measured the thermoluminescence (TL) profile of the Mediterranean Sea core CT85.5 at the same depths where the cosmogenic-isotope10Be production peak at 35 ky BP was found. Strong TL peaks are evident at 37.5 ky and 35.6 ky BP. The Fourier analysis of the
TL time series running from 32.5 ky to 42.6 ky at 100 y sampling interval shows 2500 y and 500 y periodicities. We suggest
that the Sun was ?active? at the time of the10Be enhancement.
Paper presented at the 6th Cosmic Physics National Conference, Palermo, 3–7 November 1992. 相似文献
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采用化学气相沉积法(CVD)在Si(100)衬底上以Ni为催化剂, 金属Ga和NH3为原料合成了GaN微纳米结构, 并研究了N2流量对产物GaN的形貌及光学和电学性能的影响。利用场发射扫描电子显微镜(SEM)、透射电镜(TEM)、X射线衍射仪(XRD)、X-ray能谱仪(EDS)、光致发光谱(PL)和霍尔效应测试仪(HMS-3000)等测试手段对样品的形貌、结构、成分、光学和电学性能进行了分析。结果表明, 随着N2流量的增加, 产物GaN的形貌发生了由微米棒到蠕虫状线再到光滑纳米线的转变;生成的GaN均为六方纤锌矿结构;样品均表现出383 nm的近带边紫外发射峰和470 nm左右的蓝光发射峰;所有样品均为n型;并对产物GaN的形貌转变机理进行了分析。 相似文献