抗癌药物铂络合物构效关系的物理方法研究

本文用Ｘ射线衍射、傅里叶变换红外光谱、差热分析等物理方法研究了抗癌药物铂络合物特性、结构以及构效关系．研究结果表明：ｃｉｓ－［Ｐｔ（ＮＨ３）２Ｃｌ２］属简单斜方晶系,晶格常数ａ＝０．９２２１ｎｍ,ｂ＝０．８７７１ｎｍ,ｃ＝０．６８９０ｎｍ．草酸二氨合铂的结构为斜方晶系,其晶格常数为：ａ１＝１．０７２１ｎｍ,ａ２＝０．６４０２ｎｍ,ａ３＝１．８５７０ｎｍ,并用傅里叶变换红外光谱、差热分析、元素分析等方法对它们理化特性进行了研究     

光系统Ⅱ核心复合物激发能传递光谱特性

采用ICCD皮秒、飞秒扫描成象光谱装置研究PSⅡ核心复合物激发能传递光谱特性,获得的PSⅡ积分荧光谱从661nm到693nm,峰值波长680nm,有四个组分谱,谱的峰值分别为670nm、676nm、681nm、686nm.CP43有Chla₆₆₀⁶⁶¹、Chla₆₆₉⁶⁷⁰和Chla₆₈₂⁶⁸⁶三个光谱组分;CP47有Chla₆₆₀⁶⁶¹、Chla₆₆₉⁶⁷⁰和Chla₆₈₀⁶⁸¹三个光谱组分.根据吸收光谱和组分光谱分析,PSⅡ核心天线各自有三种不同状态的Chla分子,它们是CP43-Chla₆₆₀⁶⁶¹、CP43-Chla₆₆₉⁶⁷⁰、CP43-Chla₆₈₂⁶⁸⁶与CP47-Chla₆₆₀⁶⁶¹、CP47-Chla₆₆₉⁶⁷⁰、CP47-Chla₆₈₀⁶⁸¹.通过四个光谱组分分析了PSⅡ核心复合物激发能传递的光谱特性.     

一种具有大带隙的各向异性二维光子晶体结构

提出一种新型各向异性材料(碲)二维光子晶体结构,应用有限时域差分法,对该结构特性进行数值分析,结果表明:通过优化结构参量,该结构具有较大的绝对光子禁带,禁带宽度为0.064ω_e(ω_e=2πc/a,a为晶格常量,c为光速),且该光子晶体的带隙具有很好的稳定性.     

Cr4+:Ca2GeO4激光晶体生长及结构表征

采用助熔剂法,以CaCl₂为助熔剂,生长Cr⁴⁺ :Ca₂GeO₄新型近红外可调谐激光晶体.通过X射线衍射(XRD)、激光Raman光谱、X射线光电子能谱(XPS)等方法对晶体进行结构表征.结果表明,得到的晶体为单斜晶系镁橄榄石结构的低温γ-Cr⁴⁺ :Ca₂GeO₄单晶,晶格参数为a=5.3209 (1 =0.1 nm)     

Studies in molecular structure,symmetry and conformation—Part XIV. Crystal and molecular structure of L-isoleucine hydrochloride monohydrate form II

The crystal structure of a new form of L-isoleucine hydrochloride monohydrate C₆H₁₃O₂NHClH₂O (termed form II) has been determined using three-dimensional photographic data. This differs conformationally from the hydrochloride derivative (termed form I, Trommel and Bijvoet 1954) reported earlier. The crystal belongs to the orthorhombic space group P2₁2₁2₁ with cell dimensions,a=5.87±0.01,b=24.77±0.02 andc=6.85±0.01 ? and four molecules per cell,ρ _obs=1.240 g/cm³,ρ _cal=1.238 g/cm³,μ for CuKa=32.6 cm⁻¹. Contribution No. 420 from the Department of Crystallography and Biophysics, University of Madras, Madras 600025.     

超洛伦兹-高斯光束SLG11模的分数傅里叶变换特性

 引入了一簇互相正交的超洛伦兹-高斯光束以描述半导体激光器所产生的大角度高阶模远场分布。将分数傅里叶变换应用于超洛伦兹-高斯光束SLG­₁₁模的传输特性的研究中。利用傅里叶变换的卷积原理,导出了SLG₁₁模经分数傅里叶变换系统后场分布的解析表达式。根据所得到的公式进行了数值计算,系统分析了分数傅里叶变换阶数和光束各参数对SLG₁₁模在分数傅里叶变换面上光强分布的影响。结果显示：SLG₁₁模在分数傅里叶变换面上的归一化强度分布随分数傅里叶变换的阶数呈周期性变化,周期为2;随着光束参数的增大,SLG₁₁模在分数傅里叶变换面上的光斑尺寸增大。     

稀土(镧、镨、钕)氯化物与苯并咪唑配合物的光谱特性

用傅里叶变换红外光谱、喇曼光谱、紫外光谱、荧光光谱和X粉晶衍射等多种光谱手段对氯化稀土(La、Pr、Nd)与苯并咪唑(Bim)配合物进行了分析,对配合物的光谱特性和结构进行了讨论和表征.     

氯胺铂配合物结构和理化特性的研究

采用X射线衍射、傅里叶变换红外光谱和元素分析对合成的几种胺铂配合物的结构、理化特性进行了研究元素分析结果和理论计算一致红外光谱结果表明官能团配位与结构相符X射线衍射分析表示该类化合物均属斜方晶系实验选用黑色素瘤(LiBr)做为外胚层模型,白血病细胞K₅₆₂做为中胚层模型,肝癌(7721)做为内胚层模型通过用MTT法对这几种铂类配合物抑制肿瘤细胞生长效果的测试结果表明,胺铂配合对肿瘤细胞的杀伤作用与浓度梯度和胺配体密切相关随着铂配合物浓度的增加,抗癌效果明显增强随着胺配体的不同,对不同肿瘤细胞的杀伤作用不同.     

哺乳动物五种离体组织光学特性的测量

光在哺乳动物组织中的传输依赖于组织体的光学特性,组织的光学特性是由吸收系数、散射系数和散射相位函数决定的。我们设计并实现了哺乳动物5种离休组织光学特性的测量。对实验方法和技术作了较大的改进,联合组织体漫反射特性和光能流率的测定,获得了满意的结果:光穿透深度δ=1.1～5.06mm,吸收系数μ_a=0.4～1.6cm^-1.有效散射系数μ_s(1-g)=2.7～17.7cm^-1.这种测量方法可用于人体组织光学特性的测量。     

BiFe1-xNbxO3的结构、磁性和光学性质

用溶胶凝胶法制备了Nb掺杂多铁BiFe_1-xNb_xO₃粉晶样品（0 <x <0.05）,研究Nb掺杂对样品的结构、磁学和光学性质的影响。根据XRD图谱和Rietveld精修的结果可知,所有的样品仍保持R3c相,但晶格常数a,c,晶胞体积V和Fe-O-Fe键角发生变化。适当的Nb掺杂使得样品晶粒尺寸减小,导致剩余磁化强度的增强,使得BiFe_1-xNb_xO₃样品的禁带窄化.     

新型BCN化合物的结构表征和相转变

将石墨和六方氮化硼(h-BN)混合粉球磨120h形成的非晶B-C-N粉在4.5GPa，1600K等温退火45min. XRD，TEM和Raman散射测量结果表明，高压合成的产物由晶格常数为a₁=0.2551nm，c₁=0.6716nm的六方Ⅰ相和a₂=1.2360nm，c₂=0.8570nm的六方Ⅱ相组成，其中六方Ⅱ相为B-C-N 新相. 在室温该新相在1279，1368，1398cm^-1出现三个特征Raman峰. 变温Raman测量结果表明，在测量温度T=93K时，样品中的主要相为六方Ⅰ相，随着温度的升高，六方Ⅰ相逐渐向六方Ⅱ相转变，当T>473K时，六方Ⅰ相完全转变成六方Ⅱ相. 当温度从673K降到93K过程中，样品又从六方Ⅱ相逐渐变回到六方Ⅰ相. 对这一相变的机理进行了讨论. 关键词： B-C-N 机械球磨 高温高压 相转变     

Microstructural assessment of InN-on-GaN films grown by plasma-assisted MBE

The structural properties of InN thin films, grown by rf plasma-assisted molecular beam epitaxy on Ga-face GaN/Al₂O₃(0001) substrates, were investigated by means of conventional and high resolution electron microscopy. Our observations showed that a uniform InN film of total thickness up to 1 μm could be readily grown on GaN without any indication of columnar growth. A clear epitaxial orientation relationship of , was determined. The quality of the InN film was rather good, having threading dislocations as the dominant structural defect with a density in the range of 10⁹–10¹⁰ cm⁻². The crystal lattice parameters of wurtzite InN were estimated by electron diffraction analysis to be a=0.354 nm and c=0.569 nm, using Al₂O₃ as the reference crystal. Heteroepitaxial growth of InN on GaN was accomplished by the introduction of a network of three regularly spaced misfit dislocation arrays at the atomically flat interface plane. The experimentally measured distance of misfit dislocations was 2.72 nm. This is in good agreement with the theoretical value derived from the in-plane lattice mismatch of InN and GaN, which indicated that nearly full relaxation of the interfacial strain between the two crystal lattices was achieved.     

InGaN/GaN多量子阱的组分确定和晶格常数计算

采用金属有机化学气相沉积(MOCVD)技术以蓝宝石为衬底在n型GaN单晶层上生长了InGaN/GaN多量子阱结构外延薄膜，利用高分辨X射线衍射(HRXRD)，卢瑟福背散射/沟道(RBS/channeling)，以及光致发光(PL)技术对InGaN/GaN多量子阱结构薄膜分别进行了平均晶格常数计算、In原子替位率计算和In组分的定量分析.研究表明：InGaN/GaN多量子阱的水平和垂直方向平均晶格常数分别为a_epi=0.3195nm，c_epi=0.5198nm，In原子的替位率为99.3%，利用HRXRD和RBS/channeling两种分析技术计算In的组分分别是0.023和0.026，并与样品生长时设定的预期目标相符合，验证了两种实验方法的准确性；而用室温条件下的光致发光谱(PL)来计算InGaN/GaN多量子阱中In的组分是与HRXRD和RBS/channeling的实验结果相差很大，说明用PL测试In组分的方法是不适宜的. 关键词： InGaN/GaN多量子阱 高分辨X射线衍射 卢瑟福背散射/沟道 光致发光     

Correlation of structure parameters of absorber layer with efficiency of Cu(In,Ga)Se<Subscript>2</Subscript> solar cell

Polycrystalline Cu(In, Ga)Se₂ with Ga-content x=Ga/(In+Ga) ranging from 0.0 (CuInSe₂) to 1.0 (CuGaSe₂) in heterojunction thin film solar cells were grown by multi-source evaporation. Solar cells with a highest efficiency of η=15.3% need a composition of x≈0.2. At this composition, the c/a ratio of the lattice constants for the tetragonal lattice equals c/a=2, indicating ideal tetragonality. These results suggest that low electronic defect densities occur at x≈0.2, due to the smallest possible crystallographic distortion of the tetragonal lattice at this composition. Cells with high efficiencies require grain sizes above 145 nm and a high preferred orientation (P₂₀₄/P₂₂₀ pole density ratio) for the grains.     

Growth and magneto-optical properties of LiTb(MoO<Subscript>4</Subscript>)<Subscript>2</Subscript> crystal

Lithium terbium molybdate (LiTb(MoO₄)₂) single crystal was grown by the Czochralski method. The lattice parameters of the crystal were determined by X-ray diffraction analysis. The absorption coefficient and the Faraday rotation spectrum (B=1.07 T) were investigated at wavelengths of 400–1500 nm at room temperature. Verdet constants of LiTb(MoO₄)₂ crystal at 532-, 633- and 1064-nm wavelengths were measured by the extinction method. The results show that LiTb(MoO₄)₂ crystal has a larger magneto-optical figure of merit than that of terbium gallium garnet at wavelengths of 600–1500 nm.     

Mechanochemical synthesis in the Ni-Al-C system

Specific features of the phase formation during mechanochemical synthesis of mixtures of elementary components, Ni, Al, and graphite, in an atomic ratio of 2:1:1 and a mixture of the intermetallic compound Ni₃Al and graphite (1:1) have been considered. It is shown that nanocrystalline (D = 4–6 nm) three-component solid solutions Ni(Al, C) with identical lattice constants (a = 0.366 nm) are formed during mechanosynthesis, independent of the initial components. Annealing at a temperature of 800°C for 2 h leads to decomposition of solid solutions into three phases: double carbide Ni₃AlC_0.46 (a = 0.3592 nm), solid solution Ni(Al, C) with the lattice constant 0.3546 nm, and graphite with the lattice constants a = 0.2461 nm and c = 0.660 nm.     

Crystal structural, magnetic and electrical transport properties of CeKFeMoO6 double perovskite

The crystal structural, magnetic and electrical transport properties of double perovskite CeKFeMoO₆ have been investigated. The crystal structure of the compound is assigned to the monoclinic system with space group P2₁/n and its lattice parameters are a=0.55345(3) nm, b=0.56068(2) nm, c=0.78390(1) nm, β=89.874(2). The divergence between zero-field-cooling and field-cooling M-T curves demonstrates the anisotropic behavior. The Curie temperature measured from C_p-T curve is about 340 K. Isothermal magnetization curve shows that the saturation and spontaneous magnetization are 1.90 and 1.43 μ_B/f.u. at 300 K, respectively. The electrical behavior of the sample shows a semiconductor. The electrical transport behavior can be described by variable range hopping model. Large magnetoresistance, −0.88 and −0.18, can be observed under low magnetic field, 0.5 T, at low and room temperature, respectively.     

Magnetic studies on RCo3B2 (R=Sm,Gd, Er)

Compounds RCo₃B₂ withR=Sm, Gd, and Er were prepared and identified structurally by X-ray diffraction. Magnetic properties of these materials were studied down to liquid He temperature. The materials order ferromagnetically (e.g.,T _c for GdCo₃B₂ is 58 K). The magnitude of saturation moments indicates that Co is nonmagnetic in this environment. Bulk specimens of the compound SmCo₃B₂ show extraordinarily high coercive forces at 4.2 K (H _c =50 kOe). The second-order crystal field term of Sm in this compound is calculated on the point charge crystal field model and is found to be considerably larger than the one of Sm in SmCo₅. This is mainly due to the unusual ratio of the lattice constants. This work was supported by a grant from the National Science Fundation.     

A room-temperature approach to boron nitride hollow spheres

Boron nitride hollow spheres were synthesized by the reaction of BBr₃ and NaNH₂ at room temperature; X-ray powder diffraction pattern could be indexed as hexagonal BN with the lattice constants of a=2.482 and c=6.701 Å; high-resolution transmission electron microscopy image showed the hollow spheres consisted of BN nanoparticles, with diameter between 80 and 300 nm; a possible formation mechanism of BN hollow spheres was discussed.     

Epitaxial growth of ZnSiN2 single-crystalline films on sapphire substrates

A new family of wide band gap nitride semiconductors expressed as II–IV-N₂ have recently attracted attention due to their expected properties such as optical non-linearity. In addition, among these compounds, ZnGeN₂ and ZnSiN₂ have lattice parameters close to GaN and SiC respectively. Up to now, there is very little work reported on this class of materials and no systematic thin film growth study has been reported to date. In this paper we present the first study on the growth of ZnSiN₂ on c-sapphire and (100) silicon substrates using low pressure MOVPE technique. Triethylamine:dimethylzinc adduct, silane diluted in H₂ and ammonia were used as source materials. Single crystalline epitaxial ZnSiN₂ layers were obtained on nitridated c-sapphire substrates in the temperature range 873–973 K by using an adapted II/IV molar ratio ranging from 1.2 to 12. Assuming an orthorhombic unit cell, the lattice parameters calculated from the X-ray diffraction data are a=0.534 nm, b=0.617 nm and c=0.504 nm.