CO32-掺杂纳米羟基磷灰石晶体的合成与表征

CO32-掺杂是提高纳米羟基磷灰石(n-HA)生物活性的有效方法之一。以Ca(NO3)2·4H2O和Na3PO4·12H2O为主要原料,Na2CO3作为CO2-3来源,合成纳米碳羟基磷灰石(n-CHA)晶体。采用TEM,XRD,FTIR,RS对合成晶体形貌和结构进行表征。结果表明:合成的n-HA晶体长度约为60~80nm,宽度在20~30nm之间,形状为针状,具有良好的结晶度,与自然骨磷灰石形貌相似;n-CHA晶体随CO2-3掺入量的增加,结晶度降低;合成的n-CHA晶体的晶胞参数a值随着CO2-3加入量的增大不断收缩,但c值增大,参数比c/a值增大,符合B型取代(取代PO3-4)的晶胞参数变化规律。红外谱图中,872cm-1附近出现AB混合型取代(同时取代OH-,PO3-4)的CO2-3面外弯曲振动特征红外峰,同时CO2-3的不对称伸缩振动红外峰在1 454和1 420cm-1附近出现分裂峰,1 540cm-1附近出现弱CO2-3峰;1 122cm-1附近出现CO2-3对称伸缩振动拉曼峰,1 071cm-1附近出现CO2-3的B型替代特征拉曼峰,通过计算PO3-4,CO2-3,OH-拉曼峰的积分面积比PO3-4/CO2-3,OH-/CO23,PO3-4/OH-,表明CO2-3在替换时,先以B型为主,随着CO2-3掺入量的增加,发生A型替代(取代OH-)。实验结果表明,合成的磷灰石晶体为B型取代(取代PO3-4)为主的AB混合型取代的n-CHA。与人骨磷灰石晶体在形态、尺寸、晶体结构和生长方式上具有相似性,可称为类骨磷灰石。     

CO2-3掺杂纳米羟基磷灰石晶体的合成与表征

CO2-3掺杂是提高纳米羟基磷灰石（n-HA）生物活性的有效方法之一。以 Ca（NO3）2·4H2O 和Na3PO4·12H2O为主要原料，Na2CO3作为CO2-3来源，合成纳米碳羟基磷灰石（n-CHA）晶体。采用TEM ， XRD ，FTIR ，RS对合成晶体形貌和结构进行表征。结果表明：合成的n-HA晶体长度约为60～80 nm ，宽度在20～30 nm之间，形状为针状，具有良好的结晶度，与自然骨磷灰石形貌相似；n-CHA晶体随CO2-3掺入量的增加，结晶度降低；合成的 n-CHA晶体的晶胞参数 a值随着CO2-3加入量的增大不断收缩，但 c值增大，参数比c/a值增大，符合B型取代（取代PO3-4）的晶胞参数变化规律。红外谱图中，872 cm -1附近出现AB混合型取代（同时取代O H -，PO3-4）的CO2-3面外弯曲振动特征红外峰，同时CO2-3的不对称伸缩振动红外峰在1454和1420 cm -1附近出现分裂峰，1540 cm -1附近出现弱CO2-3峰；1122 cm -1附近出现CO2-3对称伸缩振动拉曼峰，1071 cm -1附近出现CO2-3的B型替代特征拉曼峰，通过计算PO3-4，CO2-3，O H -拉曼峰的积分面积比PO3-4/CO2-3，O H -/CO23，PO3-4/O H -，表明CO2-3在替换时，先以B型为主，随着CO2-3掺入量的增加，发生A型替代（取代O H -）。实验结果表明，合成的磷灰石晶体为B型取代（取代PO3-4）为主的AB混合型取代的 n-CHA。与人骨磷灰石晶体在形态、尺寸、晶体结构和生长方式上具有相似性，可称为类骨磷灰石。     

激光工作物质

TN244 2004064075 BiB_3O6晶体的喇曼光谱=Raman spectra of bismuth triborate BiB_3O_6 crystal[刊,中]/滕冰(青岛大学物理系.山东,青岛(266071)),胡小波…∥光电子·激光.—2004,15(6).—734-738 对BiB_3O_6晶体(BIBO)的喇曼光谱进行了研究。BIBO的振动模分为外模和内模,外模总数是2A 5B,内模数是11A 10B。运用分子位置群分析的方法分析内模,BIBO的内模归属于[BO_3]三角形和[BO_4]四面体的振动模,[BO_3]和[BO_4]共享O原子。外部振动起源于Bi~(3 )、[BO_3]基团的平移模与[BO_3]基团的天平动。图2表2参9(于晓光)     

HIV蛋白酶抑制剂的定量构效关系研究及其指导下的修饰

HIV蛋白酶是一类用于治疗艾滋病具有潜在价值的关键酶,很多此类酶的抑制剂已经上市.一系列由AHPBA分子的基本骨架进行改造并合成的25个α-羟基β-氨基酸类似物对于HIV蛋白酶具有很高的活性和选择性.我们筛选合适的描述子建立一个二维定量构效关系的模型,模型的均方根误差RMSE=0.09823、相关性系数R=0.97461、F值=30.763、交叉验证的相关系数RCV=0.7071、交叉验证的预测误差平方PRESS=0.588,该模型为HIV蛋白酶抑制剂修饰和设计提供了比较可靠的预测.并且根据“变形钥匙”理论,分别用“杂化肽键”Ψ[CH2NH]、Ψ[CF2NH]、Ψ[COCF2]、替换掉这组类似物中易水解的肽键-CO=NH-,使得这个共轭π键就变成一个较强的单键,变得不易被HIV蛋白酶所水解,从而得到抗AIDS的有效的抑制剂.然后通过原子电荷分布对比、分子对接等方法检验修饰的可能性和合理性.预先设想都在计算结果中得到验证,并且用QSAR模型预测了修饰后分子的活性.     

Li_2O-WO_3二元系熔融钨酸盐原位拉曼光谱研究

本文利用原位高温拉曼光谱技术并结合量子化学从头计算方法研究了Li2O-WO3二元系钨酸盐熔体中稳定存在的结构单元随成分变化的趋势,给出了其在不同成分下微结构的具体模型,并对其主要振动模式进行了归属。研究表明成分不同会导致四面体基团聚合形成不同长度的链状,且Li2O与WO3摩尔比越小,也即WO3的含量越多,其链的长度越长;结合量子化学从头计算理论分析,认为当熔体的摩尔比为1∶1、1∶2、1∶3以及1∶4时,对应的阴离子基团模型分别为[WO4]2-、[W2O7]2-、[W3O10]2-和[W4O13]2-,其中[W2O7]2-、[W3O10]2-和[W4O13]2-分别由两个、三个、四个[WO4]2-以共顶形式连接而成。     

p型GaN低温粗化提高发光二极管特性

利用金属有机物化学气相沉积技术在蓝宝石衬底上低温生长GaN:Mg薄膜,对不同源流量的GaN:Mg材料特性进行优化研究.研究表明二茂镁(CP2Mg)和三甲基镓(TMGa)物质的量比([CP2Mg]/[TMGa])在1.4×10-3—2.5×10-3范围内,随[CP2Mg]/[TMGa]增加,晶体质量提高,空穴浓度线性增加.当[CP2Mg]/[TMGa]为2.5×10-3时获得空穴浓度与在较高温度生长获得的空穴浓度相当,且薄膜表面较粗糙.采用[CP2Mg]/[TMGa]为2.5×10-3的p型GaN层制备的发光二极管,在注入电流为20mA时,输出光强提高了17.2%.     

AMT在青铜器文物表面形成缓蚀膜的计算分析

利用密度泛函(DFT)、概念DFT、Electron Localization Function(ELF)和Fukui函数中的亲电反应函数及Multiwfn软件,在B3LYP/6-311+G(d,p)基组水平上研究了5-氨基-2-巯基-1,3,4-噻二唑[AMT(a)]及其同分异构体[AMT(b)]和四面体型配合物i Thiol-Cu-2AMT的几何构型和反应特性.通过计算研究发现,首先AMT(b)与青铜器表面的Cu2+形成平面型配合物i Thiol-Cu后再与AMT(b)相互作用,并最终形成不规则的四面体型i Thiol-Cu-2AMT.在i Thiol-Cu-2AMT中Cu19能与AMT(b)中的亲核性原子有效地结合,形成四面体结构后将Cu19离子保护起来,达到了保护青铜器不受腐蚀的目的;对i Thiol-Cu-2AMT结构中的活性位置分析及ELF拓扑研究后发现,在i Thiol-Cu-2AMT中N6、N15、S26和S35原子又可以与其它的Cu2+相互作用,逐步形成配位型聚合物保护膜[i Thiol-Cu-2AMT]n.     

六方相TbPO_4·nH_2O的控制合成及发光性能研究

通过控制PO3-4/Tb3+的量比,在低温水热条件下合成了不同形貌的TbPO4·nH2O纳米晶体。采用X射线衍射仪(XRD)、场发射扫描电镜(FE-SEM)及光致发光光谱(PL)等分析手段对所制备的样品进行了表征。研究了溶液中PO3-4/Tb3+比值变化对产物晶型结构、形貌、晶粒尺寸及发光性能的影响,给出了TbPO4·nH2O纳米粉体的生长机理。实验发现,当PO3-4/Tb3+比值达到60∶1时,产物在过量的磷酸根体系中生长成直径为100~200 nm的TbPO4·nH2O茧状微球,且产物的发光强度最大。PO3-4/Tb3+比值对TbPO4·nH2O形貌和发光性能有重要影响。     

CaO-SiO_2-Al_2O_3渣系连铸保护渣结构的拉曼光谱研究

在高铝钢连铸过程中,钢水中的Al与CaO-SiO2基连铸保护渣中的SiO2反应导致保护渣中SiO2含量降低而Al2O3含量大幅增加,CaO-SiO2基转变为CaO-SiO2-Al2O3基连铸保护渣而影响高铝钢连铸,所以研究CaO-SiO2基向CaO-SiO2-Al2O3基保护渣转变过程中结构上发生的变化有助于开发出满足高铝钢连铸需求的保护渣。本文利用拉曼光谱研究了CaO-SiO2基和CaO-SiO2-Al2O3基连铸保护渣的结构特点。研究结果表明,CaO-SiO2基保护渣主要由Q0,Q1,Q2和Q3等微结构单元构成的硅酸盐网络结构;当转变为CaO-SiO2-Al2O3基保护渣后,渣样中的网络破坏体优先用于破坏硅酸盐网络结构,当渣中SiO2含量较低时,部分网络破坏体会促进Al 3+形成[AlO4]四面体结构。渣中生成的[AlO4]四面体会进入硅酸盐网络结构形成铝硅酸盐网络结构,以Al-O-Al或Al-O-Si等方式连接,导致渣样结构变得复杂多变。使用Li2O对Na2O和CaO对MgO等摩尔替代研究表明相同价态离子之间的替换能够改变[AlO4]四面体在硅酸盐网络结构上的连接方式,导致CaO-SiO2-Al2O3基保护渣渣样结构易受成分变化而改变;CaF2对CaO等摩尔替代研究发现,当渣中CaF2小于13mol%,CaF2促进渣样网络结构解体,当高于13mol%时,CaF2又会导致渣样聚合度增加。由此可见,在设计CaO-SiO2-Al2O3基保护渣时,既要考虑不同种类离子对渣样结构产生的影响,又要考虑离子含量的影响。     

新型红色发光材料La3PO7∶Eu^3＋的合成及发光性质研究

用固相法合成了La3PO7∶Eu3 ,用X射线衍射仪测定了其晶体结构,室温下用Hitachi F-4500测定了其光致发光性质。结果表明合成的La3PO7∶Eu3 属单斜相结构,Eu3 在单斜结构的La3PO7基质中占据非对称性格位。在254 nm光激发下,La3PO7∶Eu3 发射出较强的红光,表明Eu3 的5D0→7F2跃迁强度远大于5D0→7F1的跃迁强度,其色坐标和Y2O3∶Eu3 的色坐标位置相近。另外,还研究了Eu3 在体相La3PO7材料中的猝灭浓度,发现当掺杂Eu3 浓度增大到7.6 mol%时,出现浓度猝灭。     

First-principles energy band calculation for undoped and S-doped TiO2 with anatase structure

The electronic structure of S-doped TiO₂ with an optimized anatase structure was calculated within the framework of the density functional theory (DFT). For the calculation we built four kinds of supercells; type-A and B supercells consist of 12 and 48 atoms and a centered Ti atom is substituted for an S atom, while type-C and D supercells consist of 12 and 48 atoms and a centered O atom is substituted for an S atom. The supercells (type-B and D) were employed to adjust the S-concentration in TiO₂ to an experimental value of a few %. The changes of the lattice parameters are not significant in the type-A and B supercells. The phase transition from the tetragonal to the orthorhombic occurs in the type-C and D supercells. In the small supercell (type-A), S-related states are located in the range of −1.6 to 0 eV, and the S-states are band-like. In contrast, in the large supercell (type-B), S-related states appeared at about 0.9 eV above the top of the valence band, and the S-states are atomic-like. The localization of the S-related states is remarkable in the type-B supercell. In the type-D supercell, the S-related states were merged with the top of the valence band, and as a result the band-gap energy is narrowed by 0.7 eV. Despite a low S-concentration (3%) in the type-D supercell, the S-related states are somewhat band-like.     

Measurements of the branching fractions for psi(3770)-->D(0)D[over ](0), D+D-, DD[over ], and the resonance parameters of psi(3770) and psi(2S)

We measure the branching fractions for psi(3770)-->D(0)D[over ](0), D+D-, DD[over ], and non-DD[over ] to be (46.7+/-4.7+/-2.3)%, (36.9+/-3.7+/-2.8)%, (83.6+/-7.3+/-4.2)%, and (16.4+/-7.3+/-4.2)%, respectively. The resonance parameters of psi(3770) and psi(2S) are measured to be M_(psi(3770))=3772.2+/-0.7+/-0.3 MeV, Gamma_(psi(3770))(tot)=26.9+/-2.4+/-0.3 MeV, and Gamma_(psi(3770))(ee)=251+/-26+/-11 eV; M_(psi(2S))=3685.5+/-0.0+/-0.3 MeV, Gamma_(psi(2S))(tot)=331+/-58+/-2 keV, and Gamma_(psi(2S))(ee)=2.330+/-0.036+/-0.110 keV. We also measure the light hadron R value to be R(uds)=2.262+/-0.054+/-0.109 in the energy region from 3.660 to 3.872 GeV.     

Two-photon absorption in two-dimensional conjugated quadrupolar chromophores

We present ultrafast z-scan measurements of the two-photon absorption (TPA) spectra of a pair of two-dimensionally conjugated quadrupolar donor/acceptor (D/A) chromophores. The all-donor substituted species displays a peak TPA cross section [sigma(2)=520+/-30 GM] that is more than twice that of the D-A species [sigma(2)=240+/-20 GM]. Unlike previous structure-property studies that have evaluated TPA behavior for D/A molecules through the comparison of dipolar and quadrupolar compounds, both molecules investigated herein are quadrupolar, ultimately providing a more consistent evaluation of the effects of donor and/or acceptor substitution on the TPA of conjugated chromophores.     

Observation of thirteen new exclusive multibody hadronic decays of the psi(2S)

Using data accumulated with the CLEO detector corresponding to an integrated luminosity of [symbol: see text] = 5.63 pb(-1) on the peak of the psi(2S) [3.08 x 10(6) psi(2S) decays] and 20.70 pb(-1) at square root of[s] = 3.67 GeV, we report first measurements of the branching fractions for the following 13 decay modes of the psi(2S): eta3pi, &eta'3pi, rhoK+K-, K+K-pi+pi-pi0, 2(K+K-), 2(K+K-)pi0, rhopp, pppi+pi-pi0, etapp, ppK+K-, lambdalambdapi+pi-, lambdapK+, and lambdapK+pi+pi-, and more precise measurements of 8 previously measured modes: 2(pi+pi-), rhopi+pi-, 2(pi+pi-)pi0, omegapi+pi-, K+K-pi+pi-, omegaK+K-, phiK+K-, and pppi+pi-. We also report new branching fraction measurements of phipi+pi- and omegapp and upper limits for etapi+pi-, etaK+K-, and phivpp. Results are compared, where possible, with the corresponding J/psi branching ratios to provide new tests of the 12% rule.     

Measurement of J/psi and psi(2S) polarization in pp collisions at sqrt[s] = 1.8 TeV

We have measured the polarization of J/psi and psi(2S) mesons produced in pp collisions at sqrt[s] = 1.8 TeV, using data collected at the Collider Detector at Fermilab during 1992-1995. The polarization of promptly produced J/psi [psi(2S)] mesons is isolated from those produced in B-hadron decay, and measured over the kinematic range 4 [5.5]相似文献   

QCD prediction for the non-DD[over ] annihilation decay of psi(3770)

To clarify the marked difference between BES and CLEO measurements on the non-DD[over ] decays of the psi(3770), a 1(3)D1-dominated charmonium, we calculate the annihilation decay of psi(3770) in nonrelativistic QCD. By introducing the color-octet contributions, the results are free from infrared divergences. The color-octet matrix elements are estimated by solving the evolution equations. The S-D mixing effect is found to be very small. With m_{c}=1.5+/-0.1 GeV, our result is Gamma(psi(3770)-->light hadrons)=467(+338);(-187) keV. For mc=1.4 GeV, together with the observed hadronic transitions and E1 transitions, the non-DD[over ] decay branching ratio of psi(3770) could reach about 5%. Our results do not favor the results of either the BES or the CLEO Collaborations, and further experimental tests are urged.     

Y0.5Gd0.5Ba2Cu3O7-δ体系中通氧时间对超导转变温度的影响

研究了高温氧化物超导体Y0.5Gd0.5Ba2Cu3O7-δ体系中通氧时间对超导转变温度及超导转变温区的影响。Y0.5Gd0.5Ba2Cu3O7-δ样品是按相等摩尔数的Gd与Y元素配比,采用传统的固相反应法烧结而成的多晶块材。实验结果显示:Y0.5Gd0.5Ba2Cu3O7-δ烧结样品与YBa2Cu3O7-δ烧结样品均具有很好的单相性,在一定的通氧条件下其超导临界转变温度TC与超导初始转变温度TCO值相对YBa2Cu3O7-δ烧结样品有提高。文中对此结果进行了讨论。     

Production of chi(c1) and chi(c2) in pp collisions at sqrt[S] = 1.8 TeV

We have measured the ratio of prompt production rates of the charmonium states chi(c1) and chi(c2) in 110 pb(-1) of pp collisions at sqrt[s] = 1.8 TeV. The photon from their decay into J/psi(gamma) is reconstructed through conversion into e+e- pairs. The energy resolution this technique provides makes the resolution of the two states possible. We find the ratio of production cross sections sigma(chi(c2))/sigma(chi(c1)) = 0.96+/-0.27(stat)+/-0.11(syst) for events with pT(J/psi) > 4.0 GeV/c, /eta(J/psi)/ < 0.6, and pT(gamma) > 1.0 GeV/c.     

金属羰基化合物（CpFe（CO）2）2与金属氧化物表面作用的傅里叶变…

用漫反射红外光谱和光声红外光谱研究了金属羰基化合物（ＣｐＦｅ（ＣＯ）２）２Ｃｐ＝η＾５－Ｃ５Ｈ５与酸性，中性和碱性Ａｌ２Ｏ３及ＴｉＯ２的相互作用，结果表明，在Ａｌ２Ｏ３表面生成的洗生物种类及浓度与Ａｌ２Ｏ３的酸碱度明显相关，在酸性Ａｌ２Ｏ３表面，主要存在衍生物（ＣｐＦｅ（ＣＯ）２Ｆｅ－Ｈ－Ｆｅ（ＣＯ２Ｃｐ）＾＋及少量的ＣｐＦｅ（ＣＯ）２（－Ｏ－）；在中性Ａｌ２Ｏ３表面存在的ＣｐＦｅ（ＣＯ）２（－Ｏ     

DFT approach on stability and conductance of nine different polyyne and cumulene molecules

Cumulene molecules are one of the main candidates for the use as molecular wires. Low bond length alternation (BLA) values are one of the main attractive property of cumulene molecules as it leads to high conductivity, whereas stability under normal conditions is the main problem. The study is aimed at achieving stable molecules with low BLA values by forcing cumulene structure in polyynes through substitution. Hence, we considered symmetric LCC molecules of n core carbon atoms (n?=?4–12) with nine different terminal groups substitution such as hydrogen terminated polyynes (H[n]), phenyl terminated polyynes (Ph[n]), pyridine-capped polyynes Py[n], 3, 5-diphenyl pyridyl terminated polyynes (Py*[n]) their hydrogenated forms (H-Py[n] and H-Py*[n]), oxygen substituted phenyl terminated polyynes (O=Ph[n]) and 2, 4, 6-trimethylphenyl capped cumulenes (Mes[n]). The BLA values, transport barrier, excitation energy, reorganisation energy, energy gap and vertical and adiabatic ionisation energy were analysed to find the suitable molecule for molecular wires.