δ13C difference between plants and soil organic matter along the eastern slope of Mount Gongga

Carbon isotope ratios (δ¹³C) of plants, litter and soil organic matter (0–5 cm, 5–10 cm and 10–20 cm) on the eastern slope of Mount Gongga were measured. The results show that δ¹³C values of plants, litter and soil organic matter all decrease first and then increase with altitude, i.e δ¹³C values gradually decrease from 1200 to 2100 m a.s.l., and increase from 2100 to 4500 m a.s.l. The δ¹³C altitudinal variations are related to the distribution of C₃ and C₄ plants on the eastern slope of Mount Gongga, because C₄ plants are observed to grow only below 2100 m, while C3 plants occur at all altitudes. There are significantly positive correla-tions among δ¹³C of vegetation, δ¹³C of litter and δ¹³C of soil organic matter, and litter, 0–5 cm, 5–10 cm and 10–20 cm soil or-ganic matter are 0.56‰, 2.87‰, 3.04‰ and 3.49‰ greater in δ¹³C than vegetation, respectively. Considering the influences of rising concentration of atmospheric CO₂ and decreasing δ¹³C of atmospheric CO₂ since the industry revolution on δ¹³C of plants, 1.57‰ is proposed to be the smallest correction value for reconstruction of paleovegetation using δ¹³C of soil organic matter.     

Research on C<Subscript>3</Subscript>N<Subscript>4</Subscript> superhard compound thin film and its application

By combination of DC reactive magnetron sputtering with multiple arcplating, the alternating C₃N₄/TiN compound film is deposited onto HSS. The core level binding energy and the contents of carbon and nitrogen are characterized by X-ray photoelectron spectrum. X-ray diffraction (XRD) shows that compound thin film contains hard crystalline phases of α-C₃N₄ and β-C₃N₄. The Knoop microhardness in the load range of 50, 5–54, 1 GPa is measured. According to acoustic emission scratch test, the critical load values for the coatings on HSS substrates are in the range of 40–80 N. The metal coated with C₃N₄/TiN compound films has a great improvement in the resistance against corrosion. Many tests show that such a coating has a very high wearability. Compared with the uncoated and TiN coated tools, the C₃N₄/TiN coated tools have a much longer cutting life. Foundation item: Supported by the National Natural Science Foundation of China (19875037) Biography: Wu Da-we( (1941-), male, Professor, research direction; thin film and its application.     

三聚氰胺热解产物的特性分析

以有机物三聚氰胺为初始原料, 在真空条件下使其热解（1 000 K）. 采用X射线衍射（XRD）、 透射电子显微镜（TEM）、 X射线光电子能谱(XPS)、 化学元素分析（EA）和傅里叶红外光谱(FT-IR) 分析样品的形貌、 成分和结构. 结果表明, 在真空条件下, 三聚氰胺全部分解, 分解产物为片层石墨相C₃N₄.      

Theoretical study on the lithium bond interaction of furan homologues C4H4Y （Y=O,S） with LiCH3 via DFT and MP2

The optimizations geometries and interaction energy corrected by BSSE of the complexes between C4H4Y （Y=O, S） and CHiLi have been calculated at the B3LYP/6-311＋＋G^＊＊ and MP2/6-311＋＋G^＊＊ levels. Three complexes were obtained. Abnormally, the calculations showed that all the C10--Li14 bond lengths increased obviously but the blue-shift of C10-Li14 stretching frequency occurred after formed complexes. The calculated binding energy with basis set super-position error （BSSE） and zero-point vibrational energy corrections of complexes I-III is -45.757, -35.700 and -39.107 kJ·mol^-1, respectively. The analyses on the combining interaction with the atom-in-molecules theory （AIM） also showed that a relatively strong lithium bond interaction presented in furan homologues C4H4Y-LiCH3 systems. Natural bond orbital theory （NBO） analysis has been performed, and the results revealed that the complex I is formed with n-σ type lithium bond interaction between C4H40 and LiCH3, complex II is formed with TT-s type lithium bond interaction between C4H4O and LiCH3, and complex III is formed with TT-s and n-s type lithium bond interactions between C4H4S and LiCH3, respectively.     

分子印迹电化学发光传感器检测毒死蜱

石墨相氮化碳纳米薄片（g-C₃N₄NSs）具有优良的电化学发光（ECL）性能和良好的成膜特性.以g-C₃N₄NSs作为ECL材料,利用其良好的成膜性能将其固定在玻碳电极（GCE）上,再以毒死蜱（CPF）作模板分子,甲基丙烯酸（MAA）作功能单体,通过分子自组装制备分子印迹聚合物（MIP）.将该聚合物引入g-C₃N₄NSs修饰电极,构建了一个MIP-ECL传感器.除去模板分子的传感器能够选择性识别CPF,利用CPF对g-C₃N₄NSs ECL信号的淬灭作用实现了CPF的高灵敏、高选择性检测.传感器对CPF的线性响应范围是1.0×10^-8~1.0×10^-4mol·L^-1,检出限（LOD）是5.0 nmol·L^-1,用于蔬菜中CPF残留量检测,结果令人满意.     

聚三嗪亚胺的合成及从水溶液中吸附铀

利用熔盐法合成了聚三嗪亚胺(polytriazineimide,PTI),并用来吸附水中的U(VI)。在常温下,PTI对铀的最大饱和吸附量达到了135.5 mg/g,与g-C₃N₄相比,是g-C₃N₄饱和吸附量的54.2倍。通过对动力学与吸附等温线模型的探究,发现PTI对U(VI)的吸附符合准一级动力学模型,说明PTI吸附U(VI)属于物理吸附。同时,Langmuir吸附等温线模型能更好地拟合PTI对U(VI)的吸附过程,说明U(VI)在PTI上属于单层吸附。通过对吸附铀后的材料进行XPS表征,发现铀在吸附后的价态没有改变,仍为U(VI)。     

Theoretical study on photophysical property of C60M（CO）5 （M=Cr,Mo and W）

Configurations of three η2 models of transition-metal [60]fullerene derivatives C60M（CO）5（M=Cr, Mo and W） have been optimized at B3LYP/LanL2DZ level. On the basis of the optimized geometrical structures, their electronic spectra and the frequency dependence of third-order nonlinear optical polarizabilities γ in different optical processes of third-harmonic generation （THG）, electric-field-induced second-harmonic generation （EFISHG） and degenerate four-wave mixing （DFWM） are calculated by using TDB3LYP model based on LanL2DZ level coupled with the SOS （sum-over-state） method. The obtained results show that their electronic spectra have a red shift compared with that of [60]fullerene and different transition-metal functional groups added to C60 cage may result in different spectrum properties. For the three studied species, （η^2-C60）Mo（CO）5 has the largest third-order nonlinear optical polarizability.     

粉煤灰对阿利特-硫铝酸盐水泥凝结时间及水化研究

通过在阿利特-硫铝酸盐水泥中添加粉煤灰,利用XRD、水化热和SEM来研究粉煤灰对该体系水化过程的影响.结果表明:粉煤灰对该体系有一定缓凝作用;并且随着掺量增加,作用越明显.粉煤灰主要影响水泥早期强度,对后期影响不大;当掺量≥30％时,对后期也有影响.火山灰反应在3d时不太明显,一般在28 d时较容易观察到.     

基于Fe@Fe3O4诊断和治疗平台的研究进展

Fe@Fe_3O_4纳米粒子(NPs)由于Fe核的存在具有很大的饱和磁化率和横向弛豫率,能够表现出比Fe_3O_4 NPs更好的磁共振成像(MRI)和光/磁热治疗效果,并且由于其具备光声和磁共振(MR)造影功能,可引导Fe@Fe_3O_4 NPs对肿瘤进行治疗.该材料因生物相容性好、成像和治疗方式多元化等优点而受到越来越多的关注.通过介绍和总结Fe@Fe_3O_4 NPs的几种成像模式和治疗方式,描述了目前该材料的最新研究进展,以深入了解Fe@Fe_3O_4 NPs在癌症治疗中的潜在应用.     

双亚磷酸酯催化剂体系用于羰基合成丁醛反应动力学的研究

将自主开发的双亚磷酸酯催化剂(HY-A)体系用于丙烯羰基合成制丁醛.在一定反应条件下,得到了与丙烯(C₃H₆)浓度、反应温度和催化剂铑(Rh)质量分数相关的动力学方程.在C₃H₆模试连续反应时,采用动力学方程推算的C₃H₆转化率与试验实际转化率基本一致,验证了动力学方程的可靠性.     

少层Ti_3C_2T_x基复合材料的制备及其光催化性能

通过刻蚀Ti_3AlC_2前驱体制得少层Ti_3C_2T_x(DL-Ti_3C_2T_x),以二甲基亚砜为反应溶剂采用溶剂热法控制氧化DL-Ti_3C_2T_x制备了TiO_2/DL-Ti_3C_2T_x复合材料。借助XRD、SEM、TEM、Raman等对相关样品的物相结构及微观形貌进行表征,并通过罗丹明B的光降解实验评价了所制复合材料的光催化性能。结果表明,复合材料DL-Ti_3C_2T_x片层的表面形成了均匀致密的锐钛矿型TiO_2纳米颗粒,通过控制溶剂热温度能够调控复合材料中DL-Ti_3C_2T_x和TiO_2的相对含量,并且当溶剂热温度为100℃时,所制TiO_2/DL-Ti_3C_2T_x复合材料光催化性能最佳。     

BiFeO3掺杂Pb（In1/2Nb1/2）O3-Pb（Mg1/3Nb2/3）O3-PbTiO3陶瓷的制备与磁电性能研究

以固相合成法制备了铁酸铋（BiFeO₃,简称BFO）掺杂的铌铟酸铅-铌镁酸铅-钛酸铅（Pb（In_1/2Nb_1/2）O₃-Pb（Mg_1/3Nb_2/3）O₃-PbTiO₃,简称PIN-PMN-PT）多铁性陶瓷材料,X射线衍射（XRD）测试结果表明：样品具有钙钛矿结构,电滞回线显示其铁电性良好,剩余极化值（P_r）可达18 μC·cm^-2.由于BiFeO₃掺杂后,样品电矩减小,氧空位增多,使其铁电畴翻转困难,样品的电性能略有下降,但是其磁性能随BiFeO₃掺入量的增加而逐渐增强,且样品居里温度（T_m）为200℃左右.该材料在电磁学领域有望成为具有应用前景的多铁性材料.     

α-氮化硅对硅磷酸钙生物陶瓷力学强度和生物活性的影响

理想的骨再生材料需要具有良好的生物活性和力学强度.前期的研究表明硅磷酸钙（Ca₅（PO₄）₂SiO₄,CPS）陶瓷具有良好的生物活性,可诱导骨髓基质干细胞的成骨分化,并在体内可促进新骨的形成.研究了α-氮化硅（α-Si₃N₄）对CPS生物陶瓷显微结构、抗弯强度、体外磷灰石形成能力及细胞相容性的影响.结果表明：α-Si₃N₄的添加可在一定程度上提高CPS生物陶瓷的抗弯强度,当其质量分数为1.5%时,Si₃N₄-CPS陶瓷的抗弯强度为相同温度下纯CPS陶瓷的1.2倍.模拟体液浸泡实验表明：Si₃N₄-CPS生物陶瓷均具有良好的磷灰石形成能力.CCK-8细胞相容性实验结果表明：Si₃N₄-CPS生物陶瓷无明显细胞毒性,展示出良好的生物相容性.