连翘苷荧光传感器的构建和应用

以柠檬酸为碳源,三聚氰胺和甲醛为双掺杂剂合成碳量子点,并对合成的量子点进行透射电镜(TEM)、傅里叶变换红外光谱(FTIR)、X射线粉末衍射(XRD)、紫外吸收光谱(UV)和荧光光谱(RF)表征,结果表明该量子点粒径均一,发光稳定,适合用作荧光探针。优化了碳量子点含量、pH、反应时间以及温度等影响因素,结果显示检测波长λmax=425 nm时,连翘苷在0.008~0.030 mg/mL范围内有良好的线性关系,1/△f=0.00005(1/c)+0.0003(R2=0.9948),加标回收率在92.5%~106.3%之间,RSD<5%,且干扰物质、反应时间、温度等因素在一定范围内对实验结果的测定无影响。该方法可用于药剂中连翘苷含量的测定。     

Determination of total fluoride in HF/HNO3/H2SiF6 etch solutions by new potentiometric titration methods

In the photovoltaic industry the etching of silicon in HF/HNO₃ solutions is a decisive process for cleaning wafer surfaces or to produce certain surface morphologies like polishing or texturization. With regard to cost efficiency, a maximal utilisation of etch baths in combination with highest quality and accuracy is strived. To provide an etch bath control realised by a replenishment with concentrated acids the main constituents of these HF/HNO₃ etch solutions including the reaction product H₂SiF₆ have to be analysed. Two new methods for the determination of the total fluoride content in an acidic etch solution based on the precipitation titration with La(NO₃)₃ are presented within this paper. The first method bases on the proper choice of the reaction conditions, since free fluoride ions have to be liberated from HF and H₂SiF₆ at the same time to be detected by a fluoride ion-selective electrode (F-ISE). Therefore, the sample is adjusted to a pH of 8 for total cleavage of the SiF₆²⁻ anion and titrated in absence of buffers. In a second method, the titration with La(NO₃)₃ is followed by a change of the pH-value using a HF resistant glass-electrode. Both methods provide consistent values, whereas the analysis is fast and accurate, and thus, applicable for industrial process control.     

Verbrückte und unverbrückte norbornyl-kationen in der gasphase. Berechnungen zur stabilität isomerer norbornyl-kationen mit hilfe quantenmechanischer verfahren

The geometry and the relative stability of bicyclic compounds 1–20 have been calculated by standard quantum mechanics methods.MINDO/3 yields the following stability order of isomeric norbornyl cations (relative energies in $\text{kcal}\text{mole}$): 1-norbornyl cation 9 (0.0); 1.7 σ-bridged cation 6 (0.7); 7-norbornyl cation (nonplanar) 7 (1.1); 2-norbornyl cation (classical) 2 (4.2); 7-norbornyl cation (planar) 8 (4.3); 2-norbornyl cation (bridged) 1 (6.1). The stability of the same ions calculated by ab initio methods (STO-3G, MINDO/3-geometry) leads to an order more nearly consistent with experimental results: 2-norbornyl cation (classical) 2 (0.0); 2-norbornyl cation (bridged) 1 (5.9); 7-norbornyl cation (planar) 8 (11.1); 1-norbornyl cation 9 (14.6); 7-norbornyl cation (nonplanar) 7 (21.2). For the secondary 7-norbornyl cation, MINDO/3 gives a pyramidal configuration, 3.2 $\text{kcal}\text{mole}$ more stable than the planar form. In contrast, the ab initio results (complete optimization of all geometrical parameters) indicate the planar cation to be the most stable form. The bridged structure of 2-norbornyl cation 1 is calculated (STO-3G, partly optimized) to be 4.3 $\text{kcal}\text{mole}$ less stable than the classical counterpart, 2. For the lower homologues 12 and 13 (STO-3G, complete geometry optimization), this difference is 6.4 $\text{kcal}\text{mole}$. However, more extended basis sets should favour the bridged structures. The hydrogen bridged norbornyl cations 3, 4, and 5 have been calculated (STO-3G, partly optimized) to be 14.4, 23.6 and 29.9 $\text{kcal}\text{mole}$ less stable than 2. The stability differences between the corresponding tertiary bicyclic ions 10 vs 11, and 14 vs 15 are calculated (ab initio) to be 15.3 and 19.0 kcal/mole, respectively, in favour of classical structures. The influence of methyl substitution at positions C₁ and C₆ (exo) on bridged and unbridged structure of 2-norbornyl cation is calculated. Pyramidal secondary and tertiary 2-norbornyl cations 19 (a; R=H, b; R=CH₃) and 20 (a; R=H, b; r=CH₃) have been used to model the electrical effects in the solvolysis transition states of epimeric 2-norbornyl esters. Due to more efficient hyperconjugation the pyramidal exo cation is stabilized more than the endo cation by 5.2 $\text{kcal}\text{mole}$ for the secondary series and 3.5 $\text{kcal}\text{mole}$ for the tertiary series. Bonding of endo cation 20 with a nucleophile should be stronger than bonding of exo cation 19 due to more efficient HOMO-LUMO interaction.     

Zur Kenntnis eines Oxoargentato(I)-aurats(III): Ba4AgAuO6

On the Oxoargentato(I)-aurat(III): Ba₄AgAuO₆ The hitherto unknown compound Ba₄AgAuO₆ was prepared by oxidizing Ba/Au/Ag alloy with BaO₂/Ba(OH)₂ mixture in closed Ag tubes. X-ray single crystal investigation led to orthorhombic symmetry space group D-Cmcm; a = 13.275; b = 5.782; c = 11.396 Å; Z = 4. Ba₄AgAuO₆ shows distorted pentagonal bipyramidal polyhedra around Ba²⁺ and square planar AuO₄ polygones. Ag⁺ shows an unusual 2 + 2 coordination by O^2?.     

Heating performance enhancement for a road unit by using sectorial-finned pipe

Journal of Thermal Analysis and Calorimetry - This study proposes a sectorial-finned pipe in the hydronic road heating system with a three-dimensional road model to enhance the road heating...     

Thermal performances of porous snow by a hydronic heating system at different weather conditions

Journal of Thermal Analysis and Calorimetry - The snow on the road in the cold regions is easy to cause slippery conditions, which are dangerous for vehicles and people. To remove the slippery...     

Praktische Anwendung linearer Wirtschaftsmodelle

Zusammenfassung Bei der Lösung großer linearer Gleichungssysteme muß die spezielle Struktur der Matrix berücksichtigt werden. Es wird ein Algorithmus zur Analyse der speziellen Struktur angegeben, der sich durch die Theorie der Graphen veranschaulichen läßt.

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Summary In order to solve large systems of linear equations, the special structure of the matrix must be taken into consideration. In this paper there will be indicated an algorithm for analysing the special structure; this algorithm can be illustrated by the theory of graphs.

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Unter anderem Titel in der FestschriftCarl Wurster, Ludwigshafen am Rhein, 1960.     

挡板对数据中心热环境影响的模拟研究

针对数据机房高架地板下静压箱内送风压力不平衡导致地板格栅送风不均匀而引起机柜过热的问题,以某大型数据中心内气流组织为研究对象,采用6SigmaRoom软件进行数值模拟,求解获取地板静压箱内架设挡板时数据中心内机柜进口温度分布,温度场分布和不同高度平面的速度场分布,进而对比静压箱架设挡板末端不同高度对数据中心内机柜最大进口温度的影响,最后运用供热指数(SHI)、回热指数(RHI)、机架冷却指数(RCI)和回风温度指数(RTI)详细分析其优劣.研究结果表明:静压箱架设挡板能改善数据中心的气流组织,且架设的挡板末端越高,其节能程度越高.与未架设挡板的数据中心相比,静压箱挡板末端为0.56 m时SHI降低43.1％,静压箱中压力分布更均匀,可有效解决数据中心近空调端机柜过热的问题.     

Acoustic field radiated into a transversely isotropic solid from a small aperture spherical surface

The acoustic field modelling reported in this paper finds application in the design of a scanning probe tip for measuring the near-surface elastic properties of solids and surface structures at high frequencies and with high spatial resolution. The underlying concept is for a longitudinally polarized pulse to be launched from a spherically-shaped portion of the upper surface of the pyramidal or conical shaped tip, and focused towards the narrow lower end. The change in the reflectivity when the narrow end is brought into contact with a solid will provide a measure of the local frequency dependent compliance of that solid. The calculations assume the material from which the tip is fabricated to be transversely isotropic, with symmetry axis coinciding with the axis of the tip. The main issue addressed in this paper is the role of the curvature of the radiating surface and anisotropy of the medium in determining the focal length and focal spread of the radiated field. Two complementary approaches are taken, firstly the discretization of the equations of motion on an irregular mesh of around 3 × 10⁵ triangular elements and solution using the commercial FE package ABAQUS/Explicit, and secondly an analytical approach based on ray tracing and a Green’s function method exploiting the angular spectrum method and stationary phase approximation in its evaluation. Consistency is achieved between these approaches regarding the characteristics of the focal region. With the combination of the two approaches it is thus possible to model the wave field from low frequencies, where the FE method is computationally economical and able to handle complex geometries, to high frequencies, where advantage increasingly lies with ray tracing and the Green’s function method.