浅谈灌区建筑物基础冻胀的防治

鸡东灌区地处黑龙江省东南部,冬季气温寒冷,以桥涵为主的各类建筑物经常发生冻胀现象。本文主要介绍了换基法,硬质泡沫保温法、结构法等防治建筑物基础冻胀的方法。

浅谈皖南圩区地基处理的方法和施工技术

泵站应用广泛分布在皖南沿江圩区。在进行泵站的基础设计时,时常会碰到软弱地基问题。下面就根据自己的一些工作实践经验,浅谈一下,如何采用换基和桩基二种办法处理软弱地基。下面分别阐述二种施工技术和应用情况。

Enantioselective extraction of mandelic acid enantiomers based on chiral ligand exchange

Based on the chiral ligand exchange, the distribution behavior of mandelic acid enantiomers, and the partition of Cu2+ at different pH values were studied in a water/alcohol two-phase system containing Cu2+ and N-n-（dodecyl-L-proline（A）.） The influences of the solvent sort, the pH value, the concentrations of Cu2+ and chiral ligand on the partition coefficient（K） and separation factor（α） were discussed. The experimental results show that the A formed has more stable ternary complex with D-mandelic acid enantiomer than with L-mandelic acid enantiomer. There is an important influence of the pH value on K and α. When the pH values are less than 3.5, the formation of binary complexes is thermodynamically unfavourable. K and α become maximum when pH values are above 3.5 and the molar ratio of the chiral ligand to Cu2+ is 2∶1.

MXene quantum dots of Ti_(3)C_(2):Properties,synthesis,and energy-related applications

The emerging two-dimensional MXene-derived quantum dots(MQDs)have garnered considerable research interest owing to their abundant active edge atoms,excellent electrical conductivity,and remarkable optical properties.Compared with their two-dimensional(2D)counterpart MXene,MQDs with forceful size and quantum confinement effects exhibit more unparalleled properties and have considerably contributed to the advanced photocatalysis,detection,energy storage,and biomedicine fields.This critical review summarizes the fundamental properties of MQDs in terms of structure,electricity,and optics.The mechanism,characteristics,and comparisons of two typical synthesis strategies(traditional chemical method and novel fluorine-free or chemical-free method)are also presented.Furthermore,the similarities and differences between MQDs and 2D MXenes are introduced in terms of their functional groups,light absorption capacity,energy band structure,and other properties.Moreover,recent advances in the applications of MQD-based materials for energy conversion and storage(ECS)are discussed,including photocatalysis,batteries,and supercapacitors.Finally,current challenges and future opportunities for advancing MQD-based materials in the promising ECS field are presented.

Study on one-dimensional consolidation of soil under cyclic loading and with varied compressibility

This paper presents a semi-analytical method to solve one dimensional consolidation problem by taking consideration of varied compressibility of soil under cyclic loading. In the method, soil stratum is divided equally into n layers while load and consolidation time are also divided into small parts and time intervals accordingly. The problem of one-dimensional consolidation of soil stratum under cyclic loading can then be dealt with at each time interval as one-dimensional linear consolidation of multi-layered soils under constant loading. The compression or rebounding of each soil layer can be judged by the effective stress of the layer. When the effective stress is larger than that in the last time interval, the soil layer is compressed, and when it is smaller, the soil layer rebounds. Thus, appropriate compressibility can be chosen and the consolidation of the layered system can be analyzed by the available analytical linear consolidation theory. Based on the semi-analytical method, a computer program was developed and the behavior of one-dimensional consolidation of soil with varied compressibility under cyclic loading was investigated, and compared with the available consolidation theory which takes no consideration of varied compressibility of soil under cyclic loading. The results showed that by taking the variable compressibility into account, the rate of consolidation of soil was greater than the one predicted by conventional consolidation theory.

Hermiticity of Hamiltonian Matrix using the Fourier Basis Sets in Bond-Bond-Angle and Radau Coordinates

In quantum calculations a transformed Hamiltonian is often used to avoid singularities in a certain basis set or to reduce computation time. We demonstrate for the Fourier basis set that the Hamiltonian can not be arbitrarily transformed. Otherwise, the Hamiltonian matrix becomes non-hermitian, which may lead to numerical problems. Methods for cor- rectly constructing the Hamiltonian operators are discussed. Specific examples involving the Fourier basis functions for a triatomic molecular Hamiltonian （J=0） in bond-bond angle and Radau coordinates are presented. For illustration, absorption spectra are calculated for the OC10 molecule using the time-dependent wavepacket method. Numerical results indicate that the non-hermiticity of the Hamiltonian matrix may also result from integration errors. The conclusion drawn here is generally useful for quantum calculation using basis expansion method using quadrature scheme.

New Oxorhenium（V） Complex with an Aminothiazole Ligand, and Radiochemical Behavior of Its Oxotechenetium（V） Complex Analog

A [ReO（Amino）2OH] complex was successfully synthesized by the ligand exchange method using oxorhenuim gluconate and an aminothiazole ligand. The complex was characterized elemental analysis and IR, UV-Vis, NMR and mass spectroscopes. The technetium tracer 99mTcO-complex has also been synthesized by two methods using Ligand exchange method and direct reduction method. The radiochemical purity of the complex was over 95% as measured by thin layer chromatography. In vitro studies showed that the complex possessed good stability under physiological conditions. The partition coefficient indicated that the complex hydrophilic and the electrophoresis results showed that the complex neutral. Normal biodistributions of the 99mTC complex exhibit high lung, liver and spleen uptake of 27%, I 1%, and 12%, respectively. Blood and lungs clearance was quite, while liver activity remained high for a longer period with 12% injection dose present at 1 h post-inj ection. The radioactivity from the novel technetium complex was excreted mainly through the hepatobiliary system, which passed 35% of the complex at 1 h post-injection, and partially through the kidneys.

Isolation of Lysozyme from Chicken Egg White Using Polyacrylamide-based Cation-exchange Cryogel

An effective cation-exchange chromatographic method for lysozyme isolation from chicken egg white is presented, using supermacroporous cryogel grafted with sulfo functional groups. The chromatographic processes were carried out by one-step and sequential elution, respectively. Sodium phosphate buffer （pH 7.8） containing different concentrations of NaC1 is used as elution agent. The corresponding breakthrough characteristics and elution behaviors in the cryogel bed were investigated and analyzed. Purity of lysozyme in the elution effluent was assayed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis （SDS-PAGE）. The maximum purity of the obtained lysozyme was about 96%, and the cryogel is demonstrated as a potential separation medium for purification of high-purit lysozyme from chicken egg white.

Equilibrium and kinetics of copper ions removal from wastewater by ion exchange

The removal of copper ions from wastewater by ion exchange has been studied using an iminodiacetate resin.The capacity of the resin for the copper ions has been determined to be 2.30 mmol·g^(-1) by measuring the equilibrium isotherm at 25 °C and initial pH value of 3.5 where the final equilibrium p H value is 5. An analysis of equilibrium isotherm models showed that the best fit model was the Langmuir–Freundlich. The kinetics of the ion exchange process have been investigated and four kinetic models have been tested namely: Ritchie model, pseudo-second order model, pseudo-first order model and the Elovich model. The pseudo-second order model provides the best fit to the kinetic data.

Correction method for non-landing measuring of vehicle-mounted theodolite based on static datum conversion

During the non-landing measuring of vehicle mounted theodolite, especially under high-speed tracking measurement, the misalignment of theodolite's center of mass and spindle etc. will cause high-frequency vibration of theodolite platform, increase the observation error of targets and even unbelievable results. In this paper, a correction method of non-landing measuring of theodolite based on static datum conversion is presented, which can effectively improve the observation accuracy of theodolite. The CCD camera is fixed to the theodolite platform to calculate the gesture shaking quantity of theodolite platform in geodetic coordinate system through the real time imaging of static datum. The observation results of theodolite are corrected by using such shaking quantity. The experiment shows that the correction accuracy exceeds 10 s of arc. The intrinsic parameter calibration technology of camera based on stellar angular distance and absolute conic put forward in this paper can prevent the estimated error of extrinsic parameters influencing the intrinsic parameter calibration and improve the intrinsic parameter calibration accuracy; the static datum conversion technology can reduce the influence of installation error of camera and theodolite platform on gesture measuring of the platform. The simulation experiment shows that when the shaking range of the platform is less than 30 min of arc, the influence of the three-axis installation error of camera within 3deg on the accuracy of correction results is less than 8 s of arc. The method in this paper can be extended to and used in the field of gesture shaking measuring and micro-structure deformation of various unstable platforms, therefore it is of important theoretical research significance and has wide engineering application prospect.

Development of DNA computing and information processing based on DNA-strand displacement

DNA computing, currently a hot research field in information processing, has the advantages of parallelism, low energy consumption, and high storability, therefore, it has been applied to a variety of complicated computational problems. The emerging field of DNA nanotechnology has also developed quickly; within it, the method of DNA strand displacement has drawn great attention because it is self-induced, sensitive, accurate, and operationally simple. This article summarizes five aspects of the recent developments of DNA-strand displacement in DNA computing:(1) cascading circuits;(2) catalyzed reaction;(3) logic computation;(4) DNA computing on surfaces; and(5) logic computing based on nanoparticles guided by strand displacement. The applications and mechanisms of strand displacement in DNA computing are discussed and possible future developments are presented.

Imitating trumpet shells: Mbius container molecules

Mbius container molecules C64H8,C60N4H4,and C58N6H2 with topological one-sided characteristics were constructed at the first time by imitating natural trumpet shells.The structure is an open cage with an inner hexagonal bridge.The bridge joints the outer and inner surfaces of the cage to form a new one-sided Mbius structure.The optimized structures of the three molecules in the singlet(the ground state),triplet and quintet states are obtained using the density functional theory(B3LYP).For the ground state structures of the three Mbius molecules,their oxidizabilities are weaker than that of the C60 and reducibilities are close to that of the stable C80 cage and slightly stronger than that of the C60.These may show that the unusual Mbius structures have some stability.Their potential properties were predicted,for example,the special aromaticity of the bridge ring due to the unique interaction between the bridge and the cage wall.These findings enlarge the knowledge of Mbius molecules. The idea of bionic and topological imitating in chemistry may promote the design of new complex-shaped nano-molecules and molecular devices.