Electrokinetic particle translocation through a nanopore containing a floating electrode

Electrokinetic particle translocation through a nanopore containing a floating electrode is investigated by solving a continuum model, composed of the coupled Poisson-Nernst-Planck (PNP) equations for the ionic mass transport and the modified Stokes equations for the flow field. Two effects due to the presence of the floating electrode, the induced-charge electroosmosis (ICEO) and the particle-floating electrode electrostatic interaction, could significantly affect the electrokinetic mobility of DNA nanoparticles. When the electrical double layers (EDLs) of the DNA nanoparticle and the floating electrode are not overlapped, the particle-floating electrode electrostatic interaction becomes negligible. As a result, the DNA nanoparticle could be trapped near the floating electrode arising from the induced-charge electroosmosis when the applied electric field is relatively high. The presence of the floating electrode attracts more ions inside the nanopore resulting in an increase in the ionic current flowing through the nanopore; however, it has a limited effect on the deviation of the current from its base current when the particle is far from the pore.     

Carrageenan as an elicitor of induced secondary metabolites and its effects on various growth characters of chickpea and maize plants

The effects of polysaccharide elicitor k-carrageenan obtained from Hypnea musciformis, red algae on the production of Induced Secondary Metabolites, ISMs (the disease resistance compounds) and on various growth characters of chickpea and maize plants were studied. Experiments were conducted in the field of PCSIR Laboratories Complex Karachi during December 2008–April 2009 in randomized complete block design with three replications. Three elicitor treatments were used, a solid preparation in which the elicitor was mixed with soil (T₂ 1 mg/g) and applied around the seeds in the soil. The two other preparations were liquid, T₁ and T₃ at a concentration of 100 μg glc eq ml⁻¹ and were applied around the sowing seeds and as a foliar spray on the plants, respectively. Statistical analysis of the data revealed that these treatments significantly enhanced all the growth characters of chickpea except T₂ that gave the nonsignificant difference in the plant height. Maximum plant height (80.3 cm), number of pods plant⁻¹ (76.2), number of branches plant⁻¹ (25.0), number of leaves plant⁻¹ (125.6), earlier flowering and high ISMs contents in leaves, stem and grains of chickpea were recorded in T₁ treated chickpea plants. In maize plants only T₁ and T₃ treatments (with minor exceptions) had significant effects on few characters like plant height, stem diameter, number of leaves plant⁻¹ and on ISMs contents in leaves while number of cobs plant⁻¹ and flowering time were nonsignificantly affected by these treatments. These results suggested that k-carrageenan elicitor can be used as a potent plant protectant as well as growth promoting agent especially for chickpea plants.     

First findings of monocrystalline aragonite inclusions in garnet from diamond-grade UHPM rocks (Kokchetav Massif, Northern Kazakhstan)

The crystal field effect and microscopic origins of the Zeeman g-factors g(//) and g(⊥) for (6)S(3d(5)) state ions at tetragonal symmetry crystal filed, taking into account the spin-spin (SS), the spin-other-orbit (SOO), and the orbit-orbit (OO) magnetic interactions besides the well-known spin-orbit (SO) magnetic interaction, have been investigated using the microscopic spin Hamiltonian theory and the complete diagonalization method (CDM). It is found that the g(//)(±1/2)≠g(//)(±5/2) and g(⊥)(±1/2)≠g(⊥)(±5/2), where the g-factors g(//)(±1/2) and g(⊥)(±1/2) express the g-factors of the ground state |M?(s)=±1/2), whereas the g-factors g(//)(±5/2) and g(⊥)(±5/2) express the g-factors of the ground state |M?(s)=±5/2). It is shown that although the SO magnetic interaction is the most important one, the contributions to the shifts of g-factors Δg(//)(=2.0023-g(//)) and Δg(⊥)(=2.0023-g(⊥)) from other three magnetic interactions including the SS, SOO, and OO magnetic interactions are appreciable and should not be omitted, especially for the shifts of g-factors Δg(//)(±5/2) and Δg(⊥)(±5/2). The individual contributions to the shifts of g-factors arising from the spin quartet states and spin doublet states have been studied. The investigations show that the Δg(//)(±1/2) and Δg(⊥)(±1/2) primarily result from the spin quartet states, whereas Δg(//)(±5/2) and Δg(⊥)(±5/2) from the spin quartet states as well as the combined effects between the spin quartet states and the spin doublet states. The contribution to the shifts of g-factors from the net spin doublet states is zero.     

硅铝比对完全液相法制备的一步法二甲醚合成催化剂反应性能的影响

采用完全液相法制备了不同Si/Al摩尔比的浆状一步法二甲醚合成催化荆,在搅拌式反应釜中对其催化性能进行了评价.通过XRD,NH3-TPD-MS,H2-TPR和XPS等方法表征了催化剂的体相结构和表面性质.结果表明,完全液相法制备的CuZnSiAl催化剂在反应前其活性组分Cu主要以低价态存在,Cu晶粒大小是影响其活性的主...     

Determination of the correlation effects in molecules using the complete error potential

Summary The complete error potential is used for the study of the correlation of molecules. The correlation can be seen as a relaxation of the electrons and a relaxation of the nuclei. From the Fermi sea, the electronic relaxation gives rise to a partial excitation of each orbital which collectively generates a linear, a surface or a volume pressure; the resulting forces acting on the nuclei are defined in a general theory of the intramolecular forces. H₃, H ₃ ⁺ , the diatoms and the hydrid of the first nine elements are taken as examples.     

Enhanced particle trapping performance of induced charge electroosmosis

By increasing the number of floating electrodes or enlarging the width of single floating electrode, this work provides effective ways to strongly improve the particle trapping performance of induced charge electroosmosis (ICEO). Particle trapping with double or triple separate narrow floating electrodes increases the effective actuating range of ICEO flow and therefore enhance the optimum trapping ability to be 1.63 or 2.34 times of that with single narrow electrode (width of ), and the ideal trapping frequency is independent of the electrode number due to the mutual independence of electrochemical ion relaxation over each electrode. Furthermore, using a single wide floating electrode with the effective width equal to three separate narrow floating electrodes () instead of a single narrow one slightly lowers the ideal trapping frequency due to an increase in the characteristic polarization length, but the trapping performance is only up to 1.59 times of that with original single narrow electrode, implying that vertical channel confinement effect may severely suppresses the effective actuating range of ICEO flow and renders the trapping performance not as expected. Trapping experiments over wide floating electrode with different channel height were carried out, showing that the trapping performance increases by correctly increasing the channel height.     

认识化学反应平衡

The drawbacks in interpreting the chemical equilibrium in current general chemistry textbooks were discussed. An easy-understood introduction of chemical isothermoequation of several types of reactions was proposed. Reversible and irreversible reactions, reversible and irreversible processes, and complete and incomplete reactions were distinguished, respectively.     

3-N-苄氧羰基-β-氨基丁酸糖酯的合成及生物活性

将两类具有重要生物活性的结构单元β-氨基丁酸和糖分子结合在一个分子内, 设计合成了8个新糖酯化合物. 经元素分析和1H NMR确认了其结构. 初步生物活性测定结果表明, 该类化合物具有一定的诱导活性, 且一些化合物的诱导活性比水杨酸的好.     

Development of an energy-based approach for optimized frequency selection for fatigue testing on polymers – Exemplified on polyamide 6

Polymers and composite materials show temperature-dependent material properties. Therefore, the frequency resembles a critical part in fatigue testing, due to its influence on the self-heating of the polymeric material and thereby on the number of cycles to failure. The aim of this paper is the development of a testing method, which allows comparable results with varying frequencies. To minimize the self-heating effect on the fatigue behavior, a model was established for selecting optimized frequencies regarding the load-specific temperature increase of the specimen. A new energy-parameter, the induced energy-rate, was introduced and correlated to the load-specific increase in temperature in multiple and constant amplitude tests at ambient conditions. With this approach, it was possible to determine a threshold value for the newly defined induced energy-rate. A stress-specific model was developed and a limit frequency was calculated. The results were verified in multiple and constant amplitude tests and S/N-curves.     

负载型La0.8Sr0.2MnO3燃烧催化剂的载体效应

Combustion catalysts La0.8Sr0.2MnO3 supported on γ-Al2O3, α-Al2O3, cordierite (2MgO•2Al2O3•5SiO2) and ZrO2 were compared. Further investigation was focused on LSM/ γ-Al2O3 catalyst. It was observed that LSM/γ－Al2O3 catalyst loaded with 20% (mass fraction) LSM (La0.8Sr0.2MnO3 or corresponding oxides), heated at 750℃ or above, perovskite-type oxides were found by XRD examination, whereas, the same catalyst loaded with 10% or less LSM, perovskite oxides were absent, calcination temperature about 750℃ is necessary for the formation of perovskite structure in LSM/γ-Al2O3 catalysts. High activity of complete oxidation of xylen will be obtained when perovskite-type oxides.
Investigation of TPR showed that neat LSM or LSM/γ-Al2O3(20%) was reduced by H2-N2 mixed gas. Two degradation processes took place. In the first, reduced temperature peak was about 350 - 450℃. If reduction ended at 400℃, perovskite structure was retained, which may be due to the reduction of Mn3+to Mn2+ on the surface of LSM only. In the second process, perovskite structure was destroied, and La2O3, Mn2O3, Mn - Sr - O oxides could be obtained, which took place in the temperature range 685 - 750℃ and ended at 800℃. This was proved by TPR experiments (Fig. 3, 5) and XRD patterns (Fig. 4)
Catalysts LSM/γ-Al2O3(10% or 20%) heated at 500℃ have only one TPR peak, i. e. lower temperature peak. This is due to the absence of perovskite-type oxides in the catalysts. However, neat LSM or LSM/γ-Al2O3(20%) heated 750℃ or above, not only the first low temperature TPR peak but also the second peak, which is contributed by the perovskite-type oxides in these catalysts appeared. Therefore, the second TPR peak, i. e. the higher temperatue peak is a characteristic peak for perovskite-type oxides in the reduced process. When LSM/ γ-Al2O3 (10%) catalys is heated at 750℃, no perovskite-type oxides were detected by XRD, and the second reduction peak was absent also in TPR process. \
The order of the second reduction peak temperature(characteristic peak of perovskite - type ox- ides) is: neat LSM(750℃）> LSM/γ-Al2O3 20% (685-698℃) -deposited LSM/γ-Al2O3 (698℃) > LSM/γ-Al2O3 15% (677 - 680℃) >(LSM/γ-AL2O3 10% 620 - 630℃, for Mn - Al - O medium oxides on surface). It is correleted with the increasing of the effect of support sequentially.
When LSM/γ-Al2O3 catalysts were heated at 900℃, more stable phase, spinel MnAl2O4 appeared, which could be proved by TPR of model catalyst MnAl2O4/γ-Al2O3.