用哲学原理解决化工原理流体流动定性问题

运用矛盾论、动与静的辩证关系,整体与局部的辩证关系解决简单管路、复杂管路所涉及的阻力损失的变化、流量变化及静压强变化等定性问题.教学实践表明,用哲学原理解决此类问题不仅原理清晰,判断准确、快速,而且提高了学生的辩证思维能力,获得了绝大部分学生的认可与欢迎.     

Dependence of Property of Silver Nanoparticles within Dendrimer-template on Molar Ratios of Ag+ to PAMAM Dendrimers

G5.0‐OH PAMAM dendrimers were used to prepare fluorescent silver clusters with weaker ultraviolet irradiation reduction method, in which the molar ratio of Ag⁺ to PAMAM dendrimers was the key factor to determine the geometry and properties of silver nanoparticles. The results showed that because of G5.0‐OH PAMAM dendrimers as strong encapsulatores, when the molar ratios of Ag⁺ to PAMAM dendrimers was smaller than 5, the obtained Ag_n clusters (n<5) had line structures and "molecular‐like" properties, which were highly fluorescent and quite stable in aqueous solution. Whereas when the molar ratios were between 5 and 8, the obtained Ag_n clusters were 2D structures and their fluorescence was weaker. When the molar ratio was larger than 8, the structure of silver nanoparticles was 3D and no fluorescence was observed from the obtained silver nanoparticles.     

1,3,5‐Triethynylbenzene and melamine as monomers to synthesize three‐dimensional network porous aromatic frameworks based silica/florisil for determination of carbendazim and thiabendazole in spinach

In this study, the new and efficient three‐dimensional network porous aromatic frameworks materials called Silica‐PAFs‐a, Florisil‐PAFs‐a, Silica‐PAFs‐b, and Florisil‐PAFs‐b were first synthesized. The properties of materials were analyzed by five characterization methods. The materials were used as adsorbents in pipette‐tip solid‐phase extraction for the effective determination of carbendazim and thiabendazole in spinach sample. Meanwhile, the obtained materials were tested by static adsorption and dynamic adsorption. The result showed that the specific surface area of materials greatly increased after introducing three‐dimensional network porous aromatic frameworks. Microstructural modification exposed a large number of amino reactive groups that made them have a better adsorption amount for the two targets. The calibration graphs of carbendazim and thiabendazole in methanol were linear over 0.10–300.0 µg/mL, and the limits of detection and quantification were 0.00546 and 0.0182 µg/mL, and 0.00741 and 0.0247µg/mL respectively. A reliable analytical method was developed for recognition targets in spinach sample by Silica‐PAFs‐b with satisfactory extraction recoveries (96.25 and 100.51%). The proposed method using the material was applied for trace analysis of the carbendazim and thiabendazole residue.     

2-取代-4-芳基-2H-1,2,3-三唑类化合物的合成及杀菌活性

1,2,3-三唑化合物具有广泛的生物活性,为了发现具有杀菌活性的新型化合物分子结构,以芳醛、硝基甲烷及叠氮化钠为起始原料,合成了11个2-取代-4-芳基-2H-1,2,3-三唑类系列化合物,目标物的收率为51%~91%。核磁共振谱、质谱和元素分析等技术手段对目标化合物的结构经进行了表征。结果表明,在25 mg/L的测试质量浓度下,大部分化合物对小麦赤霉病菌及辣椒疫霉病菌显示出初步的抑菌活性,其中,化合物3a对小麦赤霉病菌的抑制率为80. 4%,化合物3b对黄瓜灰霉病菌为78. 2%,化合物3b及3h对油菜菌核病菌的抑制率分别70. 3%和75. 9%。     

Two-grid stabilized mixed finite element method for fully discrete reaction-diffusion equations

Two-grid mixed finite element method is proposed based on backward Euler schemes for the unsteady reaction-diffusion equations. The scheme combines with the stabilized mixed finite element scheme by using the lowest equal-order pairs for the velocity and pressure. The space two-grid method is also used to reduce the time consuming. The benefits of this approach are to avoid the higher derivative, but to have more favorable stability, and to get the numerical solution of the two unknown variables simultaneously. Stability analysis and error estimates are given in this work. Finally, the theoretical results are verified by the numerical examples.     

SmI2-Induced Asymmetric Reduction of Benzil in the Presence of Chiral Surfactant

Enantioselective reduction reaction of benzil induced by SmI₂ with the aid of chiral surfactant was studied. The highest e.e.% value of the products was up to 15.76%.     

正庚烷在铂铬催化剂上的重整反应

以r-Al2O3为载体用浸渍法制备了铂铬重整催化剂。在微型反应器上,用正庚烷的重整反应考察了上述催化剂的活性,探讨了催化活性与催化剂各组份配比之间的关系,发现铂铬原子比为1∶1的芳构活性,在较高温度下,优于单铂催化剂,显示出良好的催化重整活性。     

铂锡稀土催化剂性能的研究

本文用共浸法制备了一系列Pt—Sn—RE催化剂,以正庚烷为原料,研究了它们的反应性能。在不同的反应条件下稀土元素对Pt—Sn催化剂的改性作用不同。此外,Sn/Pt原子比不同对催化剂的活性也有影响。     

镱对铂锡重整催化剂反应性能的影响

本文研究了正庚烷在铂锡、铂锡镱催化剂上不同反应条件下的转化。通过苛刻条件下的催速老化试验,表明铂锡镱催化剂是一种性能优良的多金属重整催化剂,它具有芳构化活性高、选择性及稳定性好的特点。     

Temperatures and Excitation Energies of Hot Nuclei in Reactions of 40Ar+natAg,209Bi at MeV/u

Coincidence measurements of fission fragment and light charged particle have been perfotrmed for the reactions of ⁴⁰Ar+^natAg,²⁰⁹Bi at E/A=25MeV using 4 PPAC and 11 sets of ΔE-E telescopes.Angular correlations of fission fragment were ploted as a function of the folding angle between the two detected fission fragments.The linear momentum transfer distributions were derived by measuring angular correlations.The backward spectra of light particles detected in coincidence with fission fragments having different average〈LMT〉are analyzed with Maxwell distribution.After some corrections the initial temperatures of the hot nuclei are determined from the energy spectra.The excitation energies corresponding to the different average〈LMT〉are obtained considering the reaction Q values and pre-equilibrum emission.In the central collision of the ⁴⁰Ar+^natAg,²⁰⁹Bi reactions,excitation energies are measured to be about 4.2MeV/u,2.4MeV/u and temperatures about 6.1MeV,5.5MeV,respecdvely.In semi-central collision,excitaionen energies are measured to be about 3.5MeV/u,1.9MeV/u and temperatures about 5.8MeV,4.8MeV respectively.