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111.
112.
研究采用视频分析法,利用NVivo软件,以东芝杯教学技能创新大赛的化学组选手为对象,从教学理念、教学情境、实验设计和教学手段等4个维度,评价卓越职前化学教师课堂教学的创新能力。结果发现:教学理念新颖,但具体落实尚有不足;情境创设生动,但主题与学生的联系不够紧密;实验设计别致,但在水平上还有提升空间;教学技术手段先进,但还需要深度融合。研究为创新型卓越化学教师的培养提供了启示。 相似文献
113.
Counting parameters has become customary in the density functional theory community as a way to infer the transferability of popular approximations to the exchange‐correlation functionals. Recent work in data science, however, has demonstrated that the number of parameters of a fitted model is not related to the complexity of the model itself, nor to its eventual overfitting. Using similar arguments, here, we show that it is possible to represent every modern exchange‐correlation functional approximations using just one single parameter. This procedure proves the futility of the number of parameters as a measure of transferability. To counteract this shortcoming, we introduce and analyze the performance of three statistical criteria for the evaluation of the transferability of exchange‐correlation functionals. The three criteria are called Akaike information criterion, Vapnik‐Chervonenkis criterion, and cross‐validation criterion and are used in a preliminary assessment to rank 60 exchange‐correlation functional approximations using the ASCDB database of chemical data. 相似文献
114.
《Journal of Saudi Chemical Society》2014,18(5):735-743
A simple, highly useful synthesis of 1-(2-(4,5-dimethyl-2-phenyl-1H-imidazol-1-yl)ethyl)piperazine derivatives is achieved by a four component cyclo condensation of diacetyl, aromatic aldehyde, 2-(piperazin-1-yl)ethanamine and ammonium acetate using SO42−/Y2O3 as a catalyst in ethanol. The synthesized compounds were characterized by IR, 1H and 13C NMR and mass spectral studies. All the synthesized compounds were screened for their in vitro antimicrobial studies. Among the newly synthesized compounds 5d, 5e, 5h and 5m showed excellent antibacterial and antifungal activities when compared to the standard drugs. 相似文献
115.
在对已有试题难度量化工具进行改进的基础上,建构了化学加试题难度评估工具。对2015年至2019年国家新高考实验区浙江省的8次化学选考加试题的难度进行了量化评价。结果表明,8次化学加试题整卷难度变化较大,但同一学年、有相同学生可能参与的2次化学选考的整体难度相近;加试题能力特征和难度差异明显,“有机化学基础”加试题(第32题)难度相对稳定,而第30题(化学反应原理)与第31题(实验化学)加试题难度却表现出一定的波动性。在对8次化学加试题的难度及相关因素进行分析的基础之上,也对如何提高加试题的编制质量,提出了可行性建议。 相似文献
116.
To improve the oil absorbency of caster oil‐based polyurethane foam, nano‐organic‐montmorillonite (OMMT) was used for the additives. The aim of this study is to evaluate the oil diffusion mechanism and dispersion uniformity of OMMT modified caster oil‐based polyurethane (MPU) using experiments and molecular dynamic simulation. Molecule movement and molecule trajectory of oil was investigated by molecular dynamic simulation and numerical simulation. According to the quantitative analyzing results, the diffusion model was put forward. The average diffusion coefficient of crude oil in 0, 1, 2 wt%, 4, and 6 wt% MPU is 2.4 × 10?4 cm2/s, 2.6 × 10?4 cm2/s, 3.0 × 10?4 cm2/s, 3.2 × 10?4 cm2/s, and 3.3 × 10?4 cm2/s, respectively. It indicated that crude oil appeared gradient in the MPU. The optimal diffusion direction of crude oil is (0, 0, 1) crystal face, and the small particles of crude oil are easy to be adsorbed. The two‐dimensional diffusion trajectory of crude oil is nonlinear. The diffusion model includes the diffusion of crude oil at the interface of oil and polyurethane, surface diffusion and pore diffusion, and pore adsorption. Furthermore, the diffusion model showed that the van der Waals force was the main reason for crude oil diffusion or adsorption. OMMT could improve the ability of oil/water separation of polyurethane. 相似文献
117.
Wencan Jiang Gongwei Sun Wenbin Cui Shasha Men Miao Jing Danna Pu Sichun Zhang Xiaozhou Yuan Xinrong Zhang Chengbin Wang 《Molecules (Basel, Switzerland)》2020,25(22)
Background: Element-tagged immunoassay coupled with inductively coupled plasma mass spectrometry (ICP-MS) detection has the potential to revolutionize immunoassay analysis for multiplex detection. However, a further study referring to the standard evaluation and clinical sample verification is needed to ensure its reliability for simultaneous analysis in clinical laboratories. Methods: Carcinoembryonic antigen (CEA) and α-fetoprotein (AFP) were chosen for the duplex immunoassay. The performance of the assay was evaluated according to guidelines from the Clinical and Laboratory Standards Institute (CLSI). Moreover, reference intervals (RIs) of CEA and AFP were established. At last, 329 clinical samples were analyzed by the proposed method and results were compared with those obtained with electrochemiluminescent immunoassay (ECLIA) method. Results: The measurement range of the assay was 2–940 ng/mL for CEA and 1.5–1000 ng/mL for AFP, with a detection limit of 0.94 ng/mL and 0.34 ng/mL, respectively. The inter-assay and intra-assay imprecision were all less than 6.58% and 10.62%, respectively. The RI of CEA and AFP was 0–3.84 ng/mL and 0–9.94 ng/mL, respectively. Regarding to clinical sample detection, no significant difference was observed between the proposed duplex assay and the ECLIA method. Conclusions: The ICP-MS-based duplex immunoassay was successfully developed and the analytical performance fully proved clinical applicability. Well, this could be different with other analytes. 相似文献
118.
《Arabian Journal of Chemistry》2020,13(2):4134-4146
The kinetics of hydrolysis of fluvoxamine maleate (FLV) has been investigated over the pH range 1.0–12.0 at 40, 60 and 80 °C. FLV degradation follows pseudo-first-order kinetics which is consistent with the kinetics of drugs that are not readily dissolved in aqueous medium. The hydrolytic degradation rate constant (kobs) range from 0.92 (pH 6.0) to 13.8 × 10−4 min−1 (pH 1.0). The kobs represents the sum of six different degradation rate constants; the kH has been found to be higher than kOH. The FLV exhibits a typical rate- pH profile with a flat bottom over the pH range 3.0–6.0 which indicates its maximum stability at pH 6.0. Ten FLV degradants have been predicted by Zeneth software and among them four degradation products (D1, D2, D3 and D4) have been identified in degraded samples. The in-silico pharmacokinetics and toxicity of degradation products have been determined using Swiss ADME and admetSAR software. The toxicity profile reveals that D2 is both AMES toxic and carcinogenic while the rest of the products are non-AMES toxic and non-carcinogenic. All of the degradation products are high in causing fish toxicity thus their presence in pharmaceutical waste is alarming for environmental safety. 相似文献
119.
经典AHP常用于武器装备效能或能力评估,然而经典AHP采用线性加权模型,即通过底层指标效能线性加权得到顶层指标效能,对非线性体系往往会引入较大评估误差,易产生决策性错误。为解决这一问题,本文以底层指标效能值等于1/2为展开点,给出基于泰勒展开的二阶加权模型,对线性体系,二阶加权模型可退化为经典线性加权模型;推导出二阶AHP的数学表达式,给出二阶AHP效能评估步骤,构建二阶AHP的基本框架。算例表明,二阶AHP评估结果相比经典AHP更接近于解析解,产生决策性错误的机率远小于经典AHP。 相似文献
120.
Wenbo Huang Liqiao Shi Manli Liu Zhigang Zhang Fang Liu Tong Long Shaohua Wen Daye Huang Kaimei Wang Ronghua Zhou Wei Fang Hongtao Hu Shaoyong Ke 《Molecules (Basel, Switzerland)》2022,27(5)
Primary arylsulfonamide functional groups feature prominently in diverse pharmaceuticals. However, natural arylsulfonamides are relatively infrequent. In this work, two novel arylsulfonamide natural products were first synthesized, and then a series of novel molecules derived from natural arylsulfonamides were designed and synthesized, and their in vitro cytotoxic activities against A875, HepG2, and MARC145 cell lines were systematically evaluated. The results indicate that some of these arylsulfonamide derivatives exhibit significantly good cytotoxic activity against the tested cell lines compared with the control 5-fluorouracil (5-FU), such as compounds 10l, 10p, 10q, and 10r. In particular, the potential molecule 10q, containing a carbazole moiety, exhibited the highest inhibitory activity against all tested cell lines, with IC50 values of 4.19 ± 0.78, 3.55 ± 0.63, and 2.95 ± 0.78 μg/mL, respectively. This will offer the potential to discover novel drug-like compounds from the sparsely populated area of natural products that can lead to effective anticancer agents. 相似文献