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551.
本文以塔里木河下游英苏断面350m处C5井为研究对象,分析了影响下游英苏断面的潜水埋深影响因素,通过三层BP神经网络模型模拟了潜水埋深变化.以Matlab7.0为工作平台,将2000.7-2008.12期间的英苏C5井的步长为3个月数据资料作为一个样本,选取每个样本的输水量、输水持续天数、上季度该井的潜水埋深平均值作为模型输入量,输出量为相应的C5井的本季度的潜水埋深平均值,建立3—11-1的BP神经网络模型,模拟了C5井潜水埋深.结果表明,网络模拟相对误差小于5%,模型具有较高的精度.通过BP模型模拟潜水埋深,为塔河下游生态恢复和水资源决策提供一定的依据. 相似文献
552.
Although worm-like micelles have been studied for over 20 years, the diversity of macroscopic behavior and the potential analogy to polyelectrolytes has driven continued study. During the last year, development and application of more realistic scattering models has yielded a deeper understanding of micelle structure. Comprehensive studies on systematic systems are being reported that combine structural and macroscopic data. These studies provide the fundamental understanding necessary to quantify the coupling between micelle structure and rheology. Finally, with increased understanding of these systems, there is a growth in the number of novel applications of worm-like micelles. 相似文献
553.
质粒DNA的阴离子交换色谱法纯化及内毒素去除 总被引:7,自引:0,他引:7
采用Fractogel EMD TMAE(M)强阴离子交换介质分离纯化质粒脱氧核糖核酸(DNA),该介质对质粒DNA的动态载样量达0.62 mg/mL。用Triton X-114或Triton X-100预先处理质粒DNA的裂解澄清液后,经阴离子交换色谱分离纯化获得的质粒DNA中内毒素含量分别为6.42 EU/mg和9.50 EU/mg,显著低于未经Triton处理的裂解澄清液(67.82 EU/mg)。该法实现了阴离子交换色谱一步纯化质粒DNA的目的,具有简便、省时、成本低等特点。 相似文献
554.
Aflatoxin determination is imperative among agricultural and food products as the pollution of the toxic aflatoxin could cause severe hazards towards animals and human beings. Here, we prepared Elaeagnus gum derived porous carbon material as electrode modified material. In situ electropolymerization of molecularly imprinted polymer utilizing phenol as monomer and aflatoxin B1 as target template was further processed onto the porous carbon surface to achieve aflatoxin B1 sensing ability. This sensitive MIP sensor has a detection range from 5 pM to 100 pM of aflatoxin B1, an electrochemical sensitivity of 82.4 μA log(pM)−1 cm−2 with a detection limit of 1.7 pM, and a recovery rate of real sample measurement is 98.21 %. Good selectivity, fair repeatability and stability was confirmed. This work demonstrates the promising application of Elaeagnus gum derived porous carbon modified electrode sensor for food and drug monitoring. 相似文献
555.
556.
Single crystals of the title compounds are prepared by solid state reactions of M2CO3 (M: K, Rb, Cs), PbO, PbF2, H3BO3, and (NH4)H2PO4 in a molar ratio of 2:5:5:4:3 (Pt crucible, 700 °C, 10 h). 相似文献
557.
Wenlong Xie Dr. Fuming Li Jianbang Chen Prof. Zhihuang Yang Dr. Guangmao Li Prof. Shilie Pan 《Angewandte Chemie (International ed. in English)》2023,62(34):e202307895
Performance enhancement induced by structural modification has long been the target in materials science fields. Direct evidence to witness the effectivity of one strategy is challenging and necessary. In this work, a tetrahedra-decoration strategy was proposed to improve the birefringent performance sharply, namely decorating the tetrahedra with a single linear [S2] unit. The strategy was verified by comprehensive characterization of two thiogermanates K2BaGeS4 and K2BaGeS5, which crystallize in the same space group, have similar unit cells and the same units arrangements. Theoretical characterization verified that the [GeS5] group has much larger polarization anisotropy than [GeS4], further demonstrated that the linear [S2] led to the sharp birefringence enlargement of K2BaGeS5 (0.19 vs 0.03 of K2BaGeS4). This work provides a new guiding thought to improve the birefringence performance. 相似文献
558.
Dr. Jingyu Guo Junben Huang Abudukadi Tudi Prof. Xueling Hou Dr. Shujuan Han Prof. Zhihua Yang Prof. Shilie Pan 《Angewandte Chemie (International ed. in English)》2023,62(28):e202304238
It is important to establish and clarify the relationship between stereochemically active lone pairs and birefringence, since it is one of the significantly effective routes to explore birefringent crystals by introducing Sn-centered polyhedra with stereochemically active lone pairs. Herein, four tin(II)-based ternary halides A3SnCl5 and ASn2Cl5 (A=NH4 and Rb) have been synthesized successfully. The experimental birefringence of Rb3SnCl5 and RbSn2Cl5 is larger than or equal to 0.046 and 0.123@546 nm, respectively. Through investigating the alkali or alkaline-earth metal tin(II)-based ternary halides, the structure-performance relationship has been concluded between stereochemically active lone pairs and optical anisotropy. It is beneficial to the analysis and prediction of birefringence in tin-based halides and provides a guide for exploring tin(II)-based optoelectronic functional materials. 相似文献
559.
Dr. Guangmao Li Prof. Zhihua Yang Prof. Xueling Hou Prof. Shilie Pan 《Angewandte Chemie (International ed. in English)》2023,62(22):e202303711
Birefringent crystals are requisite optical devices in laser and modern opto-electronic fields. Development of excellent birefringent materials is still challenging. Herein, the linear or chain-like [Sx] (x=2–6) species were theoretically proved to be the origin of the large birefringence, and could be regarded as birefringent genes. Besides, the metal polysulfide family was first proposed to be rich birefringent materials source, among which Cs2S6 realizes giant birefringence 0.58@1064 nm together with a wide band gap of 1.70 eV (based on the generalized gradient approximation). Moreover, the first dual-anion group polysulfide Na4Ba3(S2)4S3 was obtained, showing wide infrared transmission range (0.5–6.2 μm), wide band gap (2.3 eV), and large birefringence (0.37 at 1064 nm). This work provides a new guiding thought for exploring large birefringence crystals in the future. 相似文献
560.
The precise synthesis of polymer with narrow molecular weight distribution(?) and well-defined architectures is very essential to exploring the functions and properties of polymer materials. Here, a universal polymerization method capable of low ? and reactive hydrogen compatibility is reported by introducing super-Grignard reagents(R2Mg?Li Cl) into polymer chemistry. Under mild conditions, various monomers,including nonpolar polystyrene and 4-methoxystyrene that cannot be initiated b... 相似文献