玻璃电极吸附对pH值测定影响的研究(Ⅰ)——高分子、胶体溶液中pH值的测定

本文在国内首次报道了在高分子和胶体溶液中用玻璃电极测定 pH 值时具有吸附作用,并在相同溶液中与锑电极作了对比试验。文中对玻璃电极的吸附机理做了理论上的分析,两电极的差异(△pH)是由于玻璃电极吸附所致,并将两电极用于皮革生产中,绘制了两电极的△pH 关系图。     

受压容器的开口补强优化设计

将有限元应力分析方法与优化设计方法相结合，提出了基于受压容器开口补强的极限分析理论和优化设计思想。采用有限元前处理程序，自动生成常见球罐和柱罐的优化力学模型，并在屏幕上或用绘图绘制出罐体的三维图形。建立起受压容器开口补强化优化设计的数学模型。根据此问题的特殊性，采用改进后的０．６１８法进行优化计算。优化过程中将模型划分可变域和不变域两部分，利用计算机的顺序文件存贮不变域单元刚度阵，提高了有限元重分     

氯吡格雷合成工艺研究进展

氯吡格雷是一种有效的血小板聚集抑制剂,适用于治疗冠状动脉,外周血管和脑血管疾病,可减少中风、心肌梗死和血管性死亡的风险,疗效优于阿司匹林和噻氯匹定。近年来,氯吡格雷的合成工艺有了很多的改进,提高了收率,降低了成本,优化了反应条件,简化了操作。本文综述了氯吡格雷合成工艺的最新研究进展。     

Correlation between growth behavior,internal stress distribution and properties of ZnO:Zn crystals grown by carbon-assisted chemical vapor transport

Internal stress and stress-related defects are considered as the major obstacles that significantly hinder the growth of high-quality ZnO-based crystals. In this work, high-crystalline-quality ZnO:Zn bulk crystals were successfully grown by carbon-assisted chemical vapor transport (CVT). Internal stress in the crystal was directly measured by a neutron beam from a reactor, and stress distributions along the radial direction at different depths were obtained. The stress, temperature, and flow fields in the growth system were simulated by the finite element (FE) method, and the results agreed with the neutron stress analysis. The etch pit density (EPD), Hall properties, and optical transmittances of different crystal regions were studied in detail, and the distribution trend of the crystal properties was consistent with that of internal stress and stress-related defects in the crystal. It is found that the unique temperature filed in the growth system causes the crystal to bend to a slightly convex toward the growth direction and gives rise to a driving force for structural defect formation. The + c and –c faces of the crystal are subjected to tensile and compressive stress, respectively. The maximum stress values are about 280 MPa and -291 MPa near the central regions of ±c faces, while the crystal periphery is basically free of internal stress. The region near the center of +c face has an EPD of 7.5 × 10³ cm^-2 and a transmittance of 79.2% at 800 nm wavelength, while the corresponding carrier concentration and mobility are 2.27 × 10¹⁷ cm^?3 and 159 cm²/V·s, respectively. By comparison, the crystal periphery has an EPD of 10² cm^-2 with an 80.5% transmittance at 800 nm, while the carrier concentration and mobility are 1.85 × 10¹⁷ cm^?3 and 184 cm²/V·s, respectively.     

Synthesis and Bioactivity of 5-Substituted-2-furoyl Diacylhydazide Derivatives with Aliphatic Chain

A series of 5-substituted-2-furoyl diacylhydazide derivatives with aliphatic chain were designed and synthesized. Their structures were characterized by IR, ¹H NMR, elemental analysis, and X-ray single crystal diffraction. The anti-tumor bioassay revealed that some title compounds exhibited promising activity against the selected cancer cell lines, especially against the human promyelocytic leukemic cells (HL-60). Their fungicidal tests indicated that most of the title compounds showed significant anti-fungal activity. The preliminary structure-activity relationship showed that the aliphatic chain length and differences in the R² group had obvious effects on the anti-tumor and anti-fungal activities. The bioassay results demonstrated that the title compounds hold great promise as novel lead compounds for further drug discovery.     

Approaches to Evaluate the Impact of a Small-Molecule Binder to a Noncatalytic Site of the Proteasome

Proteasome activity is crucial for cell survival and proliferation. In recent years, small molecules have been discovered that can affect the catalytic activity of the proteasome. Rather than targeting the active sites of the proteasome, it might be possible to affect ubiquitin-dependent degradation of proteins by limiting the association of the 19S regulatory particle (19S RP) with the 20S core particle (20S CP) of the proteasome. We recently described the discovery of TXS-8, a peptoid that binds to Rpn-6. Rpn-6 is a proteasome-associated protein that makes critical contacts with the 19S RP and the 20S CP. Herein, we present a general workflow to evaluate the impact of a small-molecule binder on proteasome activity by using TXS-8 as an example. This workflow contains three steps in which specific probes or overexpressed proteins in cells are used to determine whether the hydrolysis activity of the proteasome is affected. Although, in our case, TXS-8 did not affect proteasome activity, our workflow is highly amenable to studying a variety of small-molecule–proteasome subunit interactions.     

Room-temperature multiferroic characteristics and unique vortex domain structures of h-Yb1−xInxFeO3 solid solutions

Hexagonal rare-earth ferrites (h-RFeO₃) have attracted much scientific attention due to their room-temperature multiferroicity. However, it is still a hard job to obtain h-RFeO₃ bulk materials because of the meta-stability of such hexagonal phase, and the evaluation of room-temperature ferroelectric and magnetoelectric characteristics in such materials is also a challengeable issue. In the present work, Yb_1−xIn_xFeO₃ ceramics with the stable hexagonal structure were obtained by introducing chemical pressure, where the unique ferroelectric domain structures of sixfold vortex combined with tenfold vortex with a typical size of ~400 nm were determined. Symmetry of the present system evolved from centrosymmetric orthorhombic Pbnm (x = 0–0.4) to non-centrosymmetric hexagonal P6₃cm (x = 0.5 and 0.6) with a ferroelectric polarization up to 3.2 μC/cm², and finally to centrosymmetric hexagonal P6₃/mmc (x = 0.7 and 0.8). The Curie point decreased monotonically from 723 K to a temperature below room temperature with increasing x, and the antiferromagnetic phase transition above room temperature was determined for all compositions. Meanwhile, a large linear magnetoelectric coefficient (α_ME) up to 0.96 mV/cm Oe was obtained at room temperature, and this indicated the great application potential for magnetoelectric devices.     

Adaptive Nonlinear Model Predictive Control Using an On-line Support Vector Regression Updating Strategy

The performance of data-drivenmodels relies heavily on the amount and quality of training samples, so itmight deteriorate significantly in the regions where samples are scarce. The objective of this paper is to develop an online SVR model updating strategy to track the change in the process characteristics efficiently with affordable computational burden. This is achieved by adding a new sample that violates the Karush-Kuhn-Tucker conditions of the existing SVR model and by deleting the old sample that has the maximum distance with respect to the newly added sample in feature space. The benefits offered by such an updating strategy are exploited to develop an adaptive model-based control scheme, where model updating and control task perform alternately. The effectiveness of the adaptive controller is demonstrated by simulation study on a continuous stirred tank reactor. The results reveal that the adaptive MPC scheme outperforms its non-adaptive counterpart for largemagnitude set point changes and variations in process parameters.     

Fabrication of a low‐cost nano‐SiO2/PVC composite ultrafiltration membrane and its antifouling performance

A novel low‐cost SiO₂/Polyvinylchloride (PVC) membrane with different nano‐SiO₂ particles loading (0–4 wt %) was prepared by the phase‐inversion process. The optimum nano‐SiO₂ dosage was determined as 1.5 wt % based on the casting solution compositions, the membranes' mechanical properties and hydrophilicities, the pure water fluxes, microstructures, and absorption of protein. Compared with the bare membrane, the membrane with 1.5 wt % nano‐SiO₂ addition presented better capabilities against the protein absorption and bacterial attachment, better antifouling performance, and higher flux recovery ratio in filtration of the supernatant liquor which collected from a secondary sedimentation tank in a municipal wastewater plant. The SiO₂/PVC membranes have applicable potential in the municipal wastewater treatment for their low price, good antifouling performance and high removal efficiencies of SS (over 97.2%), COD (up to 82.9%) and total bacteria (more than 93.6%). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41267.     

Exploring the Intrinsic Piezofluorochromic Mechanism of TPE-An by STS Technique

9,10-bis(4-(1,2,2-triphenylvinyl)styryl)anthracene (TPE-An) materials have attracted considerable attention in recent years because they have high luminescence efficiency and excellent piezofluorochromic properties, which have potential applications in organic light-emitting display (OLED) area. Scanning tunneling spectroscopy (STS) technique was used to study the piezofluorochromic mechanism of aggregation-induced emission (AIE) materials for the first time. Photoluminescence (PL) experiments revealed that the emission peak of TPE-An is observed to exhibit a red-shift with the increase of the grinding time. A theoretical calculation was carried out to find the relationship between the bandgap of TPE-An and the external force by combination of the classical tunneling theory and STS results. It is found that when the pressure variation on the surface of TPE-An film was increased to be over 4.38?×?10⁴ Pa, the shrink of the highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gap can arrive at 1.1 eV. It is concluded that the piezofluorochromic behaviors of TPE-An should originate from the shrinking effect of the bandgap under external force. Moreover, this research method may shed light on comprehending and adjusting the piezofluorochromic characters of other AIE materials.