广义V-I型多目标规划ε-有效解的充分性

利用对称梯度，定义了一类非光滑多目标规划的V-Is,ε型、拟V-Is,ε型和伪V-Is,ε型等几个广义向量，型不变凸性概念，得到了涉及这些新广义弘，型不变凸性的多目标规划的一些最优性充分条件。     

Predicting hiCE inhibitors based upon pharmacophore models derived from the receptor and its ligands

Human intestinal carboxyl esterase (hiCE) is a drug target for ameliorating irinotecan-induced diarrhea. By reducing irinotecan-induced diarrhea, hiCE inhibitors can improve the anti-cancer efficacy of irinotecan. To find effective hiCE inhibitors, a new virtual screening protocol that combines pharmacophore models derived from the hiCE structure and its ligands has been proposed. The hiCE structure has been constructed through homology techniques using hCES1’s crystal structure. The hiCE structure was optimized via molecular dynamics simulations with the most known active hiCE inhibitors docked into the structure. An optimized pharmacophore, derived from the receptor, was then generated. A ligand-based pharmacophore was also generated from a larger set of known hiCE inhibitors. The final hiCE inhibitor predictions were based upon the virtual screening hits from both ligand-based and receptor-based pharmacophore models. The hit rates from the ligand-based and receptor-based pharmacophore models are 88% and 86%, respectively. The final hit rate is 94%. The two models are highly consistent with one another (85%). This proves that both models are reliable.     

Self-calibration method for cerium-doped lanthanum bromide scintillator detector in the 0.1–2.0 MeV energy range

In recent years, the cerium-doped lanthanum bromide, LaBr₃ (Ce = 5 %) detector is increasingly playing an important role in radiation measurements because of its higher energy resolution (~3 % at 662 keV), faster luminescence decay time (~35 ns) and higher detection efficiency compared to 7.65 cm × 7.65 cm NaI(Tl) detector. Intrinsic spectra between 1,800 and 3,000 keV derived from internal radioactivity within LaBr₃(Ce) scintillators have been investigated in some literatures, and these results are confirmed by the experiments in this work. In this paper, a new method for LaBr₃(Ce) detector energy calibration from 100 to 2,000 keV is proposed using the intrinsic spectra (self-calibration) instead of the standard gamma sources. Proof-of-concept experiment results show that self-calibration can guarantee energy accuracy of better than 0.815 % and can be applied outside the laboratory. The stability and applicability of this method are also investigated systematically.     

水乡城市空间结构的演变与特点——绍兴越城组团地区城市结构变迁研究

城市空间结构发展过程中受“盲目的必然性”和“历史中必然”的影响,在历史发展中呈现出一定的特点并具有连续性.以绍兴为例,通过各时期历史文献和近代资料的分析,结合实地调研,总结其在历史发展中城市结构的不断变迁背后的规律性,认为水乡城市在后来的发展变化中,也会一直延续旧有的以水体为骨架的“鱼骨形”城市空间结构.     

In situ synthesis of CdS/ZnS composite nanoparticles from ZIF-8 for visible light disposal of Cr(VI)

Journal of Sol-Gel Science and Technology - Zeolitic Imidazolate Framework (ZIF-8) micropolyhedra were employed as a raw material for the synthesis of fine cadmium sulfide/zinc sulfide (CdS/ZnS)...     

Trapezoidal phase mask coronagraph

An angular trapezoidal phase mask used for a wideband coronagraph is proposed. The azimuthal phase of the mask is double-periodic and has both trapezoidal and constant parts in each period. This kind of continuous phase distribution can be employed to avoid the abrupt phase variation of the 6-level phase distribution we proposed previously. Numerical calculations show that this more practical phase mask can still keep its superior performance in terms of starlight elimination, small inner working angle, and good achromatism. It is of great importance that there is no singularity in this kind of mask except for a singularity at the center. This mask design is close to real manufacturing conditions, and the process technology is superior.     

Preparation and thermal properties of poly[acrylonitrile-co-(β-methylhydrogen itaconate)] used as carbon fiber precursor

In order to replace terpolymer with bipolymer, a bifunctional comonomer β-methylhydrogen itaconate (MHI) containing carboxyl group and ester group was synthesized to prepare poly[acrylonitrile-co-(β-methylhydrogen itaconate)] [P(AN-co-MHI)] bipolymers used as carbon fiber precursor for improving the stabilization and spinnability at the same time. The P(AN-co-MHI) bipolymers with different monomer feed ratios were characterized by elemental analysis, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). The results show that both the polymerization conversion and molecular mass of P(AN-co-MHI) reduce with the increasing MHI amounts in the feed due to the larger molecular volume of MHI than acrylonitrile (AN). The monomer reactivity ratios were calculated by Fineman–Ross and Kelen–Tüdõs methods, the results show good agreement and MHI possesses higher reactivity than AN. Two parameters $ E_{\text{s}} = A_{{1,629\,{\text{cm}}^{ - 1} }} /A_{{2,244\,{\text{cm}}^{ - 1} }} $ and $ SI = (I_{0} - I_{\text{S}} )/I_{0} $ were defined to evaluate the extent of stabilization, and the activation energy (E _a) of the cyclization was calculated by Kissinger method and Ozawa method. The FTIR, XRD, and DSC results show that P(AN-co-MHI) bipolymers exhibit significantly improved stabilization characteristics than PAN homopolymer, such as larger extent of stabilization, lower initiation temperature, and smaller E _a of cyclization, which is attributed to the ionic initiation by MHI comonomer and it is beneficial to preparing high-performance carbon fiber.     

Pyrolysis and combustion model of oil sands from non-isothermal thermogravimetric analysis data

Thermogravimetric (TG) data of oil sand obtained at Engineering Research Center of Oil Shale Comprehensive Utilization were studied to evaluate the kinetic parameters for Indonesian oil sand samples. Experiments were carried out at heating rates of 5, 15, and 25 °C min^?1 in nitrogen, 10, 20, and 50 °C min^?1 in oxygen atmosphere, respectively. The extent of char combustion was found out by relating TG data for pyrolysis and combustion with the ultimate analysis. Due to distinct behavior of oil shale during pyrolysis, TG curves were divided into three separate events: moisture release, devolatilization, and evolution of fixed carbon/char, where for each event, kinetic parameters, based on Arrhenius theory, were calculated. Coats–Redfern method, Flynn–Wall–Ozawa method, and distributed activation energy model method have been used to determine the activation energies of degradation. The methods are compared with regard to their characteristics and the ease of interpretation of the thermal kinetics. Activation energies of the samples were determined by three different methods and the results are discussed.