CHINESE JOURNAL OF CHEMISTRY
·
2013
·Vol. 31
·期 3
·393-400
·
IF 0.917
Anna Zheng,Bo Chen,Dihang Hu,Yong Guan,Dafu Wei,Shuzhao Li,Dandan Ji
This work confirms the new view of the initiation and propagation mechanism of the anionic polymerization previously proposed, based on the investigation of anionic bulk-polymerization of styrene and α -methyl styrene with the help of a self designed microflow device and characterized by GPC and in situ 7 Li NMR. It was found that n -BuLi tended to form the hexameric-aggregated structure and even to form the huge aggregated structure based on the former. These aggregations of initiators could directly initiate the anionic polymerization and form the supramolecule aggregations. The supramolecule aggregations inevitably blocked the diffusion of the monomers to the ion-pairs and resulted in a stationary-conversion platform. Then the aggregators were dissociated completely into equal binary-aggregated species, and the polymerization continued again rapidly before the termination. Tetrahydrofuran (THF) acted as the electron donator, which could push the electron cloud to Li cation and make the aggregated ring of the active species rather loosened and facilitated the monomer to insert in. Therefore, a little THF can greatly promote the anionic polymerization. However, further addition of THF might block the channel between the ion-pairs and decrease the propagation rate. It was also found that the aggregated structure of the active species during the anionic polymerization only depends on the initiator aggregations which were formed before the polymerization.
研究领域:
化学
·
高分子科学
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DOI
高影响因子
JOURNAL OF NUCLEAR MATERIALS
·
2017
·
IF 2.048
Kuibao Zhang,Dan Yin,Le Peng,Jingjun Wu,Jiali Xue
In this study, zirconolite/Mo composites were rapidly synthesized by a self-propagation reaction that uses MoO 3 as the oxidant accompanied with pressing. Zirconolite is one of the several materials that are being researched as host for lanthanides and actinides in nuclear waste . Nd was used in this study as a surrogate for actinides and was substituted into zirconolite at a stoichiometric ratio to charge balance the Ca and Zr sites (nominal formulation of Ca 1-x Zr 1-x Nd 2x Ti 2 O 7 ). Perovskite , zirconia, and rutile were generated as the minor phases with the addition of Nd 2 O 3 . The XRD results demonstrated that the Nd 2 O 3 loading is approximately 30 wt%. Nd was mainly incorporated into the lattice structure of zirconolite and perovskite. A 42-day leaching test of the Nd-bearing zirconolite/Mo composite showed that the computed normalized leaching rates for Ca and Nd at fairly low values of 9.02 × 10 −2 and 2.10 × 10 −4 g m −2 d −1 , respectively.
研究领域:
材料科学
·
核废物管理
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DOI
高影响因子
MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2024
·Vol. 225
·期 19
·2400159
·
IF 2.5
Yuxiao Li,Wentao Liu,Kan Liu,Qingyue Wang,Xiaohui Li,Erlita Mastan,Yuanfeng Wu,Pingwei Liu,Bo Peng,Khak Ho Lim,Wen-Jun Wang
Mechanistic understanding of free radical polymerization (FRP) in aqueous solution is hindered by the lack of kinetic coefficient data. Here, we investigated the propagation rate coefficient ( k p ) for FRP of HEMA in aqueous solution. The k p at 80 °C increased by 6 times as the monomer weight fraction in aqueous system decreases from 100 wt.% to 6 wt.%, that is., from 6.0 × 10 3 to 3.3 × 10 4 L·moL −1 ·s −1 . This increase in k p is associated with the increase in pre-exponential factor ( A ), which suggests an increase in entropy with increasing water molecules in the polymerization system. To investigate the effect of solvent on k p , pulse-laser polymerization in solvents of different hydrogen bonding affinity, that is, 50 wt.% butyl propionate (BP) and dimethyl formamide (DMF), are conducted. The k p obtained are in order of k p , bulk ∼ k p , BP > k p , DMF , suggesting that the intermolecular hydrogen bonding at carbonyl moieties critically affects the geometry of transition state quasi-equilibrium in propagation. We underpinned this observation by analyzing the carbonyl and alkene moieties of HEMA in different solvents using infrared (IR) spectroscopy. The mechanistic analyses and insights relating to hydrogen bonding and functional moieties can be relevant for future studies involving non-aqueous solvents promoting hydrogen bonds.
研究领域:
化学
·
高分子科学
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产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2025
·Vol. 49
·期 9
·3516-3525
·
IF 2.5
Junfeng Teng,Lili Wang,Yuan Tian,Xiaoyan Sun,Shuguang Xiang
Vinyl carbonate (VC) is a crucial film-forming additive for lithium-ion batteries, but its low industrial yields remain a significant challenge. This study investigated the causes of low yield by analyzing the structure and formation mechanism of polymer byproducts. Characterization, which included attenuated total reflectance–Fourier transform infrared (ATR-FTIR) spectroscopy, gas composition analysis, elemental analysis, 13C solid-state NMR spectroscopy, and 1H NMR spectroscopy, revealed that triethylamine (TEA)-initiated polymerization was a major contributor to the low yield. These polymer byproducts exhibited structural similarities to those constituting the solid–electrolyte interface (SEI) film reported in the literature, containing structural units such as cyclic carbonate, C–O, and O–C–O moieties. Density functional theory (DFT) calculations indicated that the chain initiation featured a termolecular reaction of TEA with two VC molecules. During chain propagation, intramolecular backbiting reactions drove decarboxylation, producing C–O and O–C–O structural units. This study not only provides important guidance for the synthesis of VC but may also offer theoretical insights into the formation mechanism of the SEI film.
研究领域:
材料科学
·
电化学
·
理论化学
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产品关联
DOI
高影响因子
PROPELLANTS EXPLOSIVES PYROTECHNICS
·
2021
·Vol. 46
·期 10
·1598-1610
·
IF 1.887
Xiaoxia Ma,Xi Chen,Yuxiang Li,Zhiqiang Qiao,Guangcheng Yang,Kaili Zhang
The afterburning effect of aluminized explosives makes them have strong damage ability to soft targets, but the aluminum particles in the composition often cannot achieve proper combustion. The high ignition temperature of micron aluminum powder is one of the main reasons. In this work, we introduce nanothermite reaction with low onset temperature (<660 °C) into aluminized explosives by replacing the base explosives with energetic coordination polymers (ECPs). The decomposition products of many ECPs contain corresponding metal oxides that will react with aluminum via thermite reaction. Three kinds of ECPs ([CoC 2 H 4 N 8 O 4 ] n , [NiC 2 H 4 N 8 O 4 ] n and [CuC 2 H 4 N 8 O 4 ] n ) are constructed and compounded with nano-aluminum (nano-Al) particles to form aluminized ECPs. The influence of metal ion species and Al/Metal (Al/Me) molar ratio on their energetic properties are systematically studied. The results show that the exothermic thermite reaction with low onset temperature plays an important role in the combustion propagation of aluminized ECPs, and the possible mechanism is proposed. When the Al/Me molar ratio is 3–4, the aluminized ECPs have the best peak pressure and pressurization rate. At the optimum molar ratio, the pressure and pressurization rate of aluminized ECP(Co) are much higher than those of aluminized ECP(Ni) and ECP(Cu). Among the three kinds of aluminized ECPs, the aluminized ECP(Co) has the best energetic characteristics and can be used as a preferred choice. However, for the applications that require a long-time heat supply, aluminized ECP(Cu) will be suitable.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Materials Chemistry Frontiers
·
2017
·Vol. 1
·期 10
·2031-2038
·
IF 0
Zhenzhen Cai,Yuping Zhang,Yilong Song,Qiuli Cheng,Yang Zheng,Zhanchen Cui,Zuosen Shi,Changming Chen,Daming Zhang
In this paper, we report the design, synthesis, and optical properties of novel negative-type fluorinated polycarbonate photoresists (FPC-PRs) and their use in thermo-optic switches. The novel polymer films are readily fabricated by spin coating on a silicon wafer followed by irradiation with UV light and post-baking at 110 °C. These films exhibit low roughness, good thermal stability (Td, up to 292 °C), high transparency (up to 97.8% at 400 nm) and high refractive indices (RI, 1.583–1.512 at 1550 nm). Channel optical waveguide and MZI thermo-optic waveguide switch arrays were fabricated based on the direct UV-written technique using the FPC-PR 2. The propagation loss of the channel waveguide was only 0.17 dB cm−1 at 1550 nm. The rise and fall times of the device with an applied 500 Hz square-wave voltage were 837 μs and 381.8 μs, respectively. The applied electric power as the switching power was about 35 mW, and the extinction ratio was measured to be about 14.0 dB.
研究领域:
材料科学
·
光学工程
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产品关联
DOI
JOURNAL OF THE ROYAL ASIATIC SOCIETY
·
2020
·Vol. 31
·期 2
·303-319
·
IF 0
AMY MATHEWSON
The Royal Asiatic Society in London houses a collection of magic lantern slides of China dating from the late nineteenth and early twentieth centuries. By investigating a selection of lantern slides, this article explores their epistemological nature and their wider relations to socio-cultural and political systems of power. These lantern slides highlight the complexity of our ways of seeing and representing that are embedded into particular historical and ideological systems in which meaning is both shaped and negotiated. This article argues that images are powerful conduits in disseminating and, if unchallenged, maintaining particular notions and ideas.
研究领域:
视觉人类学
·
传播学
·
图像研究
·
东亚研究
·
文化史
✓ 已验证
DOI
Journal of Materials Chemistry A
·
2024
·
IF 10.7
Xueying Liu,Weibo Li,Yingjie Jiang,Nanying Ning,Ming Tian
Dielectric elastomer generators (DEGs) based on silicone rubber composites have received considerable attention in recent years. However, the addition of traditional rigid dielectric fillers not only increases the modulus of composites but also leads to interface debonding between the filler and elastomer matrix under high stretching conditions, thereby limiting the energy harvesting performance. Here, gel-like ester group grafted butadiene rubber (GEBR) with a relatively low modulus was synthesized and used as a “soft filler” to enhance energy harvesting performance of PMVS-based DE composites. The GEBR filler with a high concentration of polar groups could lead to an increase in the dielectric constant of GEBR/PMVS composites by the introduction of interfacial polarizability and the improvement of dipole polarizability. Most notably, compared with TiO2 as the rigid filler, the combination of GEBR's deformability under stretching and strong interfacial interaction between the GEBR filler and PMVS matrix could effectively prevent weak interface formation under high strain conditions, and thus hinder the propagation of electrical treeing. As a result, benefiting from the GEBR filler with a low modulus, 5 vol% GEBR/PMVS DEG exhibits an excellent maximal energy density (65.4 mJ g−1) and outstanding power conversion efficiency (38.4%), achieving a high energy density at relatively low input mechanical force. This study presents a pioneering methodology to fabricate high-performance all-organic DE composites for DEGs through designing a soft dielectric filler with exceptional deformability under stretching.
研究领域:
材料科学
·
能源技术
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产品关联
DOI
高影响因子
AQUACULTURE
·
2025
·
IF 3.9
Li-Peng Shan,Mao-Mao Wang,Yang Hu,Lei Liu,Bin Zhu,Jiong Chen
Hepatopancreatic microsporidiosis (HPM), caused by Enterocytozoon hepatopenaei (EHP), has emerged as a major threat to the shrimp aquaculture industry. However, no effective strategies have yet been developed to control the spread of this disease. In this study, we assessed the anti-EHP activity of ten monomeric compounds in Penaeus vannamei . The results showed that tetrahydropalmatine reduced the EHP copy number by 73.8 % at a concentration of 20 mg/L. In a therapeutic experiment, feeding EHP-infected shrimp a diet containing 0.1 % tetrahydropalmatine significantly lowered the EHP load. Additionally, the growth-related gene juvenile hormone esterase-like carboxylesterase 1 was significantly upregulated, while ecdysteroid-regulated protein and farnesoic acid O-methyltransferase were significantly downregulated, suggesting that tetrahydropalmatine may enhance the growth potential of EHP-infected shrimp. After 30 days of feeding, the EHP-infected shrimp's body weight in the groups fed with tetrahydropalmatine increased by 19.9 % compared to those fed with the normal diet. In a prevention experiment, healthy shrimp fed a diet containing tetrahydropalmatine and subsequently infected with EHP showed an increase in body weight by day 30 post-infection, compared to the control group, although this difference was not statistically significant. Tetrahydropalmatine can inhibit spore germination and electron dense disc formation, which may be an important reason for its suppression of EHP infection. Moreover, tetrahydropalmatine effectively inhibited the horizontal transmission of EHP, suggesting its potential to limit HPM outbreaks. These findings indicate that tetrahydropalmatine may serve as a feed additive for the treatment of HPM caused by EHP.
研究领域:
水产养殖学
·
寄生虫学
·
分子生物学
✓ 已验证
DOI
高影响因子
BIOCHEMICAL PHARMACOLOGY
·
2025
·
IF 5.6
Chengyu Cai,Shuohui Gao,Bingmei Wang,Tong Zhao,Hang Gao,Yan Shi,Xuerui Guo,Yueshan Xu,Yun Sun,Dongbin Guo,Jinlong Zhang,Fei Gao,Quan Liu,Zeze Fu,Liang Zhu,Xiaolei Liu,Li Wang,Yicheng Zhao
The rising threat of multidrug-resistant (MDR) pathogens, especially methicillin-resistant Staphylococcus aureus (MRSA), necessitates the development of novel antiinfective strategies. Staphylococcus aureus ( S. aureus ), a significant foodborne pathogen, secretes virulence factors that are crucial to its pathogenicity. Unlike conventional antibiotics, antivirulence strategies offer a promising approach by targeting these factors without inhibiting bacterial growth, thereby reducing selective pressure for resistance. Among these factors, von Willebrand factor-binding protein (vWbp) is a key contributor to S. aureus pathogenesis, mediating prothrombin activation and subsequent blood coagulation, which is vital for pathogen survival in the host. This study identified astragaloside IV (As-IV) a bioactive compound from traditional Chinese medicine, as a potent inhibitor of vWbp coagulase. As-IV effectively prolongs coagulation time and reduces S. aureus biotic matrix formation on surfaces relevant to food safety, such as catheters, in vitro . Mechanistic studies, including thermal shift assays (TSAs) and fluorescence quenching, revealed that As-IV directly binds to vWbp, attenuating its activity without altering protein expression levels. In vivo , As-IV exhibited protective effects in infection models, underscoring its potential as a virulence-targeted therapeutic. These findings significantly contribute to the advancement of antivirulence strategies and underscore the potential of As-IV in combating S. aureus infections. This paves the way for its broader application in enhancing public health measures and promoting innovative therapeutic approaches.
研究领域:
微生物学
·
药理学
·
传染病学
✓ 已验证
DOI
PubMed
高影响因子
Journal of Materials Chemistry A
·
2017
·Vol. 5
·期 34
·18221-18229
·
IF 8.867
Chu Liang,Sheng Liang,Yang Xia,Yun Chen,Hui Huang,Yongping Gan,Xinyong Tao,Jun Zhang,Wenkui Zhang
Hierarchical porous carbon (HPC) has attracted much attention in tackling global environmental and energy problems. For the state-of-the-art routes to synthesize HPC from organic compounds, the emission of carbon dioxide (CO2) and gaseous pollutants is inevitable during thermal carbonization. Herein, we report an environmentally benign and high-yield route to synthesize HPC from CO2via H2O-induced self-propagating reactions. By introducing an initiator of H2O, CO2 can react with lithium hydride (LiH) to produce HPC in 13 seconds at low temperatures. The as-synthesized HPC exhibits an interconnected micro–meso–macropore network structure with a high porosity of 83%. The formation mechanism of HPC is discussed on the basis of the conversion reactions from CO2 to C and the gas blowing effect in producing hierarchical porosity. The HPC evaluated as an anode material for lithium-ion batteries not only delivers a high reversible capacity of ∼1150 mA h g−1 at a current density of 0.2 A g−1, but also exhibits superior rate capability (∼825 mA h g−1 at 1.0 A g−1) and excellent cycling properties (up to 2000 cycles). This research opens a new avenue both to synthesize HPC from CO2 on a large scale and to mitigate greenhouse gas from the atmosphere.
研究领域:
材料科学
·
环境科学
·
能源科学
✓ 已验证
DOI
高影响因子
JOURNAL OF NANOPARTICLE RESEARCH
·
2016
·Vol. 18
·期 7
·1-8
·
IF 2.101
Wu Hua,Zhang Yu,Lu Min,Liu Wenyan,Xu Jian,Yu William W.
Abstract With tunable emission wavelength, high photoluminescence quantum yield, and broad absorption, colloidal quantum dots are attractive for the application in optical fiber as dopants. However, most of the quantum dots have a large overlap between their absorption and photoluminescence spectra, resulting in reabsorption loss which hinders the realization of long-distance waveguides. Therefore, ZnCuInS/ZnSe/ZnS quantum dots with large Stokes shift were proposed to fabricate a liquid-core optical fiber in this work. In this work, ZnCuInS/ZnSe/ZnS QDs with an average size of 3.3 nm were synthesized and the optical properties of the QD-filled fiber were also investigated as a function of fiber length and doping concentration. Compared to the control sample filled with CdSe/CdS/ZnS quantum dots, the ZnCuInS/ZnSe/ZnS quantum dot-based waveguides showed reduced reabsorption and enhanced signal propagation, which demonstrates great potential of large Stokes-shift quantum dots in optical waveguide devices. Graphical Abstract A reduced reabsorption and enhanced propagation of ZnCuInS/ZnSe/ZnS QDs-doped liquid-core optical fiber was achieved due to the large Stokes shift.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）