Journal of Materials Chemistry C
·
2018
·Vol. 6
·期 46
·12566-12574
·
IF 5.976
Xiaohui Li,Lei Zhou,Miroslav D. Dramićanin,Qiang Tang,Xiping Jing,Jianxin Shi,Yiqin Xu,Mingmei Wu
Broad emission with a full and continuous color spectrum realized by crystal engineering is extensively desired to simulate natural sunlight and improve the white color quality. Herein, new insight into the modulation of B site order–disorder and intrinsic oxygen defects for complex perovskite (A3B′B2′′O9) Sr3−xScxZnNb2O9 (0 ≤ x ≤ 0.1) phosphors is demonstrated for broad-band emission via crystal engineering. We elucidate that the spectrum of Sr3ZnNb2O9 synthesized at an optimal temperature exhibits two emission bands under near-ultraviolet excitation (λex = 374 nm) which is readily available from near ultraviolet chips. The two broad emission bands can be ascribed to charge transfer from the empty 4d (t2g)-orbitals of Nb5+ ions to the filled 2p-orbitals of O2− ions and the intrinsic oxygen defects. Further, as a proposed strategy to optimize the luminescence property of Sr3ZnNb2O9 (SZN), we realized A-site nonequivalent doping to induce B-site disordering and cancel the luminescence quenching which results from B site ordering. The A-site nonequivalent doping efficiently offsets intrinsic oxygen defects, as validated by systematic analyses of experiments and DFT calculations. Consequently, the novel phosphor Sr3−xScxZnNb2O9 (x = 0.1) shows a high color rendering index (Ra = 82.2) and negligible color shift. In addition, its emission intensity is enhanced by ∼70 times as compared to the pristine Sr3ZnNb2O9.
研究领域:
材料科学
·
发光材料
·
固态化学
·
荧光粉
·
光学材料
✓ 已验证
DOI
高影响因子
MACROMOLECULAR RAPID COMMUNICATIONS
·
2010
·Vol. 31
·期 21
·1886-1891
·
IF 4.263
Wei Xiong,Hanfu Wang,Yanchun Han
Novel dendritic triblock co-oligomer (14G2A3) consisting of ester dendrons and aniline oligomer was synthesized and found to self-assemble into fibrils in THF. Studies reveal that the formation of the fibrils originates from both of the amphiphilic interactions between the ester dendrons and oligoaniline, as well as the intermolecular π-π stacking among oligoanilines. The shape effect of dendrons on molecular packing was comparatively analyzed with packing parameter against its linear analogous compound. At the same time, the driving forces that dominate the final aggregating state of the block oligomer were separately investigated using the bulky-group protecting method, which allows release of the intermolecular π-π stacking of oligoaniline in a controlled manner. Results show that both the introduction of dendrons and the intermolecular π-π stacking will increase the packing parameter of the block oligomer and, consequently, cause the self-assembly morphology to evolve step by step from micelles to vesicles and finally to fibrils. The fibrils can form complexes with SWNTs to increase solubility in THF. The effective fluorescence quenching accompanied also opens a gate for the block co-oligomer to have potential applications in organic electronic devices.
研究领域:
材料科学
·
化学
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DOI
高影响因子
NEUROSCIENCE
·
2024
·
IF 2.9
Xuejing Hou,Shanshan Xiao,Xiaohong Xu,Mingze Qin,Xuebing Cheng,Xiangping Xu
Epilepsy is a progressive neurodegenerative disease highlighted by recurrent seizures, neuroinflammation, and the loss of neurons. Microglial dysfunction is commonly found in epileptic foci and contributes to neuroinflammation in the initiation and progression of epilepsy. Glycoprotein non-metastatic melanoma protein B (GPNMB), a transmembrane glycoprotein, has been involved in the microglial activation and neuroinflammation response. The present study investigated the functional significance of GPNMB in epilepsy. A proven model of epilepsy was established by intraperitoneal injection of pilocarpine to male Sprague Dawley rats. Lentivirus vectors carrying GPNMB or GPNMB short hairpin RNA (shGPNMB) were injected into the hippocampus to induce overexpression or knockdown of GPNMB. GPNMB expression was significantly upregulated and overexpression of GPNMB in the hippocampus reduced seizure activity and neuronal loss after status epilepticus (SE). We here focused on the effects of GPNMB deficiency on neuronal injury and microglia polarization 28 days after SE. GPNMB knockdown accelerated neuronal damage in the hippocampus, evidenced by increased neuron loss and neuronal cell apoptosis. Following GPNMB knockdown, M1 polarization (iNOS) and secretion of pro-inflammatory cytokines IL-6, IL-1β, and TNF-α were increased, and M2 polarization (Arg1) and secretion of anti-inflammatory cytokines IL-4, IL-10, and TGF-β were decreased. BV2 cells were used to further confirm the regulatory role of GPNMB in modulating phenotypic transformations and inflammatory cytokine expressions in microglia. In conclusion, these results indicated that GPNMB suppressed epilepsy through repression of hippocampal neuroinflammation, suggesting that GPNMB might be considered the potential neurotherapeutic target for epilepsy management and play a protective role against epilepsy by modulating the polarization of microglia.
研究领域:
神经科学
·
神经病学
·
免疫学
·
分子生物学
·
药理学
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DOI
PubMed
高影响因子
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
·
2014
·Vol. 2015
·期 3
·631-637
·
IF 3.154
Laichun Luo,Lanlan Meng,Yangqiu Peng,Yongning Xing,Qi Sun,Zemei Ge,Runtao Li
Graphical A facile ZnCl 2 -promoted one-pot three-component synthesis of thiazolo[4,5- b ]pyridines and thieno[2,3- b :4,5- b′ ]dipyridines is described. This approach involves a tandem S N 2/Thorpe–Ziegler cyclization/Friedländer reaction to give fused pyridines in moderate to good yields. A ZnCl 2 -promoted one-pot synthesis of multisubstituted thiazolo[4,5- b ]pyridines and thieno[2,3- b :4,5- b′ ]dipyridines from mercaptonitrile salts, α-bromo ketones and ketones has been developed. This approach involves a tandem S N 2 alkylation/Thorpe–Ziegler cyclization/Friedländer reaction, which allows the creation of two hetero rings and four new bonds in a single operation. The reaction proceeds smoothly under solvent-free conditions to afford fused pyridines in moderate to good yields.
研究领域:
有机化学
·
药物化学
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DOI
高影响因子
Materials
·
2023
·Vol. 16
·期 3
·1053
·
IF 3.4
Yanpei Dang,Tianhao Li,Yangzhong Zhao,Liantai Duan,Jianning Zhang,Ke Chen,Liu He,Qing Huang,Chuanzhuang Zhao,Yujie Song
Polyborosilazanes with controllable B/N ratio were synthesized using high-boron-contentm-carborane, dichloromethylsilane, and hexamethydisilazane. After high-temperature pyrolysis, Si–B–C–N quaternary ceramics with SiC and B4C as the main phases were obtained. The B/N ratio in the precursors corresponded to the change in the feeding ratio of carborane and dichloromethylsilane. The effects of boron content and B/N ratio on the ceramic precursors and microphase structure in Si–B–C–N quaternary ceramics were explored in detail through a series of analytical characterization methods. A high boron content results in a significant increase in the ceramic yield (up to 71 wt%) of polyborosilazanes, and at the same time, the B/N molar ratio was regulated from 28.4:1 to 1.62:1. The appearance of the B4C structure in the Si–B–C–N quaternary ceramics through the regulation of the B/N ratio, has rarely been reported.Keywords:polyborosilazane;SiBCN;carborane;polymer derived ceramics;B/N ratio;microphase evolution
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF MATERIALS RESEARCH
·
2019
·Vol. 34
·期 12
·2057-2066
·
IF 1.982
Mingjing Zhang,Xiaofang Zhang,Pengzhi Guo,Jie Lv,Xunchang Wang,Junfeng Tong,Yangjun Xia
Two wide band gap conjugated polymers, namely PBDT-TT25 and PBDT-TT36, derived from (4,8-bis(4,5-dioctyl-thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl)bis(trimethylstannane) with 2,5-dibromothieno[3,2-b]thiophene (TT25) or 3,6-dibromothieno[3,2-b]thiophene (TT36), have been synthesized by simply altering the linker positions of thieno[3,2-b]thiophene unit. The impact of linker positions on the energy levels, aggregation, active layer morphology, and optical and photovoltaic properties was evaluated systemically. We found that the absorption was greatly broadened, and the highest occupied molecular orbital (HOMO) energy level was elevated as the result of the significantly reduced twist angle on the polymer backbone when the linker positions changed from 3,6-isomer to 2,5-isomer. Therefore, the optimal inverted polymer solar cells exhibited a 1.87 times enhancement in power conversion efficiencies (PCE), which was mainly ascribed to the higher short circuit current densities (JSC) and fill factor (FF) of the devices mainly benefited from the widened, stronger absorption, higher hole mobility, and more ordered structure.
研究领域:
材料科学
·
光伏技术
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Yongyang Zhu,Shaoyang Shen,Liuzhang Ouyang,Jiangwen Liu,Hui Wang,Zhenguo Huang,Min Zhu
Magnesium borohydride (Mg(BH 4 ) 2 ) is widely regarded as a promising hydrogen storage material due to its high capacity; however, it is still challenging to synthesize Mg(BH 4 ) 2 with low cost. Traditionally, Mg(BH 4 ) 2 has been mainly produced using other borohydride as the starting materials via exchange reactions. Herein, we report an economical method to synthesize Mg(BH 4 ) 2 by converting B-O bonds in widely available borates or boric acid to B-H. The borates or boric acid is ball-milled with MgH 2 under ambient conditions to form Mg(BH 4 ) 2 with high yield (>80%). Mg(BH 4 ) 2 was also successfully generated by reacting low-cost Mg with boric acid. Compared with previous approaches, this method avoids expensive boron sources such as LiBH 4 , NaBH 4 , and B 2 H 6 , and does not require high pressure H 2 gas and high temperatures, and therefore significantly reduces costs. This method could be an alternative to the current Mg(BH 4 ) 2 synthesis processes.
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产品关联
DOI
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2019
·Vol. 38
·期 3
·298-310
·
IF 2.804
Feng Cong-Shu,Chen Yun,Shao Jun,Li Gao,Hou Hao-Qing
In this study, the poly(D-lactide)-block-poly(butylene succinate)-block-poly(D-lactide) (PDLA- b -PBS- b -PDLA) triblock copolymers with a fixed length of PBS and various lengths of PDLA are synthesized, and the crystallization behaviors of the PDLA and PBS blocks are investigated. Although both the crystallization behaviors of PBS and PDLA blocks depend on composition, they exhibit different variations. For the PDLA block, its crystallization behaviors are mainly influenced by temperature and block length. The crystallization signals of PDLA block appear in the B-D 2–2 specimen, and these signals get enhanced with PDLA block length. The crystallization rates tend to decrease with increasing PDLA block lendth during crystallizing at 90 and 100 °C. Crystallizing at higher temperature, the crystallization rates increase at first and then decrease with block length. The crystallization rates decrease as elevating the crystallization temperature. The melting temperatures of PDLA blocks increase with block lengths and crystallization temperatures. For the PBS block, its crystallization behaviors are mainly controlled by the nucleation and confinement from PDLA block. The crystallization and melting enthalpies as well as the crystallization and melting temperatures of PBS block reduce as a longer PDLA block has been copolymerized, while the crystallization rates of the PBS block exhibit unique component dependence, and the highest rate is observed in the B-D 2–2 specimen. The Avrami exponent of PBS crystallites is reduced as a longer PDLA block is incorporated or the sample is crystallized at higher temperature. This investigation provides a convenient route to tune the crystallization behavior of PBS and PLA.
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产品关联
DOI
高影响因子
COLLOID AND POLYMER SCIENCE
·
2014
·Vol. 292
·期 5
·1061-1072
·
IF 2.41
Luo Yan-Ling,Yang Xiao-Li,Xu Feng,Chen Ya-Shao,Zhao Xu
pH-sensitive poly(methacrylic acid)- block -hydroxyl-terminated polybutadiene- block -poly(methacrylic acid) block copolymers were synthesized by atom transfer radical polymerization of t -butyl methacrylate and follow-up acidolysis. The copolymers can spontaneously assemble into stable and nearly spherical micelle aggregates in aqueous solution, with hydrodynamic diameters ( D
h
) from 51 to 92 nm and critical micelle concentration of 3.90–7.76 mg L −1 . Z eta potentials were found to be increased with increasing (monomer)/(initiator) molar ratios. A pH-dependent phase behavior is produced at approximately 5.4–5.6, as determined by D
h
and I
335 / I
332 fluorescence intensity ratios. The in vitro camptothecin (CPT) release was compositional and pH dependent, and the cumulative CPT release below pH 7.2 was higher than that in pH 7.4. They could inhibit the premature burst CPT release. The copolymer micelles were low in cytotoxicity even at a micellar concentration of 800 mg L −1 , and therefore they may be used as potential drug-delivery carriers.
ᅟ
✓ 已验证
产品关联
DOI
高影响因子
CHEMISTRY OF MATERIALS
·
2025
·
IF 7
Kexin Xu,Yifan Lv,Xinrui Cui,Wenyu Lai,Cun-Yue Guo,Baolin Li
As a type of organic small molecule (OSMs), the introduction of sulfur atoms in fused-ring thiophenes can reduce the dihedral angle between fused rings, which helps to form planar structures and makes it easier to form tightly packed crystal structures, creating more continuous paths for charge transfer. Therefore, they have aroused widespread research interest. However, little research has been conducted on benzo[1,2-b:3,4-b′:5,6-b″]trithiophenes (BTTs), and their simple and efficient syntheses still need to be urgently developed. Herein, we have developed a synthetic approach for BTTs via C–H thienannulation. This protocol features streamlined domino synthetic procedures, eliminating the requirement for the introduction of halogen functional groups, catalysts, and additives. BTTs exhibit planar structures, enabling tight crystal packing that creates a continuous pathway for charge transport. These structural attributes endow BTTs with substantial promise for application in organic electronic materials. Therefore, 2,5,8-tris(4-propylphenyl)benzo[1,2-b:3,4-b′:5,6-b″]trithiophene ((C3-Ph)3-BTT) and its brominated derivative ((C3-Ph)3-Br3-BTT) were investigated as organic small molecules (OSMs) for doping with single-walled carbon nanotubes (SWCNTs) to fabricate OSM/SWCNT composite thermoelectric materials. The composite films exhibited excellent thermoelectric performance, achieving a maximum power factor of 515.23 ± 3.54 μW m–1 K–2 at room temperature. This value represents the highest reported power factor for thiophene derivative/SWCNT thermoelectric composites, marking a significant advancement in the development of high-performance composite thermoelectric materials based on thiophene derivatives.
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DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2018
·Vol. 135
·期 23
·46351
·
IF 1.901
Li Wen,Liwen Wang,Shuyi Fang,Lei Bao,Dongdong Hu,Yuan Zong,Ling Zhao,Tao Liu
Two newly-designed hydrocarbon surfactants, that is, poly(vinyl acetate)- block -poly(1-vinyl-2-pyrrolidone) (PVAc- b -PVP) and PVP- b -PVAc- b -PVP, were synthesized using reversible addition–fragmentation chain transfer polymerization and used to form CO 2 /water (C/W) emulsions with high internal phase volume and good stability against flocculation and coalescence up to 60 h. Their structures were precisely determined by nuclear magnetic resonance, gel permeation chromatography, thermal gravimetric analysis, and differential scanning calorimetry. Besides low temperature and high CO 2 pressure, the surfactant structures were the key factors affecting the formation and stability of high internal phase C/W emulsions, including the polymerization degrees of CO 2 -philic block (PVAc) and hydrophilic block (PVP), as well as the number of hydrophilic tail. The surface tension of the surfactant aqueous solution and the apparent viscosity of the C/W emulsions were also measured to characterize the surfactants efficiency and effectiveness. The surfactants with double hydrophilic tails showed stronger emulsifying ability than those with single hydrophilic tail. The great enhancement of the emulsions stability was due to decrease of the interface tension as well as increase of the steric hindrance in the water lamellae, preventing a frequent collision of CO 2 droplets and their fast coalescence. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 46351.
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产品关联
DOI
高影响因子
Energetic Materials Frontiers
·
2023
·
IF 0
Yu-shu Xiong,Yong-qi Wang,Chong Wan,Wen-zhen Zhang,Zhao Qin,Su-hang Chen,Kang-zhen Xu
To overcome the agglomeration and insufficient combustion of nano-boron (n-B) powders, this study successfully prepared two novel types of boron-based nanocomposites using the acoustic resonance technology, namely high-substitute nitrochitosan/nano-boron (NCh-B) with ratios of 1:3, 1:5, 1:7 and 1:9, and nitrochitosan/nano-boron powder/nano-titanium (NCh-B-Ti) with Ti contents of 5 wt%, 10 wt%, 15 wt% and 20 wt%. The structural morphologies, laser ignition and combustion properties of the composites were systematically investigated. The results suggest that the addition of NCh can significantly improve the dispersion of n-B. NCh-B exhibited a higher combustion performance than n-B, as evidenced by their ignition delay and flame areas. When the laser power density was 81 W, NCh-B 5 -Ti 15% exhibited a combustion time and an ignition delay of 240 ms and 5.5 ms respectively, which were higher and lower than those of NCh-B 5 (199 ms and 17 ms, respectively). Furthermore, NCh-B 5 -Ti 15% displayed a lower ignition delay than both n-B powders (12 ms) and NCh-B (11 ms), as well as brighter flames and a larger combustion area. Therefore, the addition of n-Ti can promote the combustion of n-B powders, with the combustion products of NCh-B-Ti including H 3 BO 3 , B 2 O 3 , TiB 2 , and TiO. This study provides a new method for improving the ignition performance and combustion efficiency of n-B powders.
研究领域:
材料科学
·
燃烧学
✓ 已验证
DOI
危险品化学品经营许可证（带存储）