查找使用阿拉丁产品的科研文献

Polymer dielectrics enabled by molecular engineering design and charge trap regulation for high-temperature energy storage

Guangyu Duan,Fengying Hu,Yiran He,Zuming Hu,Ming Tian,Junwei Zha

Aromatic polyimides (PIs) are widely regarded as promising hightemperature polymer dielectric films because of their excellent thermal stability. However, the extensive intra-and inter-chain migration of delocalized π-electrons through aromatic rings, coupled with a sharp increase in the density of injected and thermally activated charge carriers, significantly weakens the high-temperature energy storage performance of conventional PI. In this work, a novel strategy combining molecular engineering design with modulation of charge energy levels was employed to fabricate a series of fluorinated polyimide/magnesium oxide (FPI/MgO) dielectric films incorporating -CF 3 groups and wide-bandgap MgO nanoparticles. Compared with conventional PI, the introduction of -CF 3 and MgO effectively suppresses π-electron migration and thermally excited charge carriers, and hinders the propagation and development of breakdown pathways along the electric field direction. These synergistic effects effectively inhibit bulk-limited hopping conduction, leading to significantly improved breakdown strength (E b ) and enhanced high-temperature capacitive performance of the FPI/MgO dielectric film. At 150 °C, the FPI dielectric film with 0.10 wt.% MgO exhibits a high E b of 501 MV/m, representing an enhancement of 54.2% over that of conventional PI (325 MV/m). Benefiting from the superior E b and suppressed leakage current density, the FPI dielectric film with 0.10 wt.% MgO achieves a maximal discharge energy density (U d ) of 4.97 J/cm 3 at 150 °C, which is 4.3 times that of conventional PI (1.15 J/cm 3 ) and exceeds most previously reported high-temperature polymer dielectric films. This work presents a new paradigm for developing PI-based dielectrics with superior high-temperature energy storage performance.

Fabricating transfer channel and charge trap in carbon nitride ultrathin nanosheet for enhanced photocatalytic hydrogen evolution

Man Yang,Ruyan Duan,Jing Mei,Bian Yang,Hao Yang,Shaodong Sun,Shuhua Liang,Jie Cui

Fabricating environmental and stable graphitic carbon nitride (g-C 3 N 4 ) photocatalyst with highly efficient visible light response and charge separation is still a challenging work. Herein, g-C 3 N 4 ultrathin nanosheets are synthesized via oxidation etching method. The as-synthesized samples show improved visible-light response and photogenerated charge separation, which is revealed to be brought from the synergy of hierarchical porous structure and nitrogen vacancies. On one hand, macropores can provide light transport channels for enhanced visible light absorption , meanwhile the photogenerated charge favors to be migrated on two-dimensional ultrathin planes and trapped in mesoporous structure to avoid the recombination. Also, macropore and mesopore promote the transport and adsorption of substrates. On the other hand, DFT calculations verify that nitrogen vacancies are conductive to the rearrangement of charge density distribution and the formation of defect levels in the band gap of g-C 3 N 4 , leading to the improvement of carrier mobility and separation. Thus, nitrogen vacancies promote more active sites generation. Consequently, the g-C 3 N 4 ultrathin nanosheet presents a promising photocatalytic hydrogen evolution rate of 1.77 mmol .g −1 .h −1 in a long time run under visible light, which is far higher than that of comparison samples (0.18 and 0.29 mmol .g −1 .h −1 respectively).

Mitochondria are essential for antibacterial extracellular trap formation mediated by zymosan in hemocytes of Ruditapes philippinarum

Yijing Han,Qianqian Zhang,Lizhu Chen,Dinglong Yang,Jianmin Zhao

The formation of extracellular traps (ETs) is an important innate immune mechanism that serves to combat different invading pathogens. In this study, zymosan significantly induced the formation of ETs in the hemocytes of Ruditapes philippinarum , and this effect was accompanied by translocation of the mitochondria to the cell surface. Zymosan stimulation clearly induced an increase in intracellular ROS and MPO production and an overexpression of ROS-related genes ( PI3K , AKT and HIF ). In response to the ROS burst, the mitochondrial membrane potential decreased, and the mitochondrial permeability transition pore opened. Conversely, mitochondrial superoxide inhibitor (Mito-TEMPO) significantly inhibited the formation of ETs, suggesting that mitochondrial ROS were necessary for the formation of ETs. In addition, we found that zymosan-induced ETs showed antibacterial activities against gram-negative and gram-positive bacteria, such as Vibrio anguillarum , Vibrio harveyi , Escherichia coli and Micrococcus luteus . Taken together, these findings elucidated a new antibacterial approach for R. philippinarum and highlighted the role of mitochondria in the formation of zymosan-induced ETs.

Effects of trap density on space charge suppression of block polypropylene/AI2O3 composite under high temperature

Chong Zhang,Jun-Wei Zha,Hong-Da Yan,Wei-Kang Li,Yong-Qiang Wen,Zhi-Min Dang

Implementation and study of dopant-assisted photoionization with a miniature capillary inlet ion trap mass spectrometer

Qian Zhang,Yuan Tian,Mushage Aliang,Quan Yu,Xiaohao Wang

Rationale Dopant-assisted photoionization (PI) has been widely used in the mass spectrometric analysis of volatile compounds. Exploring simple doping methods will benefit parameter optimization and promote the application of this technique. Methods A previously built miniature ion trap mass spectrometer was used to study dopant-assisted vacuum PI. The sampling system of this device was modified to provide three inlets for the simultaneous introduction of analytes, dopants, and auxiliary air. Then, dopant solution was directly injected into the ion trap chamber through a self-aspirating capillary inlet and rapidly evaporated without heating. Various dopant solutions were prepared and switched during the experiments. Results When analyzing some aniline compounds, the signals of all analytes were improved by more than 10 times after the injection of 2% anisole solution as a dopant. In addition, anisole can provide analyte signals more than three times stronger than those provided by the other dopants. On the basis of the ionization energy selectivity of dopant-assisted PI, some isomers in the mass spectrometric analysis were distinguished using different additives. Conclusions In general, liquid doping is as feasible and as effective as other traditional methods, and using appropriate dopants with high PI efficiency or feeding more dopants contributes to the ionization of analytes. The proposed method also offers several unique merits, such as simple operation, low consumption, and smooth switching with minimal residue.

Oxygen nanocarrier broke the hypoxia trap of solid tumors and rescued transfection efficiency for gene therapy

Qin Bing,Jiang Mengshi,Li Xiang,Shi Yingying,Zhang Junlei,Luo Zhenyu,Luo Lihua,Lu Yichao,Liu Xu,Wang Sijie,Du Yongzhong,Qiu Yunqing,Lou Yan,You Jian

Background Gene therapy shows great promise for a broad array of diseases. However, we found that hypoxic tumor microenvironment (TME) exerted significant inhibitory effects on transfection efficiency of a variety of gene vectors (such as Lipo 2000 and PEI) in an oxygen-dependent manner. Solid tumors inevitably resulted in acute hypoxic areas due to the rapid proliferation of tumor cells and the aberrant structure of blood vessels. Thus, the hypoxic TME severely limited the efficiency and application of gene therapy.Methods In our previous study, we constructed endoplasmic reticulum-targeted cationic liposomes, PAR-Lipo, which could effectively deliver genes and ensure high transfection efficiency under normoxia. Unsatisfactorily, the transfection efficiency of PAR-Lipo was rather poor under hypoxia. We believed that reoxygenation was the most direct and effective means to rescue the low transfection under hypoxia. Hence, we fabricated liposomes modified with perfluorooctyl bromide (PFOB@Lipo) to load oxygen and deliver it to tumor sites, which effectively alleviated the hypoxic nature of tumor. Then PAR-Lipo were applied to mediate high-efficiency delivery of tumor suppressor gene pTP53 to inhibit tumor progression.Results The results showed that such staged strategy augmented the expression of P53 protein in tumors and extremely suppressed tumor growth.Conclusion This work was the first attempt to utilize an oxygen nanocarrier to assist the therapeutic effect of gene therapy under hypoxia, providing a new reference for gene therapy in malignant tumors.Graphical Abstarct

40.1% Record Low-Light Solar-Cell Efficiency by Holistic Trap-Passivation using Micrometer-Thick Perovskite Film

Xilai He,Jiangzhao Chen,Xiaodong Ren,Lu Zhang,Yucheng Liu,Jiangshan Feng,Junjie Fang,Kui Zhao,Shengzhong (Frank) Liu

Perovskite solar cells exhibit not only high efficiency under full AM1.5 sunlight, but also have great potential for applications in low-light environments, such as indoors, cloudy conditions, early morning, late evening, etc. Unfortunately, their performance still suffers from severe trap-induced nonradiative recombination, particularly under low-light conditions. Here, a holistic passivation strategy is developed to reduce traps both on the surface and in the bulk of micrometer-thick perovskite film, leading to a record efficiency of 40.1% under 301.6 µW cm −2 warm light-emitting diode (LED) light for low-light solar-cell applications. The involvement of guanidinium into the perovskite bulk film and 2-(4-methoxyphenyl)ethylamine hydrobromide (CH 3 O-PEABr) passivation on the perovskite surface synergistically suppresses the trap states. The charge carrier lifetimes of the perovskite film increase by tenfold and fivefold to 981 ns and 8.02 µs at the crystal surface and in its bulk, respectively. The decreased nonradiative recombination loss translates to a high open-circuit voltage ( V oc ) of 1.00 V, a high short-circuit current ( J sc ) of 152.10 µA cm −2 , and a fill factor (FF) of 79.52%. Note that this performance also stands as the highest among all photovoltaics measured under indoor light illumination. This work of trap passivation for micrometer-thick perovskite film paves a way for high-performance, self-powered IoT devices.

Effects of trap density on separation efficiency of photogenerated carriers for Sb-SnO2/TiO2 heterojunction semiconductors

Z. L. Zhang,M. L. Wang,Y. L. Mao

In this paper, heterojunction semiconductors of Sb-SnO2/TiO2 were prepared with varying molar ratios of Sb-SnO2 to TiO2. The separation efficiency of the photogenerated carriers was characterised by the surface photovoltage (SPV) technique, and the trap density was measured by an electrochemical method. The trap density was measured to be 7·48×1016, 6·01×1016, 5·43×1016, and 6·61×1016 cm−2 for TiO2 and Sb-SnO2/TiO2 films with molar ratios of 1, 2, and 3%, respectively. The SPV enhancement was estimated to be 1, 1·36, 7·64, and 6·36 for TiO2 and Sb-SnO2/TiO2 films with molar ratios of 1, 2, and 3%, respectively. The results indicate that SPV enhancement increases with decreasing trap density, which demonstrates that the trap density is an important factor affecting the separation efficiency of photogenerated carriers in heterojunction semiconductors.

Enhanced performance of UV photodetector based on ZnO nanorod arrays via TiO2 as electrons trap layer

Zihan Yin,Yujie Shan,Mingyan Yu,Lun Yang,Jiaming Song,Peng Hu,Feng Teng

As a commonly used substrate and matrix material in the construction of high performance ultraviolet photodetector, ZnO nanorod arrays have attached much attention due to their efficiency electron transmission channels and high stability. However, they also have the problem of slow response speed inevitably. In this work, TiO 2 /ZnO nanorod arrays heterojunction structure was prepared and used to construct ultraviolet photodetector. The obtained heterojunction photodetector has a higher on/off ratio (>1000) and shorter rise/decay time (6.1/3.7 s) compared with that of photodetector based on ZnO nanorod arrays (on/off ratio ∼10 and decay time >20 s). The enhanced response speed is caused by the traps of the electron in TiO 2 layer, which can accelerate the decay of current in the OFF state. The obtained results provide a new sight for the further development of the optoelectronic devices based on ZnO nanorod arrays in future.

Rapid screening of illegally added drugs in functional food using a miniature ion trap mass spectrometer

Wenyan Shi,Xinming Huo,Xinyue Ding,Peiyuan Zhu,Yutong Wan,Xinqiong Lu,Rui Feng,Quan Yu,Xiaohao Wang

With the expansion of the functional food market, the qualification assessment of these products has become a major challenge, and efficient analytical tools are urgently needed. Here, a miniature mass spectrometer (MS) with self-aspiration capillary electrospray ionization (SACESI) source and ion trap analyzer was developed for rapid screening of various illegally added drugs in functional foods. No chromatographic separation was required, but a simplified two-step pretreatment method was developed to reduce the operational procedures and time consumption of the entire analysis. SACESI source uses capillary action to drive solution injection, which utilizes a simple structure and convenient operation to constitute a kind of disposable MS detection solution. To achieve accurate and automatic identification, an intelligent recognition algorithm with steps of spectrum preprocessing, characteristic peak matching, and support vector machine learning was constructed. The relative accuracy of rapid screening of 31 suspicious drugs in various samples is up to 99.78%. It achieves 100% correct identification for the 55 batches of actual samples captured by on-site inspection, which demonstrates the feasibility of the proposed analytical system and strategy in food safety applications.

Engineering trap distribution to achieve multicolor persistent and photostimulated luminescence from ultraviolet to near-infrared II

Luping Wang,Datao Tu,Chenliang Li,Siyuan Han,Fei Wen,Shiqi Yu,Xiaodong Yi,Zhi Xie,Xueyuan Chen

Persistent luminescence (PersL) and photostimulated luminescence (PSL) materials exhibit fascinating optical properties originating from energy harvesting and controllable release. However, it remains challenging to obtain multicolor PersL and PSL simultaneously. Herein, we develop lanthanide (Ln 3+ )-doped Cs 2 NaGdF 6 phosphors with shallow and deep defects, achieving both multicolor PersL and PSL through engineering trap distribution. Benefiting from manipulating fluorine vacancy and energy-level locations of Ln 3+ in Cs 2 NaGdF 6 phosphors by introducing different Ln 3+ dopants, the depth and density of electron and hole traps can be tuned, resulting in PersL of more than one week with emissions from 311 to 1,536 nm and multicolor PSL with high recyclability. Both thermoluminescence analysis and theoretical calculations reveal the mechanism of trap distribution regulation in Cs 2 NaGdF 6 phosphors via Ln 3+ doping. These findings provide fundamental insights into exploring multicolor PersL and PSL materials, thereby opening up new opportunities for versatile applications.

Volatiles of the trap crop sunflowers: Effects on the behaviour of adult female Conogethes punctiferalis moths

Jia Zhou,Li-Lin Chen,Yu-Tong Zhu,Evan Siemann,Nian-Feng Wan

Sunflowers ( Helianthus annuus ) are potential trap crops to attract the yellow peach moth ( Conogethes punctiferalis ) in orchards but the volatile compounds released from sunflowers and their effects on C. punctiferalis behaviour are not clear. Here we used solid phase micro-extraction to collect volatiles released from flower disks of sunflowers, identified them by gas chromatography–mass spectrometry, and examined the attractiveness of some of the compounds to mated female adult C. punctiferalis moths in Y-tube olfactometer choice tests. We detected nine volatile compounds (α-Pinene, β-Phellandrene, Camphene, β-Pinene, 3-Carene, D-Limonene, Eucalyptol, γ-Terpinen, and Valencene) with consistently large peak areas for α-Pinene and β-Phellandrene. Among tested volatiles, both α-Pinene and β-Phellandrene were attractive to C. punctiferalis in olfactometer tests but this was only significant for higher concentrations of β-Phellandrene. This suggests that β-Phellandrene may promote C. punctiferalis oviposition on sunflower disks. This study provides insights into volatile chemical mediated responses of insect herbivores to trap crops.