CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Qichen Shang,Daiwei Gu,Lin Sheng,Yu Chang,Jian Deng,Guangsheng Luo
Laminar jet flow is an underlying phenomenon used to generate droplets efficiently. However, its hydrodynamics at the microscale remains unknown. This work focuses on the scale effect. We innovatively propose the difference between the jet at the microscale and that at the regular scale is not in the wave development but in the regime of flow pattern, and it’s much more stable at the microscale. The characteristic effect at the microscale due to the intensified gas/liquid/solid–liquid interaction is first reported. The variations of characteristic sizes and hydrodynamics with the kinetic energy, physical property, and structural size at the microscale are analyzed by introducing two key parameters − wave velocity and wave numbers, which are first proposed. The result shows that the kinetic energy determines the hydrodynamics. Viscosity and interfacial tension significantly affect the microscale laminar jet. Using wave numbers, Tyler’s equation is modified, guiding the design of effective microdroplet-generation devices.
研究领域:
流体力学
·
微流控技术
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产品关联
DOI
高影响因子
Journal of Energetic Materials
·
2024
·
IF 1.7
Shijiao Li,Kai Han,Haoxing Cao,Fubing Gao,Yurong Zhang,Handong Shi,Xiaoying Cheng,Chongwei An,Jingyu Wang
Using hydroxypropyl methylcellulose (HPMC) aqueous solution and polyethyleneimine (PEI) ethanol solution as the composite bonding system, adding a certain amount of silicone defoamer and toluene diisocyanate (TDI), studied the micro-size charge forming effect of sub-micron Octogen (HMX)-based composite ink under the 3D direct writing printing process and the detonation performance and safety of sub-micron Octogen (HMX) under micro-size charges. The results show that the explosive ink with a solid content (quality score) of 90% has the best rheological properties, excellent printability, and the surface of the molded sample is smooth. The impact energy and friction of the molded sample are 7 J and 324 N, respectively, which are lower than those of the raw material HMX 100% and 237.5%, showing excellent mechanical sensitivity safety performance. In addition, XRD and FTIR show that the HMX crystal form in the composite ink remains β-type, the measured density of the molded sample is 1.432 g·cm−1, the detonation velocity is 6982 m·s−1, and the critical detonation size is 1 × 0.0771 mm, showing excellent microchannel detonation performance.
研究领域:
材料科学
·
爆炸化学
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DOI
高影响因子
Processes
·
2020
·Vol. 8
·期 11
·1493
·
IF 2.753
Yue Wang,Minqi Zhang,Shuhang Chang,Shengji Li,Xuefeng Huang
Microscale combustion has potential application in a micro power generator. This paper studied the ignition and combustion behavior of individual graphite microparticles in a micro-combustor to explore the utilization of carbon-based fuels at the microscale system. The individual graphite microparticles inside the micro-combustor were ignited by a highly focused laser in an air flow with natural convection at atmospheric temperature and pressure. The results show that the ignition of graphite microparticles was heterogeneous. The particle diameter had a small weak effect on ignition delay time and threshold ignition energy. The micro-combustor wall heat losses had significant effects on the ignition and combustion. During combustion, flame instability, photophoresis, repetitive extinction and reignition were identified. The flame structure was asymmetric, and the fluctuation of flame front and radiation intensity showed combustion instability. Photophoretic force pushed the graphite away from the focal point and resulted in extinction. Owing to large wall heat loss, the flame quickly extinguished. However, the graphite was inductively reignited by laser.Keywords:microscale combustion;graphite;photophoresis;repetitive extinction;laser ignition
研究领域:
燃烧工程
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材料科学
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激光物理
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产品关联
DOI
高影响因子
Nanomaterials
·
2017
·Vol. 7
·期 12
·448
·
IF 3.553
Dandan Ju,Feng Song,Yingdong Han,Wenjing Cui,Aihua Zhou,Shujing Liu,Xueqin Wang,Ming Feng,Chengguo Ming
We synthesized the uniform core-shell microstructured compounds with hexagonal phase NaYF4:Er/Yb microrods as the core and hexagonal phase NaLnF4(NaYbF4, NaLuF4:Yb/Tm, NaYF4:Yb/Er, NaYF4:Eu) as the shell based on the hydrothermal reaction. These microscale core-shell structures provided a platform for the spatially confining optical process while possessing high luminescence efficiency. The thickness of the shell could be controlled by adjusting the amounts of shell precursor, which significantly affected the intensity of the shell dopant ions emission and the emission color of core-shell upconversion luminescence (UCL). The uniform NaYF4@NaLnF4(Ln = Y, Lu, Yb) microrods, with a series of rare-earth ions doped into the core and shell layer at various doping concentrations, achieved color-tuning of the upconversion (UC) emission and dual-mode emission at the single-microcrystal level, thus allowing the efficient utilization of core-shell microcrystals in the photonics and security labeling. This study suggests a new class of luminescent materials in the microscopic field.Keywords:NaYF4microcrystals;microscale core-shell structures;multicolor tuning;dual-mode emission
研究领域:
材料科学
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光学
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产品关联
DOI
PubMed
高影响因子
PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY
·
2023
·
IF 4.7
Chen Wang,Guangming Ma,Shanqi Zhang,Kunhong Zhao,Xiangyang Li
The Tobamovirus helicase plays an important role in virus proliferation and host interaction. They can also be targets for antiviral drugs. Tobacco mosaic virus (TMV) is well controlled by ningnanmycin (NNM), but whether it acts on other virus helicases of Tobamovirus virus is not clear. In this study, we expressed and purified several Tobamovirus virus helicase proteins and analyzed the three–dimensional structures of several Tobamovirus virus helicases. In addition, the binding of Tobamovirus helicase to NNM was also studied. The docking study reveals the interaction between NNM and Tobamovirus virus helicase. Microscale Thermophoresis (MST) experiments have shown that NNM binds to Tobamovirus helicase with a dissociation constant of 4.64–12.63 μM. Therefore, these data are of great significance for the design and synthesis of new effective anti–plant virus drugs.
研究领域:
植物学
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病毒学
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药物化学
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产品关联
DOI
PubMed
高影响因子
LAB ON A CHIP
·
2023
·Vol. 23
·期 9
·2341-2355
·
IF 6.1
Weidong Fang,Zhi Tao,Haiwang Li,Shuai Yin,Tiantong Xu,Yi Huang,Teckneng Wong
Droplet coalescence with fast response, high controllability and monodispersity has been widely investigated in industrial production and bioengineering. Especially for droplets with multiple components, programmable manipulation of such droplets is crucial for practical applications. However, precise control of the dynamics can be challenging, owing to the complex boundaries and the interfacial and fluidic properties. AC electric fields, with their fast response and high flexibility, have attracted our interest. We design and fabricate an improved flow-focusing microchannel configuration together with a non-contact type of electrode featuring asymmetric geometries, based on which we conduct systematic investigations of the AC-electric-field-controlled coalescence of multi-component droplets at the microscale. Parameters such as flow rates, component ratio, surface tension, electric permittivity and conductivity were given our attention. The results show that droplet coalescence in different flow parameters can be achieved in milliseconds by adjusting the electrical conditions, which shows high controllability. Specifically, both the coalescence region and reaction time can be adjusted by a combination of applied voltage and frequency, and unique merging phenomena have appeared. One is contact coalescence with the approach of paired droplets, while the other is squeezing coalescence, which occurs in the start position and promotes the merging process. The fluid properties, such as the electric permittivity, conductivity and surface tension, present a significant influence on merging behavior. The increasing relative dielectric constant leads to a dramatic reduction of the start merging voltage from the original 250 V to 30 V. The range of effective voltage for coalescence decreases with the addition of surfactant, offering a stricter and yet higher selectivity on electrical conditions, about 1500 V. The conductivity presents a negative correlation with the start merging voltage due to the reduction of the dielectric stress, from 400 V to 1500 V. Finally, we achieve the precise fabrication process of the Janus droplet via implementation of the proposed method, where the components of the droplets and the coalescence conditions are well controlled. Our results can serve as a potent methodology to decipher the physics of multi-component droplet electro-coalescence and contribute to applications in chemical synthesis, bioassay and material synthesis.
研究领域:
生物工程
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化学工程
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FirePhysChem
·
2024
·
IF 0
Hongyang Chen,Yaofeng Mao,Jie Chen,Ruolei Zhong,Bo Jin,Fude Nie,Rufang Peng,Jun Wang
Microscale energetic materials have garnered considerable attention because they can be integrated in microelectromechanical systems for several potential applications. Hexanitrostilbene (HNS) has been widely utilized in ignition and initiation devices owing to its excellent thermal and shock stability and high sensitivity to short pulse shock waves. To meet the energy release requirements of micro-detonation devices, HNS sticks were prepared using direct ink writing and their reaction and flame propagation properties were studied. HNS particles sized 17.5 µm to 5 µm and ∼500 nm was prepared. Then, the viscosity of HNS-based inks prepared via acoustic resonance technology decreased when the particle size decreased or when the HNS content reduced from 97 wt.%, 95 wt.%, and 92 wt.%, to 90 wt.%. Additionally, the HNS-based inks with different binders exhibited different viscosity. The effect of the inner diameter of needle (0.4 mm, 0.6 mm, and 0.9 mm), printing rate (13 mm/s, 15 mm/s, 17 mm/s, 19 mm/s), and pressure (0.05 MPa, 0.1 MPa, 0.15 MPa, 0.2 MPa) on the width of HNS sticks was also elucidated. HNS-based sticks with a diameter of 0.9 mm underwent self-sustaining combustion reactions, and the burning rate increased from 5.1 mm/s to 6.8 mm/s as the particle size decreased from 17.5 µm to 500 nm. Overall, this work provides an effective approach to prepare microscale HNS for integration into micro-energetic devices.
研究领域:
材料科学
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化学工程
·
机械工程
✓ 已验证
DOI
ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Xiaofei Liu,Lanlan Hou,Rongjun Hu,Huiying Zhang,Xuefeng Zhang,Xinran Ge,Ying Zhang,Guichu Yue,Zhimin Cui,Jie Bai,Jingchong Liu,Nü Wang,Yong Li,Yong Zhao
Solar evaporation is an ecofriendly and practical method for seawater desalination. The photothermal layer, which absorbs solar energy and converts it to thermal energy, plays a crucial role in enhancing the efficiency of the evaporator. However, structural design methods for photothermal layers are often complex and energy-intensive. This work reports a simple and efficient strategy for fabricating a necklace-like beaded nanofiber self-organized honeycomb-structured photothermal material. The honeycomb-like cavities form numerous microscale thermal traps, achieving thermal localization while maintaining high energy utilization efficiency, which not only increases light absorption but also facilitates the diffusion and escape of steam. Besides, the hydrophobic honeycomb layer separates the photothermal layer and the interface water, which reduces considerable heat conduction loss and achieves an effective antisalting performance. These functional features endow the evaporator with an evaporation efficiency of 92.9%, and the evaporation rate reaches 2.11 kg m–2 h–1 at 1 sun irradiance, demonstrating its great potential for practical solar-driven seawater desalination under natural sunlight.
研究领域:
材料科学
·
能源科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Research and Technology-JMR&T
·
2022
·
IF 6.267
Jirui Zou,Xiang'an Yue,Weiqing An,Lijuan Zhang
In this paper, the gas–liquid static contact angles in silica microtubes (inner diameter range of 5–700 μm) are measured by optical microscope. The experimental results show that the gas–liquid contact angles in the microtube have microscale wetting effect, which decrease monotonically with the decrease of the tube diameter and regularly deviate from the contact angle measured on the plate. When the tube diameter decreases from 700 μm to 5 μm, the contact angles of water and hexadecane decrease from 42.87° to 13.22° and 15.94°–9.09°, respectively. Actual microscale wetting effect causes the gas–liquid capillary force and driving resistance of residual droplets in pore-throat to be bigger than the value determined by the contact angle on the plate. The smaller the pore radius, the greater the influence of the microscale wetting effect on the capillary force. The larger pore-throat ratio and smaller throat radius, the greater influence of the microscale wetting effect on the driving resistance. These results advance our current understanding of wettability in porous media and offer us directly measured contact angles from pore scale which are better representation of actual pores than flat plate to characterize the fluid wettability in porous media.
研究领域:
材料科学
·
流体力学
✓ 已验证
DOI
高影响因子
ACS Omega
·
2021
·
IF 3.512
Yu Wu,Danjiao Zhao,Jidi Zhang,Aiping Lin,Yu Wang,Lei Cao,Shufen Wang,Shixian Xiong,Feng Gu
Additive manufacturing techniques have revolutionized the field of fabricating micro-supercapacitors (MSCs) with a high degree of pattern and geometry flexibility. However, traditional additive manufacturing processes are based on the functionality of microstructural modulation, which is essential for device performance. Herein, Ti3C2Tx MXene was chosen to report a convenient aerosol jet printing (AJP) process for the in situ curling and alignment of MXene nanosheets. The aerosol droplet provides a microscale regime for curling MXene monolayers while their alignment is performed by the as-generated directional stress derived from the quasi-conical fiber array (CFA)-guided parallel droplet flow. Interdigital microelectrodes were further developed with the curled MXene and a satisfying areal capacitance performance has been demonstrated. Importantly, the AJP technique holds promise for revolutionizing additive manufacturing techniques for fabricating future smart microelectronics and devices not only in the microscale but also in the nanoscale.
研究领域:
材料科学
·
纳米技术
·
电子工程
✓ 已验证
DOI
高影响因子
Soft Matter
·
2016
·Vol. 12
·期 10
·2751-2756
·
IF 3.798
Yingjue Wang,Yiwei Zhuang,Jiangang Gao,Gang Zou,Qijin Zhang
Enantioselective assembly is observed during preparation of vesicles from a solution mixture of an amphipathic block copolymer bearing pendent chiral L- or D-phenylalanine groups in hydrophobic segments and racemic chiral small molecules. Primary experimental results reveal that racemic chiral small molecules have been enantioselectively encapsulated into the hydrophobic shells of assembled vesicles with homochiral bilayer membrane structure, showing reverse CD signals compared with the original vesicles. A further study shows that the enantiomeric excess obtained through the enantioselective assembly is directly dependent on the molecular weight of the hydrophobic chiral chain segments, implying both the hydrophobic interaction and chirality are key points during the assembly of vesicles. Other factors, such as hydrogen-bonding interactions and π–π stacking interaction, are also found to be responsible for the enantioselective assembly phenomenon during the formation of the vesicles.
研究领域:
高分子化学
·
物理化学
·
生物化学
✓ 已验证
DOI
PubMed
高影响因子
International Journal of Peptide Research and Therapeutics
·
2019
·Vol. 26
·期 1
·121-128
·
IF 1.219
Wang Mengwei,Lv Mingxiu,Lu Kui,Liu Guangbin,Mai Wenpeng,Yu Bo,Lou Yudan
Six breast cancer susceptibility gene 1 (BRCA1) peptide fragments were designed by removing N-terminal amino acid residues of BRCA1(846–871). Peptide fragments BRCA1(846–871), BRCA1(852–871), BRCA1(854–871), BRCA1(856–871), BRCA1(857–871) and BRCA1(861–871) were obtained by Fmoc solid-phase synthesis, purified by reversed-phase high-performance liquid chromatography and characterized by electrospray ionization mass spectrometry. The interaction between BRCA1 fragment peptides and RAD51(181–200) target peptides were investigated using circular dichroism (CD) spectroscopy, fluorescence spectroscopy, and microscale thermophoresis (MST). The results of CD spectroscopy showed that the secondary structures of RAD51(181–200) were altered after the addition of BRCA1 peptide fragments. The fluorescence results proved that all six BRCA1 peptide fragments BRCA1(846–871), BRCA1(852–871), BRCA1(854–871), BRCA1(856–871), BRCA1(857–871) and BRCA1(861–871) could bind to RAD51(181–200) independently, their quenching processes were static, and the binding constant of peptide fragments with RAD51(181–200) were 4.01 × 10 5 L mol −1 , 7.22 × 10 5 L mol −1 , 7.84 × 10 5 L mol −1 , 1.1 × 10 4 L mol −1 , 6.19 × 10 3 L mol −1 , 6.18 × 10 3 L mol −1 . The results of MST displayed that BRCA1(854–871) could combine with RAD51(181–200), and the dissociation constant K d was 126.44 µM. Compared with other five peptide fragments, the interaction between BRCA1(854–871) and RAD51(181–200) was much stronger.
研究领域:
生物化学
·
分子生物学
·
癌症研究
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）