Nanofibrous Membranes with High Air Permeability and Fluffy Structure based on Low Temperature Electrospinning Technology

2020 ◽  
Vol 21 (7) ◽  
pp. 1466-1474
Author(s):  
Siying Lin ◽  
Xiang Huang ◽  
Zhenxiang Bu ◽  
Zhihong Lin ◽  
Peiqin Xie ◽  
...  
Keyword(s):  
Low Temperature ◽  
Air Permeability ◽  
Nanofibrous Membranes

Binary Structured Polypropylene/Polyethylene Glycol Micro-nanofibrous Membranes with Enhanced Water and Air Permeability

2021 ◽  
Vol 22 (1) ◽  
pp. 69-76
Author(s):  
Heng Zhang ◽  
Qi Zhen ◽  
Jing-Qiang Cui ◽  
Huan-Wei Sun ◽  
Rang-Tong Liu ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Air Permeability ◽  
Nanofibrous Membranes

Photo-crosslinked nanofibrous membranes as advanced low-temperature regenerative desiccant

2019 ◽  
Vol 78 ◽  
pp. 105947 ◽  
Author(s):  
Ye Yao ◽  
Li Dai ◽  
Fengjing Jiang
Keyword(s):  
Low Temperature ◽  
Nanofibrous Membranes

Low-temperature synthesis of novel polyvinylalcohol (PVA) nanofibrous membranes for catalytic dye degradation

2020 ◽  
Vol 262 ◽  
pp. 121301 ◽  
Author(s):  
Md Nahid Pervez ◽  
George K. Stylios ◽  
Yonghong Liang ◽  
Feifan Ouyang ◽  
Yingjie Cai
Keyword(s):  
Low Temperature ◽  
Dye Degradation ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis ◽  
Nanofibrous Membranes

scholarly journals Temperature adjusting performance of thermoregulated woven fabric finished with phase-change microcapsule in low-temperature environment

2019 ◽  
Vol 14 ◽  
pp. 155892501988728 ◽  
Author(s):  
Xu Chen ◽  
Bingyang Wu ◽  
Ying Fan ◽  
Xingyuan Duan ◽  
Musheng Yang
Keyword(s):  
Low Temperature ◽  
Phase Change ◽  
Average Particle Size ◽  
Air Permeability ◽  
Woven Fabric ◽  
Average Particle ◽  
Gravimetric Analysis ◽  
Temperature Resistance ◽  
Temperature Environment ◽  
Low Temperature Resistance

This study deals with the temperature adjusting performance of thermoregulated woven fabric based on phase-change microcapsules in low-temperature environment. Phase-change microcapsules containing n-octadecane (MicroC18) with melamine–urea–formaldehyde as shell were synthesized by an in situ polymerization using styrene maleic anhydride copolymer as emulsifying agent. Surface morphology, chemical structure, and thermal properties of MicroC18 were, respectively, characterized using field emission scanning electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, and thermal gravimetric analysis. The results indicate that a series of microcapsules with spherical shapes were fabricated with about 20.6-μm weight-average particle size. Latent heat is about 188.2 J/g and encapsulation efficiency of n-octadecane (C18) is 85.2%. Phase-change microcapsule composite fabric was prepared through foaming method with plain weave, twill weave, and satin weave as substrates. Thermal insulation property, low-temperature resistance, air permeability, and mechanical property of the finished fabric were investigated. The results show that the cooling rate of finished fabric is significantly slower, and low-temperature resistance time increases. Finished satin fabric has the best thermal resistance performance. The air permeability of finished fabrics is lightly reduced, and final elongation in warp and weft are increased by 16.5% and 15.2%, respectively.

Preparation of PVDF Nanofibrous Membrane and its Waterproof and Breathable Property

2013 ◽  
Vol 796 ◽  
pp. 327-330 ◽  
Author(s):  
Ying Zhou ◽  
Li Rong Yao ◽  
Qiang Gao
Keyword(s):  
Contact Angle ◽  
Volume Ratio ◽  
Air Permeability ◽  
Nanofibrous Membrane ◽  
Pvdf Membrane ◽  
Nanofibrous Membranes ◽  
The Relationship

PVDF nanofibrous membranes were successfully prepared by electrospinning in this paper, and the component solvent of DMF/acetone was used. The concentration of PVDF and the volume ratio of component solvents of DMF/acetone were the most important variables to affect the morphology, diameter and uniformity of the nanofibers. The concentration of spinning fluid changed from 10 wt% to18 wt% and the volume ratio of DMF/acetone ranged from 2/8 to 8/2. The results of the study showed that the better nanofibrous membrane was prepared when the concentration of PVDF was 12 wt% and the ratio of component solvent DMF/acetone was 6/4. At this moment, the morphology and contact angle of PVDF membrane were better in comparison with other groups. The contact angle, waterproof properties, air permeability were measured, which indicated that the PVDF nanofibrous membrane showed a good air permeability and had an excellent waterproof properties at the same time. In the meantime, by changing the thickness of membrane, we could analyze the relationship between the thickness of the membrane and its breathability and waterproofness.

Exsolution and inversion in pigeonite from the Whin Sill, Northern England

1978 ◽  
Vol 36 (1) ◽  
pp. 474-475
Author(s):  
P.P.K. Smith
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Homogeneous Nucleation ◽  
Silicate Mineral ◽  
Antiphase Boundaries ◽  
Two Phase ◽  
Primitive Form ◽  
The Core ◽  
Nucleation Mechanisms ◽  
And Inversion

Grains of pigeonite, a calcium-poor silicate mineral of the pyroxene group, from the Whin Sill dolerite have been ion-thinned and examined by TEM. The pigeonite is strongly zoned chemically from the composition Wo8En64FS28 in the core to Wo13En34FS53 at the rim. Two phase transformations have occurred during the cooling of this pigeonite:- exsolution of augite, a more calcic pyroxene, and inversion of the pigeonite from the high- temperature C face-centred form to the low-temperature primitive form, with the formation of antiphase boundaries (APB's). Different sequences of these exsolution and inversion reactions, together with different nucleation mechanisms of the augite, have created three distinct microstructures depending on the position in the grain.In the core of the grains small platelets of augite about 0.02μm thick have farmed parallel to the (001) plane (Fig. 1). These are thought to have exsolved by homogeneous nucleation. Subsequently the inversion of the pigeonite has led to the creation of APB's.

Low temperature x-ray microanalysis of frozen-hydrated tobacco leaves

1984 ◽  
Vol 42 ◽  
pp. 284-285
Author(s):  
S. Edith Taylor ◽  
Patrick Echlin ◽  
May McKoon ◽  
Thomas L. Hayes
Keyword(s):  
Low Temperature ◽  
Lemna Minor ◽  
Root Tips ◽  
Tobacco Leaves ◽  
X Ray ◽  
Whole Cells ◽  
Carbon Coated ◽  
The Right ◽  
Beam Currents ◽  
The University

Low temperature x-ray microanalysis (LTXM) of solid biological materials has been documented for Lemna minor L. root tips. This discussion will be limited to a demonstration of LTXM for measuring relative elemental distributions of P,S,Cl and K species within whole cells of tobacco leaves.Mature Wisconsin-38 tobacco was grown in the greenhouse at the University of California, Berkeley and picked daily from the mid-stalk position (leaf #9). The tissue was excised from the right of the mid rib and rapidly frozen in liquid nitrogen slush. It was then placed into an Amray biochamber and maintained at 103K. Fracture faces of the tissue were prepared and carbon-coated in the biochamber. The prepared sample was transferred from the biochamber to the Amray 1000A SEM equipped with a cold stage to maintain low temperatures at 103K. Analyses were performed using a tungsten source with accelerating voltages of 17.5 to 20 KV and beam currents from 1-2nA.

Bulk standards for low-temperature biological x-ray microanalysis

1984 ◽  
Vol 42 ◽  
pp. 282-283
Author(s):  
P. Echlin ◽  
M. McKoon ◽  
E.S. Taylor ◽  
C.E. Thomas ◽  
K.L. Maloney ◽  
...  
Keyword(s):  
Phase Separation ◽  
Low Temperature ◽  
Analytical Method ◽  
Salt Solutions ◽  
Absolute Concentration ◽  
Cooling Process ◽  
X Ray ◽  
The Absolute ◽  
Analytical Procedures ◽  
Electrical Conductors

Although sections of frozen salt solutions have been used as standards for x-ray microanalysis, such solutions are less useful when analysed in the bulk form. They are poor thermal and electrical conductors and severe phase separation occurs during the cooling process. Following a suggestion by Whitecross et al we have made up a series of salt solutions containing a small amount of graphite to improve the sample conductivity. In addition, we have incorporated a polymer to ensure the formation of microcrystalline ice and a consequent homogenity of salt dispersion within the frozen matrix. The mixtures have been used to standardize the analytical procedures applied to frozen hydrated bulk specimens based on the peak/background analytical method and to measure the absolute concentration of elements in developing roots.

Field ion microscopy

1988 ◽  
Vol 46 ◽  
pp. 434-435
Author(s):  
Gert Ehrlich
Keyword(s):  
Low Temperature ◽  
Sample Surface ◽  
Low Pressure ◽  
Radius Of Curvature ◽  
Field Ion Microscopy ◽  
Phosphor Screen ◽  
Ion Microscopy ◽  
Field Ion Microscope

The field ion microscope, devised by Erwin Muller in the 1950's, was the first instrument to depict the structure of surfaces in atomic detail. An FIM image of a (111) plane of tungsten (Fig.l) is typical of what can be done by this microscope: for this small plane, every atom, at a separation of 4.48Å from its neighbors in the plane, is revealed. The image of the plane is highly enlarged, as it is projected on a phosphor screen with a radius of curvature more than a million times that of the sample. Müller achieved the resolution necessary to reveal individual atoms by imaging with ions, accommodated to the object at a low temperature. The ions are created at the sample surface by ionization of an inert image gas (usually helium), present at a low pressure (< 1 mTorr). at fields on the order of 4V/Å.

High-Vacuum Evaporation and a Cryostage to Observe Fractured Yeast

1988 ◽  
Vol 46 ◽  
pp. 256-257
Author(s):  
William P. Wergin ◽  
Eric F. Erbe ◽  
Eugene L. Vigil
Keyword(s):  
Electron Microscope ◽  
Low Temperature ◽  
Standard Specimen ◽  
High Vacuum ◽  
Specimen Holder ◽  
Sputter Coating ◽  
Fresh Frozen ◽  
Gain Access ◽  
Scanning Electron ◽  
Transfer Device

Investigators have long realized the potential advantages of using a low temperature (LT) stage to examine fresh, frozen specimens in a scanning electron microscope (SEM). However, long working distances (W.D.), thick sputter coatings and surface contamination have prevented LTSEM from achieving results comparable to those from TEM freeze etch. To improve results, we recently modified techniques that involve a Hitachi S570 SEM, an Emscope SP2000 Sputter Cryo System and a Denton freeze etch unit. Because investigators have frequently utilized the fractured E face of the plasmalemma of yeast, this tissue was selected as a standard for comparison in the present study.In place of a standard specimen holder, a modified rivet was used to achieve a shorter W.D. (1 to -2 mm) and to gain access to the upper detector. However, the additional height afforded by the rivet, precluded use of the standard shroud on the Emscope specimen transfer device. Consequently, the sample became heavily contaminated (Fig. 1). A removable shroud was devised and used to reduce contamination (Fig. 2), but the specimen lacked clean fractured edges. This result suggested that low vacuum sputter coating was also limiting resolution.

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