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101.
为了揭示不同工况下喷淋水幕对化工聚集区火灾抑制效果影响规律,建立了FDS数值模型,通过改变单一变量分别模拟水幕开合状态、不同水幕排数、不同水幕喷头高度下火灾发展过程,分析不同工况条件下火源温度变化规律和烟气蔓延规律。结果表明:喷淋水幕开启后,位于储罐上方及水幕帘后的测点温度峰值同比下降19%及36%,可有效抑制高温烟气层蔓延;双排水幕帘相比单排水幕帘在抑制火源温度及烟气蔓延更具成效;初始喷头高度5.8 m时,相比其他高度在降低温度、加速烟气沉降方面更具优势。 相似文献
102.
Ajit Sharma Doan Van Thuan Thanh-Dong Pham Mai Hung Thanh Tung Nguyen Thi Thanh Truc Dai-Viet N. Vo 《化学工程与技术》2020,43(4):752-761
FeO-doped TiO2 nanoparticle photocatalysts were immobilized onto the surface of fibrous activated carbon (ACF) via a sol-gel process. As an adsorbent and photocatalyst, FeO-TiO2 on immobilized ACFs (FeO-TiO2/ACF) greatly improved the photocatalysis rate of hydrogen production as compared with pure TiO2 and ACF-TiO2 under UV irradiation and visible light. The addition of ACFs surface significantly reduced the photogenerated pairs of electrons-hole recombination, thereby promoting the photocatalysis action of doped photo-metal oxides of FeO-TiO2. Co-doping of FeO onto the lattice of the TiO2 approach can improve the absorption activity of visible light through photo-metal oxide of TiO2 and further enhance hydrogen production under visible light. The photocatalytic fabrics (FeO-TiO2/ACF) were effortlessly split out from the experimental solution for re-utilization and exhibited high stability even after five complete regeneration cycles. 相似文献
103.
Understanding of the tensile deformation in HDPE/LDPE blends based on their crystal structure and phase morphology 总被引:1,自引:0,他引:1
The mechanisms of tensile deformation in high density polyethylene/low density polyethylene (HDPE/LDPE) blends were studied by a video-controlled tensile set-up, combined with dynamic mechanical analysis and small angle X-ray scattering. When quenching from the melt to room temperature, HDPE forms well-organized spherulits with high crystallinity and rigid amorphous layers between lamellae, and LDPE forms irregular aggregates with low crystallinity and mobile amorphous layers between lamellae. A separate lamellar stack-like structure is formed in HDPE/LDPE blends during the quenching. The deformation is affected by both the crystal structure and the phase morphology. Because the semi-crystalline polymers are made up of two interpenetrating networks, one is built up by the entangled fluid part and the other by the crystallites, at low deformations the coupling and coarse slips of the crystalline blocks dominate the mechanical properties, which allows the system to maintain a homogeneous strain distribution in the sample. The assumption of a homogeneous strain distribution can now be further proved by the tensile deformation in HDPE/LDPE blends, which shows two-step processes, with HDPE crystallites being broken down first at imposed strain of 0.4 and then LDPE crystallites being broken later, at an imposed strain of 0.6. 相似文献
104.
105.
MicroRNAs are known to play a critical role in skeletal myogenesis and maintenance, and cofilin-2 (CFL2) is necessary for actin cytoskeleton dynamics and myogenic differentiation. Nonetheless, target molecules and the modes of action of miRNAs, especially those responsible for the inhibitory mechanism on the myogenesis by saturated fatty acids (SFA) or obesity, still remain unclear. Here, we reported the role played by miR-429-3p on CFL2 expression, actin filament dynamics, myoblast proliferation, and myogenic differentiation in C2C12 cells. Palmitic acid (PA), the most abundant SFA in diet, inhibited the myogenic differentiation of myoblasts, accompanied by CFL2 reduction and miR-429-3p induction. Interestingly, miR-429-3p suppressed the expression of CFL2 by targeting the 3′UTR of CFL2 mRNA directly. Transfection of miR-429-3p mimic in myoblasts increased F-actin formation and augmented nuclear YAP level, thereby promoting cell cycle progression and myoblast proliferation. Moreover, miR-429-3p mimic drastically suppressed the expressions of myogenic factors, such as MyoD, MyoG, and MyHC, and impaired myogenic differentiation of C2C12 cells. Therefore, this study unveiled the crucial role of miR-429-3p in myogenic differentiation through the suppression of CFL2 and provided implications of SFA-induced miRNA in the regulation of actin dynamics and skeletal myogenesis. 相似文献
106.
Tran Thi Ngoc Lan Rokuro Nishimura Yukihiro Satoh Masayuki Yokoi 《Corrosion Science》2005,47(4):1023-1038
The atmospheric corrosion of marble was evaluated in terms of SO2 concentration as air pollution and climatic factors such as rainfall, relative humidity, temperature and so on under the field exposure. Marble of calcite type (CaCO3) was exposed to outdoor atmospheric environment with and without a rain shelter at four test sites in the southern part of Vietnam for 3-month, 1- and 2-year periods from July 2001 to September 2003. The thickness loss of marble was investigated gravimetrically. X-ray diffraction and X-ray fluorescent methods were applied to study corrosion products on marble. The corrosion product of marble was only gypsum (CaSO4 · 2H2O) and was washed out by rain under the unsheltered exposure condition. It was found that the most substantial factors influencing the corrosion of marble were rainfall, SO2 concentration in the air and relative humidity. Based on the results obtained, we estimated the dose-response functions for the atmospheric corrosion of marble in the southern part of Vietnam. 相似文献
107.
以电熔刚玉为骨料、氢氧化钡为粘结剂、铝粉为添加剂的型芯混合料在吹入CO_2气体后即可实现硬化。本文研究了这种型芯的硬化工艺和常温特性,并采用X射线衍射分析、失重—示差热分析等方法,结合粘结膜的扫描电镜照片,对型芯的受热物理化学变化、高温强度、水溶性等行为进行了实验研究。 相似文献
108.
A new strategy for the selective coating of tin sulfide (SnS) on the surface of moth‐eye patterned (MEP) conducting polymer film is studied by considering the optical properties of the antireflective moth‐eye pattern and flexibility of polymer films. The semiconductor SnS is selectively coated on the surface of MEP microdomes of poly(3,4‐ethylenedioxythiophene) poly(styrene‐sulfonate) (PEDOT:PSS) film. The SnS coated MEP film is obtained by using pore selectively SnS thin layer functionalized polystyrene honeycomb‐patterned porous (HCP) film as a template. Aqueous PEDOT:PSS solution is poured on the SnS functionalized HCP films and detached for the fabrication of SnS coated MEP films. The films show a satisfactory photo‐responsive property under solar stimulated light illumination due to the antireflective MEP structure of PEDOT film and homogenous SnS coating on the surface of the conducting polymer. 相似文献
109.
Adem Sreedhar I. Neelakanta Reddy Qui Thanh Hoai Ta Gitae Namgung Eunbin Cho Jin-Seo Noh 《Ceramics International》2019,45(6):6985-6993
In this paper, novel morphology correlation between silver nanowires (AgNWs) and cobalt (Co)-doped ZnO (Co-ZnO) flake-like thin films (nanowire/flake-like) has been proposed for enhanced photoelectrochemical (PEC) water splitting activity. Here in, high-quality AgNWs/Co-ZnO heterostructures enabled superior visible light water splitting activity compared to the pure ZnO and AgNWs/ZnO. To address the strategic effect of AgNWs coupling and transition metal (Co-2?at%) doping into the ZnO host lattice, we have carried out the X-ray diffraction, field emission scanning microscopy, X-ray photoelectron spectroscopy, UV–Vis transmittance, water contact angle and PEC analyses. In this way, PEC water splitting activity was mainly examined by linear sweep voltammetry (I-V), amperometric I-t and photoconversion efficiency (η) studies. The experimental results provide clear evidence of morphology correlation between AgNWs and Co-ZnO flake-like structures for strong visible light absorption. Specifically, AgNWs/Co-ZnO composites exhibited significant enhancement in the photocurrent density (7.0?×?10?4 A/cm2) than AgNWs/ZnO (3.2?×?10?4 A/cm2) and pure ZnO (1.5?×?10?6 A/cm2). As a result, detailed AgNWs/Co-ZnO geometry has great potential for photoconversion efficiency (0.73%). In a word, the merits of controllable AgNWs/Co-ZnO heterostructure are proposed to improve the visible light harvesting and charge carrier generation for energy conversion devices. 相似文献
110.
The sterol substrate analog 25-thialanosterol and its corresponding sulfonium salt were evaluated for their ability to serve
as antifungal agents and to inhibit sterol methyltransferase (SMT) activity in Candida albicans. Both compounds inhibited cell proliferation, were fungistatic, interrupted the yeastlike-form to germ-tube-form transition,
and resulted in the accumulation of zymosterol and related Δ24-sterols concurrent with a decrease in ergosterol, as was expected for the specific inhibition of SMT activity. Feedback on
sterol synthesis was evidenced by elevated levels of cellular sterols in treated vs. control cultures. However, neither farnesol
nor squalene accumulated in significant amounts in treated cultures, suggesting that carbon flux is channeled from the isoprenoid
pathway to the sterol pathway with minor interruption or redirection until blockage at the C-methylation step. Activity assays using solubilized C. albicans SMT confirmed the inhibitors impair SMT action. Kinetic analysis indicated that 25-thialanosterol inhibited SMT with the
properties of a time-dependent mechanismbased inactivator K
i of 5 =gmM and apparent k
inact of 0.013 min−1, whereas the corresponding sulfonium salt was a reversible-type transition state analog exhibiting a K
i of 20 nM. The results are interpreted to imply changes in ergosterol homeostasis as influenced by SMT activity can control
growth and the morphological transition in C. albicans, possibly affecting disease development. 相似文献