59 research outputs found
Quality Mapping of Offset Lithographic Printed Antenna Substrates and Electrodes by Millimeter-Wave Imaging
Offset lithographic printed flexible antenna substrate boards and electrodes have attracted much attention recently due to the boost of flexible electronics. Unmanned quality inspection of these printed substrate boards and electrodes demands high-speed, large-scale and nondestructive methods, which is highly desired for manufacturing industries. The work here demonstrates two kinds of millimeter (mm)-wave imaging technologies for the quality (surface uniformity and functionality parameters) inspection of printed silver substrates and electrodes on paper and thin polyethylene film, respectively. One technology is a mm-wave line scanner system and the other is a terahertz-time domain spectroscopy-based charge-coupled device (CCD) imaging system. The former shows the ability of detecting transmitted mm-wave amplitude signals only; its detection is fast in a second time scale and the system shows great potential for the inspection of large-area printed surface uniformity. The latter technology achieves high spatial resolution images of up to hundreds of micrometers at the cost of increased inspection time, in a time scale of tens of seconds. With the exception of absorption rate information, the latter technology offers additional phase information, which can be used to work out 2D permittivity distribution. Moreover, its uniformity is vital for the antenna performance. Additionally, the results demonstrate that compression rolling treatment significantly improves the uniformity of printed silver surfaces and enhances the substrate’s permittivity values
Anthocyanins in Red Wine: Origin, Coloration and Reactions
Anthocyanins are important compounds contributing to the color of red wine, which play a crucial role in the quality of red wine. Anthocyanins are biosynthesized via the phenylpropanoid-flavonoid pathway during the growth of wine grapes. In red wine, there is an equilibrium among anthocyanin species, and the color of red wine is closely related to the diverse structure and morphology of anthocyanins. However, anthocyanins are not stable and could be degraded through a series of reactions including oxidation. From a winemaking perspective, anthocyanins are extracted from grape skin into the wine by maceration, and anthocyanin concentrations and color of red wine vary with changes in fermentation conditions and the composition of red wine during fermentation. During wine aging, anthocyanins can react with other components to form new anthocyanin derivatives. The evolution of anthocyanins and these derivatives can lead to constant changes in red wine color during wine fermentation, aging and storage. So far, few systematic reviews have been carried out on the origin, coloration mechanism and reactions of anthocyanins in red wine, and their evolution during the production of red wine. Therefore, this paper aims to fill this lacuna in order to provide a theoretical basis for further investigation of anthocyanins in red wine
Atmospheric new particle formation from sulfuric acid and amines in a Chinese megacity
Atmospheric new particle formation (NPF) is an important global phenomenon that is nevertheless sensitive to ambient conditions. According to both observation and theoretical arguments, NPF usually requires a relatively high sulfuric acid (H2SO4) concentration to promote the formation of new particles and a low preexisting aerosol loading to minimize the sink of new particles. We investigated NPF in Shanghai and were able to observe both precursor vapors (H2SO4) and initial clusters at a molecular level in a megacity. High NPF rates were observed to coincide with several familiar markers suggestive of H2SO4-dimethylamine (DMA)water (H2O) nucleation, including sulfuric acid dimers and H2SO4-DMA clusters. In a cluster kinetics simulation, the observed concentration of sulfuric acid was high enough to explain the particle growth to similar to 3 nanometers under the very high condensation sink, whereas the subsequent higher growth rate beyond this size is believed to result fromthe added contribution of condensing organic species. These findings will help in understanding urban NPF and its air quality and climate effects, as well as in formulating policies to mitigate secondary particle formation in China.Peer reviewe
Research on the influence of design parameters on mechanical performance of net arch bridge
In order to study the suspender layout parameters and design parameters of the tied arch bridge with mesh suspenders under the action of vehicle load, the structure stress is more reasonable and meets the higher economy and aesthetics. Taking a 96m span reticulated tied arch bridge as the engineering background, the finite element model is established by using Midas/Civil 2019 program. The variation law of internal force and Suspender Force of the structure is calculated and analysed under the change of rise span ratio and suspender number parameters, and the relatively optimal value range of corresponding parameters is given. The results show that the rise span ratio should be 0.2-0.24; The number of Suspenders for one side arch rib should be 34-38; The relatively optimal range of the above parameters is discussed for reference
Network Patterns of Zhongyuan Urban Agglomeration in China Based on Baidu Migration Data
As a new product of the Internet and big data era, migration data are of great significance for the revealing of the complex dynamic network patterns of urban agglomerations and for studying the relations between cities by using the “space of flows” model. Based on Baidu migration data of one week in 2021, this paper constructs a 30 × 30 rational data matrix for cities in Zhongyuan Urban Agglomeration and depicts the network pattern from static and dynamic perspectives by using social network analysis and dynamic network visualization. The results show that the network of Zhongyuan Urban Agglomeration is characterized by a circular structure with Zhengzhou as the center, a city belt around Zhengzhou as the connection, subcentral cities as the support and peripheral cities as the extension. Zhengzhou is the core city of the entire network, related to which the central and backbone networks divided in this paper account for nearly 40% of the total migration. Shangqiu, Luoyang, Zhoukou and Handan also play an important role in the structure of the migration network as subcentral cities. For a single city, the migration scale generally peaks on weekends and reaches its minimum during Tuesday to Thursday. Regarding the relations between cities, the migration variation can be divided into four types: peaking on Monday, peaking on weekends, bimodal and stable, and there are obvious phenomena of weekly commuting. In general, the links between cities outside Henan Province and other cities in the urban agglomeration are relatively weak, and the constraints of administrative regionalization on intercity migration are presumed to still exist. According to the results, the location advantage for multi-layer development and construction of Zhongyuan Urban Agglomeration should be made use of. In addition, the status as the core city and the radiation range should be strengthened, and the connections between the peripheral cities and the other cities should be improved, so as to promote the integrated and efficient development of the whole urban agglomeration
Tunable glycyrrhizic acid supramolecular hydrogels via metal ion complexation
Glycyrrhizic acid (GA) is a natural edible chiral triterpene saponin that can undergo hierarchical self-assembly in water to form supramolecular hydrogels. Customizing the properties of GA supramolecular hydrogels is crucial for their wide food and biomedical applications, and the incorporation of specific metal ions can be an attractive way for this purpose. Herein, this study investigates the effects of metal ions with different valence states and concentrations on the linear and nonlinear rheological properties and network structures of GA supramolecular hydrogels. Monovalent metal ions (Na+ and K+), exhibiting weak binding affinity to GA, rely on the electrostatic screening effects at high concentrations (e.g., 50 mM) to enhance the GA interfibrillar interactions and thus the formation of a more compact and ordered gel network, which displays a pronounced nonlinear rheological behavior with a typical transition from elastic to viscous response. Polyvalent metal ions (Ca2+, Zn2+, and Al3+), owing to their greater charge density and stronger binding with GA, significantly enhance the network strength of the hydrogels at low concentrations (e.g., 5 mM). Nonetheless, at high ion concentrations (e.g., 50 mM), the GA-Mn+ forms discrete aggregated network structures due to excessively strong cation-carboxylate complexation, leading to the irregular nonlinear rheological responses and the lower resistance to large deformations. These findings can deepen our understanding of the highly tunable rheological behaviors and network structures of GA hydrogels, which demonstrates a new possibility for the design and development of responsive natural supramolecular hydrogels with controlled properties through the strategy of metal ion complexation
Current-Collapse-Free and Fast Reverse Recovery Performance in Vertical GaN-on-GaN Schottky Barrier Diode
Study on Mechanism and Regularity of Rock Breaking by Pulsed Water Injection with Particles
In recent years, the drilling technology applied to deep and ultra-deep formations has developed rapidly, but the drilling speed for hard formations is low. Therefore, it is very important to study the drilling methods for deep and hard strata. Particle pulsed jet drilling is a new drilling method based on particle jet impact drilling technology and high-pressure pulsed water jet impact drilling technology. In this paper, the mathematical models of the shear layer amplification coefficient and wave velocity are established based on a similar network theory, and the motion equations of a single particle and particle swarm are established according to the motion of particles in a pulsed jet environment. Then, based on the self-designed particle jet impact rock-breaking experimental platform, the numerical simulation results are compared, analyzed, and verified. The results show that the rock-breaking efficiency increases with the increase in the average velocity of the particle pulsed jet. When the average speed exceeds 160 m/s, the rock-breaking efficiency increases significantly. With the increase in the particle concentration, the rock-breaking efficiency of the particle pulsed jet also increases, but there is an optimal value. When the concentration is too high, the impact of particles on the rock is affected by the collision between particles, and the wear of the drill intensifies. This research is helpful for understanding deep-well drilling-speed-increasing technology and promotes the development and engineering applications of particle jet impact drilling theory
Anthropogenic-Biogenic Interactions at Night: Enhanced Formation of Secondary Aerosols and Particulate Nitrogen- and Sulfur-Containing Organics from beta-Pinene Oxidation
International audienceMixing of anthropogenic gaseous pollutants and biogenic volatile organic compounds impacts the formation of secondary aerosols, but still in an unclear manner. The present study explores secondary aerosol formation via the interactions between β-pinene, O3, NO2, SO2, and NH3 under dark conditions. Results showed that aerosol yield can be largely enhanced by more than 330% by NO2 or SO2 but slightly enhanced by NH3 by 39% when the ratio of inorganic gases to β-pinene ranged from 0 to 1.3. Joint effects of NO2 and SO2 and SO2 and NH3 existed as aerosol yields increased with NO2 but decreased with NH3 when SO2 was kept constant. Infrared spectra showed nitrogen-containing aerosol components derived from NO2 and NH3 and sulfur-containing species derived from SO2. Several particulate organic nitrates (MW 215, 229, 231, 245), organosulfates (MW 250, 264, 280, 282, 284), and nitrooxy organosulfates (MW 295, 311, 325, 327, and 343) were identified using high-resolution orbitrap mass spectrometry in NO2 and SO2 experiments, and their formation mechanism is discussed. Most of these nitrogen- and sulfur-containing species have been reported in ambient particles. Our results suggest that the complex interactions among β-pinene, O3, NO2, SO2, and NH3 during the night might serve as a potential pathway for the formation of particulate nitrogen- and sulfur-containing organics, especially in polluted regions with both anthropogenic and biogenic influences
CircSMARCA5 functions as a potential biomarker for clinicopathology and therapy in solid tumors: A systematic review and meta‐analysis
Abstract Circular RNAs (circRNAs) have been implicated in cancer proliferation, migration, and invasion. Among various circRNAs, circSMARAC5 attracted our great attention. The research aimed at broadening the knowledge on circSMARCA5 and exploring its function in clinicopathology and therapy in solid tumors. The incorporated research was explored via Web of Science, PubMed, Embase, and Cochrane Library, consisting of 1048 patients. This study was calculated using STATA 12.0 and Review Manager 5.3 software. Clinicopathological characteristics and therapeutic targets were analyzed using pooled odd ratios (ORs) with 95% confidence intervals (CIs). And the ceRNA network of circSMARCA5 was constructed via Cytoscape 3.9.0. Eventually, there were eight studies included in conducting clinicopathological characteristics and four literature used in exploring therapeutic targets. Patients with low expression of circSMARCA5 were closely associated with gender (OR = 1.367, 95% CI = 1.003–1.862, p = .048) and pathological differentiation (OR = 1.627, 95% CI = 1.130–2.343, p = .009). Among these modulating axes, the most commonly microRNA was miR‐432. In the near future, circSMARCA5 may be a promising diagnostic biomarker and a new therapeutic target
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