The purple hilly area of Sichuan basin,located in the upper reach of the Yangtze River,is one of the most severe soil erosion in China,where three quarters of its land surface are seriously affected by soil erosion and the average erosion rate can reach 3200-7900 t/km2/a.This area is the most important agricultural section of Sichuan province and Chongqing municipal.Extensively cultivation,dense population and heavy soil and water losses is not only a severe environmental problem but also an obstacle to agricultural sustainable development.To improve soil erosion environment,reduce soil and water losses using hedgerow system is one of the most important issues in over-farming land and ecological fragile area.Eulaliopsis binata(Retz.)G.E.Hubb has abundant roots and high yield,and the time when Eulaliopsis binata(Retz.)G.E.Hubb growths fast is as the same as the time of the rainy season in this area,so Eulaliopsis binata(Retz.)G.E.hubb can mulch soil surface well and reduce soil and water losses significantly.The total length of roots in a 120 cm wide and 90 cm deep soil profile is 98714.8cm,which can enlace soil about 235 circles.The average diameter of Eulaliopsis binata(Retz.)G.E.Hubb root is from 0.20 mm to 0.50 mm,and 95% roots,diameter is thinner than 0.40 mm.The total surface areas of roots is 10139.68 cm2,and the surface areas of roots is about 2 to 3 times to soil surface areas in the surface layer.Enlacing and concretion to soil profile of Eulaliopsis binata(Retz.)G.E.Hubb root and the gigantic adsorption to soil grains of root surface are the mechanism why Eulaliopsis binata(Retz.)G.E.Hubb can reduce soil and water loss significantly.The monitoring result from 2003 to 2004 indicates that,when the gradient is 12 degrees,the runoff rate of planting Eulaliopsis binata(Retz.)G.E.Hubb completely after changing slope land to ladder(PECC,so as the follows) is only 49.90 m3/hm2·yr.and the soil loss rate is 155.78 kg/hm2·yr,however,the runoff rate of farming and being not change slope land to ladder(FNC,so as the follows) is 314.29 m3/hm2·yr that is 6.30 times to PECC,and the soil loss rate is 3322.50 that is 21.33 times to PECC;When the gradient is 24 degrees,the runoff rate of planting eulaliopsis binata(Retz.)G.E.Hubb in the ridge and border slope land after changing slope land to ladder(PERBC,so as the follows) is 248.04 m3/hm2·yr and the soil loss rate is 612.00 kg/hm2·yr,the runoff rate of PECC is only 42.44 m3/hm2·yr and the soil loss rate is 153.75 kg/hm2·yr,however,the runoff rate of FNC reaches to 785.73 m3/hm2·yr that is 3.17 times to PERBC and 18.52 times to PECC,and the soil loss rate reaches to 37503 m3/hm2·yr that is 61.33 times to PERBC and 244.12 times to PECC.
The past decade has witnessed a great deal of optical systems designed for exceeding the Abbe's diffraction limit. Unfortunately, a deep subwavelength spot is obtained at the price of extremely short focal length, which is indeed a near-field diffraction limit that could rarely go beyond in the nanofocusing device. One method to mitigate such a problem is to set up a rapid oscillatory electromagnetic field that converges at the prescribed focus. However, abrupt modulation of phase and amplitude within a small fraction of a wavelength seems to be the main obstacle in the visible regime, aggravated by loss and plasmonic features that come into function. In this paper, we propose a periodically repeated ring-disk complementary structure to break the near-field diffraction limit via plasmonic Fano resonance, originating from the interference between the complex hybrid plasmon resonance and the continuum of propagating waves through the silver film. This plasmonic Fano resonance introduces a π phase jump in the adjacent channels and amplitude modulation to achieve radiationless electromagnetic interference. As a result, deep subwavelength spots as small as 0.0045λ(2) at 36 nm above the silver film have been numerically demonstrated. This plate holds promise for nanolithography, subdiffraction imaging and microscopy.
As a fundamental property of waves, diffraction plays an important role in many physical problems. However, diffraction makes waves in free space unable to be focused into an arbitrarily small space, setting a fundamental limit (the so-called diffraction limit) to applications such as imaging, lithography, optical recording and waveguiding, etc. Although the diffraction effect can be suppressed by increasing the refractive index of the surrounding medium in which the electromagnetic and optical waves propagate, such a technology is restricted by the fact that natural medium has a limited refractive index. In the past decades, surface plasmon polaritons (SPPs) have received special attention, owing to its ability to break through the diffraction limit by shrinking the effective wavelength in the form of collective excitation of free electrons. By combining the short wavelength property of SPPs and subwavelength structure in the two-dimensional space, many exotic optical effects, such as extraordinary light transmission and optical spin Hall effect have been discovered and utilized to realize functionalities that control the electromagnetic characteristics (amplitudes, phases, and polarizations etc.) on demand. Based on SPPs and artificial subwavelength structures, a new discipline called subwavelength electromagnetics emerged in recent years, thus opening a door for the next-generation integrated and miniaturized electromagnetic and optical devices and systems. In this paper, we review the theories and methods used to break through the diffraction limit by briefly introducing the history from the viewpoint of electromagnetic optics. It is shown that by constructing plasmonic metamaterials and metasurfaces on a subwavelength scale, one can realize the localized phase modulation and broadband dispersion engineering, which could surpass many limits of traditional theory and lay the basis of high-performance electromagnetic and optical functional devices. For instance, by constructing gradient phase on the metasurfaces, the traditional laws of reflection and refraction can be rewritten, while the electromagnetic and geometric shapes could be decoupled, both of which are essential for realizing the planar and conformal lenses and other functional devices. At the end of this paper, we discuss the future development trends of subwavelength electromagnetics. Based on the fact that different concepts, such as plasmonics, metamaterials and photonic crystals, are closely related to each other on a subwavelength scale, we think, the future advancements and even revolutions in subwavelength electromagnetics may rise from the in-depth intersection of physical, chemical and even biological areas. Additionally, we envision that the material genome initiative can be borrowed to promote the information exchange between different engineering and scientific teams and to enable the fast designing and implementing of subwavelength structured materials.
A super-resolution imaging method for the deep sub-wavelength structure has been proposed, which is achieved by controlling the propagating direction of the evanescent components of the incident field through a one-dimensional metamaterial structure (ODMS) with an anisotropic dielectric permittivity. We provide the mechanism of this kind of super-resolution imaging method in detail and discuss some factors influencing image quality. A two-dimensional finite element method (FEM) has been used to verify the imaging mechanism. Furthermore, the same sub-diffraction limited image could be obtained at different incident wavelengths at the far side of the imaging structure with different working distances.
Abstract As a probiotic, Weizmannia coagulans ( W. coagulans ) is often used in food and medicine to regulate intestinal flora and resist specific inflammation. In this study, the anti-acne efficacy and mechanism of YTCY extracellular proteins (YTCY-EPs) from a strain of W. coagulans are analyzed. The main components of YTCY-EPs, extracted and separated from the fermentation broth, are peptides ranging from 1.51–11.44 kDa, accounting for about 80%. Among the peptides identified by LC/MS-MS, YTCY A-F possess the properties of antimicrobial peptides, while YTCY 1–4 possess antioxidative properties. These peptides have a strong effect on Cutibacterium acnes ( C. acnes ) and significantly inhibit Staphylococcus aureus . The adhesion of YTCY-EPs has a 50% inhibition rate. It is found that YTCY-EPs possess strong antioxidant and anti-inflammatory properties, and can reduce the downstream TLR2/NF-κB and MAPKs/AP-1 pathways by regulating the nuclear translocation of NF-κB and AP-1 in vitro. The transcriptional expression of inflammatory cytokines, inflammatory chemokines, and matrix metalloproteinase genes is also regulated, thereby slowing the recruitment of inflammatory cells and the development of inflammation, and increasing keratinocyte mobility. YTCY-EPs can also effectively solve such problems as erythema, papules, cysts, skin lesions, hyperkeratinization, and desquamation caused by C. acnes in rabbit ears. Additionally, the treatment effectively improves the condition of wounds and inflammation. The results of this study prove that YTCY-EPs can be used as a potential anti-acne raw material in cosmetics.
Spectral reflectometry is widely used to measure the crucial parameters such as thickness and refractive index of film, surface morphology and grating constant in a convenient way. In this work, we focus on the measurement of air gap between two parallel plates. The transfer matrix method (TMM) and rigorous coupled-wave analysis (RCWA) are independently used to build the theoretical model of the air gap with micro and nano scale between two parallel plates, and then we compare the results. Through the simulation of reflectance spectrum based on optimized TMM. The influence of interfacial roughness of multilayer structure is analyzed. Then we introduce a merit function which includes air gap and interfacial roughness and then optimize them using genetic algorithm to solve the measured air gap value. The absolute measurement of air gap thickness and subsequent displacement measurement result indicate that our method has the advantage of high precision, resolution and stability.
Abstract We proposed a dual-channel narrow band filter consisting of top and bottom-distributed Bragg reflectors (DBRs) and a dielectric interlayer inserted with a metasurface. Through the design of the metasurface, the two channels of the filter are guaranteed to exhibit high-quality factors with transmittance beyond 90% and full width at half maximum (FWHM) less than 10 nm. We demonstrate that the central wavelengths of each dual-channel filter can be controlled with a total of 50 nm shifts by only changing the width of the metasurface. Compared with the traditional dual-channel filter, our design is easier to fabricate and more convenient to tune the central wavelength, which is promising for ultracompact optical devices.
UVB radiation is known to induce photodamage to the skin, disrupt the skin barrier, elicit cutaneous inflammation, and accelerate the aging process. Agaricus blazei Murill (ABM) is an edible medicinal and nutritional fungus. One of its constituents, Agaricus blazei Murill polysaccharide (ABP), has been reported to exhibit antioxidant, anti-inflammatory, anti-tumor, and immunomodulatory effects, which suggests potential effects that protect against photodamage. In this study, a UVB-induced photodamage HaCaT model was established to investigate the potential reparative effects of ABP and its two constituents (A1 and A2). Firstly, two purified polysaccharides, A1 and A2, were obtained by DEAE-52 cellulose column chromatography, and their physical properties and chemical structures were studied. A1 and A2 exhibited a network-like microstructure, with molecular weights of 1.5 × 104 Da and 6.5 × 104 Da, respectively. The effects of A1 and A2 on cell proliferation, the mitochondrial membrane potential, and inflammatory factors were also explored. The results show that A1 and A2 significantly promoted cell proliferation, enhanced the mitochondrial membrane potential, suppressed the expression of inflammatory factors interleukin-1β (IL-1β), interleukin-8 (IL-8), interleukin-6 (IL-6), and tumor necrosis factor α (TNF-α), and increased the relative content of filaggrin (FLG) and aquaporin-3 (AQP3). The down-regulated JAK-STAT signaling pathway was found to play a role in the response to photodamage. These findings underscore the potential of ABP to ameliorate UVB-induced skin damage.
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