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The advent of lidar has revolutionized the way we observe and measure vegetation structure from the ground and from above and represents a major advance toward the quantification of 3D ecological observations. Developments in lidar hardware systems and data processing algorithms have greatly improved the accessibility and ease of use of lidar observations in ecological studies. A wide range of studies has been devoted to accurately measuring and modeling vegetation structural and functional attributes from lidar data across a range of spatial scales (from individual organs to global scales) and ecosystem types (e.g., forest, agricultural, grassland, and urban ecosystems).

Loess covers approximately 6.6% of China and forms thick extensive deposits in the northern and northwestern parts of the country. Natural erosional processes and human modification of thick loess deposits have produced abundant, potentially unstable steep slopes in this region. Slope deformation monitoring aimed at evaluating the mechanical behavior of a loess slope has shown a cyclic pattern of contraction and expansion. Such cyclic strain change on the slope materials can damage the loess and contribute to slope instability. The site showing this behavior is a 70-m high loess slope near Yan’an city in Shanxi Province, northwest China. A Ground-Based Synthetic Aperture Radar (GB-SAR) sensor and a displacement meter were used to monitor this cyclic deformation of the slope over a one-year period from September 2018 to August 2019. It is postulated that this cyclic behavior corresponds to thermal and moisture fluctuations, following energy conservation laws. To investigate the validity of this mechanism, physical models of soil temperature and moisture measured by hygrothermographs were used to simulate the observed cyclic deformations. We found good correlations between the models based on the proposed mechanism and the exhibited daily and annual cyclic contraction and expansion. The slope absorbed energy from the time of maximum contraction to the time of maximum expansion, and released energy from the time of maximum expansion to the time of maximum contraction. Recoverable cyclic deformations suggest stresses in the loess are within the elastic range, and non-recoverable cyclic deformations suggest damage of the loess material (breakage of bonds between soil grains), which could lead to instability. Based on these observations and the models, we developed a quantitative relationship between weather cycles and thermal deformation of the slope. Given the current climate change projections of temperature increases of up to 3.5 °C by 2100, the model estimates the loess slope to expand about 0.35 mm in average, which would be in addition to the current cyclic “breathing” behavior experienced by the slope.

The accuracy of ground-based synthetic aperture radar (GB-SAR) interferometry is highly affected by the atmospheric phase screen (APS). A multiple-regression model (MRM) for APS estimation with two parameters (line of sight (LOS) distance and the height difference between the targets and the GB-SAR sensor) was proposed. However, this MRM is inapplicable if the LOS deformation of the observed objects has similar behavior to that of the APS. For example, both the APS and the LOS deformation of observed objects can have an increasing trend along the LOS direction. In this article, an improved MRM (IMRM) that considers the spatial pattern of the LOS deformation of observed objects was proposed. The spatial pattern can be expressed by the location information of the observed objects. The applicability of this improved model was demonstrated in a deformation-measured campaign carried out on a high loess cut slope using 285 images obtained by the GB-SAR sensor during a three-day measurement. The similarity and dissimilarity between the APS and the behavior of the LOS deformation of the slope were illustrated and used to estimate the APS. The accuracy of this IMRM was verified using deformation data measured by a displacement meter. This IMRM will be helpful in APS estimation and compensation in GB-SAR interferometry in case studies where the APS and the LOS deformation of observed objects have similar behavior.

Most of TiO2 particles can be used as a photocatalyst for the selective oxidation of cyclohexane under ultraviolet light illumination. In this paper, Ti3+ self-doped TiO2 submicron-sized particles (i.e., Ti3+/TiO2 SMP) were used as a catalyst for visible-light driven photocatalytic cyclohexane oxidation. The microstructure and properties of the Ti3+/TiO2 SMP were characterized by X-ray diffraction (XRD), UV–visible diffuse reflection (UV–Vis DRS), scanning electron microscopy (SEM), electron paramagnetic resonance (EPR), solid-state photoluminescence spectroscopy (PLS) and X-ray photoelectron spectroscopy (XPS). The Ti3+/TiO2 SMP exhibits good visible-light driven photocatalytic performances for cyclohexane oxidation with cyclohexanone as a dominate product. Effects of solvent, reaction temperature, reaction time and oxygen pressure on the formation of cyclohexanone were investigated. The cyclohexane oxidation over the Ti3+/TiO2 SMP photocatalyst using carbon tetrachloride as a solvent under the optimal conditions presents a greater selectivity to cyclohexane (i.e., 95.1%). Based on the controlled experimental results with different radical scavengers, the hole (h+) is critical for the activation of cyclohexane. Keywords: Ti3+ self-doped TiO2, Cyclohexane oxidation, Photocatalysis, Selectivity

Minimizing the power consumption of the belt conveyor is the common wish of all enterprises and even countries. Among all the resistances generated by the belt conveyor during the operation, the indentation rolling resistance accounts for the largest proportion and the power consumed is the largest. Therefore, accurately predicting and reducing the rolling resistance of indentation is the focus of current research. Firstly, based on the three-element Maxwell solid model, the dynamic loading experiments of cylindrical rubber made of conveyor belt cover material were carried out at different temperatures. The identification models of elastic moduli E2 and E3 and viscosity coefficient η2 in the three-element Maxwell model were obtained, and then the fitting functions of the three parameters were gotten, which can intuitively reflect the influence of temperature. Secondly, the mathematical model of the indentation rolling resistance was derived. The mathematical model is characterized by the direct parameters such as belt speed v, thickness of backing material h, the idler radius R, and the rubber viscoelastic parameters E2, E3, and η2 and the indirect parameters such as normal force P and temperature T. Afterwards, the effects of belt speed, normal force, temperature, idler radius, and thickness of underlay on the indentation rolling resistance were studied under different working conditions. After that, experimental testing and analysis were fulfilled using test equipment and compared with theoretical analysis results. The results prove that the theoretical results are basically consistent with the experimental results, in line with the actual engineering rules. Finally, the application of the results in practical engineering was analyzed superficially.

In the last few decades, the recovery of and exploration for shale gas has increased. This has led to increased interest in the mechanical characterization of shale formations as relates to enhancing the conductivity of such formations. Characterization and modeling of these materials typically assumes transverse isotropy associated with the direction of bedding, despite some studies showing anisotropy in these materials. In this work, we evaluate the validity of transverse isotropy for the Longmaxi Shale Formation, which has been targeted for shale gas exploration in China. This evaluation is done through analysis of the macro- and microstructure distribution, confined triaxial tests, and compression and shear wave velocity measurements. These tests were performed parallel and perpendicular to the bedding and in the directions interpreted as the tectonic principal stresses. The effect of tectonic stress on shale anisotropy is also discussed. We found that the assumption of transverse isotropy for the mechanical behavior of the Longmaxi Shale might not be adequate under low confinement stresses. The trends in the measured behavior suggest that transverse isotropy might provide adequate estimations as confinement increases. The data also suggest that tectonic stresses affected the Longmaxi Shale rock mass characteristics at the study site in terms of macro- and microstructure, as well as mechanical properties. The results also indicate that isotropic rocks may show anisotropy in subsurface engineering. Directing more attention to the possible mechanical differences in the field may provide implications for engineering safety.

In this study, piezoelectric energy harvesting using depressions in roads generated by traffic loads was investigated theoretically and experimentally. The elastic double-layer plate model was used...

The river centerline is a basic hydrological characteristic. Most prior studies have used remote sensing data to extract the river centerline from the open water region in a pure water pixel region...

Semiconductor-metal-organic framework (MOF) hybrid photocatalysts have aroused increasing interest because of their enhanced photocatalytic activity. In this work, NH2-MIL-125(Ti)/TiO2 composites with different molar ratios were successfully prepared by a facile one-pot solvothermal method and used for visible-light driven photocatalytic selective oxidation of cyclohexane. The as-prepared NH2-MIL-125(Ti)/TiO2 composites presented better catalytic performances compared with NH2-MIL-125(Ti). This is due to the energy bands coupling and intimate interfacial contact between NH2-MIL-125(Ti) and TiO2, which can improve the photon-generated carrier transfer and minimize the recombination of electron-hole pairs. For the optimum composite photocatalyst, the activity was three times higher than that of NH2-MIL-125(Ti) in visible-light driven photocatalytic cyclohexane oxidation using molecular oxygen as oxidant at room temperature and under ambient pressure. Additionally, the effects of illumination time on the photocatalytic performance and reusability of the optimum composite photocatalyst were investigated in detail. Finally, a possible reaction mechanism has been proposed based on controlling experiments using different radical scavenger techniques, which prove that the photogenerated holes are significantly involved in the oxidation process.

In this study, a C-doped Cr2O3/NaY composite membrane supported on stainless steel mesh with layer-by-layer structure was successfully synthesized and used in the partial oxidation of cyclohexane. In the composite membrane, NaY zeolite membrane acted as absorbent and the C-doped Cr2O3 behaved as photocatalyst, which was successfully prepared using a chromium-containing MOF as precursor. The supported composite membrane was characterized by a series of analysis techniques. Comparing with the stainless steel mesh-supported C-doped Cr2O3 membrane, the supported C-doped Cr2O3/NaY composite membrane exhibited superior visible-light-driven photocatalytic performance for cyclohexane oxidation. This is due to its layer-by-layer structure and NaY membrane with high surface areas and polarity which can preferentially adsorb KA oil products, avoiding their overoxidation.

Fe3O4 nanoclusters anchored on porous reduced graphene oxide (Fe3O4@rGO) have been synthesized by a one-step hydrothermal route, and then ball milled with LiBH4 to prepare a hydrogen storage composite with a low onset dehydrogenation temperature, and improved dehydrogenation kinetics and rehydrogenation reversibility. The LiBH4–20 wt% Fe3O4@rGO composite begins to release hydrogen at 74 °C, which is 250 °C lower than for ball-milled pure LiBH4. Moreover, the composite can release 3.36 wt% hydrogen at 400 °C within 1000 s, which is 2.52 times as high as that of pure LiBH4. Importantly, it can uptake 5.74 wt% hydrogen at 400 °C under 5 MPa H2, and its hydrogen absorption capacity still reaches 3.73 wt% after 5 de/rehydrogenation cycles. The activation energy (Ea) of the hydrogen desorption of the composite is decreased by 79.78 kJ mol−1 when 20 wt% Fe3O4@rGO is introduced into LiBH4 as a destabilizer and catalyst precursor, showing enhanced thermodynamic properties. It could be claimed that not only the destabilization of Fe3O4, but also the active Li3BO3 species formed in situ, as well as the wrapping effect of the graphene, synergistically improve the hydrogen storage properties of LiBH4. This work provides insight into developing non-noble metals supported on functional graphene as additives to improve the hydrogen storage properties of LiBH4.

Piezoelectric energy harvesting in roads generated by traffic loads was theoretically and experimentally investigated, and an indoor model of a layered road for piezoelectric transformation was dev...

The wettability of Gemini surfactants with ester bond at Polytetrafluoroethylene (PTFE) and Paraffin surfaces have been investigated and the different physicochemical parameters such as surface tension (γLV), contact angle (θ), spreading coefficient (S), adhesional tension (γLVcosθ) and work of adhesion (WA) have been estimated. The obtained results indicate that the surface tension and contact angle decrease with the increase of surfactant concentration, and they tend to be stable when the concentration is more than CMC. The wettability of m-6-m on PTFE and Paraffin surfaces is better than that of m-2-m. A linear relationship exists between the adhesional and surface tension during a range of certain concentrations, the absorption amount of the surfactant at the liquid-air interface is larger than that at the PTFE-liquid interface. Meanwhile, this linear relationship is only applicable for 12-2-12 and 14-2-14 in the case of Paraffin. The adhesional tension increases with the increase of concentration, and it keeps constant when the saturated adsorption film has been formed at both liquid-air and solid-liquid interfaces. The better wettability of Gemini surfactants with ester bond on PTFE and Paraffin has the better adhesion.

The surface tension of five biquaternary ammonium salt Gemini surfactants with hydroxyl and the corresponding contact angles (θ) on Polytetrafluoroethylene (PTFE) and Paraffin are measured. The interfacial properties of surfactant solution in liquid-air-solid are investigated and changes in spreading coefficient (S), adhesive tension ( γ L V cos θ ) and the work of adhesion (WA) are discussed. The obtained results indicate that the surface tension decreases with the increase of surfactant concentration, and it tends to be stable when the concentration is more than CMC. The contact angle has the similar trend with surface tension. A linear relationship exists between the adhesional and surface tension in a range of certain concentrations, the slope is less than 1. It means that the adsorption amount of the surfactant solution at the liquid-air interface is larger than that at the PTFE-water interfaces. However, there is no linear relationship between the adhesional and surface tension for Paraffin-surfactant solution systems. The adhesional tension increases with the increase of concentration, and it keeps constant when the saturated adsorption film has been formed at both liquid-air and solid-liquid interfaces. The wettability of biquaternary ammonium salt Gemini surfactants with hydroxyl solutions on PTFE is poorer than that of Paraffin. The wettability of C10-OH solution on PTFE surface is best, and C14-OH solution has the best wetting effect on Paraffin.

The indentation rolling resistance of a belt conveyor with stable operation accounts for more than 60% of the total resistance. Thus, the effective reduction of indentation rolling resistance and its energy consumption have attracted considerable attention of engineers. Indentation rolling resistance is due to the viscoelasticity of conveyor belt. A three-parameter Kelvin solid model is used to characterize the viscoelasticity of materials. The parameters of the Kelvin solid model include two elastic moduli E 0 and E 1 and one viscous coefficient η 1 , and their fitting functions are obtained by completing a dynamic tensile test. A mathematical model of indentation rolling resistance is derived, on the basis of theoretical analysis, which is directly expressed by belt speed, idler radius, and cover layer thickness under the conveyor belt, and is indirectly expressed by normal load and temperature. The influence of five factors on indentation rolling resistance and the influence of combined conditions of any two factors on indentation rolling resistance are separately analyzed on the basis of the mathematical model. The theory in this study is accurate based on the consistency between the theoretical calculation and experimental results. In practical engineering, the operating conditions of belt conveyors are any combination of all factors. Various factors should be considered to reduce indentation rolling resistance.

The dynamic characteristics of a road on a subgrade filled with different materials under traffic loads are studied. An elastic double-layer plate model on a viscoelastic subgrade is established to describe the dynamic behavior of the road. The load diffusion path in the form of a cone in the stabilised layer under single vibration source and three vibration sources is considered, and the equations for the displacement and effective soil pressure of the elastic double-layer plate on the viscoelastic subgrade are derived. The relevant empirical formulae are then properly revised to reflect the dynamic behavior of the road. The dynamic response of the road is analysed by adjusting factors such as the excitation load, excitation frequency, and subgrade filling materials. The results show that gravel as a subgrade filling material has a better vibration reduction effect than sand bag. In addition, the test data not only have good consistency with the theoretical formulae but also validate the reliability of the empirical formulae.

Five quaternary ammonium salt Gemini surfactants 2-hydroxyl-propanediyl-α,ω-bis (alkyldodecyl ammonium chloride) (n-3(OH)-n, where n represents hydrocarbon chain lengths of 10, 12, 14, 16, and 18) were synthesized and characterized by 1H NMR. Surface activity, adsorption and aggregation behaviors of these cationic Gemini surfactants were investigated by methods of measuring equilibrium surface tension, dynamic surface tension and transmission electron microscope (TEM). The critical micelle concentration (CMC) decreased with an increase in hydrophobic chain length, while the surface tension at the CMC (γCMC) showed little change. With TEM measurements, formations of vesicles in n-3(OH)-n (n = 16, 18) solutions occurred and vesicles dimensions depended on their n values. Moreover, data obtained were analyzed in accordance with Word-Tordai equation, and the diffusion coefficients for ionic liquid molecular adsorption in the initial stage and final stage under different concentration were figured out respectively. The results indicated that the adsorption process was controlled by a diffusion step at low surfactant concentration while by a mixed kinetic-diffusion adsorption mechanism at high surfactant concentration.

A series of Cr-supported mesoporous silica (Cr-PFMS) photocatalysts were prepared via phenyl-functionalized mesoporous silica (PFMS) by two steps. Namely Cr-PFMS photocatalysts were firstly assembled by co-condensation of tetraethoxysilane (TEOS) and various amounts of phenyltriethoxysilane (PTES) using PEO–PPO–PEO triblock copolymer (P123) as the template, and then loaded with chromium species with the aid of the phenyl groups. The physical and photophysical properties of the Cr-PFMS photocatalysts were characterized by various techniques including inductive couple plasma optical emission spectrometer (ICP-OES), X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible diffuse reflection spectroscopy (DRS). The visible-light-driven (λ > 420 nm) photocatalytic performance of the Cr-PFMS materials for the cyclohexane oxidation with O2 at room temperature was investigated. Results showed that the introduction of phenyl groups derived from PTES not only promoted the phase transition of PFMS from high-curvature hexagonal structure to low-curvature cubic structure, but also increased the loading amounts of Cr species of which Cr6+ chromate species were active sites. Consequently, the hexagonally structured Cr-PFMS photocatalysts possessed higher photocatalytic activity than their counterpart photocatalyst, Cr-SBA-15 prepared without adding PTES. Moreover, the activity of the Cr-PFMS samples with cubic structure was also higher than that of those samples with hexagonal structure. This work may provide more insight into the design of novel supported photocatalysts with high metal loading and catalytic activity for cyclohexane oxidation under mild reaction conditions.

In the present work, the parameters of laser-induced Sn plasma are studied using the fundamental of a Q-switched Nd:YAG. An improved iterative Boltzmann plot method is developed to calculate the electron temperature of the plasma to be 5116 K with 14 Sn (I) emission lines. The Sn (I) 303.41 nm emission line is Lorentz fitted and the electron number density is inferred to be 7.6 × 1016 cm−3. Moreover, the validity of local thermodynamic equilibrium is elucidated.

Split aptamers find growing interest as recognition elements for sandwich electrochemical sensors. Here, we report a convenient and highly sensitive sandwich electrochemical sensor based on a new conception of bivalent split aptamer signal probe, which is readily engineered through a simple hybridization of two identical monovalent split aptamers to a DNA template strand. Because of the bivalence cooperativity enhanced sandwich binding to target molecules, this type of DNA-scaffolded bivalent signal probe exhibits significantly increased signal gain for sandwich electrochemical detection of target analytes in comparison with the conventional monovalent signal probe. Through rational optimization of the length of anchor duplex in DNA scaffold and concentration of bivalent signal probe in electrochemical test solution, high signal sensitivity for ATP detection is achieved with a detection limit of 41 nM. The DNA-scaffolded bivalent signal probe based sandwich electrochemical sensor is also specific, selective and applicable for ATP detection in real samples. Due to its simplicity in design and high sensitivity for target recognition, we hope that the conception of DNA-scaffolded bivalent signal probe will provide a useful guide to further developing split aptamer-based sandwich electrochemical sensors for a wide variety of other target analytes.

The degradation characteristics of MOCVD grown InGaAsP/InGaAs dual junction solar cells, irradiated by 1 MeV electron, 3 MeV and 10 MeV proton, have been investigated. Main electrical and optical properties of solar cell degraded seriously with the increase of irradiation fluences due to the irradiation induced defects which are acting as non-radiative recombination centers in the active layers of the solar cell. The remaining factor of P m a x is 0.67, 0.53 and 0.51 for 1 MeV electron, 10 MeV proton, and 3 MeV proton irradiation, respectively, when the displacement damage dose (DDD) is 3 . 16 × 1 0 10 MeV/g. The degradation of external quantum efficiency (EQE) of each subcell mainly occurred in the long wavelength region, the integrated current density J s c of InGaAsP and InGaAs subcells degraded more seriously upon 3 MeV and 10 MeV proton irradiation comparing to 1 MeV electron irradiation. The InGaAsP subcell turned out to be the current limiting unit due to the lower J s c before and post irradiation. By applying equivalent displacement damage dose model, the relative damage coefficient for 3 MeV proton to 10 MeV proton and 1 MeV electron to 10 MeV proton have been calculated.

Low-temperature (T = 30 K) photoluminescence (PL) and post thermal annealing effects on 150 KeV proton irradiated GaInAsN bulk, single quantum well and triple quantum well structures (Eg ~ 1.0 eV) have been investigated. The nitrogen proportion of the samples was confirmed by high-resolution X-ray diffraction (HR-XRD) measurement as 0.26%, 0.30% and 0.20% for GaInAsN bulk, SQW, and MQW samples, respectively. The result shows that the PL intensity of GaInAsN materials degraded seriously by proton irradiation. The PL intensity enhancement were observed for all three types of sample after thermal annealing at 650 °C for 5 min, and MQW sample was recovered by the factor bigger than 100. The irradiation induced red-shift and thermal annealing induced blue-shift phenomena were analyzed by SRIM simulation result and theoretical models of InGaAs band structure.

This study was designed to explore the functions of soil fungal communities in the Cd tolerance of Q. acutissima seedling. Three Cd levels of 15, 30, and 40 mg kg−1 were set up using the soils collected from Q. acutissima forests. The benomyl was applied to inhibit the fungal communities in the soil. Following a 100-day pot cultivation of Q. acutissima seedlings, the plant growth, Cd content, N uptake, and fungal communities were evaluated. The results showed that the root dry weights were significantly reduced after the benomyl addition at the Cd concentrations of 30 and 40 mg kg−1. Root fungi colonization was enhanced under higher Cd concentrations when soil fungi are present (without the benomyl treatment). The fungi associated with root increased the Cd accumulation in the roots while decreased the Cd transfer to the shoot at 40 mg Cd kg−1. The 15N enrichment in root tip was positively correlated with enzyme activities of soil catalase and urease. And the activities of acid phosphatase, catalase, and urease were inhibited at each Cd level. The abundance of the dominant fungal genus differed in their response to Cd contamination. The ectomycorrhizal fungi of Tomentella and Cortinarius were identified under the higher Cd levels (40 mg kg−1). Our results implied Tomentella and Cortinarius could be applied to enhance the capacity of Quercus acutissima in the bioremediation of Cd polluted soil.

The anhydrite (AII) is treated with different methods: calcination (c-AII) and surface modification (c-AIIg, AIIg) by γ-glycidoxy-propyltrimethoxysilane (GPS), and the polyamide 6 (PA6)/anhydrite composites are prepared by a twin-screw extruder. The effects of different anhydrites as well as their contents on the thermal and mechanical properties of PA6 composites are studied in the present work. Fourier transform-infrared spectroscopy and X-ray photoelectron spectroscopy demonstrate that the active GPS chains are chemically tethered onto the surface of the anhydrite. The differential scanning calorimetry measurements indicate that different anhydrites act as a heterogeneous nucleation agent in PA6 matrix and lead to the appearance of new γ-PA6 crystalline form. Thermogravimetric analysis suggests that the addition of anhydrite after calcination or surface modification has little effect on the thermal stability of the composites. Moreover, it is found that the impact strength of the composites is decreased with the increasing content of different anhydrites, while the tensile strength is increased with the increase of c-AIIg and AIIg content and the most significant improvement of the tensile strength of PA6/c-AIIg and PA6/AIIg composites is obtained when the content of c-AIIg and AIIg is 15 wt%, respectively. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers

Laminaria japonica was extracted with ethanol, and tested for antimicrobial activity against Clavibacter michiganensis subsp. michiganensis (Cmm). This gram-positive bacterium is the agent of a serious tomato disease called bacterial canker. On in vitro antimicrobial assays, L. japonica extracts showed intensive antimicrobial activity to inhibit Cmm. Extracting parameters (time, temperature, and solid/liquid ratio) were investigated and further optimized integratedly with L27(313) orthogonal array design (OAD). Our data implied that the optimum extraction conditions were A3B3C3, that were extracting time 12 h, extracting temperature 80 °C, and solid/liquid ratio 1:30 (g:mL). Extracting temperature was the significant factor affecting extracting condition. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of L. japonica extracts against Cmm were 2.5 mg/mL and 5 mg/mL. Scanning electron microscopy (SEM) observation indicated L. japonica extracts caused considerable morphological alterations in Cmm cells, such as protoplast leakage, cell membrane disruption, cell clumped, and cell fragmented. Reactive oxygen species (ROS) level determination and ATPase activity assay revealed that L. japonica extracts did cause significant accumulation in ROS and reduce the intracellular ATPase activity rapidly. Accordingly, these results indicated that L. japonica extracts could open a new promising opportunity for this tomato disease control., Journal of Applied Botany and Food Quality, Vol 90 (2017): Journal of Applied Botany and Food Quality

A subwavelength interference nanolithography scheme is numerically demonstrated based on a metallic–insulator–metallic waveguide combined with unidirectional couplers. The coupler is a single right-angled (or left-angled) trapezoid metallic nanoslit that can carry out efficient unidirectional generation of surface plasmon polaritons under normal incidence. Simulation results show that a feature size to 50 nm half-pitch uniformity pattern can be obtained at the working wavelength of 365 nm with the proposed scheme. This proposed scheme can enhance the intensity of the interference pattern with higher contrast and field depth and is advantageous for the fabrication process in practical applications.

The X-ray crystal structure of Cowpea chlorotic mottle bromovirus (CCMV) revealed a unique tubular structure formed by the interaction of the N-termini from six coat protein subunits at each three-fold axis of the assembled virion. This structure, termed the β-hexamer, consists of six short β-strands. The β-hexamer was postulated to play a critical role in the assembly and stability of the virion by stabilizing hexameric capsomers (Speir et al., 1995). Mutational analyses of the β-hexamer structure, utilizing both in vitro and in vivo assembly assays, demonstrate that this structure is not required for virion formation devoid of nucleic acids in vitro or for RNA-containing virions in vivo. However, the β-hexamer structure does contribute to virion stability in vitro and modulates disease expression in vivo. These results support a model for CCMV assembly through pentamer intermediates.