This is the first time; it was employed Successive Ionic Layer Adsorption and Reaction (SILAR) method in order to prepare Zn/ZnO/n-Si/Au–Sb sandwich structure. The ZnO interface layer was directly ...formed on n-type Si substrate using SILAR method. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) studies were showed that the film is covered well on n-type Si substrate and have polycrystalline structure. An Au–Sb electrode was used as an ohmic contact. The Zn/ZnO/n-Si/Au–Sb sandwich structure demonstrated clearly rectifying behavior by the current–voltage (
I–
V) curves studied at room temperature. The sample temperature effect on the current–voltage (
I–V) characteristics of Zn/ZnO/n-Si/Au–Sb structure was investigated in temperature range 80–320
K by steps of 20
K. The parameters such as barrier height, ideality factor and series resistance of this structure were calculated from the forward bias
I–V characteristics as a function of sample temperature. It was seen that the ideality factor and series resistance were decreased; the barrier height were increased with increasing temperature. The experimental values of barrier height and ideality factor for this device were calculated as 0.808
eV and 1.519 at 320
K; 0.220
eV and 4.961 at 80
K, respectively. These abnormal behaviors can be explained by the barrier inhomogeneities at the metal–semiconductor (
M–
S) interface.
Unmanned Aerial Vehicles (UAVs) have been developed to perform various military and civilian applications, such as reconnaissance, attack missions, surveillance of pipelines, and interplanetary ...exploration. The present research is motivated by the need to develop a fast adaptable UAV design technologies for agile, fuel efficient, and flexible structures that are capable of adapting and operating in any environments. The objective of this research is to develop adaptive design technologies by investigating current design methods and knowledge of deployable technologies in the area of engineering design and manufacturing. More specifically, this research seeks to identify one truss lattice with the optimal elastic performance for deployable UAV wing design according to the Hashin & Shtrikman theoretical bounds. We propose three lattice designs — 3D Kagome structure, 3D pyramidal structure and the hexagonal diamond structure. The proposed lattice structure designs are fabricated using an Objet 350 3D printer while the material chosen is a polypropylene-like photopolymer called Objet DurusWhite RGD430. Based on compression testing, the proposed inflatable wing design will combine the advantages of compliant mechanisms and deployable structures to maximize flexibilities of movement in UAV design and development.
Handle with care: CL‐20, a high‐power explosive suffering from high sensitivity, has been cocrystallized with TNT to produce a novel high‐power, low‐sensitivity explosive. This cocrystal can be used ...directly for explosives applications or stored in this insensitive form then activated by heat to return it to its high‐sensitivity form.
The article proposes a simple and efficient system for connecting the bars and the linkages in deployable structures. These structures must allow precise movements for unfolding and folding, which ...requires specific linkages that have been the subject of numerous studies. In contrast, the linkage-bar connection has hardly been studied. This article analyses this connection using a system based on crushing the ends of the bars, but introducing a modification that considerably improves its efficiency. It consists of flattening the end of the tube in a press with lateral confinement, which concentrates the entire section of the tube, but which limits the transversal expansion. The response of flattened tubes without accessory elements is studied, as well as other variants of the system by inserting at the ends of the bar either intermediate plates or a section of tube. The different types of bars with flattened ends have been tested to failure and the resistance capacities of the proposed solutions have been analysed. The results obtained demonstrate the structural efficiency of the proposed system, with a clear improvement over unflattened tubes.
Lattice structures are meant for light weight structure with a high strength to weight ratio used to carry high loads and high energy absorption capabilities. In the lattice structures, the ...non-stochastic arrangement of members has the ability to control and customize their mechanical properties. The recent developments in additive manufacturing provides freedom in design and gives flexibility to manufacture tailored complex novel lattice structures. In the present investigation, the traditional 2.5D honeycomb and the tessellated open lattice structures with basic crystalline arrangements of the members are considered to study the load carrying capacity, stiffness and energy absorption capabilities by keeping constant volume for each lattice. The results through the experiments and finite element analysis are compared with a novel open lattices structure to show significant improvement in stiffness and high energy absorption with the volume of the material. However, the novel open lattice structure has displayed prominent post yield plateau stresses and energy absorption with sacrificing stiffness and strength significantly.
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We critically review documented glucosinolate structures, methods for qualitative glucosinolate analysis, glucosinolate evolution, and recent advances in glucosinolate biochemistry. Rather than being ...neutral markers of evolutionary origin, glucosinolates are bioactive specialized metabolites, and their evolution can be traced using phylogenetic trees. Display omitted
► We provide a critical review of reported natural glucosinolate structures. ► A considerable number of suggested structures are insufficiently documented. ► By 2011, around 132 natural glucosinolates were scientifically documented. ► Glucosinolates are specialized metabolites subject to frequent evolution. ► Side chain specific in planta metabolic reactions may influence glucosinolate evolution.
By 2000, around 106 natural glucosinolates (GSLs) were probably documented. In the past decade, 26 additional natural GSL structures have been elucidated and documented. Hence, the total number of documented GSLs from nature by 2011 can be estimated to around 132. A considerable number of additional suggested structures are concluded not to be sufficiently documented. In many cases, NMR spectroscopy would have provided the missing structural information. Of the GSLs documented in the past decade, several are of previously unexpected structures and occur at considerable levels. Most originate from just four species: Barbarea vulgaris, Arabidopsis thaliana, Eruca sativa and Isatis tinctoria. Acyl derivatives of known GSLs comprised 15 of the 26 newly documented structures, while the remaining exhibited new substitution patterns or chain length, or contained a mercapto group or related thio-functionality.
GSL identification methods are reviewed, and the importance of using authentic references and structure-sensitive detection methods such as MS and NMR is stressed, especially when species with relatively unknown chemistry are analyzed. An example of qualitative GSL analysis is presented with experimental details (group separation and HPLC of both intact and desulfated GSLs, detection and structure determination by UV, MS, NMR and susceptibility to myrosinase) with emphasis on the use of NMR for structure elucidation of even minor GSLs and GSL hydrolysis products. The example includes identification of a novel GSL, (R)-2-hydroxy-2-(3-hydroxyphenyl)ethylglucosinolate.
Recent investigations of GSL evolution, based on investigations of species with well established phylogeny, are reviewed. From the relatively few such investigations, it is already clear that GSL profiles are regularly subject to evolution. This result is compatible with natural selection for specific GSL side chains. The probable existence of structure-specific GSL catabolism in intact plants suggests that biochemical evolution of GSLs has more complex implications than the mere liberation of a different hydrolysis product upon tissue disruption.
Materials with dynamically controlled electronic structures (i.e., upon external stimuli) are at the forefront of the renewable energy sector with applications as memory devices, smart ...supercapacitors, programmable solar cells, and field‐effect transistors. Moreover, their continued development as device components is critical for the field of optoelectronics since their performance is comparable, or could even surpass, the current benchmarks. Adaptive electronic properties are the main focus of this review that discusses recent developments in the modulation of electronic behavior that can be tuned using external stimuli in metal–organic frameworks (MOFs), covalent–organic frameworks (COFs), primarily inorganic hybrids, polymers, and graphitic‐type materials. Triggers to achieve “dynamic” behavior discussed within this manuscript are primarily light‐based switches that include different classes of photochromic molecules such as naphthalene diimide, viologen, diarylethene, azobenzene, and spiropyran. The effect of material dimensionality and photoswitch connectivity achieved through integration of photochromic moieties inside 0D, 1D, 2D, and 3D hybrid matrices is discussed. This review showcases the prospects of advancing the material and energy landscapes through employment of structural motifs with adaptive electronic structures occurring as a function of their dimensionality and connectivity.
The desire to explore the convergence of electronic properties, dimensionality of materials, and connections of photoswitchable molecules has led to momentous progress in the field of stimuli‐responsive materials. Their applications as memory devices, smart supercapacitors, programmable solar cells, and field‐effect transistors can bring dynamically controlled photoresponsive motifs to the forefront of material engineering.
2,3‐bis(diphenylphosphino)butane enantiomers (chiraphos, L) used as chiral auxiliaries results in the preferential formation of an unprecedented Au24 framework with inherent chirality. The crystal ...structure of Au24L6Cl42+ (1) has a square antiprism‐like octagold core twinned by two helicene‐like hexagold motifs, where the inherent chirality is associated with the helical arrangement. The clusters carrying (R,R)‐ and (S,S)‐ diphosphines had right‐ and left‐handed strands, respectively. Circular dichroism spectra showed peaks in the visible to near‐IR region, some of which did not coincide with absorption bands, suggesting the enantiomeric Au24 frameworks possess unique chiroptical properties. The Au24 frameworks were thermally robust, which could be attributed to the superatomic concept (18 e− system) and the steric constraint effects of the bridging ligand units.
Hexagold strands: An unprecedented Au24 framework with inherent chirality was synthesized by the use of optically pure chiraphos ligands. The chiral structure was characterized by the duplex of 6‐helicene‐like hexagold strands twinning around the square antiprism‐like octagold core. The enantiomeric clusters showed characteristic circular dichroism responses in the visible to NIR region.
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We have studied the fabrication of line-like and pillar-like periodic microstructures on stainless steel by means of direct laser interference patterning. A picosecond (10ps) pulsed ...Nd:YAG laser operating at 1064nm wavelength was used to produce the microstructures with spatial periods ranging from 2.6μm to 5.2μm. By varying the laser parameters (laser fluence, pulse-to-pulse overlap) structure depths ranging from 500nm to nearly 11.5μm could be obtained. Furthermore, low and high frequency laser induced periodic surface structures (LIPSS) have been generated, resulting in three-level multi-scaled patterns. The orientation of the laser induced periodic structures with respect to the interference patterns could be adjusted by controlling the laser beam polarization. Finally, static water contact angle measurements are performed to investigate its correlation with the surface morphology. The treated surfaces are characterized using confocal and scanning electron microscopy.
Tumor-associated tertiary lymphoid structures (TLS) play a critical role in the progression of various tumors. However, the dynamics of lymphocyte recruitment during hepatocellular carcinoma (HCC) ...clinical progression have not been fully elucidated. In the present study, tissue microarrays and hematoxylin-eosin staining were used to evaluate the existence and degree of TLS in HCC patients. Nine immune biomarkers in intratumoral tissues were examined by immunohistochemical staining. A total of 462 patients were recruited for the study. Kaplan-Meier analysis showed that TLS was inversely correlated with the risk of early tumor recurrence (P=0.014), whereas no association was found between TLS and overall survival. Cox regression analysis identified TLS as an independent prognostic factor for early HCC recurrence (P=0.005). In addition, TLS was associated with increased intratumoral CD3+, CD8+, CD20+, and decreased infiltration of Foxp3+ and CD68+ cells. A lower density of PD1+, TIM3+, and LAG3+ were found in TLS+ cases. Sub-analysis revealed the prognostic value of TLS on early-stage HCC (BCLC 0-A, TNM stage I-II) and HCC with solitary nodule. The validation cohort verified the prognostic value of TLS in early-stage HCC patients. These results suggest that TLS-targeted immune-modulating therapies may be a potential strategy for effective immune-mediated tumor suppression.
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