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At present, the automatic generation of tolerance types based on rule-based reasoning has an obvious characteristic: for the same assembly feature, tolerance items are recommended that satisfy all feature characteristics, with a large number of recommendations. For this reason, automatically selecting tolerance types and reducing designer autonomy remains a challenging task, especially for complex mechanical products designed using heterogeneous CAD systems. This article proposes a tolerance specification design method for the automatic selection of assembly tolerance types. Based on the construction of a hierarchical representation model of assembly tolerance information with tolerance-zone degrees of freedom (DOFs), a semantic model of geometric tolerance information with tolerance-zone DOFs and a meta-ontology model of assembly tolerance information representation are constructed. Descriptive logic is used to express the attribute relationships between different classes in the assembly tolerance information meta-ontology model, and screening inference rules are constructed based on the mechanism for selecting assembly tolerance types based on tolerance-zone DOFs. On this basis, a process for selecting assembly geometric tolerance types based on the ontology of tolerance-zone DOFs is formed. Finally, the effectiveness and feasibility of this method were verified through examples. [ABSTRACT FROM AUTHOR]

A new phosphine‐catalyzed reaction of α‐substituted allenes with aryl imines, in stark contrast to classic cycloaddition reactions, has been developed. This reaction delivers valuable highly functionalized itaconimides with excellent stereoselectivities by a new «un‐cyclizing» reaction mode involving β′‐carbon of α‐substituted allenes. Moreover, the present «un‐cyclizing» reaction can also be carried out in a one‐pot fashion and scaled up to the gram scale by using aryl aldehydes, without the need to isolate the aryl imines. Mechanistic studies and control experiments reveal the crucial role of H2CO3 for the present reaction mode. In addition, density functional theory (DFT) calculations were performed to understand the possible mechanism. [ABSTRACT FROM AUTHOR]

Bogda Shan is a mountain belt located at the eastern extremity of the Chinese Tianshan and records a complex and debated exhumation history. Previous studies have reported a young Cenozoic thermal history for the exhumation of Bogda Shan, which is in conflict with the observation of preserved Mesozoic erosion surfaces in the area. This study re-evaluates the Meso-Cenozoic thermo-tectonic evolution of Bogda Shan using apatite fission track (AFT) thermochronology. Palaeozoic basement (meta-sandstone) samples collected from the northern and southwestern flanks of the mountain ranges reveal apparent Mesozoic AFT ages ranging from ~202 Ma to ~97 Ma. Inverse thermal history modelling results reveal slow to moderate basement cooling during the early Mesozoic, corresponding to relatively low levels of exhumation. This accounts for the preservation of low-relief Mesozoic peneplanation surfaces recognized at elevations of ~3500–4000 m. None of the presented AFT data and thermal history models show any evidence for significant deep Cenozoic exhumation. In the neighbouring Junggar Basin, a Middle Jurassic sandstone sample records partial resetting of the AFT system during the Cretaceous. This observation conflicts with previous data (from the same Jurassic strata) where complete resetting of the AFT clock during the Cenozoic was suggested. Furthermore, Lower Cretaceous and Palaeogene sediments from the Turpan-Hami Basin show non-reset detrital AFT age populations of ~197, ~135, and ~104 Ma, which are coincident with the main pulses of exhumation recorded in the Chinese North Tianshan. Based on a comprehensive summary of the published data, we argue for a Mesozoic building of the Bogda–Balikun–Harlik mountain chain in the eastern Chinese Tianshan. Subsequent Cenozoic exhumation must have been relatively modest at most (<2 km) as it was not recorded by AFT thermochronology. [ABSTRACT FROM AUTHOR]

The southeastern (SE) Tibetan Plateau (Yunnan) is characterized by low‐relief uplands that were deeply incised by large rivers. The thermal history of basement rocks in this region remains poorly investigated, while this data is needed to elucidate the complex relationship between tectonics and climate in shaping the surface. To better understand its thermo‐tectonic evolution, we carried out apatite fission track thermochronology on 31 samples collected from a large area that covers different tectonic units, including a vertical profile in the middle Mekong River valley; additional zircon LA‐ICP‐MS U‐Pb dating was performed on four basement rocks. Our results confirm that a large portion of Mesozoic crystalline rocks constitute the basement of the SE Tibetan Plateau. Inverse thermal history modeling of fission track data reveal extensive late Oligocene to Miocene rapid basement cooling and exhumation episodes from both inside and outside the active zones (i.e., ductile shear zone and river valley). These thermal events were coincident with the activities of large‐scale strike‐slip faults that dominate the structural framework. Combined with the published data, we propose that widespread crustal shortening and thickening took place in the SE Tibetan Plateau during the Oligocene‐Miocene in the context of a compressive tectonic regime. Low‐temperature thermochronological data reveal that both tectonic forcing and climate‐driven erosion have played important roles in exhuming the basement rocks in the region. It is also deduced that the present‐day relatively low‐elevation landscape of the Yunnan area resulted from complex interaction between regional tectonic activity and surficial erosion since the late Oligocene. Key Points: The southeastern Tibetan Plateau (Yunnan) underwent widespread Oligocene‐Miocene moderate to rapid surface coolingBoth tectonic forcing and climate‐driven erosion played important roles in exhuming the southeastern Tibet basement rocksThe Yunnan landscape was formed by long‐term and complex interaction between tectonics and surface erosion since the late Oligocene [ABSTRACT FROM AUTHOR]

The swelling pressure of bentonite changes dramatically due to diffused nuclear radiation heat and underground osmosis, causing the failure of the buffer isolation layer in deep geological repositories for the disposal of high-level radioactive waste. A detailed overview of the relevant research results on the swelling pressure variation of bentonite under thermo-chemical effects is presented in this paper. The results showed that the values of the swelling pressure obtained by different test methods are dissimilar. The swelling pressure of bentonite decreased with the increasing pore solution concentration; nevertheless, the effect of temperature on the swelling pressure is still controversial. At the micro-level, crystal layer swelling and double- layer swelling are generally considered to be the main factors affecting the swelling pressure; the pore structure and water distribution of bentonite will change owing to thermo-chemical effects. At the macro-level, involving intergranular stress, a mechanical parameter was proposed to explain the mechanism of the changes in the swelling pressure of bentonite. Finally, future research directions for the study of the evolution of bentonite swelling properties under thermo-chemical effects are proposed, based on the current research results. [ABSTRACT FROM AUTHOR]

The self-cleaning ability of superhydrophobic metal surfaces has attracted extensive attention. The preparation of superhydrophobic material using the coating method is a common processing method. In this experiment, aluminum fins were processed by laser etching and perfluorinated two-step coating. The aluminum surface was modified using a femtosecond laser and 1H,1H,2H,2H- perfluorooctane triethoxysilane (PFOTES). A superhydrophobic aluminum surface with excellent mechanical stability and self-cleaning properties was obtained with the superhydrophobic contact angle (WCA) of 152.8° and the rolling angle (SA) of 0.6°. The results show that the superhydrophobic surface has an excellent cleaning effect compared with an ordinary surface in unit time. Then, a wear resistance test of the superhydrophobic surface was carried out by using the physical wear method. The results show that physical wear had a low influence on the hydrophobic property of the specimen surface. Finally, the Vickers hardness analysis found that the superhydrophobic surface hardness was significantly better than the ordinary surface hardness compared with the superhydrophobic surface hardness. Based on the excellent self-cleaning properties, wear resistance, and robustness of superhydrophobic materials, the laser-etched and perfluorinated superhydrophobic aluminum fins designed and manufactured in this study have broad application prospects in improving the heat transfer efficiency of finned heat exchangers. [ABSTRACT FROM AUTHOR]

A novel photocatalytic water splitting device was constructed using economic graphene quantum dots as a photocatalyst and a Ni-based complex [(tpy-CH＝N)2Ni]Cl2 (tpy = terpyridine) as a co-catalyst. Under visible light irradiation and with a bias of −0.1 V vs. NHE, it produced an extremely stable photocurrent density of −9 μA cm−2 for 3 h. [ABSTRACT FROM AUTHOR]

The temporal activation of siRNA provides a valuable strategy for the regulation of siRNA activity and conditional gene silencing. The bioorthogonal bond-cleavage reaction of benzonorbonadiene and tetrazine is a promising trigger in siRNA temporal activation. Here, we developed a new method for the bio-orthogonal chemical activation of siRNA based on the tetrazine-induced bond-cleavage reaction. Small-molecule activatable caged siRNAs were developed with the 5′-vitamin E-benzonobonadiene-modified antisense strand targeting the green fluorescent protein (GFP) gene and the mitotic kinesin-5 (Eg5) gene. The addition of tetrazine triggered the reaction with benzonobonadiene linker and induced the linker cleavage to release the active siRNA. Additionally, the conditional gene silencing of both exogenous GFP and endogenous Eg5 genes was successfully achieved with 5′-vitamin E-benzonobonadiene-caged siRNAs, which provides a new uncaging strategy with small molecules. [ABSTRACT FROM AUTHOR]

Abstract Text. A general method for the synthesis of structural diversity and complexity of azepines from aldimine esters and β′‐acetoxy allenoates is reported. Under phosphine catalysis, a [4+3] cycloaddition for the formation of 1,3‐dihydro‐2H‐azepine‐2,2,4‐tricarboxylates was achieved with broad substrate scope under mild reactions. A switchable process was given and a variety of important 2,3‐dihydrochromeno[4,3‐b]azepin‐6(1H)‐ones were selectively formed when the reaction was performed in the presence of Cs2CO3 and PPh3, which involved an intramolecular ester group migration and subsequent lactonization of 1,3‐dihydro‐2H‐azepine‐2,2,4‐tricarboxylates. Besides easy handle process, high synthetic value of resulting products, it is worth to note that this work showed the novel example of 1,5‐ethoxycarbonyl migration. [ABSTRACT FROM AUTHOR]

This article presents an extensive relative permeability study for low salinity water flooding (LSWF) in minerally different carbonate rocks. The experiments were performed with unsteady state method using artificial cores, crude oil and synthetic brines. The effect of water salinity and rock composition on relative permeability was obtained. The results show that the oil (water) relative permeability increases (decreases) first and then decreases (increases) with the decrease of the salinity of brines. Actually, there exists an optimal salinity (2384.6 mg/L) which maximizes the oil relative permeability and minimizes water relative permeability. When low salinity water is kept the same, the higher calcite content in the carbonate rock, the bigger oil relative permeability and the smaller water relative permeability will be. [ABSTRACT FROM AUTHOR]

There is not a consistent view about the mechanism of wettability alteration during low salinity water flooding. This paper highlights extensive wettability studies to investigate the wettability alteration on mineralogically different carbonates. Contact angle measurements were conducted to characterize wettability changes quantitatively. The results clearly revealed that wettability of carbonate rock surfaces can be altered to a more water-wet condition by lowering water salinity. The trend of the maximum change of contact angle (MCCA) variation with dolomite/calcite content in the rock is fairly linear under the same salinity, which demonstrates that carbonate minerals can affect rock wettability in a way. Also, the higher calcite content in the rock, the greater MCCA, i.e. the stronger effect of LSWF. Besides, the sensitivity of rock wettability to minerals is different under different salinity conditions. When the salinity is in the range of 2384.6 ∼ 4769.2 mg/L, rock wettability is most sensitive to minerals. The analysis of the effect of ion composition showed that the effect of Ca2+ on wettability alteration is greater than that of Mg2+ at room temperature, and with the increase of the content of calcite in the rock, the effect of Ca2+ is more pronounced than that of Mg2+. [ABSTRACT FROM AUTHOR]

Abstract: The K-bentonite, black shale and flysch successions at the Ordovician–Silurian transition in South China have been the subject of comprehensive investigations relative to the probable accretion of the Yangtze Block and the questionable Cathaysia Block. First, the geochemical analyses of K-bentonites show that the parent magma originated in syn-collisional, volcanic-arc and within-plate tectonic settings, which produced mainly intermediate-to-felsic series magmas, associated with continuous collision and subduction of paleo-continental blocks/arcs. Further, the regional distribution of K-bentonite thickness indicates that voluminous explosive volcanism was located in the present southeastern shoreline provinces of China. Secondly, northwestwardly migrating, Ordovician–Silurian, transitional flysch successions, and the accompanying diachronous K-bentonite-bearing black-shale interval, as well as the related, overlying, shallowing-upward succession at the interior of the Yangtze Block, developed as an unconformity-bound sequence that mirrors foreland-basin tectophase cycles in the Appalachian basin. The above features suggest that the sequence accumulated in a similar foreland basin, which formed in response to adjacent deformational loading in a northwesterly migrating orogen located to the southeast. Geochemical and paleocurrent data from the turbiditic flyschoid sandstones also support these depositional settings. Accordingly, it seems that all criteria strongly support the presence of an Ordovician–Silurian, subduction-related orogen resulting from collision with a block to the southeast that must have been the original “Cathaysia Block” of Grabau and later workers. The K-bentonite, black-shale and flysch successions can be regarded as distal, foreland responses to the continuous northwestward collision and accretion of the Cathaysia Block to the Yangtze Block. Hence, we prefer to suggest that the suture zone with the sensu stricto Cathaysia Block probably developed along previously identified late Early Paleozoic suture relicts in the shoreline provinces of southeast China. On the other hand, although accretion of fragments with Cathaysian affinities to the Yangtze Block may have begun as early as Middle to Late Proterozoic time, the Ordovician–Silurian orogeny described above probably reflects the final phase of accretion between the two blocks. Moreover, when combined with similar peri-Iapetan orogenic events in other areas during the same period, this accretion event may have been part of a major stage of global tectonic reconstruction in the evolution of Gondwana. [Copyright &y& Elsevier]

Abstract: We report SHRIMP U–Pb zircon ages from K-bentonite beds from different locations in the Xiamaling Formation near Beijing at the northern margin of the North China Craton (NCC). The 1379±12 Ma and 1380±36 Ma ages obtained in our study correlate with similar data (1368±12 Ma) obtained from recent studies and assign a Mid-Mesoproterozoic (Ectasian Period) age for the formation. In addition, a detailed bed-by-bed study of the K-bentonite sequence indicates that the present dated successions northwest of Beijing can be correlated fairly well with that of the well-known Meso- to Neoproterozoic standard section in Jixian to the east of Beijing. The new data call for a major revision of the previous Meso- to Neoproterozoic chronostratigraphic subdivision of the northern NCC, with a revised calibration into the early to middle Mesoproterozoic Era. Our data suggest that the Tawuia-bearing assemblage in the lower part of the Xiamaling Formation in the NCC could be older than ~1380 Ma, and is not limited to a representative feature of the Neoproterozoic Little-Dal-Group-type macroalgal biota. Combined with other similar discoveries, we conclude that the macro-evolution of Proterozoic eukaryotic biotas, represented by macroalgal assemblages, would have probably been a long, protracted, and somewhat monotonous process. On the other hand, reassessment of the paleomagnetic database for these successions, combined with stratigraphic correlations and similarities in the macroalgal assemblages on the NCC and Laurentia, support a configuration in which the NCC was in close proximity to the Laurentia–Siberia–Baltica grouping during much of the Mesoproterozoic to Neoproterozoic time. Furthermore, our study suggests recent assumptions linking δ 34SCAS and δ 13Ccarbonate fluctuations in the Jixian section with the assembly and breakup of Rodinia must now be reconsidered, as these fluctuations may correlate better with the tectonics associated with the Columbia supercontinent cycle. [Copyright &y& Elsevier]

• Multifunctional panels from jute fibers for interior wall covering are prepared. • The thermal insulation property is superior to most natural thermal insulators. • The noise reduction coefficient values satisfy the commercial requirement. • Excellent humidity control performance is achieved under high-relative humidity. Jute fibers are an important cash crop in the world with a series of advantages such as high-yield, low-cost and easy biodegradation, etc. They also exhibit high potentials for providing hygrothermal and acoustic functions due to inherent chemical composition and internal structure. In this paper, multifunctional panels made from jute fibers blended with polyester fibers were explored as a new kind of interior wall covering material beneficial for both building energy conservation and indoor comfort. The fabricated jute/polyester fiber-based panels (JPs) were characterized in terms of morphology, pore structure, surface chemistry and functional performance including thermal insulation, sound absorption and humidity control properties. The results showed that thermal insulation properties of JPs were comparable for commercial thermal insulators with thermal conductivities of 0.0372–0.0418 W/(m·K), superior to most natural thermal insulators. Sound absorptions mainly occurred in the middle to high frequencies, and noise reduction coefficients reached to the commercial level. It was found that the thermal and acoustic properties were significantly influenced by the density and thickness of JPs. Moreover, JPs exhibited good potential in humidity control with high 24 h desorption ratios of 79.87–96.61 %. The maximum 24 h absorption amount was 183.05 g/m2 under high-relative humidity (RH), approximately 3.1 times as much as the standard limit value. Meanwhile, the moisture absorption amount was largely dependent on the surface chemistry and pore structure of JPs as well as environment RH. In general, JPs could be commercially used as a promising interior wall covering material for improving building energy efficiency and indoor environmental quality. [ABSTRACT FROM AUTHOR]