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Herein, 11 artificially corroded steel plates and one intact steel plate specimen were designed to study the influence of corrosion on steel plates on the degradation of their shear capacity. The shear capacity of corroded steel plates was experimentally investigated. Furthermore, the shear performance of corroded plates, including their critical shear load and shear capacity, was evaluated. In addition, the influence of the location of pitting, shape of pitting, and the degree of pitting on the degradation of the shear capacity was discussed and variations in the regular pattern of the tension field of corroded steel plate specimens were investigated. Test results show that the location pitting was primarily responsible for the degradation of the shear capacity, yield load, and critical shear load. Moreover, the degradation degree of the shear capacity in the direction of the pressure band was observed to be greater than that in the direction of the tension field. Results also show that the shear capacity of specimens decreased with increasing pitting corrosion distribution. The shear capacity of the specimen with the largest corrosion distribution decreased to 42% of that of the intact plate. Compared with the uncorroded specimen, the angle and width of the tensile band were greatly affected by the corrosion area. This study provides reference data for evaluating the degradation degree of the shear capacity of corroded steel plate.

Lithium-ion batteries (LIBs) are considered as one of the most successful energy storage technologies due to the high energy density, long cyclability and no memory effect. With the ever-increasing energy density of LIBs in practical applications, operational safety becomes more critical because unintentional release of energy can lead to devastating accidents related to fire and explosions of LIBs. The flammable polymer separators and liquid electrolytes are the root causes of such safety hazards. For the advancement of safe LIB design, this review summarizes the recent developments towards highly flame-retardant separators and solid-state electrolytes. The composition, structure and the performance of flame-retardant separators for liquid LIBs are firstly discussed, which include inorganic particle blended polymer separators, ceramic material coated separators, inherently nonflammable polymer separators, and separators with flame-retardant additives. Then much attention is paid on the solid-state electrolytes including inorganic solid electrolytes, solid polymer electrolytes, and inorganic/organic composite electrolytes. Future outlooks for the challenges of flame-retardant separators to practical applications are also discussed.

In a broad sense, the term “Xia culture” means the culture of the Xia dynasty [ca. 2100-1600 BCE] period. In a narrower sense, however, it refers to the culture of the Xiahou 夏后 clan of the mythical founder Yu 禹. In much of the contemporary research, the question of the primary ethnic affiliation of Xia culture is often overlooked and obscured, thus blurring the distinction between Xia culture in the broad and narrow senses. This has resulted in considerable conceptual and epistemological imprecision. Research on Xia culture can be conducted in two main ways: on the one hand, what has been called “metropolitan conjecture” and, on the other, cultural comparison. Departing from the method of cultural comparison and bringing together temporal, spatial, and cultural elements in our analysis allows us to distinguish a primary central area within the “region of Yu” that coincides with Xia culture in the narrow sense, as reflected in later phases of the Wangwan 王灣 and Meishan 煤山 regional subtypes of Longshan culture [Longshan wenhua 龍山文化], from the later phases of the various archaeological remains found within a secondary and tertiary central area, which can be included in the category of Xia culture in a broad sense. Erlitou 二里頭 culture should be regarded principally as part of Xia culture. As such, the Meishan and Wangwan subtypes of Henan Longshan culture, along with the first to the fourth phases of Erlitou culture, can be seen as making up a consistent Xia culture.

The reinforced concrete-filled steel tube (RCFST) column solves several of the problems of the concrete-filled steel tube (CFST) column in practical engineering applications. Moreover, RCFST has a simple joint structure, high bearing capacity, good ductility, and superior fire resistance. From a structural safety perspective, designers prioritize the creep performance of CFST members in structural design. Therefore, the creep behavior of RCFST columns should be thoroughly investigated in practical engineering design. To study the influence of the creep behavior of RCFST columns under axial compression, this work analyzed the mechanical behavior of composite columns based on their mechanical characteristics under axial compression and established a creep formula suitable for RCFST columns under axial compression. A creep analysis program was also developed to obtain the creep strain–time curve, and its correctness was verified by existing tests. On this basis, the effects of the main design parameters, such as the stress level, steel ratio, and reinforcement ratio, on the creep behavior were determined and analyzed. The creep of the tested composite columns increased rapidly in the early stages (28 days) of load action; the growth rate was relatively low after 28 days and tended to stabilize after approximately six months. The stress level had the greatest influence on the creep of RCFST columns under axial compression, followed by the steel ratio. The influence of the reinforcement ratio on the creep behavior was less. The results of this study can provide a reference for engineering practice.

Uniaxial compression testing was combined with the digital speckle correlation method (DSCM) to explore the deformation field evolution characteristics and the Poisson’s ratio and energy release responses of a geopolymer cemented coal gangue-fly ash backfill (GCGFB) sample under uniaxial compression. The results showed that in the initial stage of loading, the deformation of the GCGFB sample was small and evenly distributed, and no localized deformation zone formed in the sample. As the loading progressed, a localized deformed zone gradually appeared, and the formation rate gradually accelerated. The maximum shear strain value at the start of localized deformation was 0.06. In the post-peak loading process, the localized deformed zone gradually expanded, and the degree of unevenness of the localized deformation was much greater than that before the peak; the maximum shear strain value at this time was 0.22. During the localization of the deformation to the peak intensity stage, the growth rate of the Poisson’s ratio of the GCGFB sample was markedly increased, and the growth rate after the peak was notably slowed and exhibited unstable fluctuations. When the stress reached the peak, the Poisson’s ratio was 0.24. The peak strain of the GCGFB sample was large, and the failure characteristics of the GCGFB sample showed multiple shear deformation zones, which is indicative of a typical cylindrical splitting failure. The deformation energy density of the GCGFB sample exhibited a slow decline after the peak, and the rate of decline gradually decreased. The deformation energy density drop time of the GCGFB sample was 96 s, which is much longer than that of high-strength rock.

As a new paste backfill material, geopolymer cemented coal gangue-fly ash backfill is prepared from fly ash geopolymer and spontaneous combustion gangue and can be beneficial to the cleaner production of coal mines and coal-fired power plants. A new mixing technique, in which a small amount of fly ash was mixed with cement, slag and water and allowed to react for a period of time before an aggregate and residual fly ash were added, was proposed. The influences of the solid mass concentration, the fine gangue ratio and the fly ash content on the workability and strength of the paste backfill material were analyzed, and ratio optimization was carried out using the response surface method, multi-objective multi-verse optimization and the desirability function approach. The results show that the optimal mixture is obtained when the mass concentration is 79.65%, the fine gangue rate is 57.19%, and the fly ash content is 15.67% of the total mass. The new mixing technique makes the fly ash more active to stimulate the early formation of calcium silicate gel and calcium silicate hydrate gel that improve the aggregate formation strength. In the later stage, amorphous hydrated calcium aluminate gel-coated ettringite and calcium carbonate formed a flocculation structure between the fly ash particles that gradually formed a condensation-crystallization structure. The research results can make extensive use of fly ash and gangue to promote cleaner production.

The safety of lithium ion batteries is correlated closely to the mechanical property and thermal stability of separators. The polymer/ceramic particle composite separators are widely investigated for quasi-solid gel separators of lithium ion batteries, but the nonuniform dispersion of ceramic particles limits their performance. In this study, ball-milled Al-doped Li6.75La3Zr1.75Ta0.25O12 suspension is incorporated into poly (vinylidene fluoride-co-hexafluoropropylene) gel to prepare a highly uniform quasi-solid composite separator. The results show that adding only 4.29 wt% Li6.75La3Zr1.75Ta0.25O12 into PVDF-HFP increases ductility by three times and the mechanical strength by 38% as compared with pure PVDF-HFP separator. Batteries with the composite separator show significantly improved cyclic stability and rate performance at both room temperature and temperatures up to 80 °C. In particular, the composite separator promotes homogenous Li+ flux through the separator and suppresses Li dendrite growth in Li-metal based batteries.

Semi-rigid connections are widely used in steel frame structures. The bending and axial stiffness of connections have a significant influence on the mechanical performance of frame structures. However, most finite-element models of an actual project established in general finite-element software are rigid or hinge-connected for simplicity. Thus, the results are not consistent with the actual situation and may cause large errors. To estimate the influence of joint stiffness, including bending and axial stiffness, a novel numerical beam model is proposed in this paper. This method can be used for inelastic analysis with axial and bending stiffness considered separately. The accuracy of the proposed element model is first validated by comparing it with an ordinary beam element. Then, the model is used for seismic analysis of a steel frame structure, and the influence of bending stiffness on the dynamic response of a steel frame is derived. Progressive collapse analysis is conducted, and the influence of bending and axial stiffness on the mechanical behaviour of the steel frame structure during collapse is also determined. The proposed element model can consider semi-rigid joints and inelasticity at the same time with high accuracy, and it can be conveniently incorporated in general finite-element software.

A hierarchically laminated nanostructured PVdF–HFP membrane is deposited directly on a carbon anode through efficient, scalable electrophoretic deposition (EPD) in a surfactant-free colloidal system. Lithium ion batteries based on the separator–anode configuration have a well-structured microscopic interface with uniform, reinforced separator/electrode contact. The resulting separator enables a high ionic conductivity of 8.1 × 10−4 S cm−1, and exhibits a low thermal shrinkage of 3% after annealing at 160 °C for 5 h, a high isotropic mechanical strength (∼33 MPa) and an ultra-high ductility (∼450%). The battery with the separator–anode configuration delivers a discharge capacity of 370 mA h g−1 (99.5% of the theoretical capacity) at 0.1C, an excellent capacity retention of ∼100% after 300 cycles, and a pronounced rate capability of 270 mA h g−1 at 1C. This work opens up the opportunity to realize both reliable and high-capacity material platforms for next-generation lithium ion batteries.

The post-tensioned energy dissipating connection for steel frames has drawn considerable attention because of its good seismic performance. Friction mechanisms, such as friction damped post-tensioned (FDPT) steel connections, are typically used to improve energy dissipating capacity. Many researchers have investigated the seismic behavior of FDPT through numerical or experimental method. Prior studies have indicated that the analysis by elaborate FE models is very time-consuming. To overcome this disadvantage, a friction element was first proposed based on general FE code and then incorporated into a simplified numerical model of PT connection to consider the effects of friction. The accuracy of results derived by this model was validated against prior experimental investigations. The effects of friction force value and initial PT force seismic behavior of FDPT connection was investigated. The geometric and material nonlinearities and strands can be considered in the modeling. A planar steel frame structure was established, and hysteretic analysis was conducted in the end. Results indicated the computational cost can be reduced significantly by this model.

Natural rubber (NR) is acknowledged to be a strategically important material, which spans multiple applications from tires to shock absorbers, generally, the antioxidant is indispensable for NR to prolong the service life and improve the long-term reliability. Recent reports demonstrated that the purified carbon dots with the capability of scavenging oxy radicals can be effective antioxidants for rubbers. However, the application of purified CDs is greatly restricted by the multiple tedious, complicated, time-consuming, and expensive post-purification processes. Herein, we first synthesize the amine-passivated crude carbon dots (CCDs) by a facile microwave-assisted pyrolysis method, and we attempt to directly use the CCDs (without any purifications) as a novel and inexpensive antioxidant for NR. To achieve a fine CCDs dispersion within NR matrix, we disperse the CCDs into the NR matrix by the liquid feeding and in-situ compatibilizing. The CCDs fluid was firstly prepared by mixing the CCDs with water, then the CCDs fluid together with the compatibilizer was melt-compounded with NR. The results showed that the well-dispersed CCDs endowed NR with the impressive antioxidative property. Overall, this work extends application scope of CCDs and provides unique inspiration to develop novel and effective antioxidants for elastomers.

Steel plates with opening have been widely used in various structures, including buildings, bridges, ocean platforms, and industrial equipment. In addition, corrosion can cause an opening on the surface of steel panels. The shear capacity of steel panels is the most important performance utilized by steel structures, such as the steel plate shear wall. This capacity can be significantly deteriorated by these openings. Hence, this study investigated the shear capacity of steel panels with multiple openings. The influence of opening position and shape, panel thickness, and material strength were evaluated. An analytical method for predicting the shear capacity of panels with multiple openings was proposed. The accuracy of the proposed method was validated by experimental and numerical results.

Branching structures are beginning to draw the engineering designer’s attention for their novel appearance and high structural efficiency. Detailed form-finding analysis is important for branching structures and there are few applicable methods for this kind of analysis. A novel numerical method was proposed based on this research background. Double-element method was firstly introduced and the iterative program was proposed. Then the accuracy and reliability of the proposed method were validated by existing research results. The proposed method was utilized for form-finding analysis of three different kinds of tree structures. Results indicated that the proposed method was highly efficient in dealing with form-finding analysis of tree structures. In addition, the proposed method was easy and convenient to be adopted.

A high-strength geopolymer was prepared with fly ash as a raw material by mixing 25% slag and 15% cement at an ambient temperature. The influence law of water glass modulus and alkali activator dosage on geopolymer strength at an ambient temperature was systematically investigated. Results indicated that an alkali activator dosage of 7% to 8% and a sodium silicate modulus of 1.4 to 1.6 are optimal ranges to increase geopolymer strength. In addition, the microstructure of fly ash geopolymer was observed through scanning electron microscopy, X-ray diffraction, and mercury intrusion porosimetry. The relation between the microstructure and mechanical properties of the material was revealed.

The use of deep learning for image segmentation has proven to be an efficient and accurate method, but with the complexity of the network structure, it takes up a lot of computing resources. The consumption of computing resources may be unacceptable during tasks. Aiming at this problem, a fast and light segmentation network (FLSNet) is proposed, which uses the Encoder-Decoder method to extract features. All convolutional layers use depthwise separable convolutions and the channel attention module is linked between Encoder and Decoder. Experiments are performed on the autonomous driving dataset CamVid. The results show that with a slight increase in segmentation accuracy, the model size becomes 8.65% of SegNet, the required computing resources are reduced by a dozen times, and the segmentation speed is increased by about 12%, which show that our network is efficient.

Steel plates have been widely used in various structures, including buildings, bridges, ocean platforms, and industrial equipment. Corrosion is inevitable for steel plates adopted in these structures, of which pitting corrosion is one of the most common types. The shear capacity of steel plates is the most important performance utilized by steel structures, such as a steel plate shear wall. However, corrosion can significantly deteriorate the shear capacity of steel plates. Hence, the shear capacity of corroded steel plates is investigated to reveal the influence of corrosion. Stochastic numerical analysis is performed and the randomness of the pitting corrosion, including corrosion location and pitting size, is accurately considered. The relationship between shear capacity and mass loss ratio is the key research content. The influences of geometrical parameters and the constitutive model of steel on randomly corroded steel plates are investigated. Lastly, the changing trends of shear capacity and mass loss ratio are derived.

In rechargeable lithium ion batteries (LIBs), the separator undergoes stresses in repeated charge and discharge processes. Polyvinylidene fluoride (PVDF) gel separators own excellent thermal stability and electrolyte wettability, but their limited mechanical strength cannot sustain severe strains under the conditions of large Li ion fluxes, mechanical and thermal shocks of batteries. In this report, a solid-electrolyte-reinforced gel separator is prepared through a single-step electrophoretic deposition on a stable surfactant-free colloid of PVDF-HFP and Al-doped Li6.75La3Zr1.75Ta0.25O12 (LLZTO). The LLZTO/PVDF-HFP separator owns a 3D laminated structure, a mechanical strength of 28.6 MPa, a room-temperature ionic conductivity of 7.13 × 10−4 S cm−1 and improved thermal stability. With the LLZTO/PVDF-HFP separator, LiFePO4 LIBs deliver a threshold discharge capacity of 170 mAh g−1 at 0.1 C and stable cycling with nearly zero capacity decay over 100 cycles at 0.5 C.

With the rapid development of mobile devices, Android applications (apps) are universally used. However, attackers repackage Android apps and release them to the markets for illegal purposes, which brings great threats to the Android ecosystem. To leverage the popularity of original apps, they keep similar software behaviors to confuse app users. Furthermore, repackaged apps can be obfuscated or encrypted to avoid being detected. Besides, hybrid mobile apps, built by combining web technology and native elements, are becoming a preferred choice for developers. The structure of hybrid apps differs a lot from that of native apps which would raise great challenges to repackaging detection. Existing works still have some limitations in detecting repackaging from obfuscated and encrypted apps. Besides, few of them can deal with hybrid apps. In this paper, we proposed an approach based on the app UI regions extracted from app's runtime UI traces. We also implement a tool named RegionDroid based on the approach. We apply RegionDroid to tree datasets with totally 369 apps. It successfully finds all the 98 obfuscated or encrypted repackaged pairs in dataset S1. It also shows good credibility in distinguishing another 114 commercial apps in dataset S2. We also test our approach in dataset S3 with 157 hybrid apps by comparing them pairwisely and the false positive rate is 0.016%.

On 19 October, 1955, the Academy of Traditional Chinese Medicine affiliated with the Ministry of Health of the People's Republic of China was established formally. On 8 October, 1985, its name was changed to "China Academy of Traditional Chinese Medicine", which was renamed as "China Academy of Chinese Medical Sciences (CACMS)" on 15 November, 2005. During its six decades of history, the construction of the institutions in the CACMS were improved constantly. Nowadays, there are altogether 17 academic institutions, 6 clinical institutions, 1 educational institution and 6 industrial institutions in the CACMS, which has become a comprehensive research institution of traditional Chinese medicine (TCM), embodying scientific research, clinical service, education and industry as a whole, under the direct control of the State Administration of Traditional Chinese Medicine of the People's Republic of China.

Several reports link printing and photocopying with genotoxicity, immunologic and respiratory diseases. Photocopiers and printers emit nanoparticles, which may be involved in these diseases. The physicochemical and morphological composition of these emitted nanoparticles, which is poorly understood and is critical for toxicological evaluations, was assessed in this study using both real-time instrumentation and analytical methods. Tests included elemental composition (40 metals), semi-volatile organics (100 compounds) and single particle analysis, using multiple high-sensitivity/resolution techniques. Identical analyses were performed on the toners and dust collected from copier's exhaust filter. Engineered nanoparticles, including titanium dioxide, iron oxide and fumed silica, and several metals were found in toners and airborne nanoscale fraction. Chemical composition of airborne nanoscale fraction was complex and reflected toner chemistry. These findings are important in understanding the origin and toxicology of such nanoparticles. Further investigation of their chemistry, larger scale exposure studies and thorough toxicological characterisation of emitted nanoparticles is needed.

Four sets of remote sensing images from 1987, 1994, 2000, and 2006, 50 years of meteorological and soil moisture data corresponding to different desertified lands were combined with populations and livestock data to analyze the process and cause of desertification in a portion of the Qinghai–Tibetan Plateau (QTP). It showed that surface soil temperature in the region has increased at an average rate of 0.6 °C per decade between 1980 and 2005, the thawing days on the surface have increased by 60 days from 1983 to 2001, and the depth of the seasonal thawing layer has increased by 54 cm, 102 cm and 77 cm in April, May and June, respectively, from 1983 to 2003. As a result, the upper soil layer has become drier due to the thickening active layer and soil water infiltration. These changes, in turn, have inhibited the growth of alpine meadow vegetation that has shallow root systems. It is concluded that climate warming and permafrost thawing have caused desertification in grazing regions of the Qinghai–Tibetan Plateau (QTP).

Sandy desertification is a land degradation characterized by wind erosion, mainly resulted from the excessive human activities in arid, semiarid and part of sub-humid regions in North China. It is one of main kinds of desertification/land degradation as well as water-soil erosion and salinization in China. Rapid and continuous spread of sandy desertification during last 50 years has created a major environmental and socio-economic problem in North China. Remote sensing monitored results in 2000 showed that the sandy desertified land area has been 38.57 × 104 km2. The area of potential to slightly sandy desertified land is 13.93 × 104 km2, moderately land 9.977 ×104 km2, severely land 7.909 × 104 k2 and very severely land 6.756 × 104 km2. Sandy desertification mainly occurs in the semi-arid mixed farming-grazing zone and its northern rangeland zone, semi-arid dryland rainfed cropping zone and arid oasis-desert margin zone. The average annually developmental rate of sandy desertified land increased from 2,100 km2 · a-1 in 1976–1988 to 3,600 km2 · a-1 in 1988–2000. The basic status of sandy desertification in North China is “overall deterioration, while local rehabilitation”. Already achieved rehabilitation results and monitoring assessment show that about 60% of desertified land in North China can be restored under the conditions of rational land-use ways and intensity.

Tibetan Plateau plays an important role in past and present global climate; its modern environment change is both locally and worldwide significantly. In this article, we analyse the reason and consequences of the rapidly developing of desertificati on of Northeast Plateau grassland. It is found that the reason of desertificati on lie s in the rapid growing population and under-developed economy; the affect of local human factors may be magnified through the desertification process and air circulation; through the surface albedo change and increased dust emission, this local environmental change may affect East Asia, the north hemisphere or even the global climate.

Results from remote sensing and field survey show that desertification of Sunite Steppe increased rapidly since the 1980s’ and 26 percent of the 6092533 hectare grassland has become desertification land, of which there are 1073600 hectare slight desertification land, 311900 hectare moderate desertification land, 122700 hectare severe desertification land and 54700 hectare very severe desertification land. Three ty pes of desertification land exist here: coarse gravel surface resulting from wind erosion, shrub -coppice dunes and sand sheets from sand deposit, and fixed dunes reactivation. It is found that the cause of desertification in Sunite Steppe lies in the non--equilibrium between changeful natural environments and human activities. In the arid and semi arid human-nature ecological system, there exists some kind of hysteresis that people adjust actions themselves with the change of environment factors. That shoul d be why desertification develops rapidly today in a flourish steppe at one time.