The development of new‐type memristors with special performance is of great interest. Herein, an inorganic‐organic hybrid crystalline polyoxometalate (POM) with usual dynamic structures is reported ...and used as active material for fabricating memristor with unique temperature‐regulated resistive switching behaviors. The hybrid POM not only exhibits tunable thermochromic properties, but also thermal‐induced reversible aggregation and disaggregation reactions, leading to reversible structural transformations in SCSC fashion. Further, the memory device using the hybrid POM as active layer exhibits uncommon performance, which can keep resistive switching silent in the low temperature range of 30–150 °C, but show nonvolatile memory behavior in the high temperature range of 150–270 °C. Particularly, the silent and working states at three special temperatures (30, 150 and 270 °C) can be monitored by chromism. The correlation between structure and resistive switching property of the material has been discussed. The work demonstrates that crystalline inorganic‐organic hybrid POMs are promising materials for making memristors with superior performance.
An unusual polyoxometalate‐metalloviologen hybrid with thermal‐triggered reversible intermolecular multi‐component reaction and structural transformation is made and used as a nonvolatile memristor, which exhibits unique temperature‐regulated behavior and visual color changes for its silent and working states.
Cup‐shaped molecules are of great interest due to their appealing architectures and properties. Compared with widely studied calixarenes, polyoxometalate‐based cup‐shaped molecules currently remain a ...virgin land waiting for exploration. In this work, we report the first discovery of two giant cup‐shaped inorganic–organic hybrid polyoxoniobates (PONbs) of {Cu12Nb120} and {Cd16Nb128}. The former integrates three tricyclic Nb24 clusters and a hexacyclic Nb48 cluster into a cup‐shaped molecule via a Cu12 metallacalixarene, while the latter unifies two tricyclic Nb24 clusters and a brand‐new pentacyclic Nb40 cluster into another cup‐shaped molecule via a hybrid Cd16 unit. With 132 and 144 metal centers, {Cu12Nb120} and {Cd16Nb128} show the largest two inorganic–organic hybrid PONbs known to date.
Calixarene‐like polyoxoniobates: Two unprecedented giant calixarene‐like polyoxoniobate (PONb) nanocups based on multiple macrocyclic clusters have been made, showing the fusion of two areas of metallacalixarene and PONb chemistry. The two molecular nanocups are by far the largest two inorganic–organic hybrid PONbs and hold promise for developing largely unexplored inorganic–organic hybrid PONb chemistry.
Only rarely have polyoxometalates been found to form core–shell nanoclusters. Here, we succeeded in isolating a series of rare giant and all‐inorganic core–shell cobalt polyoxoniobates (Co−PONbs) ...with diverse shapes, nuclearities and original topologies, including 50‐nuclearity {Co12Nb38O132}, 54‐nuclearity {Co20Nb34O128}, 62‐nuclearity {Co26Nb36O140} and 87‐nuclearity {Co33Nb54O188}. They are the largest Co−PONbs and also the polyoxometalates containing the greatest number of Co ions and the largest cobalt clusters known thus far. These molecular Co−PONbs have intriguing and atomically precise core–shell architectures comprising unique cobalt oxide cores and niobate oxide shells. In particular, the encapsulated cobalt oxide cores with different nuclearities have identical compositions, structures and mixed‐valence Co3+/Co2+ states as the different sized Co−O moieties of the bulk cubic‐spinel Co3O4, suggesting that they can serve as various molecular models of the cubic‐spinel Co3O4. The successful construction of the series of the Co−PONbs reveals a feasible and versatile synthetic method for making rare core–shell heterometallic PONbs. Further, these new‐type core–shell bimetal species are promising cluster molecular catalysts for visible‐light‐driven CO2 reduction.
A series of rare Co−Nb‐based core–shell polyoxometalates containing 50, 54, 62 and 87 metal polyhedra is prepared. The cobalt oxide cores correspond to increasingly large molecular analogues of infinite cubic‐spinel Co3O4. They are the largest cobalt polyoxoniobates and the polyoxometalates with the greatest number of Co ions and the highest‐nuclearity cobalt clusters known thus far. They are shown to be efficient photocatalysts for CO2 reduction.
Two hybrid back-propagation neural network (BPNN) models optimized by two heuristic search algorithms, namely genetic algorithm (GA-BP) and particle swarm optimization (PSO-BP), are proposed in this ...paper to predict radial maximum wall shear stress instead of traditional computational fluid dynamics (CFD) methods. The two proposed models are trained and validated using a database of 150 radial maximum wall-shear-stress values obtained via CFD simulations. The best fit model is identified from various BPNN models based on the Akaike information criterion (AIC) and the Bayesian information criterion (BIC), balancing the trade-off between goodness-of-fit and model complexity. The model performance is evaluated by MAE, RMSE, regression coefficient (R), and Nash-Sutcliffe efficiency (NSE). The best fit model is a three-layered BPNN model consisting of a 4:4:1 topology. In almost all evaluation indicators, the two hybrid BPNN methods outperform three existing algorithms, namely classical BPNN, random forest (RF), and gradient boosting decision tree (GBDT). Both PSO-BP and GA-BP can provide a more precise assessment of radial maximum wall shear stress, with maximum errors being 5.81% and 8.24% respectively. The proposed PSO-BP prediction model is promising and has great feasibility in predicting the radial maximum wall shear stress of UHP water-jet nozzle in engineering applications.
Highlights • The first study to summarize the global trends in incidence and mortality of NPC. • Decreased NPC incidence with maximum AAPCs of −5.4% in males and −4.1% in females. • Declines in NPC ...mortality rates worldwide with AAPCs varying from −0.8% to −6.5%.
Background: We estimated the incidence and mortality of nasopharyngeal carcinoma (NPC) in China in 2010 according to the data of 145 domestic population-based cancer registries in 2014, and no such ...reports since then.Hence, to further and better understand its epidemiology in China and to provide more precise scientific information for its control and prevention in China, we analyzed the NPC incidence and mortality of 255 domestic populationbased cancer registries, and estimated the national rates in 2013 again.Methods: NPC incidence and mortality data of 255 domestic cancer registries in 2013, accepted by the 2016 National Cancer Registry Annual Report, were collected and collated, and the indices of NPC such as the numbers of new cases and deaths, crude rates, age-standardized rates, and truncated rates of incidence and mortality were calculated and analyzed. The incidence and mortality in China and its constituent areas were estimated according to the national population in 2013.Results: An estimated 42,100 new cases and 21,320 deaths were attributed to NPC in China in 2013, accounting for 1.14% of all new cancer cases and 0.96% of all cancer-related deaths that year in China. Crude incidence and mortality of NPC were 3.09/100,000 and 1.57/100,000, respectively. World age-standardized incidence and mortality were 2.17/100,000 and 1.08/100,000, respectively. The incidence and mortality of males were obviously higher than those of females and slightly higher in urban areas than in rural areas. Among seven Chinese administrative regions, NPC incidence and mortality were obviously higher in South China than in other regions and lowest in North China. Top 3 incidence and mortality provinces and registering areas all located in South China. The age-specific incidence and mortality rose quickly from age 25–29 and 35 to 39 years, respectively, peaked at different ages and varied by location.Conclusions: These results demonstrated that NPC incidence and mortality in China in 2013 were also at high levels worldwide, which suggested that its control and prevention should be enhanced.
Numerical simulations of the Vortex-Induced Vibration (VIV) about a large-scale flexible pipe subject to shear flow were carried out in this paper. Efficiency verification was performed firstly, ...validating that the proposed fluid–structure interaction solution strategy is competent in predicting the VIV response. Then, the VIV characteristics related to multi-mode and spanwise hybrid waveform about the flexible pipe attributed to shear flow were investigated. When inflow velocity rises, higher vibration modes are apt to be excited, and the spanwise waveform easily convertes from a standing-wave-dominated status to a hybrid standing–traveling wave status. The multi-mode or even multiple-dominant-mode is prone to occur, that is, the dominant mode is often followed by several apparent subordinate modes with considerable vibration energy. Hence, the shedding frequencies no longer obey Strouhal law, and vibration trajectories become intricate. According to the motion analysis concerning the coupled cross-flow and in-line vibrations, as well as the corresponding wake patterns, a tight coupling interaction exists between the structural deformation and the wake flow behind the flexible pipe. In addition, the evolution of the vortex tube along the pipe span and a strong 3D effect are observed due to the slenderness of the flexible pipe and the variability of the vortex shedding attributed to the shear flow.
Four seven-nuclearity 3d-4f heterometallic cluster {Fe6LnO28} substituted polyoxometalates (HPz)11K4Fe6Ln(μ3-O)2(B-α-GeW9O34)2(GeW6O26)·xH2O (1-Ln, Pz = piperazine, Ln = Tb, Dy, Ho, Er for x = ...27, 25, 25, 24, respectively) have been hydrothermally prepared and structurally characterized by single-crystal X-ray diffraction, powder X-ray diffraction, infrared spectrometry, thermogravimetric analyses, elemental analyses, and electrospray ionization mass spectrometry. Single-crystal X-ray diffraction analyses revealed that 1-Ln contain an unprecedented banana-shaped polyanion constructed from an iron-lanthanide heterometallic {Fe6LnO28} cluster, two trilacunary {B-α-GeW9O34} units, and one hexalacunary {GeW6O26} fragment. The magnetic susceptibility surveying proved the presence of antiferromagnetic coupling in 1-Ln.
Ultra-high-pressure (UHP) water jetting is commonly used to remove rust from ship hulls. However, few studies have been undertaken to optimize the topology of reaction rotating sprinklers (RRS) using ...UHP. This work proposes two contributions aimed at optimizing the RRS topology and maximizing the efficiency of rust removal. The first contribution is a novel accumulative impinging-duration model, which can accurately quantify the spiral trajectory density of multiple water jets and provide a practical means to evaluate the feasibility of RRS topology. The second contribution is the development of a new meta-heuristic algorithm called adaptive genetic algorithm (AGA), which offers high-quality solutions for the combinatorial topology optimization problem associated with RRS. The AGA converges significantly faster than the conventional genetic algorithm (CGA) and avoids being trappped at a local optimum. The effectiveness of the proposed topology optimization method is demonstrated through two case studies involving RRS with different model specifications. The AGA significantly increases the utilization ratio of water-jet energy by more than 50.6 %, outperforming CGA. The rust-removal efficiency of AGA-optimized RRS is theoretically predicted by analyzing the maximal translation speed and further validated through field experiments. Results show that the rust-removal efficiency of AGA-optimized RRS for ship hulls is greatly improved, with improvements of over 50 % and 43 % in theoretical and practical verification, respectively. This research introduces a unique quantization method and an efficient optimization algorithm for practical RRS design.
Cancer Incidence and Mortality in China, 2007 Chen, Wan-qing; Zeng, Hong-mei; Zheng, Rong-shou ...
Chinese journal of cancer research,
03/2012, Letnik:
24, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Objective： Cancer incidence and mortality data collected from population-based cancer registries were analyzed to present the overall cancer statistics in Chinese registration areas by age, sex and ...geographic area in 2007. Methods： In 2010, 48 cancer registries reported cancer incidence and mortality data of 2007 to National Central Cancer Registry of China. Of them, 38 registries＇ data met the national criteria. Incidence and mortality were calculated by cancer sites, age, gender, and area. Age-standardized rates were described by China and World population. Results： The crude incidence rate for all cancers was 276.16/100,000 （305.22/100,000 for male and 246.46/100,000 for female; 284.71/100,000 in urban and 251.07/100,000 in rural）. Age-standardized incidence rates by China and World population were 145.39/100,000 and 189.46/100,000 respectively. The crude mortality rate for all cancers was 177.09/100,000 （219.15/100,000 for male and 134.10/100,000 for female; 173.55/100,000 in urban and 187.49/100,000 in rural）. Age-standardized mortality rates by China and World population were 86.06/100,000 and 116.46/100,000, respectively. The top 10 most frequently common cancer sites were the lung, stomach, colon and rectum, liver, breast, esophagus, pancreas, bladder, brain and lymphoma, accounting for 76.12% of the total cancer cases. The top 10 causes of cancer death were cancers of the lung, liver, stomach, esophagus, colon and rectum, pancreas, breast, leukemia, brain and lymphoma, accounting for 84.37% of the total cancer deaths. Conclusion： Cancer remains a major disease threatening people＇s health in China. Prevention and control should be enhanced, especially for the main cancers.
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