Search

A convenient and robust protocol for the selective transfer semireduction of alkynes was developed, using bio-renewable formic acid as the hydrogen source and easily handled supported gold nanoparticles as the catalyst. The catalytic system showed several attractive features such as high activity and selectivity, recyclability, scalability and adaptability to continuous operation under mild reaction conditions, thus providing a practical alternative to current methods for alkyne semireduction.

A propagation force is introduced into the analysis of rumor propagation to address uncertainty in the process. The propagation force is portrayed as a fuzzy variable, and a category of new parameters with fuzzy variables is defined. The classic susceptible, infected, recovered (SIR) model is modified using these parameters, a fuzzy reproductive number is introduced into the modified model, and the rationality of the fuzzy reproductive number is illuminated through calculation and comparison. Rumor control strategies are also discussed.

Given the vital importance of furfural (FFA) upgrading towards a sustainable bio-based economy, an eco-friendly aqueous route to produce a sole valuable product from FFA is highly desirable. We herein describe an efficient approach to quantitatively convert FFA into cyclopentanone (CPO) in neat water, employing H2 as the clean reductant and supported gold nanoparticles as a simple yet versatile catalyst. The use of anatase TiO2 featuring only mild Lewis acidic sites as the underlying support is essential, not only for preventing undesirable side reactions, but also for attaining high CPO selectivity. The feasibility of using biogenic CPO and CO2 as benign carbon sources to synthesize the industrially important feedstock dimethyl adipate is also demonstrated.

Reductive amination (RA) is one of the most important transformations in organic chemistry. A versatile and sustainable gas-free RA of aldehydes carried out directly with cheaply available nitroarenes using stoichiometric amounts of non-toxic and entirely renewable formic acid (FA) as the terminal reductant is described herein. A single phase rutile titania supported gold (Au/TiO2-R) catalyst is shown to catalyse efficiently this FA-based direct RA in neat water under mild reaction conditions. The broad scope, mild and neutral conditions, together with CO2 and water as environmental harmless byproducts, make this transformation very useful. Moreover, straightforward examples of the direct construction of bioactive heterocyclic compounds containing a benzimidazole motif were achieved through this protocol.

According to WHO, one of these mass gatherings with critical risk is stampedes. Shanghai "12.31" stampede was a preventable tragedy that the government and event planner hold responsibility for. At the same time, it can be a legacy for improvement in the future. The government should draw experience on the implementation of an emergency preparedness system, in order to improve the rapid emergency response during mass gatherings in the future.

Rapid and accurate estimation of soil nutrient content based on hyperspectral data is an optimal method for the monitoring of soil nutrient and inversion of soil physical and chemical characters. The relationship between soil nutrient content and spectral reflectance was analyzed with soil samples being collected from the loess hilly-gully region of northern Shaanxi Province. The prediction models of the content of soil organic matter, total nitrogen, total phosphorus and total potassium were constructed by the combination of three techniques, including partial least squares (PLS), multiple linear regression (MLR), and support vector machine (SVM). Then, the optimal model was selected by comparison analysis. The results showed good correlations between the content of soil nutrients and spectral reflectance in visible region (400-760 nm) and near infrared region (760-1100 nm). The maximum values of correlation coefficient located in both spectral regions. The SPA-SVM model had the best applicability and highest inversion accuracy for the contents of all soil nutrients, with simple and efficient modeling process. Our results provided a reference for applying machine learning algorithm in the construction of hyperspectral prediction model of soil nutrient content in the loess hilly-gully region.基于高光谱数据快速准确估算土壤养分含量,可为土壤养分监测及土壤理化参数反演提供优化方法.本研究在陕北黄土丘陵沟壑区选取典型样地,分析土壤养分含量与光谱反射率的定量关系,采用连续投影算法提取其光谱特征波长,利用偏最小二乘法、多元线性回归法、支持向量机法分别对土壤有机质、全氮、全磷、全钾含量进行预测并对比分析,构建该区域土壤养分含量的最优高光谱预测模型.结果表明: 黄土丘陵沟壑区土壤养分含量与光谱反射率在可见光区(400～760 nm)和近红外区(760～1100 nm)相关性较高,相关系数最大值均位于这两个光谱区间.4种土壤养分含量的SPA-SVM模型的普适性好且反演精度高,建模过程简单高效,适用于小数据量试验.本研究结果可为采用机器学习算法构建黄土丘陵沟壑区土壤养分含量高光谱预测模型提供参考.

Quantifying plant litter cover is important to evaluate the effectiveness of vegetation to protect soil against soil erosion. Field campaign was carried out in the Loess Hilly-gully Region of Northern Shaanxi to acquire the spectral reflectance data of plant-soil mixed scenes for two broadleaf forests and rehabilitated grassland. Spectral behavior of plant-soil mixed scenes was analyzed and the effectiveness of hyperspectral indexes NDLI (normalized difference lignin index) and CAI (cellulose absorption index) for quantifying plant litter cover was evaluated based on lab and field experiments. The results showed spectra reflectance of plant-soil mixed scenes with different proportions of litter and soil varied greatly by the influence of color and water content. The NDLI and CAI values increased with the rise of proportion of litter within the mixed scene under dry and wet status, regression analysis between the two indexes and plant litter cover of mixed scenes showed that the obviously better result for CAI (R2=0.98, rehabilitated grassland and broadleaf forests under dry status). The discrimination between mixed scenes and soil using CAI significantly outperformed NDLI under dry status; the estimation of plant litter cover by CAI is more effective compared to NDLI. Lab analysis was validated by field measuring: R2=0.90 showed highest correlation between CAI and plant litter cover for rehabilitated grassland. The validity of estimation of plant litter cover by both two indexes reduced to some degree in the field. The research enhanced the scientific basis for remote sensing estimation of plant litter cover.

Single phase rutile titania supported gold nanoparticles (Au/TiO2-R) are found to be efficient and versatile catalysts for chemo- and regioselective transfer hydrogenation of quinoline derivatives to 1,2,3,4-tetrahydroquinolines (THQs) using formic acid (FA) as a safe and convenient hydrogen source under mild conditions. The activity and chemoselectivity of the Au/TiO2-R catalyst towards THQs is excellent, with a substrate to catalyst ratio (S/C) of 1000 being feasible. Furthermore, a straightforward and selective route to N-formyltetrahydroquinolines (FTHQ) directly from quinoline compounds and FA by one-pot, gold-catalyzed reductive N-formylation protocol is also established.

A facile and efficient catalytic system based on a mesostructured ceria-supported gold (Au/meso-CeO2) catalyst was developed for the synthesis of various aromatic azo compounds by the reductive coupling of the corresponding nitroaromatics, using CO as the sole deoxygenative reagent, under additive-free and mild reaction conditions.

Lung cancer in elderly patients poses an increasingly challenge for oncologists. The optimal treatment needs to be explored. The purpose of this study was to evaluate the safety and efficacy of the novel form of paclitaxel liposome for elderly patients with non-small cell lung cancer (NSCLC). This multi-center prospective trial recruited patients aged at least 70 years with advanced or recurrent NSCLC. Eligibility criteria included presence of measurable lesions, an Eastern Cooperative Oncology Group performance status of 0-2, as well as adequate organ function. Patients received paclitaxel liposome at the escalating dose of 135 mg/m Forty-two patients were enrolled with a median age of 73 years (range 70-81). No complete response was observed. Partial response was obtained in 6.7%, 14.2% and 7.7% of patients, and 13.3%, 42.9% and 38.5% had stable disease from the three dose groups. In these groups, 26.7%, 21.4% and 25% of patients experienced grade 3-4 neutropenia. Time to progression was 1.2 months (95% confidence interval [CI], 1.1-1.3 months), 1.2 months (95% CI, 0.9-1.3 months) and 1.9 months (95% CI, 1.4-2.3 months), respectively. Overall survival in the dose group of 135 mg/m Paclitaxel liposome administered at the dose of 150 mg/m

BACKGROUND: Adherence to a combination of healthy lifestyle factors has been related to a considerable reduction of cardiovascular risk in white populations; however, little is known whether such associations persist in nonwhite populations like the Asian population. OBJECTIVES: This study aimed to examine the associations of a combination of modifiable, healthy lifestyle factors with the risks of ischemic cardiovascular diseases and estimate the proportion of diseases that could potentially be prevented by adherence to these healthy lifestyle patterns. METHODS: This study examined the associations of 6 lifestyle factors with ischemic heart disease and ischemic stroke (IS) in the China Kadoorie Biobank of 461,211 participants 30 to 79 years of age who did not have cardiovascular diseases, cancer, or diabetes at baseline. Low-risk lifestyle factors were defined as nonsmoking status or having stopped smoking for reasons other than illness, alcohol consumption of

With the development of the society, traditional video monitoring could not meet the users’ demand of video surveillance. Setting up a video monitoring system on the cloud platform is necessary. Video monitoring system can meet the users’ demand of search video, upload video, video storage, video transcoding and download video.

To guarantee the protocol implementation is correct, protocol testing is essential. Formal specification provides a middle method for protocol testing, which can support verification and testing protocol semi-automatically or automatically. RRC is an important protocol in WCDMA system. So the paper describe RRC protocol process as a formal model based CPN modeling method, then analysis and verify the model with CPN Tools to ensure it is correct.

The azo linkage is a prominent chemical motif which has found numerous applications in materials science, pharmaceuticals, and agrochemicals. Described herein is a sustainable heterogeneous-gold-catalyzed synthesis of azo arenes. Available nitroarenes are deoxygenated and linked selectively by the formation of N=N bonds using molecular H2 without any external additives. As a result of a unique and remarkable synergy between the metal and support, a facile surface-mediated condensation of nitroso and hydroxylamine intermediates is enabled, and the desired transformation proceeds in a highly selective manner under mild reaction conditions. The protocol tolerates a large variety of functional groups and offers a general and versatile method for the environmentally friendly synthesis of symmetric or asymmetric aromatic azo compounds.

Nanowire Na0.35MnO2 was prepared by a simple and low energy consumption hydrothermal method; its electrochemical performance as a cathode material for aqueous asymmetric supercapacitors in Na2SO4 solution was investigated. Due to the nanowire structure its capacitance (157 F g−1) is much higher than that of the rod-like Na0.95MnO2 (92 F g−1) from solid phase reaction although its sodium content is lower. When it is assembled into an asymmetric aqueous supercapacitor using activated carbon as the counter electrode and aqueous 0.5 mol L−1 Na2SO4 electrolyte solution, the nanowire Na0.35MnO2 shows an energy density of 42.6 Wh kg−1 at a power density of 129.8 W kg−1 based on the total weight of the two electrode material, higher than those for the rod-like Na0.95MnO2, with an energy density of 27.3 Wh kg−1 at a power density of 74.8 W kg−1, and that of LiMn2O4. The new material presents excellent cycling behavior even when dissolved oxygen is not removed from the electrolyte solution. The results hold great promise for practical applications of this cathode material since sodium is much cheaper than lithium and its natural resources are rich.

Propylene, one of the most demanded commodity chemicals, is obtained overwhelmingly from fossil resources. In view of the diminishing fossil resources and the ongoing climate change, the identification of new efficient and alternative routes for the large-scale production of propylene from biorenewable resources has become essential. Herein, a new selective route for the synthesis of propylene from bio-derived glycerol is demonstrated. The route consists of the formation of 1-propanol (a versatile bulk chemical) as intermediate through hydrogenolysis of glycerol at a high selectivity. A subsequent dehydration produces propylene.

This paper solves the distributed generation (DG) planning problem. Firstly, multiple-objective functions have been formed with the consideration of minimum line loss, minimum voltage deviation and maximal voltage stability margin. Secondly, the proposed improved NSGA-II algorithm has been described in detail to solve the multi-objective planning problem. An improved Non-dominated Sorting Genetic Algorithm II has been proposed for optimal planning of multiple DG units in this paper. Experiment has been made on the IEEE 33-bus test case with the consideration of multiple DG units. The computational result and comparison indicate the proposed algorithm for optimal placement and sizing of DG in distribution system is effective.

In this paper, the optimum process parameters were obtained through treating phenol of simulated semi-coking wastewater using heat, Fe2+, Fe0 and semi-coke to catalyze persulfate. The results of phenol decomposition using PS catalyzed by heating, Fe2+, Fe0 and semi-coke were compared for selecting a better activating way. The article investigated the effects of temperature, catalyzer dosage, pH value and reaction time. The experiment showed the four methods can all catalyzed the process. Under the experimental conditions of heating, Fe2+, Fe0 and semi-coke degradation rate could reach to 20.7%, 75.1%, 94.5% and 40.0%, respectively. On this basis, this study established an L16(45) table to analyze the main influencing factors in semi-coke/Fe0 catalyzing system. Under the optimum conditions, the degradation rate of Phenol reached to 93.6%. However, the PS dosage was reduced by 14.4%.

We describe a sustainable, cost-effective, and highly efficient H2-free protocol for catalytic hydrogenolysis of glycerol to 1,2-propanediol (1,2-PDO) using formic acid (FA) as the H2 source. The process is catalyzed by an earth-abundant and robust Cu-based metal oxide catalyst, in which the high performance of the Cu catalyst for the in situ generation of H2 gas in the system by highly selective decomposition of FA in an aqueous medium is essential. The activity test results showed that a synergy effect of well-dispersed Cu and amphoteric ZrO2 is essential for FA decomposition as well as for glycerol conversion to 1,2-PDO. The Cu content of the Cu/ZrO2 catalyst prepared by the oxalate gel method has a significant role in the FA-mediated glycerol conversion to 1,2-PDO, and a Cu content of 20 wt% on ZrO2 was identified as the optimum Cu content. Moreover, the creation and maintenance of high component dispersion is essential for high glycerol hydrogenolysis activity of the Cu/ZrO2 system. Because selective hydrogenolysis with minimum use of external fossil-fuel H2 is a critical issue in the realization of biorefinery concepts, the procedure described here is expected to be of broad applicability in biomass use.

nanoTiO2photocatalyst modified by N and Fe3+ion were loaded on fly ash forming adsorbent (FFA) using the sol-gel dip-coating technique. The structure and properties of the samples were characterized by UV-Vis spectrum, SEM and XRD. The related influencing factors were also discussed. The results showed that modified TiO2was immobilized on the surface of FFA in the form of nanocrystalline and an apparent absorption peak appears in the visible region of photocatalyst doped with N,Fe ion. Moreover, under visible light irradiation for 6h, the degradation rate of 50mg/L of methylene blue by loaded catalyst reached 92.6 %.

The electronic structure and optical properties of Cu-doped SnS2with Sn-substituted content of 0, 12.5 and 37.5 at.% were successfully calculated by the first principles plane-wave pseudopotentials based on the density functional theory. It is found that the intermediate belts appear near the Fermi level and the energy band gap becomes narrower after the doping of the Cu atoms. The absorption peaks show a remarkable redshift and the absorption region broadens relatively after introducing acceptor impurity level. When Sn atoms of 37.5 at% were substituted by Cu, the optical absorption coefficient is significantly improved in the frequency range below 5.58 eV and over 8.13 eV.

The testability is one of the important features to the quality of software, which can guide the intensity and degree of the test, arrange test progress better. Any embedded software can not only contain just a fault, there may be two or more faults, and there is correlation among these faults. In order to arrange testing resources more reasonably, this paper uses correlation matrix to put forward the Embedded Software Testability Fault Model, ESDFM, which based on fault/failure model, and introduces the process of the measurement.

A new method has been developed for the catalytic conversion of biomass-derived levulinic acid (LA) into gamma-valerolactone (GVL) with molecular hydrogen (H-2) using a series of heterogeneous noble metal catalysts. Excellent yields of the GVL were obtained under mild reaction conditions of 50 degrees C and 2 MPa of H-2 using iridium nanoparticles supported on carbon nanotubes (Ir/CNT). It is noteworthy that the reaction proceeded smoothly in the presence of formic acid (FA, co-produced with LA in equimolar amounts during the acid-mediated hydrolysis of lignocellulosic biomass). Furthermore, the FA remained intact, highlighting the practical advantages of this process for the convenient and cost-effective processing of a biomass-derived LA/FA solution. The method is effective for the simultaneous production of GVL and FA from a wide variety of renewable biomass resources. (C) 2013, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

We investigate the dynamic evolution behaviors of entanglement and geometric quantum discord (GQD) of hybrid qubits in a circuit QED system. Under certain initial conditions, interactions between qubits and that between the qubit and the cavity can suppress the decay of entanglement and GQD of qubits. Under the initial condition |ψ Q (0)〉 I =sinα|↓↑〉+cosα|↑↓〉, such decay was avoided by increasing the coupling strength ratio between qubits and that between the qubit and the cavity. Under the aforementioned condition, the survival time of entanglement and GQD was prolonged by decreasing the coupling strength ratio between qubits and that between the qubit and the cavity.

Clean alcohol-alcohol cross-coupling: A clean and efficient one-pot direct C-C cross-coupling of equimolar amounts of primary and secondary alcohols by a facile hydrogen autotransfer pathway is achieved over a robust and easily recovered hydrotalcite-supported Au-Pd bimetallic catalyst system. A variety of primary and secondary alcohols have been selectively converted into the corresponding β-alkylated ketones in good yields.

A series of mesoporous β-Ga 2 O 3 with high surface area have been prepared using eco-friendly sucrose as a non-surfactant template and studied in relation to their performance in the dehydrogenation of propane to propylene in the presence of CO 2 . Among the four sucrose-derived samples tested, the material prepared from a sucrose/Ga 2 O 3 molar ratio of 4 achieved the highest propane conversion, which was approximately the double efficiency of the conventional β-Ga 2 O 3 . The enhanced activity of the sucrose-derived materials is attributed to a high abundance of coordinative unsaturated surface Ga sites as a consequence of their favorable textural properties and enhanced surface areas.

Based on the change of type of figure, constant research has been done on the theory of Chinese clothing prototype——Donghua Prototype (Patent No. 02150747). Through contrasts and analysis of various grading methods, the simplified version of Donghua Prototype grading has been developed. According to the change of type of figure of Chinese female, we modified the version of Donghua Prototype grading by body measurements, wearing experiments, and analysis of coverage rate and dispersion tendency on the experiment data.

This article studies on automatic pattern generation of female pants. The authors analyze and summarize the structure of the female pants, and divide plants into different units. Then the authors extract shape and structure factors form the every element of plants, parameterize the factors, build modules with Modasoft system. At last, the authors test the validation of every module by changing the value of variables, and combines operation of different modules. These modules save the time of pattern-making significantly and improve efficiency. With these modules, technical personnel avoid large number of repetitive work. The automatic pattern generation is the trend of garment CAD.

The purpose of this study was to provide the reference information for current and potential users of apparel 3D CAD system by studying the functional characteristics of apparel 3D CAD study. The apparel 3D CAD system of Optitex, V-Stitcher and DC-Suite was selected for technical compara tive study.The results were at follows: 1. Three systems are similar in basic 3D system configuration and working flow. 2. In configuring a module, Optitex and V-Stitcher separate a 2D pattern and a 3D simulation, whereas DC-Suite configures a 2D pattern and a 3D simulation in one system. 3. In Optitex, a 3D Runway system performs 3D simulation works linked with its own 2D pattern - making software, Optitex PDS, after the 2D pattern is made. 4. In case of V-Stitcher, 2D pattern making is done linked with Gerber Pattern CAD and a 3D simulation proceeds. 5. DC-Suite was developed based on 3D simulation technologies, different from other systems. It includes its own 2D pattern-making technologies.

Reductive amination (RA) is one of the most important transformations in organic chemistry. A versatile and sustainable gas-free RA of aldehydes carried out directly with cheaply available nitroarenes using stoichiometric amounts of non-toxic and entirely renewable formic acid (FA) as the terminal reductant is described herein. A single phase rutile titania supported gold (Au/TiO2-R) catalyst is shown to catalyse efficiently this FA-based direct RA in neat water under mild reaction conditions. The broad scope, mild and neutral conditions, together with CO2 and water as environmental harmless byproducts, make this transformation very useful. Moreover, straightforward examples of the direct construction of bioactive heterocyclic compounds containing a benzimidazole motif were achieved through this protocol.

A convenient and robust protocol for the selective transfer semireduction of alkynes was developed, using bio-renewable formic acid as the hydrogen source and easily handled supported gold nanoparticles as the catalyst. The catalytic system showed several attractive features such as high activity and selectivity, recyclability, scalability and adaptability to continuous operation under mild reaction conditions, thus providing a practical alternative to current methods for alkyne semireduction.

The pursuit of modern sustainable chemistry has stimulated the development of innovative catalytic processes that enable chemical transformations to be performed under mild and clean conditions with high efficiency. Herein, we report that gold nanoparticles supported on TiO(2) catalyze the chemoselective hydrogenation of functionalized quinolines with H(2) under mild reaction conditions. Our results point toward an unexpected role for quinolines in gold-mediated hydrogenation reactions, namely that of promoter; this is in stark contrast to what prevails in the traditional noble metal Pd-, Pt-, and Ru-based catalyst systems, in which quinolines and their derivatives typically act as poisons. As a result of the remarkable promotional effect of quinoline molecules to H(2) activation over supported gold, the transformation can proceed smoothly under very mild conditions (even at temperatures as low as 25 °C). Of practical significance is that various synthetically useful functional groups including halogens, ketone, and olefin remain intact during the hydrogenation of quinolines. Moreover, the protocol also shows promise for the regiospecific hydrogenation of the heterocyclic ring of a variety of other biologically important heteroaromatic nitrogen compounds, such as isoquinoline, acridine, and 7,8-benzoquinoline, in a facile manner. Apart from its importance in catalytic hydrogenation, we believe that this intriguing self-promoted effect by reactant molecules may have fundamental implications for the broad field of gold catalysis and form the basis for development of new catalytic procedures for other key transformations.

To investigate the effect of Yisui Shengxue Granule (益髓生血颗粒, YSSXG), a complex Chinese medicine, on the oxidative damage of erythrocytes from patients with hemoglobin H (HbH) disease. Twenty-two patients with HbH disease and 22 healthy volunteers were observed. YSSXG was given to patients with HbH disease for 3 months. Before and after the 3-month treatment, blood parameters [hemoglobin (Hb), red blood cells (RBCs), and reticulocyte percent (Ret)] were examined; inclusion bodies in erythrocytes were observed by transmission electron microscopy (TEM); activities of antioxidant defense enzymes [superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (Cat)] and erythrocyte membrane malondialdehyde (MDA) concentrations were determined. In patients with HbH disease, measured values of RBC and Hb obtained from the first to the third months after treatment with YSSXG were significantly higher than before treatment (P 0.05) or MDA concentration (P>0.05). However, compared with the healthy counterparts, SOD, GSH-Px, and Cat activities presented at high levels (P

To find the changing regularity of stress and displacement, a 3MW wind-turbine main shaft was modeled and analyzed at startup time of operation. The results were verified by theoretical calculation. Parametric design of the shaft was used through orthogonal experiment method in which parameters were consisted of structural and load ones. The optimal regression equation, which indicated the relationship between the shaft stress or displacement and the parameters, was given by using polynomial regression with the test results.

In terms of keeping material costs low and increasing competitive advantage, supplier selection is one of the most important functions of a business. This paper uses an effective solution based on a combined Analytic Network Process (ANP) and Decision-Making Trial and Evaluation Laboratory (DEMATEL) approach to find the criteria that are key to performance improvement. This paper surveys the multicriteria supplier selection approaches and reveals the most popular criteria and sub-criteria. Based on experts’ suggestions and the most popular criteria, the key factors in the selection of food industry suppliers are identified. Then, the causal relationships and relative importance weights of the criteria in the system are computed using the cluster-weighted DEMATEL with ANP method. This paper compares the results of experts and purchasing managers and discovers a cognitive gap. The managers agree that cost and delivery are very important; they need to keep material costs down and increase the company’s competitive advantage. The experts value customer satisfaction and Corporate Social Responsibility (CSR), so they feel that quality and service are the most important criteria.

Formic acid (FA) has tremendous potential as a safe and convenient source of hydrogen for sustainable chemical synthesis and renewable energy storage, but controlled and efficient dehydrogenation of FA by a robust solid catalyst under ambient conditions constitutes a major challenge. Here, we report that a previously unappreciated combination of subnanometric gold and an acid-tolerant oxide support facilitates the liberation of CO-free H(2) from FA. Applying an ultradispersed gold catalyst comprising TEM-invisible gold subnanoclusters deposited on zirconia to a FA-amine mixture affords turnover frequencies (TOFs) up to 1590 per hour and a turnover number of more than 118,400 at 50 °C. The reaction was accelerated at higher temperatures, but even at room temperature, a significant H(2) evolution (TOFs up to 252 h(-1) after 20 min) can still be obtained. Preliminary mechanistic studies suggest that the reaction is unimolecular in nature and proceeds via a unique amine-assisted formate decomposition mechanism on Au-ZrO(2) interface.

ed to this work, Ru(OH)x supported on TiO2 proved to be an efficient catalyst for the direct amination of alcohols with urea. One critical limitation associated with this process, however, is that a large excess of relatively expensive alcohols (alcohol/ urea = 10:1) was required to obtain high yields of the desired substituted amines. From a synthetic and economic point of view, an atom-efficient catalytic transformation that can be carried out using stoichiometric amounts of alcohol and urea is preferred. On the basis of our ongoing interest in the unique catalytic properties of supported gold nanoparticles (NPs) [10] and their applications to green and sustainable organic synthesis, [11] we have recently discovered that very small Au NPs (mean size ca. 1.8 nm) supported on acid-tolerant TiO2 (Au/TiO2-VS, see Supporting Information) can promote selective N-alkylation of amines with alcohols under mild conditions. [12] A wide range of secondary amines were obtained with high atom efficiency by the employment of equimolar amounts of starting materials. In view of the excellent performance of the gold system for the alkylation of amines with alcohols, we reasoned that the heterogeneous Au-mediated hydrogen-borrowing strategy could afford a sustainable protocol for the amination of alcohols with urea. Herein, we report for the first time that gold catalysis enables the clean and selective formation of tertiary or secondary amines from the direct amination of stoichiometric amounts of alcohols with urea. By using this method, the reactions of primary alcohols with urea exclusively gave tertiary amines, while those of secondary alcohols selectively afforded

Gearbox was a key component of wind turbine but with the highest failure rate, so it was necessary to analyze its safety and reliability. In this paper, gears in MW wind turbine gearbox were analyzed by nonlinear finite element contact analysis method. The changing regularity of the stress was found as tooth mesh, and it was proved to be reliable by comparing with the result of theoretical calculations. The maximum contact stress existed on the second engaged tooth as well as the vicinity of the pitch circle of gears. The stress concentration phenomena occurred at the tooth root fillet which caused the main failure form of gears.

Stellera chamaejasme is one of the main poisonous weeds distributed in alpine meadow of Qinghai Province. Rapid spreading of S. chamaejasme has done serious harm to local animal husbandry and caused continuous grassland ecosystem degradation. This paper focused on the spectral differences between S. chamaejasme and herbage, taking the typical degraded alpine meadow dominated by S. chamaejasme in Qilian County of Haibei Region as the test site and using the spectral measurements acquired in the full-blossom period of S. chamaejasme from 2012 to 2014. The results showed that the spectral behavior of flowers of S. chamaejasme differed significantly from green background that included leaves of S. chamaejasme and herbage within 350-900 nm of VIS-NIR wavebands. The biggest reflectance difference between flowers of S. chamaejasme and green background was located in the red valley, followed by the blue valley. The reflectance of S. chamaejasme community increased with the rising of coverage, the biggest reflectance difference between S. chamaejasme and herbage communities lied in the near-infrared peak, and the best separability between S. chamaejasme communities with different coverage was also at the point. The difference of first derivative spectra between flowers of S. chamaejasme and green background located in amplitude of yellow edge was remarkable, followed by amplitude of blue edge, the same as differences between S. chamaejasme and herbage communities. Linear regression analysis between coverage of S. chamaejasme and spectral feature parameters showed best result for red valley (R2 = 0.94). Finally, the red valley, the blue valley and the near-infrared peak were proposed for discriminating S. chamaejasme from herbage in the full-blossom period of S. chamaejasme, and the combination of corresponding red, blue and near-infrared bands could be used to build sensitive indices for S. chamaejasme recognition.

A series of yttrium-doped lithium trivanadates LiV3-yYyO8 (y=0, 0.01, 0.03, 0.05, 0.1 and 0.2) were synthesized by a solid-state reaction. X-ray diffraction (XRD) tests show that a proper amount of yttrium doping in LiV3O8 can modify its structure. Charge-discharge tests show that doped samples with a proper amount of yttrium display good cycling stability compared with undoped sample. The cyclic voltammetry (CV) tests indicate that the proper amount of yttrium doping in LiV3O8 can stabilize its original structure. Yttrium doping is a convenient and effective method for improving the electrochemical performances of LiV3O8.

A practical two-stage reactive grinding-assisted pathway waste-free and cost-effective for the synthesis of NiMoO{sub 4} has been successfully developed. It was demonstrated that proper design in synthetic strategy for grinding plays a crucial role in determining the ultimate polymorph of NiMoO{sub 4}. Specifically, direct grinding (DG) of MoO{sub 3} and NiO rendered {alpha}-NiMoO{sub 4} after annealing, whereas sequential grinding (SG) of the two independently pre-ground oxides followed by annealing generated {beta}-NiMoO{sub 4} solid solution. Characterizations in terms of Raman and X-ray diffraction suggest the creation of {beta}-NiMoO{sub 4} precursor in the latter alternative is the key aspect for the formation of {beta}-NiMoO{sub 4}. The DG-derived {alpha}-NiMoO{sub 4} tested by oxidative dehydrogenation of propane exhibited superior activity in contrast to its analog synthesized via conventional coprecipitation. It is suggested that the favorable chemical composition facilely obtained via grinding in contrast to that by coprecipitation was essential for achieving a more selective production of propylene. - Graphical Abstract: Grinding-assisted synthesis of NiMoO{sub 4} offers higher and more reproducible activities in contrast to coprecipitation for oxidative dehydrogenation of propane, and both {alpha}- and {beta}-NiMoO{sub 4} can be synthesized. Highlights: Black-Right-Pointing-Pointer NiMoO{sub 4} was prepared through grinding-assisted pathway. Black-Right-Pointing-Pointer Direct/sequential grinding rendered {alpha}-, {beta}-NiMoO{submore » 4}, respectively. Black-Right-Pointing-Pointer Grinding-derived {alpha}-NiMoO{sub 4} showed high and reproducible activity for oxidative dehydrogenation of propane.« less

Two series of binary In 2 O 3 /MO x (M = Al, Zr, Si) catalysts with low (3 wt%) and high (10 wt%) In 2 O 3 loadings were prepared via an incipient wetness impregnation method. The support effect has been investigated in detail by testing the propane dehydrogenation (PDH) reaction both in the presence and absence of CO 2 . Physico-chemical properties including surface composition, redox and acidic/basic properties of the supported In 2 O 3 were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, H 2 temperature-programmed reduction, NH 3 and CO 2 temperature-programmed desorption, respectively. It was demonstrated that a higher population of the specific highly dispersed In 2 O 3 species on support is favorable for propylene production, and the maximum propylene yield was achieved with the high-loading In 2 O 3 /Al 2 O 3 . Properties including high In 2 O 3 dispersion and balanced acidic/basic properties, rendering synergism between dehydrogenation and reverse water gas shift, are essential for achieving high catalytic performance of PDH.

Mesostructured doped Ce 1− x M x O catalysts (M = Al, Sn, Zr, Mn, and Ni) with large surface area prepared via template-assisted precipitation method have been tested for the oxidative dehydrogenation (ODH) of ethylbenzene (EB) to styrene. Several techniques including N 2 desorption–adsorption, X-ray diffraction, H 2 -temperature programmed reduction (H 2 -TPR), total oxygen storage capacity (OSC), and X-ray photoelectron spectroscopy (XPS) were applied to characterize the physicochemical properties of the as-synthesized materials. Of the Ce 1− x M x O catalysts tested, the CeNiO composite containing 10 mol% Ni demonstrates the highest ST yield of 55% with long-term stability for ODH of EB under 450 °C. By analysis of H 2 -TPR and total OSC characterization profiles, the superior performance of Ce 0.90 Ni 0.10 O catalyst can be attributed to the dramatic improvement in oxygen mobility and storage capacity of the ceria materials, resulting from the introduction of Ni species into ceria cubic structure and hence a further shrinkage of ceria lattice. A catalytic mechanism via a simple surface redox cycle has been tentatively proposed based on the XPS results.

As the main load-bearing component, the tower supports the weight as well as the wind force and the dynamic load in operation of the wind turbine. It also endures the blow of itself. The level of the tower design directly affects the performance of wind turbines. This paper discusses static characteristic and dynamic model anasysis of the tower of an 1.5MW horizontal axis wind turbine. It is also about choice and calculation method of finite element.

Armhole is a base part of the sleeve. The sleeve morphological characteristics affect the construction and shape of sleeve. The underarm point is one of key restraining factors affecting armhole’s three-dimensional configuration. The experiments of armhole’s three-dimensional configuration and attaching sleeve experiments were designed according to the changes of the vertical and horizontal displacement of underarm point. The regression equation is established through the method of correlation analysis and regression analysis.

The ligand-free Ir/TiO2 nanocluster catalyst allows for the synthesis of various quinolines (III) under mild conditions.