Search

With the continuous improvement of the accuracy of machine tools, the proportion of the thermal error of machine tools in the total error is increasing. In this paper, the thermal error of horizontal machining center is analyzed by finite element simulation, a three-dimensional model is established in SolidWorks, and some details (such as bolt holes) are simplified and imported into ANSYS Workbench to determine the heat generation model, heat dissipation model, convection heat transfer coefficient and other boundary conditions. On the basis of the temperature field, the thermal-structural coupling analysis is carried out, and the temperature cloud field of the whole machine tool is obtained through the analysis, which provides a theoretical basis for the experimental design. Then, the data are divided into four categories by fuzzy cluster analysis, and finally, the thermal error model is established by BP neural network based on time series. It provides a theoretical reference for the compensation of thermal error.

The purpose of this work was to analyze and evaluate the functional properties of a new nanoemulsion that contained cordycepin. Droplet size and distribution were measured, and the stability of the nanoemulsion in different storage conditions was evaluated. We also tested skin irritation caused by the nanoemulsion, cordycepin stability in the nanoemulsion, anti-aging effect, and microbial challenge. The nanoemulsion was homogeneous with proper dispersion stability, and cordycepin was stable for eight months within the cosmetic nanoemulsion. The nanoemulsion did not irritate human hand and face skin, and the cosmetic nanoemulsion was effective in preventing microbial contamination of the product during use and storage. The new nanoemulsion containing cordycepin satisfied provisions of the 2015 Safety and Technical Standards for Cosmetics of the Ministry of Health, People’s Republic of China.

With the expanding of economy,the environment protection has become more and more critical especially in developing countries.China is the 2nd economic entity in the world and faces even more challenge.Heavy metals are naturally found in soils and rock formations but may also occur in fertilizers and pesticides,as a result of which may cause heavy-metal contamination.The global rate of heavy metal pollution is rapidly increasing in various habitats,heavy metals such as Cadmium(Cd) are one of the most fundamental causes of soil and water pollution in industrialized and developing countries.Metal pollution is a serious environmental problem worldwide,and severely threatens biological diversity and human health.Cadmium(Cd) is a heavy metal that accumulates in the environment and causes pollution as well as intoxication of both vertebrates and invertebrates.Cd biomagnification in the terrestrial food chain appears to be dependent on the physiological properties of the organisms rather than on their trophic level.Although high Cd body burdens in spiders from the field have been reported many times,experimental verification of the key factors that determine the rate of cadmium accumulation is lacking.Metals can accumulate in plants,and via food webs can cause harmful effects to herbivorous and pollinating insects and their predators,among other members of the biota.Biological indicator species are species that can be measured as surrogates for environmental health and levels of pollution before adverse environmental impacts become obvious. spiders are exposed to environmental pollutants,growth and reproduction can be sharply reduced due to an increased detoxification effort.Spiders,at the individual level,have great potential as biological indicators of metal contamination in soil,because of their position in the food web and consequent biological magnification.Spiders occupy an important part of the predatory arthropod fauna in terrestrial ecosystems.They also play a large role in the regulation of pest species in agriculture.Wolf spiders are generalist predators of other terrestrial invertebrates.The wolf spider Pirata subpiraticus(Araneae,Lycosidae) is a common,surface-active wolf spider that inhabits very wet places and can be used as a very important bio-indicator for heavy metals pollution.Here,we investigated the cadmium assimilation rate in the common wolf spider Pirata subpiraticus for three generations fed by Drosophila melanogaster reared on artificial diets with 20 mg/kg.In addition,biological response traits of P.subpiraticus to adapt to heavy metal polluted diets was tested experimentally.It was demonstrated that a high cadmium assimilation(65.4%,68.5% and 69.1%) and an excretion rate approaching zero resulted in high Cd concentration factors in P.subpiraticus for three generations.Cd biomagnification fators were 1.71,2.12 and 2.17,respectively.The results indicate the importance of spiders in cadmium biomagnification along critical pathways.Furthermore,Our results illustrate that P.subpiraticus responds behaviorally to the presence of high concentrations of heavy metals in food.The results also indicate the metal-selected P.subpiraticus have a significantly lower width of carapace,survival rate,cocoon weight and egg number.And P.subpiraticus also exhibit behaviors resulting in extended total duration,increased egg volume and decreased tolerance starvation life span.Our results suggest that although P.subpiraticus displays the potential to develop tolerance to heavy metals,particularly Cadmium,this may occur at a significant biological cost,which can adversely affect its ecological fitness. From these observations,we speculate that P.subpiraticus avoidance behavior towards high concentrations of heavy metals may have a positive effect on their survival and reproductive success in nature,particularly in the presence of metal-contaminated food sources.P.subpiraticus can be employed as a specific indicator for metal exposure,and also for the evaluation of chronic effects of metals in foodchains after long-term exposure.The results might provide more adequate theoretical basis insight into Cd along the soil-insects-predators transmission,biomagnification and physiological tolerance.

Densities have been measured for Glucose + HCl +Water at 10-degree intervals from 278.15 to 318.15 K. The apparent molar volumes (V Φ,G) and standard partial molar volumes (V Φ,G 0 ) for Glucose in aqueous solution of 0.2, 0.4, 0.7, 1.1, 1.6, 2.1 mol·kg−1 HCl have been calculated as well as volumetric interaction parameters (V EG) for Glucose — HCl in water and standard partial molar expansion coefficients (∂V Φ,G 0 / ∂T)p. Results show that (1) the apparent molar volume for Glucose in aqueous HCl solutions increases lineally with increasing molality of Glucose and HCl; (2) V Φ,G/0 for Glucose in aqueous HCl solutions increases lineally with increasing molality of HCl; (3) the volumetric interaction parameters for Glucose — HCl pair in water are small positive and vary slightly with temperature; (4) the relation between V Φ,G 0 and temperature exists as V Φ,G 0 = a 0 + a 1(T − 273.15 K)2/3; (5) values of (∂V Φ,G 0 / ∂T)p are positive and increase as temperatures rise, and at given temperatures decrease slightly with increasing molalities of HCl, indicating that the hydration of glucose decreases with increasing temperature and molality of HCl. These phenomena are interpreted successfully by the structure interaction model.