Effects of the terms associated with phi(zz) in free surface condition on the attitudes and resistance of different ships

One of approaches for numerical simulation of a ship moving in a still water is based on the composition of double-body flow and wavy flow solved by a boundary element method. There are several terms related to the second order derivative (ϕzz) of double-body flow velocity potential with respect to the vertical coordinate in the free surface conditions. Understanding of the effects of the terms is very limited so far. In many cases, they are just ignored even for ships with a high forward speed, particularly in the cases associated with multihull ships, for which no investigations on their effects have been found. This paper will present a study on the effects of the terms on the numerical prediction of the attitudes and resistance of different ships in various situations, including monohull, catamaran and trimaran with different parameters and at different Froude numbers. The results will demonstrate that the effects of the terms are significant in many cases and that considering this term may lead to the results similar to those obtained by fully nonlinear models at high Froude numbers

Microsite Effects on Physiological Performance of <i>Betula ermanii</i> at and Beyond an Alpine Treeline Site on Changbai Mountain in Northeast China

The alpine treeline demarcates the temperature-limited upper elevational boundary of the tree life form. However, this treeline does not always occur exclusively as a sharp &#8220;line&#8221;, outposts of tree groups (OTG) with a height of at least 3 m are often observed in microsites up to several hundred meters beyond the line of continuous forest on some mountains. This suggests that other factors such as microenvironment may play a significant role in compensating for the alpine tree facing growth-limiting low temperature conditions. To test the microenvironment effects, this study compared the differences in growing conditions (climate and soil properties) and ecophysiological performance of Erman&#8217;s birch (Betula ermanii Cham.) trees growing in a continuous treeline site (CTL, ~1950 m above sea level, a.s.l.) and OTGs (~2050 m a.s.l.) on Changbai Mountain in northeastern China. The results show the average 2-m air temperature for OTG was slightly lower in the non-growing season than which at the CTL (&#8722;10.2 &#176;C &lt; &#8722;8.4 &#176;C), there was no difference in growing season air temperature and soil temperature at 10 cm depth between CTL and OTG. The contents of focal soil nutrients in CTL and OTG were similar. Difference in K and Mn contents between sites were detected in leaves, difference in K, Mn, and Zn in shoots. However, comparing similarity of ecophysiological performances at an individual level, trees at CTL and OTG show no significant difference. Our study reveals that mature trees at the CTL and OTG experience generally similar environmental conditions (climate and soil properties) and exhibit similar overall ecophysiological performance (reflected in carbon reserves and nutrients). This might provide insight into how mature trees might be able to survive in areas higher than the continuous treeline, as well as the importance of microclimatic amelioration provided by protective microsites and the trees themselves

Determination of Senegenin and Tenuifolin in Mouse Blood by Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry and Their Pharmacokinetics

An ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the determination of senegenin and tenuifolin in mouse blood was developed. The pharmacokinetics of senegenin and tenuifolin in mice after intravenous (5 mg/kg) and oral (60 mg/kg) administration were studied, and the absolute bioavailability was calculated. A CORTECS T3 column was used, with a column temperature set at 40°C. The mobile phase was acetonitrile and 0.1% formic acid. Gradient elution was adopted, using a flow rate of 0.4 mL/min and an elution time of 4 min. Quantitative analysis was performed using electrospray ionization (ESI) with multiple reaction monitoring (MRM) in negative ion mode. Institute of Cancer Research (ICR) mice were bled from the tail vein after intravenous or oral administration of senegenin and tenuifolin. A UPLC-MS/MS method was established to determine the blood concentrations of each drug in mice, and the noncompartmental model was used to fit the pharmacokinetic parameters. Senegenin and tenuifolin showed a good linear relationship (r > 0.995) within a concentration range of 5–400 ng/mL in mouse blood. The intraday precision was 88%, and the matrix effect was 87–94%. The oral bioavailability of senegenin and tenuifolin in mice was 8.7% and 4.0%, respectively. The established UPLC-MS/MS method is suitable for pharmacokinetic studies of senegenin and tenuifolin in mice

Effect of Ce addition on the nucleation and growth of austenite in ultra-high-strength steel

The effect of varying rare earth element cerium (Ce) contents (0∼0.0792 wt%) on the austenite grain size of ultra-high-strength engineering steel has been studied under different austenitization conditions (holding time of 5∼360 min at temperatures ranging from 900 °C to 1200 °C). Results show that the addition of Ce can refine grains, and the refining effect becomes more pronounced as the Ce content increases. The inhibition of austenite grain growth by fine Ce-containing inclusions during the holding process has been observed through laser scanning confocal microscopy (LSCM) and field-emission scanning electron microscope (FE-SEM) equipped with an energy dispersive spectrometer (EDS), and the pinning effect of Ce-containing inclusions on the austenite grain boundaries is the primary factor for the refinement of austenite grains. Besides, theoretical calculations have shown that the lattice misfits between the (100) plane of CeP and the (111) plane of the γ-phase is 7.83%, indicating that CeP could serve as a heterogeneous nucleation core for the γ-phase and was moderately effective. Furthermore, the uniformization effect of Ce on the grains is more prominent than the refining effect at the holding temperatures of 1000 °C and 1200 °C

Significantly improvement in formability and ductility of AZ31 Mg alloy by differential temperature rolling

The implementation of asymmetric deformation proves to be an effective approach towards optimizing the basal texture of wrought Mg alloys, ultimately leading to improved plasticity and formability. This work performs differential temperature rolling (DTR) on AZ31 Mg alloy to achieve asymmetric deformation. After the DTR process, the ductility and formability of the RT-200 sample are comparable to the traditional cold rolling and annealing combination process. Combined with the annealing treatment (AT), the fracture elongation and Erichsen value of the RT-200/AT sample are reached 32.4% and 4.49 mm, respectively. The improvement of the ductility and formability is mainly attributed to the texture weakening, which originates from the temperature gradient formed in the DTR process. The gradient temperature field modifies the dynamic recrystallization behavior during the rolling deformation process, as well as the static recrystallization behavior during annealing. The microstructure evolution and the texture weakening mechanism are discussed in detail. The findings can serve as a theoretical reference for the development of high-ductility Mg alloys and for optimizing the continuous hot-rolling process of Mg alloys

A Tomato Putative Metalloprotease SlEGY2 Plays a Positive Role in Thermotolerance

Intramembrane proteases play very important roles in plants, such as chloroplast development, flower morphology, and response to abiotic stress. In this study, a putative metalloprotease gene, homologous to Ethylene-dependent Gravitropism deficient and Yellow-green2 (EGY2) of Arabidopsis, was isolated from tomato (Solanum lycopersicum) plants and named SlEGY2. We found that SlEGY2 was a member of the metalloprotease family M50 which contained conserved motifs HEXXH and NPDG and was localized in the chloroplast. SlEGY2 antisense transgenic tomato plants (AS) have similar hypocotyls phenotype to the Arabidopsis egy2 mutant. Heat (42 °C), PEG, ABA and MeJA treatments can upregulate the expression of SlEGY2. Under heat stress, SlEGY2 AS lines are more sensitive, with more water loss (lower fresh weight), seriously damaged membrane, and ROS accumulation, but lower activities of APX and CAT. In addition, suppression of SlEGY2 decreases the content of chlorophyll and photosynthetic activities, especially photosystem II. These results suggest that SlEGY2 can regulate the thermotolerance of tomatoes by affecting ROS accumulation and photosynthetic activities

Microstructure design of advanced magnesium-air battery anodes

Metal-air battery is an environmental friendly energy storage system with unique open structure. Magnesium (Mg) and its alloys have been extensively attempted as anodes for air batteries due to high theoretical energy density, low cost, and recyclability. However, the study on Mg-air battery (MAB) is still at the laboratory level currently, mainly owing to the low anodic efficiency caused by the poor corrosion resistance. In order to reduce corrosion losses and achieve optimal utilization efficiency of Mg anode, the design strategies are reviewed from microstructure perspectives. Firstly, the corrosion behaviors have been discussed, especially the negative difference effect derived by hydrogen evolution. Special attention is given to the effect of anode micro-structures on the MAB, which includes grain size, grain orientation, second phases, crystal structure, twins, and dislocations. For further improvement, the discharge performance, long period stacking ordered phase and its enhancing effect are considered. Meanwhile, given the current debates over Mg dendrites, the potential risk, the impact on discharge, and the elimination strategies are discussed. Microstructure control and single crystal would be promising ways for MAB anode

Transient Study of Femtosecond Laser–Induced Ge2Sb2Te5 Phase Change Film Morphology

Femtosecond laser-induced crystallization and ablation of Ge2Sb2Te5 (GST) phase change film is investigated by reflectivity pump-probing technology. Below the ablation threshold, the face-centered cubic structure (FCC) state in the central area can be formed, and cylindrical rims are formed in the peripheral dewetting zone due to the solidification of transported matter. The time of surface temperature dropping to the crystallization point needs about 30 ps for 5.86 mJ/cm2 and 82 ps for 7.04 mJ/cm2, respectively. At higher laser fluence, crystallization GST island structures appear in the central ablation region due to the extremely short heating time (100 ps). Furthermore, crystallization rate is faster than the ablation rate of the GST film, which is caused by different reflectivity