Search

The present study investigated the embryonic development, growth, metamorphosis, locomotory patterns, and feeding behaviors of Paphia textile larvae, offering dietary suggestions based on observed patterns. The larvae were subjected to a dietary regimen consisting of nine microalgae species at various developmental stages (1, 4, 7, 10, 13, and 16 days post-hatching). One hour after each feeding session, their feeding patterns were carefully documented. To assess digestion, larvae that had consumed the microalgae were filtered, rinsed, and placed in filtered seawater. The embryonic development of P. textile encompassed distinct stages, including the fertilized egg, emergence of the first and second polar bodies, progression through the 2–32 cell stage, morula stage, blastula stage, gastrula stage, trochophore stage, and ultimately the D-larvae stage. Movement patterns revealed that the larvae primarily utilized their cilia for locomotion and feeding. From a transverse perspective, they moved clockwise, tracing an irregular circular path. Vertically, they exhibited spiral movements, ascending or descending as needed. As they entered the late stage, they transitioned to using reciprocal expansion of their axe feet for crawling and filtering food through their gills. Throughout their development, the larvae were fed a variety of microalgae species, including Chlorella vulgaris, Nannochloropsis oculata, Pavlova viridis, Dicrateria zhanjiangensis, and Isochrysis galbana. At 4 days old, they began consuming Dunaliella salina, and at 7 days, they incorporated Platymonas subcordiformis into their diet. By 10 days of age, they had expanded their food choices to include Chaetoceros muelleri. However, it was noted that larvae frequently suffered from indigestion or incomplete digestion when fed excessive amounts of C. vulgaris and N. oculata. Therefore, it is recommended to commence the larval culture of P. textile using P. viridis, D. zhanjiangensis, and I. galbana as the primary dietary sources. Furthermore, a feeding strategy emphasizing small, frequent meals is recommended to promote optimal digestion and larval health.

Cash holding is an important area of corporate financial management. Reasonable cash holding can help a company improve its competitiveness and development prospects. This paper examines the link between control level and cash holdings in different level intervals, and the regulating effect of ultimate controller characteristics on the relationship between control level and cash holdings. The results show that it is a nonlinear relationship between the control level and corporate cash holdings, which first decreases, then rises and then decreases. The nature of ultimate controller can enhance the relationship between the control level and cash holdings, and the negative correlation between control level and cash holdings is stronger in non-governmental control company than in governmental control company. The influence of control intensity on relationship decreases with the increase of control level. The study has certain reference significance for enterprises to optimize the level of cash holdings and improve the efficiency of resource allocation., Author(s): Xiao Hu [sup.1] , Bin Liu [sup.1] , Zhenghua Deng [sup.2] Author Affiliations: (1) grid.190737.b, 0000 0001 0154 0904, School of Economics and Business Administration, Chongqing University, , 174 [...]

In this study, the effect of different amounts of molybdenum disulfide (MoS2) content on the microstructure and mechanical properties of Cu–10Al–4Ni–4.8Fe powder alloys was investigated. The results showed that the alloy initially consisted of KⅠ, KⅡ, KⅢ, and α phases without MoS2. However, when 2% MoS2 content was added, the lamellar Cu1.84Mo6S8 phase appeared in the alloy, and with increasing MoS2 content, the lamellar Cu1.84Mo6S8 phase and the number of pores increased. A gradual increase in the MoS2 content initially increased the sintered density, hardness, and yield strength of the alloy and then decreased. The sintered density and hardness reached their maximum values at 2% MoS2 content, while the yield strength reached its maximum value at 4% MoS2 content. With increasing MoS2 content, the friction coefficient fluctuated, while the wear loss decreased after first increasing. By applying the study results, the wear resistance of aluminum-bronze powder alloys can be improved to meet its rapidly growing industrial requirements. [ABSTRACT FROM AUTHOR]

A robot which redesigned based on the omnibearing level posture robot is introduced. By adding a rotating mechanism on each sole,the redesigned robot can walk on the slope surface,thereby,it can walk on the two special surfaces as horizontal surface,slope surface,and overcome the vertical surface. The modeling of robot is carried out,and calculate the stroke relations among all the legs,the location relations between the robot and the environment,and the gradeability of the robot and so on are analyzed. The simulation analysis of two kinds of contact way and force condition of the key parts while it walks from horizontal surface to slope surface are analyzed by using Solidworks and ADAMS software.

Magnesium alloys are well known for their excellent properties, but the potential issues with oxidation and burning during melting and casting largely limit its industrial applications. The addition of Ce in magnesium alloys can significantly raise ignition-proof performance and change the structure of the oxide film on the surface of the molten metal as well as the surface tension values. Surface tension is an important physical parameter of the metal melts, and it plays an important role in the formation of surface oxide film. In this present work, the ignition temperature and the surface tension of Mg-9wt.%Al alloy with different Ce concentrations were studied. Surface tensions was measured using the maximum bubble pressure method (MBPM). Ignition temperature was measured using NiCr-NiSi type thermocouples and was monitored and recorded via a WXT-604 desk recording device. The results show that the ignition point of Mg-9wt.%Al alloy can be effectively elevated by adding Ce. The ignition temperature reaches its highest point of 720 ℃ when the addition of Ce is 1wt.%. The surface tension of the molten Mg-9wt.%Al alloy decreases exponentially with the increase of Ce addition at the same temperature. Similarly, the experiment also shows that the surface tension of Mg-9wt.%Al alloy decreases exponentially with the increase of temperature.