Measurement of Photoionization Cross Sections of the Excited States of Titanium

Resonance-enhanced multiphoton ionization of the titanium atoms has been investigated in the 293 321 nm wavelength. We couple a laser-ablated metal target into a molecular beam to produce free atoms. Ions produced from photoionization of the neutral atoms are monitored by a home-built time-of-flight mass spectrometer. Photoionization cross sections of the excited states of Ti I were deduced from the dependence of the ion signal intensity on the laser intensity for photon energies close to the ionization threshold. The values obtained range from 0.2 Mb to 6.0 Mb. No significant isotope-dependence was found from measurements of the photoionization cross sections of ^46Ti, ^47Ti, and ^48Ti.

Partial replacement of soybean meal by yellow mealworm(Tenebrio molitor)meal influences the flesh quality of Nile tilapia(Oreochromis niloticus)

This study investigated the effects of yellow mealworm meal(YM)replacing soybean meal(SBM)at different proportions(0%,15%,30%and 45%,referred as YM0,YM15,YM30 and YM45,respectively)on the flesh quality of Nile tilapia.A total of 360 fish(70.0±0.12 g)were randomly divided into 4 groups(3 tanks per group).Fish were fed the experimental diet twice daily for 10 wk.The results showed that muscle protein content significantly decreased in YM30 and YM45,while the lipid content significantly decreased in YM45(P<0.05).The essential amino acids and flavor amino acids of the muscle were not affected by the YM substitution,while saturated fatty acid content decreased in YM30 and YM45 compared with YM0(P<0.05).Fillets in YM45 had higher hardness,gumminess,and a higher proportion of thin myofibers(≤100μm,P<0.05)than those in other groups.Further analysis revealed that apoptosis and atrophy related genes were up-regulated,while the muscle antioxidant capacity decreased significantly in YM45(P<0.05),which may be related to the high acid value in YM45 diet.Our findings indicated that YM could replace up to 30%SBM without substantially altering the flesh quality.When the replacement ratio increased to 45%,the flesh quality would change.Special attention should be paid to avoid feed rancidity which may affect the flesh quality of fish.

Uridine alleviates high-carbohydrate diet-induced metabolic syndromes by activating sirt1/AMPK signaling pathway and promoting glycogen synthesis in Nile tilapia(Oreochromis niloticus)

Carbohydrates have a protein sparing effect,but long-term feeding of a high-carbohydrate diet(HCD)leads to metabolic disorders due to the limited utilization efficiency of carbohydrates in fish.How to mitigate the negative effects induced by HCD is crucial for the rapid development of aquaculture.Uridine is a pyrimidine nucleoside that plays a vital role in regulating lipid and glucose metabolism,but whether uridine can alleviate metabolic syndromes induced by HCD remains unknown.In this study,a total of480 Nile tilapia(Oreochromis niloticus)(average initial weight 5.02±0.03 g)were fed with 4 diets,including a control diet(CON),HCD,HCD+500 mg/kg uridine(HCUL)and HCD+5,000 mg/kg uridine(HCUH),for 8 weeks.The results showed that addition of uridine decreased hepatic lipid,serum glucose,triglyceride and cholesterol(P<0.05).Further analysis indicated that higher concentration of uridine activated the sirtuin1(sirt1)/adenosine 5-monophosphate-activated protein kinase(AMPK)signaling pathway to increase lipid catabolism and glycolysis while decreasing lipogenesis(P<0.05).Besides,uridine increased the activity of glycogen synthesis-related enzymes(P<0.05).This study suggested that uridine could alleviate HCD-induced metabolic syndrome by activating the sirt1/AMPK signaling pathway and promoting glycogen synthesis.This finding reveals the function of uridine in fish metabolism and facilitates the development of new additives in aquatic feeds.

战略性新兴产业发展的理论、政策与实践——文献综述

战略性新兴产业是近年来的热门研究领域。本文从发展理论、政策和实践三个方面对战略性新兴产业文献发展脉络进行梳理。首先,回顾了战略性新兴产业理论研究的一些重点研究领域;其次,总结了政策支持在战略性新兴产业发展中的作用及存在的问题;再次,归纳了中国及全球战略性新兴产业发展现状的研究;最后,在述评基础上提出了此领域未来值得深入研究的方向,以期为战略性新兴产业的理论研究与发展政策提供有价值的思路。

Modeling, Experimental Study on the Heat Transfer Characteristics of Thermoelectric Generator

This paper investigates the heat transfer characteristics of a thermoelectric generator. The influence of heat dissipation intensity to the sub-thermal resistances distribution is experimentally studied. Based on the thermal network analysis and finite time thermodynamics, an analytical model including all thermal resistances (in both thermocouples and external heat exchangers) is developed to predict the performance of the generator. The results show that the computed values of output power agree well with the experimental values. The heat transfer enhancement on the generator cold side greatly reduces the cold side temperature and thermal resistance, and obviously improves the output power. Compare with air natural convection cooling, the main thermal resistance changes from the resistance between the fins and the ambient to the thermal contact resistances between the generator and the heat sink at the conditions of forced convection and water cooling. This study may be guide the optimization of generator structure.