滩涂新生土地“稻-蟹-鱼”综合种养模式应用初探

近年,通过“重盐土三合一脱种一体化栽培方法”可将滩涂盐碱地改造成可种植水稻等农作物的土地,但单独种、养殖经济效益不理想。因此,针对盐城沿海滩涂湿地实际情况,笔者于2022年在盐城东台市沿海滩涂新生土地开展“稻-蟹-鱼综合种养”试验,现将试验情况介绍如下。

Stamping Reliability of Rocket Engine Cover Based on Finite Element Anglysis and Experiments

This paper mainly focuses on the simulation and experimental study of the reliability of the solid rocket nozzle cover.The test-bed is designed according to the technical requirements in order to provide different stamping rates and tests for different sizes of covers.The gas source,the four valves and the installation container structure are used to realize the stamping.The installation container is a multistage flange stacking structure to achieve the installation of different sizes of plugging covers,and then the opening process of the plugging cover is recorded by the high speed pressure sensor and the automatic control system.The fluid solid coupling method is used to simulate the impact state of plugging cover in the flow field at 10,20,30 and 35 ms,and the maximum pressure at 35 ms is 1.244 MPa.Then the deformation of aluminum alloy plugging cover is observed by stress analysis and display dynamic method.The maximum value of Von Mises Stress of the simulation result is 277.600 MPa.In the experimental test,the performance of the system is tested with a high strength plugging cover.In the opening state of the two large flux control valves,the pressure in the installation container reaches 1.000 MPa at 35 ms.And then we modify the experimental system with the knowledge of aerodynamic theory.Finally,the plugging cover is installed to carry out the experiment,so as to obtain the reliable stamping rate of the plugging cover.Simulations,blind measurements and measurement results provide strong data for reliability of the plugging cover opening,and provide reliable reference data for rocket engine charge structure and nozzle shape optimization.

饲料不同水平磷脂和胆固醇对克氏原螯虾肝胰腺转录组的影响

为研究饲料中磷脂和胆固醇不同添加水平对克氏原螯虾(Procambarus clarkii)肝胰腺转录组的影响,采用3×3因子试验法,设计3个磷脂(phospholipid,PL)水平(0、20、60 g/kg)和3个胆固醇(cholesterol,CH)水平(0、5、10 g/kg)共9种饲料,分别标记为A~I组。饲喂克氏原螯虾雌性幼虾60 d后,基于RNA-seq技术对其肝胰腺的转录组数据进行分析。测序共得到508051个Unigenes,平均长度为521.6 bp。设置显著差异基因筛选条件为P<0.05并随机选取若干显著差异表达基因(differentially expressed genes,DEGs)进行实时荧光定量PCR(quantitative real-time PCR,RT-qPCR)验证。对高添加量(PL 60 g/kg;CH 10 g/kg)I组、中添加量(PL 20 g/kg;CH 5 g/kg)E组和低添加量(PL 0 g/kg;CH 0 g/kg)A组肝胰腺样本的测序文库分别进行两两比较。GO功能富集分析结果显示,差异表达基因主要集中在生长、繁殖、免疫系统过程、代谢过程等通路中;KEGG通路富集分析发现脂肪的消化吸收、卵巢类固醇生成、脂肪酸生物合成、维生素消化吸收、甘油酯脂代谢等过程被显著富集,与脂质代谢和类固醇激素合成相关的差异表达基因均显示显著上调(P<0.05)。本研究为探究饲料中磷脂和胆固醇调控克氏原螯虾生长发育机制等方面提供参考数据。