共查询到10条相似文献，搜索用时 31 毫秒
1.
本文主要讨论了函数exp（q）的pade逼近的A（α）-可接受性．对a∈（0，π／2），m≥n，m≥2，得到了exp（q）的有理逼近R（q）为A（α）-可接受的充要条件和paed逼近（q）为A（α）-可接受的几个充分条件．证明了（q）是A（π／3）-可接受的．文末构造了5阶A（π／3）-稳定的四阶导数单步方法与三阶导数混合单步法． 相似文献
2.
Turpan is one of the major high-quality grape production bases in the world for years because its climate is so special (hot, dry, and windy). The grape market needs the varieties with high yield, quality, and environmental adaptability. ‘Xinyu’ is a new variety bred by crossing selection of E42-6 (a self-pollinated inbred of Vitis vinifera cv. ‘Red Globe’) as female and Vitis vinifera cv. ‘Rizamat’ as male parents and registered in the Crop Varieties Registered Commission of Xinjiang Uygur Autonomous Region in 2005. In this study, we determined the impacts of environmental factors on its photosynthesis. The results showed the climate in Turpan was characterized by long-time intensive sunshine, high temperature and relatively low humidity. The peak value of photosynthetic available radiation (PARi) was 1 454 μmol·m-2·s-1, and the minimum and average values were 111 μmol·m-2·s-1and 938.889 6 μmol·m-2·s-1, respectively. Air temperature and sunlight intensity reached the highest values during 1 p.m. to 4 p.m. Net photosynthetic rate (Pn) of Xinyu increased stably before 11 a.m. and there was a midday depression during 11 a.m. to 2 p.m. The minimum value of Pn appeared at noon (2.77 μmol·m-2·s-1). It was concluded that as a new grape cultivar, “Xinyu” could withstand extreme climate conditions in Turpan. 相似文献
3.
设E1={arg (z)=θj∣0≤ 1<θ2<…θq1<2π},E2={arg (z)=(p)j∣0≤ (p)1<(p)1<…<(p)1<(p)2<2π},且E1∩E2=φ,q1和q2是任意正整数.证明了(1)存在△内下级为任一正数的无穷级亚纯函数f(z),恰以E1 ∪ E2为其T-半径且恰以E2为其Borel半径;(2)存在△内下级为无穷的亚纯函数g(z),恰以E1 ∪ E2为其Borel半径且恰以E2为其T-半径. 相似文献
4.
Zhengxin FEI Zijie DING Xuan ZHENG Liang FENG Qingyao HE Shuiping YAN Long JI 《农业科学与工程前沿(英文版)》2023,(3):479-491
Chemical precipitation is a widely applied approach for a liquid fraction of digestate(LFD) of agricultural waste but its large-scale application requires low-cost and efficient precipitating agents and novel process design. This study evaluated novel approach for the efficient removal of contaminants from the LFD using fly ash-based chemical precipitation, followed by filtration and CO2 mineralization. The technical feasibility of this approach was evaluated using p H and electrical ... 相似文献
5.
《东北农业大学学报(英文版)》2020,(1)
Avian infectious bronchitis(IB)is an acute and highly contagious disease caused by infectious bronchitis virus(IBV).In the study,according to IBV gene sequences published in Gen Bank,specific primers were designed to clone N gene by RT-PCR,and this gene was inserted into p ET-30a(+)vector resulting in a prokaryotic expression plasma p ET-30a-N.The results of SDS-PAGE and Western Blot analysis showed that the recombinant protein was expressed successfully and had good reactivity with IBV positive serum.Using purified recombinant N protein as a coating antigen,the indirect ELISA protocol was established and optimized,in which N protein was 2.5μg·m L~(-1) of concentration,sample serum of 1:40 dilution.For clinical specimen,the IBV antibodies could be detected by this method efficiently and got nearly the same results as those of IBV-mediated ELISA.It would provide a good tool for rapid diagnosis and epidemiological study of avian infectious bronchitis. 相似文献
6.
采用吸附动力学方法,探讨了赤铁矿(a-Fe_2O_3)对重金属Cr(Ⅲ)的吸附动力学特征.研究结果表明,赤铁矿对Cr(Ⅲ)的吸附动力学特征可以采用松弛动力学方程很好地加以描述,吸附反应表现为初始快反应和随后的慢反应两个阶段,控速步骤是Cr(Ⅲ)在赤铁矿表面水膜和毛细孔的扩散作用.Abstract： Characteristics of the adsorption dynamics of Cr(Ⅲ) ion on hematite (a-Fe_2O_3) surface were stud-ied by the adsorption dynamics method.The results showed that the adsorption dynamics of Cr(Ⅲ) adsorp-tion on the hematite surface could well be described by a relaxation dynamic equation.The adsorption reac-tion could be divided into two processes, a fast reaction stage and a slow reaction stage, and the process of Cr(Ⅲ) diffusion on hematite surface water velum and capillary was shown to be the control step. 相似文献
7.
对系数为对称正定矩阵的线性方程组Ax=b,利用系数矩阵A主对角线上元素的和构造了一种新的收敛迭代格式xk+1=(I-2/a11+…+ann A)xk+2/a11+…+ann b,并进一步对这种格式进行了改进.Abstract： Using the sum of the elements of the principal diagonal of the coefficient matrix A, a new iterative schine ,i.e.xk+1=(I-2/a11+…+ann A)xk+2/a11+…+ann b,is constructed for the linear equation Ax = b, of which the coefficient is a symmetric positive definite matrix. Further improvement is made of the scheme. 相似文献
8.
Titanate nanofibers(TNFs) were synthesized using a hydrothermal method and were employed for the first time in this study to photocatalytically degrade organic pollutants found in flocculated liquid digestate of poultry litter. The photocatalytic performance of TNFs, with a bandgap of 3.16 eV, was tested based on degradation of organic pollutants and removal of color. Five combinations of pollutant concentration and p H were examined(0.2 to1.3 g·L-1 at pH 4 to 10). Central composite d... 相似文献
9.
ZHAO Zhuo XI Geng-si 《中国农业科学(英文版)》2007,6(7):825-831
The aim of this study was to elucidate the expression and regulation of the c.kit protein in spermatogenesis of locusts. Immunohistochemistry and biological statistics were used to investigate the expression of the c-kit protein in four representative phases of spermatogenesis of three dominant species of locusts of Arcypteridae （Orthoptera： Acridoidea）, namely, Omocestus viridulus （Linnaeus）, Euchorthippus unicolor （Ikonn.）, and Euchorthippus vittatus Zheng, and so on, in Siping area of Jilin Province, China. The results revealed the following： （1） There was weak positive expression of the c-kit protein in spermatogonia and the positive granules were thinner; （2） there was a strong positive expression of the c-kit protein in primary spermatocyte and the positive granules became the largest than in all developmental stages; （3） the c-kit protein positive expression became stronger in secondary spermatocyte, while the positive granules became thinner; （4） there was strong positive expression of the c-kit protein and the positive granules were thinner in mature sperm, which were distributed on its head and tail; （5） there were strong positive protein granules massing at the end of spermary; （6） the positive intensity of the c-kit protein in spermatogenesis was significantly different among different species of locusts. The data suggested that the c-kit protein may play a crucial role in spermatogenesis as well as maintain the physiological action of sperms and fertilization, regulate the developmental speed of spermatogenesis, and/or maintain species isolation, etc. 相似文献
10.
The objective was to evaluate the toxicity effect of gossypol on ultrastructure of mouse testis and the expression of Bax mRNA and Bcl-2 mRNA of sperm cells in mice.Forty-eight male mice were randomly divided into four groups:control group,L-group(30 mg·kg~(-1)·d),M-group(60 mg·kg~(-1)·d)and H-group(120 mg·kg~(-1)·d)and were orally administrated with gossypol diluted by sodium carboxymethyl cellulose(SCC)or SCC(control group)for 20 days.On the 21st day,all the mice were killed and ultrastructure changes of testis were observed by TEM.mRNA expression of Bax and Bcl-2 in testis was measured by semiquantitative RT-PCR.The results showed that the testicular ultrastructure in three treated groups was gradually damaged,according to the dosage of gossypol and cellular structure disordered and organelle degenerated,manifesting vacuolation of mitochondria,expansion of endoplasmic reticulum.mRNA expression of Bcl-2 in testis significantly increased(p0.05)in L-group and then significantly decreased(p0.05,p0.01)in M-group and H-group compared with that in the control group;mRNA expression of Bcl-2 in M-group and H-group significantly decreased(p0.05,p0.01)than that in L-group and Bcl-2 mRNA expression in H-group showed a significant decrease(p0.05)compared with that in M-group.On the other hand,mRNA expression of Bax significant increased(p0.05,p0.01)in M-group and H-group than that in the control group.The ratio of Bcl-2/Bax significantly reduced(p0.05,p0.01)in the treated group than that in the control group and was found to be an obvious dose-dependent.It demonstrated that the gossypol could induce the changes on ultrastructure of mice testis,down-regulate mRNA expression of Bcl-2 and up-regulate mRNA expression of Bax,which indicated that sperm cells were induced apoptosis. 相似文献