Results 31 to 40 of about 23,967 (131)

关于丢番图方程x⁴-pqy²=1（Ⅱ）

四川大学学报. 自然科学版, 1980
3.方程(1)在p≡17(mod24),q≡3(mod8)或p≡5(mod24),q≡23(mod24)或p≡5(mod24),q≡3(mod8),(p/q)=1时均无正整数解.4.当D=2p时,方程(1)除开有解p=3,x=7,y=20外,无其他的正整数解.5.方程(1)在p≡3(mod4),q≡3(mod4)时无正整数解.国外,Nagell,Ljunggren,Cohn等人有过不少工作,可参看文[4]所附文献.本文用不同于前面诸文的方法,对于D=pq的情形,得到进一步的结果 ...
柯召, 孙琦
doaj  

Preparation of nano ZSM-5 with hydrophobic surfaces and application to catalytic cracking of hydrocarbon fuels(亲油性纳米ZSM-5分子筛的制备及其对碳氢燃料的催化性能)

Zhejiang Daxue xuebao. Lixue ban, 2013
采用不同链长的有机硅烷作为表面修饰剂，在正庚烷/正丁醇中利用溶剂热合成法制备得到亲油性纳米ZSM-5分子筛.通过有机硅烷与氧化物晶种表面的羟基作用，其长链化学键合到晶种表面，形成保护层，既抑制了氧化物颗粒间的团聚，又控制了纳米ZSM-5的粒径.所制备的纳米ZSM-5平均粒径为20~70 nm，且粒径随着有机硅烷碳链长度的降低而逐渐减小.添加一定量的该纳米ZSM-5到碳氢燃料模型化合物正十二烷中，在管式反应器中（550 ℃，4 MPa）考察催化裂解行为，结果表明该亲油性纳米ZSM ...
LIUJia-zhen(刘家珍), XULi(许莉), FANGWen-jun(方文军), GUOYong-sheng(郭永胜), SHANGZhong-jin(尚忠进)   +4 more
doaj   +1 more source

The Impact of AI‐Assisted L2 Learning on Learners’ Emotions: A Meta‐Analysis

International Journal of Applied Linguistics, EarlyView.
ABSTRACT The scope of research on AI‐assisted second/foreign language (L2/FL) learning has expanded beyond learning outcomes to focus on learners’ emotional experiences. Despite their proliferation, existing empirical findings are inconsistent, and few studies have systematically synthesized the impacts of AI‐assisted L2 learning on learners’ emotional
Jiaqi Jing, Xinjie Chen, Timothy Teo, Ziwei Xiao, Nandini Agarwal   +4 more
wiley   +1 more source

关于方程sum from j=0 to h（x+j）ⁿ=（x+h+1）ⁿ

四川大学学报. 自然科学版, 1978
我们曾证明6≤n≤33时,（1）无正整数解,以及其他若干结果。P.Erd?o对于x=1的情形,曾猜测（1）除开1+2=3外,无其他正整数解,L.Moser证明了这个猜测在h+2≤1010～6时成立。本文将证明:方程（1）在n是奇数时,除开已知的n=3,h=2,x=3和n=h=x=1外无其他正整数解,这个证明初等而简短。运用这个方法还可证明在2β|n,h（?）1,2(mod2β+3),β>0或n=2s,3·2s,s>1时,（1）均无正整数解。
柯召, 孙琦, 邹兆南
doaj  

Existence and multiplicity of positive solutions to nonlinear fourth-order three-point boundary value problems(非线性四阶三点边值问题的正解存在性与多解性)

Zhejiang Daxue xuebao. Lixue ban, 2008
考察了非线性四阶三点边值问题的正解.通过构造适当的锥并且利用相应的积分方程证明了n个正解的存在性.主要工具是锥上的Krasnosel'skii不动点定理.
YAOQing-liu(姚庆六)
doaj   +1 more source

Unraveling Student Anxiety in EFL Classrooms in China: The Roles of the Classroom Environment and Control–Value Appraisals

International Journal of Applied Linguistics, EarlyView.
ABSTRACT In this study, control–value theory (CVT) was used to investigate how students’ perceptions of the classroom environment shape their anxiety in the context of English as a foreign language (EFL) learning through the mediating effects of control and intrinsic value appraisals.
Quan Qian, Xianhan Huang
wiley   +1 more source

关于方程4/n=1/x+1/y+1/z

四川大学学报. 自然科学版, 1980
时方程（1）有正整解,Webb证明使方程（1 ...
李德琅
doaj  

AI foundation models in plant biology

New Phytologist, EarlyView.
Foundation models decode genomes, engineer proteins, phenotype crops, and drive AI agents across plant biology. This figure was created in BioRender (BioRender.com/xcmmkel). Summary Rapid technological progress has enabled plant biologists to accumulate unprecedented volumes of multi‐scale, multi‐modal data, yet this abundance of data has intensified ...
Haopeng Yu
wiley   +1 more source

一个反应扩散系统解的周期渐近性态

四川大学学报. 自然科学版, 1989
证明了一个二维反应扩散系统,当扩散系数相等且充分大时,其整体正解或趋于系统的正常数平衡解,或趋于一个空间齐次周期解的渐近结果.
陆征一
doaj  

Existence of single and multiple positive solutions of singular boundary value problem(一类奇异边值问题正解的存在性及多解性)

Zhejiang Daxue xuebao. Lixue ban, 2017
应用Dancer全局分歧理论，研究奇异边值问题正解的存在性和多解性，其中f：[0，1]×[0，∞）→[0，∞）连续.给出了关于此类问题正解存在的充分条件，该充分条件与相应线性问题的第1个特征值有关，且所涉及的值是最优的.
YANDongming(闫东明)
doaj   +1 more source