某类一阶中立型微分方程的振动性

研究具有正负系数的多滞量一阶中立型微分方程 d/dt[y(t)-Σk=1mRl(t)y(t-rl)]+Σi=1nPi(t)y(t-τi)-Σj=1kQj(t)y(t-σj)=0.其中 Pi,Qj,Rl∈C([t0,∞],R+),rl,τi,σj∈(O,∞)(i=1,2,3,…,k;l=1,2,3,…,m),r1相似文献   

一类拟线性波动方程整体解的存在性与渐近性

研究初边值问题得到了该问题{uu-△u-△ut-n∑i=1(e)/(e)xiβ(utxi) f(ut)=g(u)x∈Ω,t＞0u|(e)Ω=0t≥0u(x,0)=u0,ut(u,0)=uqx∈Ω得到了该问题整体广义解的存在性、惟一性和渐近性.     

integral from x to 0 sin(t)dt在x=0的右导数

设 f(x)在区间[0,a]上可积,在[0,a]上连续,且有无限多个零点 x_i(i=1,2,3,…):a≥x_1>x_2>…>x_m>x_(n+1)>…>0,■(x_n-x_(n+1))/x_n=0;■■f(t)dt 则 F■(0)=0.     

一类二阶常微分方程泛函边值问题解的存在性

运用打靶法考虑了二阶常微分方程泛函边值问题{x″（t）=f（t,x（t）,x′（t））,t∈[0,1],x（0）=0,x（1）=∫0^1α（t）x（t）dt解的存在性,给出了此类问题解的存在性判据,其中f：[0,1]×R^2→R满足Carathéodory条件,α∈C（[0,1],[0,∞））,且∫0^1α（t）tdt〈1.     

一类自变数镜射微分方程伪概周期解的存在性

设f:R×R×R→R的连续函数.在f是伪概周期函数的前提下研究自变数镜射微分方程.x(t) ax(t) bx(-t)=f(t,x(t),x(-t)),b≠0,t∈R.伪概周期解的存在惟一性.研究工具是压缩映射原理.     

非线性波动方程的长时间解

主要讨论非线性波动方程u_(?)-△u=f(t,x,u) (*)的小初值问题的几乎整体解(almost global solution)的存在问题,证明了,若|f(t,x,u)|≤C|u|~p,x∈ R~(?),14);10存在,当初值 u(0,x),u_(?)(0,x)的范数‖u(0)‖(?)(R~(?))+‖u_(?)‖(?)(R~(?))≤δ时,(*)式的 Cauchy 问题的小振幅解在 C~1(0,T;H~1)∩ C(0,T;H~2)中唯一存在.     

关于双向加细方程的L1-解的一点注记

研究了双向加细方程f(x)=∑Nn=0c(n,1)f(αx-βn)+∑Nn=0c(n,-1)f(-αx-βn)的L1-解,其中α∈R且α＞1,β0＜…＜βN∈R.利用傅里叶方法和迭代函数系将证明双向加细方程的所有L1-解所做成的解空间至少是1维的,并且给出了双向加细方程非平凡L1-解存在的充分条件与必要条件,同时给出非...     

Non-Archimedean空间中三次方程的稳定性

研究了三次方程Ef(x,y):=f(mx+y)+f(mx-y)-mf(x+y)-mf(x-y)-2m(m2-1)f(x)=0在non-Archimedean空间中的稳定性问题,其中m为任一实数且m≠1且m≠0.证明了如果G为一赋范空间,X为一完备的non-Archimedean空间.f:G→X是一个映射,δ＞0,使得当(A)x,y∈G时,有‖Ef(x,y)‖≤δ(ρ(‖x‖3)+ρ(‖y‖3)),其中ρ:[0,+∞)→[0,+∞)满足ρ(|m|t)≤ρ(|m|)ρ(t)及ρ(|m|)＜|m|,那么存在惟一三次映射Q:G→X,使得‖f(x)-Q(x)‖≤(δ)/(2|m|3)ρ(‖x‖3) ((A)x∈G).     

Grushin平面上次椭圆和抛物方程的比较原理

设X1,X2是定义在有界区域ΩR2内的满足Hrmander有限秩条件的光滑向量场,{aij}2×2(a12=a21=0)是由实函数构成的一致对称正定矩阵.Gn是由向量场Xi(i=1,2)张成的空间,并在Gn上赋予了从Xi诱导的度量(Carnot-Carathéodory度量).通过构造辅助函数,得到了一类次椭圆和抛物算子LE=-∑2i,j=1aij(x)XiXj+∑2i=1bi(x)Xi+c(x),LP=/t-i∑,j2=1aij(x,t)XiXj+∑i2=1bi(x,t)Xi+c(x,t)的极大值原理和比较原理.     

一类二阶三点奇异常微分方程解的存在性

设f:[0,1]×R2→R满足Caratheodory条件,且k≠1,0<η<1,(1-t)e(t)∈L1(0,1).运用Leray-Schauder原理考虑了二阶奇异边值问题x″(t)=f(t,x(t),x′(t)) e(t),t∈(0,1),x′(0)=0,x(1)=kx(η)在C1[0,1)上解的存在性.     

Methodology for design of suitable dishes for dysphagic people

A methodology to adapt dishes for cerebral palsy (CP) dysphagic people was developed. Five conventional dishes were cooked, blended and texturized with mixtures of thickeners and gelling agents based on xanthan gum. The most appropriate texturizing agents were selected, the textural thermostability of the dishes was studied, and the shelf-life was evaluated by back extrusion, sensory and microbiology analysis. Information about the acceptability of the adapted dishes by CP dysphagic people was obtained through the control of the consumed fraction and the liking or disliking reaction after eating the dishes. The adapted dishes considered suitable for swallowing process showed maximum force between 6.2(0.1) N and 18.9(3.3) N, minimum force between −3.9(0.3) N and −9.2(1.3) N, and F_min/F_max ratio between 0.4(0.0) and 0.7(0.0). Regarding sensory characteristics, the adapted dishes showed low stickiness, residue and firmness, and high suitable texture score. The methodology was appropriate for developing suitable dishes, sensorially accepted by dysphagic people, thermostable for 7 days refrigerated storage and ready-to-eat.Industrial relevanceThis study presents the technological basis for the standardized design of suitable ready-to-eat dishes for dysphagic people. The methodology developed is of great interest to the industry of ready-to-eat dishes.     

游戏机手柄上盖注射模设计

文章分析了游戏机手柄上盖塑料件的工艺特点,介绍了游戏机手柄上盖注射模结构设计和工作过程。该模具采用浇口开设在顶杆上,在分型时实现自动拉断凝料,同时将曲面分型改为平面分型,降低模具加工的难度,节约成本和提高注塑、脱模的稳定性。生产实践证明,该套模具结构合理,运行可靠。     

Computation method for optimization of recipes for protein content

The authors propose a calculated protein utilization coefficient. This coefficient considers the difference between the utilization rates of the proteins being contained in the mixture and their amino-acid composition. The proposed formula allows calculations by computer. The data obtained show high correlations with the results received by biological tests with Tetrahymena cultures.     

Screening of industrial enzymes for deproteinization of shrimp head for chitin recovery

Food grade proteolytic enzymes were examined for deproteinization of shrimp head. Shrimp head was easily deproteinized by Alcalase ® and trypsin at a pH of 8.0. Alcalase was chosen as the most efficient commercial enzyme for deproteinization of shrimp head. Alcalase treatment of shrimp head recorded 61% of weight loss on dry basis and a residual protein of 275 mg/g dried shrimp head. The enzymatically deproteinized shrimp head was later demineralized with lactic acid using microwave radiation at 400W. The combination of enzymatic and physicochemical treatments promoted the chitin recovery from dried shrimp head under eco-friendly conditions.     

FTA滤膜用于PCR检测单核细胞增生李斯特氏菌的研究

建立单核细胞增生李斯特氏菌(Listeria moncytones,LM)快速、敏感、特异的PCR检测方法.利用FTA滤膜提取模板DNA,采用PCR特异性扩增单增李斯特菌的溶血素基因(HIyA),并评价该方法的特异性与灵敏性.引物能特异性的扩增单增李斯特的HIyA基因,而其他细菌的扩增结果均呈现阴性:利用FTA滤膜提取模板直接检测单增李斯特具有较高的灵敏度,灵敏度为l 02 cfu/mL.利用FFA滤膜提取模板,操作简便,成本低且具有较高的灵敏度,为食品中单核细胞增生李斯特氏菌的快速检测提供新的手段.     

Comparison of Iterative Procedures for Solving Equations for Sire Evaluation

Gauss-Seidel, successive overrelaxation, end-of-round relaxation, and block iteration methods of obtaining solutions for sire effects from equations rising from progeny with records in mixed model procedures were compared. Equations transformed to provide direct solutions for genetic group plus sire effects as well as constrained and unconstrained equations were compared also. Equations for milk yield for the Northeast Artificial Insemination Sire Comparison numbered 301 for Ayrshires, 325 for Brown Swiss, 6,010 for Holsteins, and 926 for Jerseys after absorption of herd-year-season effects. Numbers of coefficients were 15 to 20% less for transformed equations, which decreased computing time per round of interation about 15%. Solutions for transformed equations converged more rapidly than solutions for untransformed equations with convergence criterion the ratio of the residual norm to the norm of the right-hand sides. Successive overrelaxation generally was more efficient than Gauss-Seidel iteraton. Solutions for equations constrained to full rank converged more slowly than unconstrained equations. Block iteration was more efficient than single equation iteration.     

圆形钢丝断面收缩率的快速计算法

按照ＧＢ２２８—８７《金属拉力试验法》中的公式计算断面收缩率既费时又复杂。在对原公式作进一步推导之后得出一新的计算式，按此公式可快速、难确地计算出值。