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1.
选取向列相液晶MLC-7700-100制备液晶光栅,三种液晶光栅的光栅常数分别为200μm、100μm、66.7μm,采用与计算机相连的UV-Vis 8500型双光束紫外/可见分光光度计,在温度为25℃的环境下.同时对液晶光栅施加频率为f=100Hz的交流电信号.研究在电压驱动下,不同光栅常数液晶光栅红(R)、绿(G)... 相似文献
2.
DíAZ Marlén Pérez RIZO Oscar Díaz DíAZ Adlin López APARICIO Eric Estévez DíAZ Reinaldo Roque 《Journal of Zhejiang University. Science. B》2006,(12)
INTRODUCTION Image quality in nuclear medicine tomography is critically dependent on the activity undergone by the patient. The optimal activity is the smallest amount of activity which preserves diagnostic accuracy. Nev- ertheless, the optimum depends on the gamma camera used for imaging, the size of the patient and the im- aging application (Mattsson et al., 1998). To optimize, one has to study how diagnostic accuracy depends on the activity undergone for each particular study, taking i… 相似文献
3.
本文应用复合度的方法在f(x,y,z,u)无界的条件下证明了一般的四阶方程y=f(x,y,y′,y″) (*)在边界条件y(0)=A_1,y(1)=A_2,y″(0)=B_1,y″=B(_2或y(0))=A_1,y(1)=A_2,y″(0)=B_1,y(1)=B_2下解的存在性。 相似文献
4.
本文定义并讨论了分次zip环,讨论了交换环的Split—null扩张的zip性,推广了C.Faith的部分结果。 相似文献
5.
变色酸2B光度法测定血清蛋白质的研究 总被引：3，自引：0，他引：3
在pH1.62的Clark-Lubs(C-L)缓冲介质中,变色酸2B能与血清蛋白质形成有色复合物,其λmax为579nm,比试剂本身红移约65nm,表观摩尔吸光系数为2.09×105L·mol-1·cm-1(HSA),线性范围为0-100mg·L-1.研究了该反应体系的影响因素,确定了最佳反应条件,应用于人血清样品总蛋白的测定,结果与经典的考马斯亮蓝G-250法一致,而且线性范围宽,基本无干扰,操作与重现性都优于考马斯亮蓝法. 相似文献
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本试验采用尼龙袋技术研究了用早灿稻谷替代玉米的肉牛饲粮中有机物在瘤胃中的降解规律，试验处理为早灿稻谷分别替代肉牛饲粮中０％、５０％、７５％、１００％玉米四个替代水平的饲粮．结果表明：１、四组饲粮有机物动态降解率分别为６９．８７％、６７．０８％、６３，８９％和６４．４２％；２、随早灿稻谷替代水平的增高，有机物潜在的可消化组分比例不断降低； ３、各组饲粮有机物消失率观察值对动态消化模拟方程（Ｐ＝ ａ＋ ｂ－ｂｅ－ａ）的拟合度高（ Ｒ２＝０．９７３～０．９９６）． 相似文献
8.
以2年龄桐花树(Aegiceras corniculatum)为试验材料,研究了不同光照强度[全光照(Ac100)、75%光照(Ac75)、45%光照(Ac48)、20%光照(Ac20)]对桐花树根系生长和根系活力的影响.结果表明,处理360d后,随着光照强度的减弱,桐花树的根生物量和根冠比均呈显著下降的趋势,其中Ac100的根生物量和根冠比最大,分别是Ac25的15.42倍和2.08倍;营养根和贮气根的根数、根长和根直径均呈逐渐递减的趋势,Ac100的营养根根数和根长显著高于其他处理,其中Ac100的营养根和贮气根的根数、根长分别是Ac25的3.85、1.37倍和14.59、1.68倍;根系含水量呈上升趋势,其在6月份最高,冬春季最低;而根系活力则呈下降趋势,其在冬春季呈下降趋势,在夏秋季呈先升后降的趋势.试验表明,不同光照强度对桐花树根系生长和根系活力有显著影响,在100%光照强度下其根系发达,根系活力较高.而在25%光照强度(过度遮光)下不利于根系生长,且桐花树能适应一定程度的遮荫环境. 相似文献
9.
郝文华 《郧阳师范高等专科学校学报》2010,30(5):43-45
＂青＂是个表示颜色的词。其特殊之处在于,它反映了植物生长过程中颜色的变化：白里透红、浅绿、深绿。同时,它又有自己的发展轨迹,顺着颜色的深浅继续发展,表示浅蓝、深蓝甚至黑色。因此它几乎能表示各种颜色。而在＂白里透红＂的意义上,更是引申出了不少意义。 相似文献
10.
Allen Leung Anna Baccaglini-Frank Maria Alessandra Mariotti 《Educational Studies in Mathematics》2013,84(3):439-460
In this paper, we discuss discernment of invariants in dynamic geometry environments (DGE) based on a combined perspective that puts together the lens of variation and the maintaining dragging strategy developed previously by the authors. We interpret and describe a model of discerning invariants in DGE through types of variation awareness and simultaneity, and sensorimotor perception leading to awareness of dragging control. In this model, level-1 invariants and level-2 invariants are distinguished. We discuss the connection between these two levels of invariants through the concept of path that can play an important role during explorations in DGE, leading from discernment of level-1 invariants to discernment of level-2 invariants. The emergence of a path and the usefulness of the model will be illustrated by analysing two students’ DGE exploration episodes. We end the paper by discussing a possible pathway between the phenomenal world of DGE and the axiomatic world of Euclidean geometry by introducing a dragging exploration principle. 相似文献
11.
Creemers, B. (1994). The Effective Classroom. London Cassell. ISBN: 0-304-32709-3. Freiberg, H.J. & Driscoll, A. (1996). Universal Teaching Strategies. Needham Heights: Allyn and Bacon. ISBN: 0-205-16722-5. Hargreaves, A. (1994). Changing Teachers, Changing Times. London: Cassell. ISBN: 0-304-32281-4. Sizer, T.R. (1996). Horace's Hope. New York: Mariner Books. ISBN: 0395-87754-7. Slavin, R. (1996). Education for all. Lisse: Swets & Zeitlinger. ISBN: 90-265-1472-7. 相似文献
12.
以铝型材碱洗废渣为原料,采用酸溶——聚合一步法工艺,制得符合行业标准的工业聚合氯化铝产品。推导得产品盐基度B与外加酸量nHY及产品Al2O3含量nAl之间的经验式B％=（1-nny／6nAl）＊100％,可用于产品设计和产品质量改进的指导。通过正交试验确定了适宜的制备工艺条件,每114g铝渣用浓盐酸83ml、酸浓度4mol／1、在80℃下反应3h。制得产品盐基度47．1％、Al2O3％11．2％、密度1．23g／cm^3。 相似文献
13.
Gao Min Zhou Wen Shi Jian-ming Hong De-fei Mu Yi-ping Wang Jian-guo Wang Yao-dong 《浙江大学学报(A卷英文版)》2000,1(4):456-458
Objective: To evaluate the benefit of intraoperative ERCP and endoscopic sphincterotomy (EST) combined with laparoscopic cholecystectomy
(LC) in the treatment of cholelithiasis with choledocholithiasis. Methods: Fifty-two patients with cholelithiasis and choledocholithiasis
(as determined by intraoperative cholangiography) were randomly divided into 2 groups during LC. In group A (27 patients),
common bile duct stones were extracted by intraoperative EST during LC. In group B(25 patients), common bile duct (CBD) stones
were extracted by conversion to open CBD exploration and cholecyctectomy. Results: The success rate was 26/27 (96.3%) in group
A and 25/25 (100%) in group B (0.25<P<0.5); The mean postoperative hospitalization was 3.32±0.56 days in group A and 17.5±4.61 days in group B (P<0.001). In group A, two cases were complicated transient hyperamylasemia after the combined procedure. In group B, one case
of bile leakage and one case of duodenal ulcer occurred after conversion to open cholecystectomy with CBD exploration. There
were no retained stones in group A but 2 cases in group B. Conclusion: Intraoperative ERCP and endoscopic sphincterotomy combined
with LC for treatment of cholelithiasis and chiledochlithiasis is safe, effective and results in shorter hospitalization and
fewer complications than traditional open cholecystectomy with CBD exploration. 相似文献
14.
将200只1日龄AA肉仔鸡随机分成5组,分别饲喂含脱毒菜粕0、5％、10％、15％、20％的日粮进行为期21天的饲养试验。结果表明:在脱毒菜粕的添加量小于15％的情况下,鸡的平均日增重、饲料转化率与对照组(Ⅰ组)相比差异不显著(P>0.05),且生长状况无明显异常;当添加量超过15％时,仔鸡的生产性能比对照组有所下降(P<0.05)。 相似文献
15.
The sequential organization of actions necessary to construct a figure in a dynamic geometry environment (DGE) introduces
an explicit order of construction. Such sequential organization produces what is, in effect, a hierarchy of dependences, as
elements of the construction depend on something created earlier. This hierarchy of dependences is one of the main factors
that determine the dynamic behavior (DB) within a DGE, and the order is often explicitly stated by terms such as parent and
child.
This article is a part of a larger study that examines various instruments developed by users when they use dragging. It addresses
one aspect of dragging: the connection between dynamic behavior and the sequential order of construction. Junior high students
and graduate students in mathematics education were asked to predict the DB of points that were part of a geometric construction
they had executed using a DGE according to a given procedure, and to explain their predictions.
The study reveals that while hierarchy in geometric constructions in a DGE is mirrored by the DB, user actions and perceptions
of DB indicate that users often grasp a reverse hierarchy in which dragging a child affects its parent.
The study reveals four categories of reverse-order predictions, and suggests that these may be caused by terms and knowledge
built into paper-and-pencil geometry, which are part of the resources users bring to dragging. Examining various DGEs1 in detail reveals that in some cases the DB is in fact compatible with the reverse-order predictions.
The paper concludes with a brief discussion of some implications for learning activities and software design.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
16.
In order to compare two kinds of blue electroluminescent materials,we have investigated two kinds of blue OLEDs with the similar structure ITO/CuPc/NPB/JBEM:perylene/Alq/Mg:Ag[device(J)] and ITO/CuPc/NPB/DPVBi:perylene/Alq/Mg:Ag[device(D)].The difference of luminance and efficiency was not obvious for the two devices,However,there was remarkable difference for their lifetime.The device(J) achieved longer half lifetime of 1035h at initial luminance of 100 cd/m^2,and that of device(D) was only255h,According to their energy level diagrams,the differentce of their stability may originate from different host materials in the two devices.It may be attributed to the better thermal stability of JBEM molecues than that of DPVBi.It is shown that JBEM may be a promising blue organic electroluminescent material with great stability. 相似文献
17.
设B(H)是维数大于2的复可分Hilbert空间,B(H)代表H上所有有界线性算子全体,假设线性映射φ:B(H)→B(H)满足对所有A,B∈B(H),(?)=0时,有(?)+(?)=0.文中运用可交换迹双线性映射对φ进行了刻画,证明了存在实数c∈R,算子T∈B(H)且T~*+T=cI,使得对任意X∈B(H),有φ(X)=XT+T~*X. 相似文献
18.
试验用酵母蛋白替代进口鱼粉进行饲养肥育猪试验。试验结果显示：按２５％、５０％、７５％、１００％来替代进口鱼粉与全鱼粉组对照，增重、料肉比均差异不显著（Ｐ＞０．０５）。 相似文献
19.
Edson M. Huziwara Saulo M. Velasco Gerson Y. Tomanari Deisy G. de Souza Armando D. Machado 《Learning & behavior》2013,41(2):192-204
In two experiments, we investigated emergent conditional relations in pigeons using a symbolic matching-to-sample task with temporal stimuli as the samples and hues as the comparisons. Both experiments comprised three phases. In Phase I, pigeons learned to choose a red keylight (R) but not a green keylight (G) after a 1-s signal. They also learned to choose G but not R after a 4-s signal. In Phase II, correct responding consisted of choosing a blue keylight (B) after a 4-s signal and a yellow keylight (Y) after a 16-s signal. Comparisons G and B were both related to the same 4-s sample, whereas comparisons R and Y had no common sample. In Phase III, R and G were presented as samples, and B and Y were presented as the comparisons. The choice of B was correct following G, and the choice of Y was correct following R. If a relation between comparisons that shared a common sample were to emerge, then responding to B given G would be more likely than responding to Y given R. The results were generally consistent with this prediction, suggesting, for the first time in pigeons, the emergence of novel relations that involve temporal stimuli as nodal samples. 相似文献
20.
Sap flow and environmental conditions were monitored at two Eucalyptus (Eucalyptus urophylla S.T.Blake)plantations at Hetou and Jijia, located in Leizhou, Zhanjiang, Guangdong Province. It was found that daily sap flux density (SFD) of Eucalyptus was closely related to daily atmospheric vapor pressure deficit (VPD) (R2=0.76, P=0.01 at Hetou and R2=0.7021, P=0.01 at Jijia) at both sites. No significant relationship existed between daily SFD and mean daily air temperature at both sites. Daily SFD varied with wind speed Y=-17585X3 15147X2-1250.7X 2278.4 (R2=0.68; P=0.01) at Hetou and Y=-101.67X3-1.65X2-376.4X 1914.8 (R2=0.40, P=0.05) at Jijia, where Ywas daily SFD, Xwas daily wind speed.Experimental observations yielded the following data: (1) the critical lower and upper daily VPD threshold were 0 and 2 kPa,slightly lower under high relative humidity (＞80%) compared with those at the Jijia site; (3) The upper and lower threshold 相似文献