12 research outputs found

    蜂窝网络中用户移动参数对越界率的影响

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    越界率是衡量无线蜂窝网络性能的重要指标之一。主要考察用户移动模型中3个要素(速度、方向和蜂窝小区的信号覆盖范围)对用户越界率的影响。这种影响的检测是分别在简单移动模型和支持突发事件影响的移动模型上进行多组实验所得的,分别画出了两种移动模型下用户最大速度、最小速度以及平均速度的变化、BS的信号覆盖范围和用户移动方向改变频率与用户越界率之间的曲线图。通过对比两种不同移动模型下的实验数据,发现用户的越界率与用户的移动速度和BS的信号覆盖范围关系较大,而用户移动方向的改变频率对越界率的影响相对较弱。国家自然科学基金项目(61173032,60970016)|天津市教委科技发展基金项目(20110808

    制备小晶粒SAPO-34分子筛的方法及其产品和用途

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    本发明涉及制备小晶粒SAPO-34分子筛的方法及其产品和用途。更具体地,涉及的方法包括将作为原料的SAPO-34分子筛预处理成粒度为10~800nm的颗粒,得到低结晶度的晶化前驱体;将有机胺模板剂R和水以及可选的硅源、铝源和磷源混合以制得晶化液,或者在制备SAPO-34分子筛过程中将分离产物后的母液作为晶化液;以及将上述晶化前驱体与晶化液混合并进行水热晶化,最后分离得到所述小晶粒SAPO-34分子筛。该方法不但可以在不使用有机胺模板剂四乙基氢氧化铵下简单地制备小晶粒SAPO-34分子筛,而且制得的产品作为催化剂对含氧化合物如甲醇制烯烃反应的催化寿命明显延长,选择性明显提高

    Current patient delay among breast cancer patients and related factors

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    目的 针对乳腺癌患者的就诊延误现状,分析就诊延误的相关因素.方法 选择就诊于北京市某三甲医院符合纳入标准的354名乳腺癌女性患者,采用问卷调查法进行调查,问卷包括一般资料、就诊情况、症状的看法与态度、社会支持评定量表和一般自我效能感量表.结果 该组乳腺癌患者的就诊延误发生率为20.62%,延误组与非延误组相比,其忽视得分高(P&lt;0.05),焦虑和害怕得分低(P&lt;0.05),支持利用度得分低(P&lt;0.05).Logistic回归分析显示,就诊延误与社会支持利用度相关(OR=0.849).结论 在乳腺癌常见症状、治疗方法及预后等方面应加强健康教育,家庭及社会的支持在减少就诊延误中发挥重要作用.</p

    橄榄油基二酰甘油油酸酯基油凝胶的 物理性质及其在饼干中的应用Physical properties of olive oil diacylglycerol oleate (O-DAGO) - based oleogel and its application in cookies

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    为开发基于双甘油酯(DAG)的油凝胶作为饼干馅料中起酥油替代品,使用橄榄油基二酰甘油油酸酯(O-DAGO)为基料油,5%的小烛树蜡(CLW)和0~35%的橄榄油基二酰甘油硬脂酸酯(O-DAGS)组合为凝胶剂制备O-DAGO基油凝胶。研究了O-DAGO基油凝胶脂肪酸组成、微观结构、固体脂肪含量、硬度及热力学性能,并将其用作饼干的油脂基质,研究了O-DAGO基油凝胶对饼干基本理化性质的影响。结果表明:O-DAGO基油凝胶的饱和脂肪酸含量(≤23.50%)低于起酥油(52.07%),O-DAGO基油凝胶主要含有油酸(>63%);当O-DAGS含量增加时,O-DAGO基油凝胶的晶体数量增加,固体脂肪含量也逐渐升高;O-DAGS含量15%的O-DAGO基油凝胶硬度(73.19 g)与起酥油(75.42 g)接近,当O-DAGS含量为25%和35%时硬度则显著大于起酥油(p<0.05);随O-DAGS含量增加,油凝胶的熔融和结晶温度升高;O-DAGS含量不超过25%的油凝胶应用在饼干中显示出与起酥油饼干相似的硬度,更低的油脂迁移率。总的来说,O-DAGO基油凝胶应用于饼干中显示出较高的起酥油替代潜力。For the development of diacylglycerol (DAG)-based oleogels as shortening substitutes in cookie fillings, olive oil diacylglycerol oleate (O-DAGO) was used as the base oil, complex of 5% candelilla wax (CLW) and 0-35% olive oil diacylglycerol stearate (O-DAGS) was used as gelling agent to prepare O-DAGO-based oleogel. The fatty acid composition, microstructure, solid fat content, hardness and thermodynamic properties of O-DAGO-based oleogel were studied, and using O-DAGO-based oleogel as a oil base for cookies, the influence of O-DAGO-based oleogel on the basic physicochemical properties of cookie was studied. The results showed that the saturated fatty acid content of O-DAGO-based oleogel (≤2350%) was lower than that of shortening (5207%), and O-DAGO-based oleogel mainly contained oleic acid (>63%). When the content of O-DAGS increasing, the number of crystals of O-DAGO-based oleogel increased, and the solid fat content also increased gradually. The hardness (73.19 g) of O-DAGO-based oleogel with O-DAGS content 15% was close to that of shortening (75.42 g), but it was significantly higher than shortening when O-DAGS content was 25% and 35%(p<0.05). The melting and crystallization temperatures of oleogel increased with the increase of O-DAGS content. The application of oleogel with no more than 25%O-DAGS in cookies showed similar hardness, lower oil migration rate to shortening. Generally speaking, the application of O-DAGO-based oleogel in cookies shows a high substitution potential for shortening
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