静电纺纳米纤维非织造布的热湿传递性能

从静电纺纳米纤维非织造布的空气体积分数出发,研究其热传递性能和湿传递性能,发现静电纺纳米纤维具有优良的保暖性和不良的透湿性.并通过实验得到一定体积分数的纳米纤维非织造布的导热系数,定量描述了纳米纤维非织造布的导热性能.分析了影响透湿性的因素,展望了它在防护性服装应用上的潜力.     

钛纤维多孔材料孔径分布与吸声性能研究

金属纤维多孔材料是一类重要的吸声材料,采用驻波管法检测钛纤维多孔材料的空气声吸收系数,研究材料的孔隙度、纤维直径以及材料厚度等参数对吸声性能的影响,结果表明,钛纤维多孔材料具有较好的吸声性能,材料的孔隙度越高、纤维越细,材料的吸声性能越好,在材料背后设置空气层可显著改善其低频吸声性能,材料背后的空气层厚度越大,材料的低频吸声性能越好.     

HPEI接枝改性PAN/GO-PAA静电纺纳米复合纤维膜对Au(Ⅲ)的吸附

以丙烯酸(AA)为单体,过氧化苯甲酰(BPO)为引发剂,通过原位聚合法,在氧化石墨烯(GO)表面包覆聚丙烯酸(PAA),得到GO-PAA纳米复合物.将GO-PAA纳米复合物分散在聚丙烯腈(PAN)基体中,利用静电纺丝技术得到PAN/GO-PAA静电纺纳米复合纤维膜.利用化学接枝反应在PAN/GO-PAA静电纺纳米复合纤维膜表面接枝超支化聚乙烯亚胺(HPEI),构筑HPEI-g-PAN/GO-PAA静电纺纳米复合纤维膜.研究了HPEI-g-PAN/GO-PAA静电纺纳米复合纤维膜对Au(Ⅲ)的吸附性能.结果表明:HPEI-g-PAN/GO-PAA静电纺纳米复合纤维膜对Au(Ⅲ)的最大吸附量为1 808.60 mg·g^－1,在吸附过程中,部分Au(Ⅲ)被还原为片状和不规则颗粒状的Au单质.在共存离子体系中,HPEI-g-PAN/GO-PAA对Au(Ⅲ)具有较好的吸附选择性.     

MEM纳米复合非织造材料的过滤性能

为了研发高效低阻过滤材料,采用正交设计的试验方法,研究了纳米纤维直径、纳米纤维材料的厚度和不同熔喷材料对熔喷-静电纺-熔喷(MEM)纳米复合非织造材料过滤性能的影响.结果表明,纳米纤维材料的厚度和纳米纤维直径对材料的过滤性能影响最大,通过复合一层很薄的纳米纤维膜(0.029~0.116μm),熔喷材料的过滤效率从38.100%提高到99.429%以上,品质因数提高近2倍.该材料能够有效拦截空气中的PM2.5和病毒等微小有害粒子,可应用于高性能防护口罩.     

聚多巴胺涂覆改性聚丙烯腈纳米纤维膜及其油水分离性能

以聚多巴胺(PDA)为涂层剂,静电纺聚丙烯腈(PAN)纳米纤维膜为基体,制备了PDA/PAN纳米纤维复合材料,测试多巴胺涂层处理对复合材料的表面形貌、力学性能、孔径分布、纯水通量与乳化油截留率等相关性能的影响。研究结果表明:涂层后的静电纺纳米纤维断裂强度明显增加;膜纯水通量明显增大,在涂层液质量浓度为1 mg/mL时静电纺纳米纤维膜纯水通量最高达到14 656L/(m~2·h),较未改性纳米纤维膜增加63%;在涂层液质量浓度为1.5mg/mL时纤维膜获得了最小孔径,其乳化油截留率也达到最佳值(96.1%),同时可以保证高水通量和高乳化油截留率。     

抗菌型苯丙氨酸基聚酯脲静电纺复合纳米纤维敷料的制备及性能

采用静电纺丝技术分别制备聚己内酯(PCL)、苯丙氨酸基聚酯脲(PBP)/PCL和PBP/PCL/姜黄素(Cur)纳米纤维膜,通过对比分析PCL、PBP/PCL和PBP/PCL/Cur 3种静电纺纳米纤维膜,探究了PBP/PCL/Cur静电纺纳米纤维膜形貌、纤维直径、力学性能、姜黄素释放行为、抗菌性能、细胞毒性.研究表明...     

微穿孔板作护面板对多孔材料吸声效果的影响

分析了微穿孔板做护面板对多孔材料吸声效果的影响。通过实验测得多孔材料的复阻抗和复波数,给出了复合结构的吸声系数计算公式,并在阻抗管内进行实验验证,实验结果与理论计算吻合良好。实验结果表明,使用微穿孔板作多孔材料护面板,具有较低声阻抗的微穿孔板能减小对多孔材料高频吸声性能的影响;具有较高声抗的微穿孔板会更好的提升多孔材料的低频吸声效果,但会使吸声系数在高频下降严重,同时过高的声阻会使吸声系数峰值下降。     

胆管支架静电纺覆膜工艺及性能

以聚ε-己内酯(PCL)为溶质,二甲基甲酰胺(DMF)和二氯甲烷(DCM)为溶剂,制备静电纺丝溶液.采用正交试验法研究静电纺溶液中PCL质量浓度、溶剂中DMF体积分数和静电纺电压值3个因素对纤维的形态和直径、纤维膜的孔隙率和表面积-体积比的影响,并对纤维膜的力学性能进行了测试.结果表明:溶剂中DMF体积分数对纤维膜结构影响最为显著,其次是静电纺电压,PCL质量浓度影响最小;PCL质量浓度为0.180g/mL时,静电纺纤维膜中纤维粗细最为均匀;PCL质量浓度、DMF体积分数和静电纺电压的最优水平分别为0.165g/mL、43%、15kV;随着PCL质量浓度增大,PCL大分子链增多,分子间作用力增大,纤维膜拉伸强力增大.     

导电型静电纺纳米纤维的制备及其表征

以六氟异丙醇(HFIP)为溶剂,乳酸己内酯共聚物(P(LLA-CL))掺杂聚苯胺(PANi)和樟脑磺酸(CPSA)作材料,采用静电纺技术制备导电型纳米纤维膜,并对其纤维的物理学特征进行表征.通过控制导电材料的添加量,探究纳米纤维直径和电导率的变化.研究表明:P(LLA-CL)纳米纤维分布均匀表面光滑,添加聚苯胺的纳米纤维直径变粗,电导率增大.     

纳米纤维基可水洗口罩的制备及性能

以不同质量分数的聚酰胺酸(PAA)溶液为前驱体，采用静电纺丝法制备不同结构的PAA纳米纤维膜，并对其微观形貌进行表征。结果表明，当PAA的质量分数为20%时，静电纺纳米纤维表面光滑且直径均匀。测试不同面密度下PAA纳米纤维膜的过滤性能及力学性能，结果显示，面密度为5 g/m²的PAA纳米纤维膜具有较为优异的过滤性能及力学性能。进一步探究热交联工艺对聚酰亚胺(PI)纳米纤维膜成型的影响，并将逐级交联20 min处理后的PI纳米纤维膜与熔喷层、针织层复合，得到具有多层结构的纳米纤维防护口罩，结果表明，口罩的初始过滤效率高达98.1%,水洗30次后仍可保持81.8%的过滤效率。由此可见，PI纳米纤维膜具有优异的结构稳定性与过滤性能，对提升口罩的耐水洗性具有重要意义。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-