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161.
基于现有的文氏咀流量供给管道,提取出轴对称2维计算模型,计算了不同背压下文氏咀及下游管道的流场特性。计算结果显示,随着背压的升高,激波在管道内经历了3种状态,在直管道内为斜激波,到转接段时为拟正激波,进入文氏咀后则为正激波。在进行文氏咀流量计的设计时,应尽量将正激波控制在文氏咀喉道或向下游延伸的一小段距离内,此时是文氏咀的最佳工作状态。另外,采用壁面开孔法在文氏咀下游选取测压点时,为了准确测量截面上的静压,应将测压点选取在距离直管道入口数倍管径处,一般不低于8倍管径。 相似文献
162.
Let c>1 and : We study the solubility of the Diophantine inequality in Piatetski-Shapiro primes p1,p2, .., ps of the form for some , and improve the previous results in the cases s = 2, 3, 4. 相似文献
163.
In this paper, sodium dodecyl sulfate (SDS) is used as dopant to manipulate both morphology and wettability of polyaniline (PANI). When SDS amount is controlled within a certain range, micro/nano double-rough PANI with hydrophobic surface can be obtained, while insufficient or excess SDS can only lead to hydrophilic PANI. The double-rough PANI shows stimuli-responsive change in wettability to either alkaline reaction or reduction reaction from hydrophobicity to hydrophilicity. This quick response can be applied to quantitatively estimate NaOH concentrations within the range of 10(-3)-10(-1)M and to detect various reducing liquids. 相似文献
164.
采用改进的溶胶-凝胶法合成固体氧化物燃料电池阴极系粉体Pr0.6-zSr0.4Co0.8Fe0.2O3-δ(PSCF)(z=0,0.02,0.05,0.1)。使用X射线衍射(XRD)、扫描电子显微镜(SEM)对其相结构与形貌进行了分析,结果表明:900℃以上焙烧后的阴极粉体Pr0.6-zSr0.4Co0.8Fe0.2O3-δ(z=0,0.02,0.05,0.1)为单一的钙钛矿结构。1000℃烧结的样品内粒子分布比较均匀,且颗粒内部存在一定程度的空隙,并与电解质附着情况良好。用直流四电极法测试阴极体系样品在400~750℃的电导率,发现各试样混合离子电子电导率均高于786 S.cm-1,能够满足固体氧化物燃料电池对阴极电导率的要求。用交流阻抗法测定PSCF-Ce0.8Sm0.2O1.9体系样品的阻抗谱,得到1000℃烧结的阴极体系对称电池在测试温度为750℃z=0,z=0.02,z=0.05时的极化电阻分别为0.041,0.040,0.034Ω.cm-2。 相似文献
165.
Linear and star-shaped pyrazinacenes 1a-b and 2 were synthesized via condensation between a new building block 11 and pyrene tetraones or cyclohexaone. Compound 2 represents the largest star-shaped dihydropyrazine fused pyrazinacene reported so far. These largely expanded pyrazinacenes show good solubility and have a strong tendency to aggregate in both solution and thin films, indicating their potential applications for organic electronic devices. 相似文献
166.
Patent data contain plenty of valuable information. Recently, the lack of innovative ideas has resulted in some enterprises encountering bottlenecks in product research and development (R&D). Some enterprises point out that they do not have enough comprehension of product components. To improve efficiency of product R&D, this paper introduces natural-language processing (NLP) technology, which includes part-of-speech (POS) tagging and subject–action–object (SAO) classification. Our strategy first extracts patent keywords from products, then applies a complex network to obtain core components based on structural holes and centrality of eigenvector algorism. Finally, we use the example of US shower patents to verify the effectiveness and feasibility of the methodology. As a result, this paper examines the acquisition of core components and how they can help enterprises and designers clarify their R&D ideas and design priorities. 相似文献
167.
168.
设g(n)>0为任一实值函数,加性函数G(n)定义为G(1)=0,G(n)+k≥1为一固定正整数。本文研究了和式∑2≤n≤x ,并得到了渐近公式。 相似文献
169.
Novel Fungal Pelletization-Assisted Technology for Algae Harvesting and Wastewater Treatment 总被引:2,自引:0,他引:2
Wenguang Zhou Yanling Cheng Yun Li Yiqin Wan Yuhuan Liu Xiangyang Lin Roger Ruan 《Applied biochemistry and biotechnology》2012,167(2):214-228
A novel fungi pelletization-assisted bioflocculation technology was developed for efficient algae harvesting and wastewater treatment. Microalga Chlorella vulgaris UMN235 and two locally isolated fungal species Aspergillus sp. UMN F01 and UMN F02 were used to study the effect of various cultural conditions on pelletization process for fungi?Calgae complex. The results showed that pH was the key factor affecting formation of fungi?Calgae pellet, and pH could be controlled by adjusting glucose concentration and fungal spore number added. The best pelletization happened when adding 20?g/L glucose and approximately 1.2E8/L spores in BG-11 medium, under which almost 100?% of algal cells were captured onto the pellets with shorter retention time. The fungi?Calgae pellets can be easily harvested by simple filtration due to its large size (2?C5?mm). The filtered fungi?Calgae pellets were reused as immobilized cells for treatment wastewaters and the nutrient removal rates of 100, 58.85, 89.83, and 62.53?% (for centrate) and 23.23, 44.68, 84.70, and 70.34?% (for diluted swine manure wastewater) for ammonium, total nitrogen, total phosphorus, and chemical oxygen demand, respectively, under both 1- and 2-day cultivations. The novel technology developed is highly promising compared with current algae harvesting and biological wastewater treatment technologies in the literature. 相似文献
170.
Xiai Luo Wenguang Li Haiyan Lu Guobo Deng Yuan Yang Chunming Yang Yun Liang 《中国化学快报》2021,32(2):713-716
A simultaneous C2-H arylation and C8-H alkylation of naphthalene ring has been achieved by palladiumcatalyzed cascade reaction of N-(2-halophenyl)-2-(naphthalen-1-yl)acrylamides with aryl iodides,which provides an efficient method for synthesizing various aryl-substituted spirocyclic oxindoles.The protocol enables three C-C bonds formation via an intramolecular Heck reaction and sequentially regioselective C-H bond activation. 相似文献