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排序方式: 共有198条查询结果,搜索用时 15 毫秒
1.
2.
建立了再生喷射燃烧过程的多功能实验装置和瞬态参数测量系统。针对点火器参数对点火特性的影响规律进行了大量的实验研究,导出了点火器参数与点火特性之间的实用定量关系曲线。在此基础上,进行了相应的再生喷射燃烧过程实验,取得了较好地实验结果。研究表明:通过控制点火器参数以获得与再生喷射燃烧过程的匹配要求相适应的点火特性,对获得性能良好的燃烧过程具有重要意义。 相似文献
3.
Xu Ziyi Fu Taotao Zhu Chunying Jiang Shaokun Ma Youguang Wang Kai Luo Guangsheng 《Electrophoresis》2019,40(3):376-387
For revealing the dynamics of partially obstructed breakup of bubbles in microfluidic Y‐junctions, the combination of dimensionless power‐law and geometric model was applied to study the effects of capillary number, bubble length, and channel angle on the bubble rupture process. In the squeezing process, the gas‐liquid interface curve follows the parabolic model. For the evolution of the bubble neck during breakup, the increase of the bubble length, the channel angle, and the capillary number leads to the decrease of the focus distance α. The chord m increases with the increase of the capillary number and the decrease of the bubble length, and it would reach the maximum value when the channel angle is 90°. In the fast pinch‐off stage during bubble breakup, the bubble's neck curve no longer conforms to the parabolic model so the focus and chord no longer exist. For the evolution of the bubble head during breakup, the value of γ approaches 1 with the increase of the capillary number and the bubble length, and with the close of the channel angle to 90°. It is found that the quadrilateral model can be applied for the partially obstructed rupture of bubbles in the symmetrical microfluidic Y‐junction. 相似文献
4.
窄内径多孔层毛细管开管柱(NPLOT柱)在生命科学领域,特别是单细胞分析领域具有较好的应用前景。本研究采用原位热引发聚合法来制备窄内径奎尼丁类手性固定相多孔层开管柱,在6 μ m i.d.的毛细管中制备有机聚合物多孔层,考察了不同热聚合时间(3、6和9 h)对NPLOT柱形貌的影响,热聚3 h和6 h制备的NPLOT柱形貌均一,多孔层厚度分别为103±51 nm和210±51 nm。将热聚合3 h制备的NPLOT柱用于纳流高效液相色谱分离N-衍生化氨基酸对映体,在2 min内即可实现基本分离,消耗的样品量仅为皮升级别。该研究将为单细胞分析提供研究手段。 相似文献
5.
Shufang Wang Huiling Li Kun Zhao Songqing Zhao Mingjing Chen Jingchun Chen Jianglong Wang Guangsheng Fu 《Applied Physics A: Materials Science & Processing》2011,105(2):407-410
A heterojunction was fabricated by growing a layer of Bi2Sr2Co2O
y
thin film on the 0.7 wt% Nb-doped SrTiO3 substrate. Such heterojunction showed good rectifying characteristics over a wide temperature range, and its transport mechanism
under the forward bias can be attributed to a space charge limited conduction mechanism via defects near the interface of
the heterojunction. Photovoltaic properties of the heterojunction were studied by using both continuous-wave and pulsed irradiations
and the results can be well explained by the photovoltaic effect of a p–n junction. 相似文献
6.
Trivalent dysprosium ions (Dy3+) doped strontium molybdate (SrMoO4) phosphors were synthesized by solid-state reaction and their photoluminescence (PL) properties were investigated. X-ray powder diffraction (XRD) analysis confirmed the formation of SrMoO4:Dy3+. PL measurements indicated that the phosphor exhibited intense emission at 482, 490 (4F9/2→6H15/2) and 575 nm (4F9/2→6H13/2) under UV excitation. The effect of the doping concentration of Dy3+in SrMoO4:Dy3+ on the PL was investigated in detail. Na+ ion was a good charge compensator for SrMoO4:Dy3+. 相似文献
7.
建立柱后衍生–高效液相色谱法测定功能性饮料中牛磺酸的含量。功能性饮料中的牛磺酸经水溶提取后与邻苯二甲醛柱后衍生,以柠檬酸三钠溶液(p H 3.2)为流动相,用AMINO–NA色谱柱分离,荧光检测器检测,激发波长为338 nm,发射波长为425 nm,柱后衍生反应温度为55℃,流量为0.4 m L/min。牛磺酸质量浓度在5.0~25.0μg/m L范围内与色谱峰面积线性关系良好,r=0.999 8,检出限(S/N=3)为0.11μg/m L,测定结果的相对标准偏差为0.73%(n=6),加标回收率在99.2%~101.6%之间。该方法灵敏度高、选择性好,可用于市售功能性饮料中牛磺酸的测定。 相似文献
8.
采用微流控技术结合悬浮聚合方法实现了百微米级含膦配体聚苯乙烯微胶囊的可控制备, 微胶囊尺寸在320~420 μm范围内可调, 且单分散性好. 扫描电子显微镜、能量散射光谱和电感耦合等离子发射光谱结果证实了其形貌和组成的均匀性及钯负载的可控性和有效性. 以溴代芳烃与苯硼酸的Suzuki偶联反应为模型反应评价了负载Pd(PPh3)4的百微米级微胶囊的催化性能, 发现其性能与文献报道的7~8 μm的同类催化剂微胶囊接近, 且均优于均相催化剂; 该催化剂经简单过滤后, 可实现多次循环使用, 未发现活性物种的流失. 该法实现了连续制备, 因而有助于提高制备的效率和可控性. 另外, 所制百微米级催化剂微胶囊在固定床反应器内具有较高催化剂浓度和机械性能, 且优于浆态床中使用的微米级催化剂微胶囊. 相似文献
9.
Longguang Yang Yunfei Li Qian Chen Jianfeng Zhao Changsheng Cao Yanhui Shi Guangsheng Pang 《Transition Metal Chemistry》2013,38(4):367-375
The synthesis of a series of chiral Pd(L)PyBr2 (3a–3e) and Pd(L)PyCl2 (4d and 4e) complexes from l-phenylalanine is presented (L = (S)-3-allyl-4-benzyl-1-(2,6-diisopropylphenyl)-imidazolin-2-ylidene (a), (S)-4-benzyl-1-(2,6-diisopropylphenyl)-3-(naphthalen-2-ylmethyl)imidazolin-2-ylidene (b), (S)-4-benzyl-3-(biphenyl-4-ylmethyl)-1-(2,6-diisopropylphenyl)imidazolin-2-ylidene (c), (S)-4-benzyl-1-(2,6-diisopropylphenyl)-3-(naphthalen-1-ylmethyl)imidazolin-2-ylidene (d) or (S)-4-benzyl-1-(2,6-diisopropylphenyl)-3-(2,4,6-trimethylbenzyl)imidazolin-2-ylidene (e). The complexes were characterized by physicochemical and spectroscopic methods, and the X-ray crystal structures of 3a–3c and 4d are reported. In each case, there is a slightly distorted square-planar geometry around palladium, which is surrounded by imidazolylidene, two trans halide ligands and a pyridine ligand. There are π–π stacking interactions in the crystal structures of these complexes. Complex 3a showed good catalytic activity in the Cu-free Sonogashira coupling reaction under aerobic conditions. 相似文献
10.
Fei Zhao Zai-Dong Li Qiu-Yan Li Lin Wen Guangsheng Fu W.M. Liu 《Annals of Physics》2012,327(9):2085-2095
We present the current controlled motion of a dynamic soliton embedded in spin wave background in ferromagnetic nanowire. With the stronger breather character we get the novel magnetic rogue wave and clarify its formation mechanism. The generation of magnetic rogue wave mainly arises from the accumulation of energy and magnons toward to its central part. We also observe that the spin-polarized current can control the exchange rate of magnons between the envelope soliton and the background, and the critical current condition is obtained analytically. Even more interesting is that the spin-transfer torque plays the completely opposite role for the cases below and above the critical value. 相似文献