Zhifeng Ren

Bio: Zhifeng Ren is an academic researcher from Texas Center for Superconductivity. The author has contributed to research in topics: Thermoelectric effect & Thermoelectric materials. The author has an hindex of 122, co-authored 695 publications receiving 71212 citations. Previous affiliations of Zhifeng Ren include Massachusetts Institute of Technology & University of Cincinnati.

Structural study of undoped and doped Bi2Sr2CuO6 phases by transmission electron microscopy

Abstract: Bi‐based superconducting phases have been studied by transmission electron microscopy. The strong one‐dimensional modulations in undoped and Ce‐doped monoclinic Bi2 Sr2 CuO6 (2201) samples are different from one another. We have found a new 2201 phase containing Pb and Ca with orthorhombic symmetry in nominal (Bi0.90 Pb0.10 )2 Sr2 CaCu2 O8 crystals. Its structure with space group Bbmb and two‐dimensional modulation are analogous to those of the Pb‐doped higher members of the structural series Bi2 Sr2 Can−1 Cun O2n+4 . Hence, this new orthorhombic rather than the monoclinic 2201 phase should be the first member of the structural series.

Femtosecond dynamics of BSCCO-2212 in the weak and strong excitation limits

Abstract: We present measurements of the ultrafast optical response of BSCCO-2212 in the weak perturbation limit (photoexcitation density ≤ 10μJcm−2), where we focus attention on the dynamics of electronic correlations associated with the pseudogap, and also in the strong perturbation limit (≥ 1JJcm−2), where the superconducting condensate is destroyed.

Enhanced thermal stability on multi-metal filled cermet based spectrally selective solar absorbers

Abstract: A spectrally selective solar absorber is described and comprises a substrate, double cermet layers comprising multi-metal nanoparticles embedded in a dielectrics matrix, and double antireflection layers deposited on cermet layers. The tungsten or titanium or tantalum infrared reflector layer suppressing the diffusion of substrate elements and multi-metal nanoparticles in the cermet are disclosed.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Carbon Nanotubes--the Route Toward Applications

Abstract: Many potential applications have been proposed for carbon nanotubes, including conductive and high-strength composites; energy storage and energy conversion devices; sensors; field emission displays and radiation sources; hydrogen storage media; and nanometer-sized semiconductor devices, probes, and interconnects. Some of these applications are now realized in products. Others are demonstrated in early to advanced devices, and one, hydrogen storage, is clouded by controversy. Nanotube cost, polydispersity in nanotube type, and limitations in processing and assembly methods are important barriers for some applications of single-walled nanotubes.