Zhengyi Zhang

Learn More
A parametric study of so-called "super growth" of single-walled carbon nanotubes (SWNTs) was done by using combinatorial libraries of iron/aluminum oxide catalysts. Millimeter-thick forests of nanotubes grew within 10 min, and those grown by using catalysts with a thin Fe layer (about 0.5 nm) were SWNTs. Although nanotube forests grew under a wide range of(More)
Organ printing offers a great potential for the freeform layer-by-layer fabrication of three-dimensional (3D) living organs using cellular spheroids or bioinks as building blocks. Vascularization is often identified as a main technological barrier for building 3D organs. As such, the fabrication of 3D biological vascular trees is of great importance for the(More)
We present the successful synthesis of aligned 13 C labeled single-walled carbon nanotube (SWNT) arrays from alcohol by a modified no-flow chemical vapor deposition (CVD) method which makes possible efficient growth using a small amount of carbon source. Synthesis of high-quality SWNTs by this alternate method was confirmed by Resonance Raman spectroscopy,(More)
The bright exciton emission of carbon nanotubes is appealing for optoelectronic devices and fundamental studies of light-matter interaction in one-dimensional nanostructures. However, to date, the photophysics of excitons in carbon nanotubes is largely affected by extrinsic effects. Here we perform time-resolved photoluminescence measurements over 14 orders(More)
Based on POJ (PKU Judge Online), an online judge system for ACM/ICPC in Peking University, we develop a system called Programming Grid (PG), which is aimed at computer-aided education (CAE) for programming courses. PG is a course-centered system for CAE, while POJ is a problem-centered system for programming training. PG system designs many resources to(More)
Matrix-assisted pulsed-laser evaporation direct-write (MAPLE DW) has been successfully implemented as a promising laser printing technology for various fabrication applications, in particular, three-dimensional bioprinting. Since most bioinks used in bioprinting are viscoelastic, it is of importance to understand the jetting dynamics during the laser(More)
An in situ optical absorbance technique was used to monitor the growth of vertically aligned single-walled carbon nanotubes (VA-SWNTs) at various temperatures and pressures. The effects of the growth temperature and ethanol pressure on the initial growth rate and catalyst lifetime were investigated. It was found that the ideal pressure for VA-SWNT synthesis(More)
Laser printing is an orifice-free printing approach and has been investigated for the printing of two-dimensional patterns and simple three-dimensional (3D) constructs. To demonstrate the potential of laser printing as an effective bioprinting technique, both straight and Y-shaped tubes have been freeform printed using two different bioinks: 8% alginate(More)
The complex mol-ecule of the tetra-nuclear cubane-type title compound, [Cu(4)I(4)(C(11)H(12)N(2)O(2))(4)], has crystallographically imposed fourfold inversion symmetry. The Cu(I) ions are coordinated in a distorted tetra-hedral geometry by an N atom of a benzimidazole ring system and three μ(3)-iodide ions, forming a Cu(4)I(4) core. In the crystal, complex(More)
The ligament pinch-off process of viscoelastic fluids during jetting is a key step in various biotechnology and dropwise three-dimensional printing applications. Various pinch-off locations have been investigated as a function of material properties and operating conditions during the drop-on-demand (DOD) inkjet printing of viscoelastic alginate solutions.(More)