Showing papers by "Jiandong Ye published in 2008"
TL;DR: In this paper, the authors report on the realization of the p-type ZnO film by in situ nitrogen doping and subsequent thermal activation, as well as the discussions on the doping mechanism.
36 citations
TL;DR: A novel partially crystallized calcium phosphate (PCCP) + dicalcium phosphate anhydrous (DCPA) system bone cement was introduced and the mechanism of the hydration was studied, showing that DCPA was more soluble than PCCP and HA was the most insoluble compound, and DCPA disappeared fast during hydration of the cement.
Abstract: A novel partially crystallized calcium phosphate (PCCP) + dicalcium phosphate anhydrous (DCPA) system bone cement was introduced and the mechanism of the hydration was studied by means of solubility product constant (K (sp)), XRD, pH value, and BET. Results showed that DCPA was more soluble than PCCP and HA was the most insoluble compound, and DCPA disappeared fast during hydration of the cement. Therefore, the mechanism of the hydration in the PCCP + DCPA system cement was the dissolution and hydrolysis of DCPA and PCCP. And their by-products H(3)PO(4) and Ca(OH)(2) reacted through a acid-base neutralization reaction, thus the DCPA and PCCP dissolution and hydrolysis process happened until DCPA and/or PCCP was exhausted. As the conserving time prolonged, fine nano-scale pores were formed due to the hydroxyapatite precipitated into the pores, which were occupied by water before.
34 citations
TL;DR: In this paper, transmission electron microscopy and Raman spectra were used to investigate the behavior of impurity carbon usually unintentionally introduced in N-doped ZnO by metal-organic chemical vapor deposition.
Abstract: We employed transmission electron microscopy and Raman spectra to investigate the behavior of impurity carbon usually unintentionally introduced in N-doped ZnO by metal-organic chemical vapor deposition. Unintentional doped carbon may form graphite clusters along grain boundaries resulting in n-type domains and possibly be a big obstacle for the realization of p-type conductivity. The enhanced desorption rate of hydrocarbon radicals by high temperature and oxygen atom will significantly suppress carbon incorporation rate. The results provide understandings of the formation mechanism of carbon clusters and help us find some available routines to minimize carbon impurity for realization of p-type N-doped ZnO.
31 citations
TL;DR: In this paper, secondary ion mass spectroscopy analysis indicates that Mn and N atoms have been in situ incorporated into the ZnO epilayer, which is attributed to the low formation energy of Mn-N neighboring bonds in the co-doped epilayers.
Abstract: Mn-N co-doped Zn epilayers were grown by metal-organic chemical vapor deposition. The Mn-N co-doped epilayers exhibit single phase hexagonal wurtzite structure, indicative of the small lattice damage from co-doping. Secondary ion mass spectroscopy analysis indicates that Mn and N atoms have been in situ incorporated into the ZnO epilayer. Hall measurements exhibit the conduction transition from n-type of the N mono-doped ZnO to p-type of the Mn-N codoped ZnO epilayer. This behavior is attributed to the low formation energy of Mn-N neighboring bonds in the co-doped epilayers. Mn doping leads to the low incorporation of N-H and N-N complexes, which are abundant in the N mono-doped epilayer and always act as compensation centers of holes. Moreover, room temperature ferromagnetism has been observed on the above co-doped epilayer, which is possibly due to the hole mediation on the ferromagnetic ordering of Mn atoms.
20 citations
TL;DR: In this paper, double-walled microspheres trapping gentamicin sulphate were prepared from poly( l -lactic acid) (PLLA) and poly(l-lactic-co-glycolic acid (PLGA) as a delivery system for highly hydrophilic antibiotics.
16 citations
TL;DR: In this article, an excellent agreement between the redshift of the experimental depth-resolved cathodoluminescence (CL) emission and theoretically simulated values was observed, which clearly identified its origin to be the strong internal absorption in ZnO epilayer.
Abstract: In this letter, the excitonic emissions from ZnO epilayers were studied by depth-resolved cathodoluminescence (CL) microanalysis. An excellent agreement between the redshift of the experimental depth-resolved CL emission and theoretically simulated values was observed, which clearly identified its origin to be the strong internal absorption in ZnO epilayer. Moreover, the rigorous Monte Carlo simulated CL generation profiles with the correction of self-absorption exhibit the reasonable correspondence with the measured CL intensities. The intensity discrepancies for low and high excitation cases have been interpreted by the occurrence of the excess carrier nonradiative recombination on the surface space charge layer and the exciton nonradiative quenching processing by defects or structural disorders near the interface of ZnO and sapphire.
9 citations
TL;DR: In this article, a modified oxidized tapioca starch was analyzed by optical microscope, and two other corn starches (common corn starch and high amylose corn starch) were also analyzed for comparison.
Abstract: The alumina ceramics with the homogeneous microstructure and the higher density were fabricated via the modified-starch consolidation process by 1.0 wt% of a modified starch as a consolidator/binder. The swelling behavior of the modified oxidized tapioca starch was analyzed by optical microscope, and two other corn starches (common corn starch and high amylose corn starch) were also analyzed for comparison. The modified starch used as a binder for the consolidation swelled at about 55 °, began to gelatinize at 65 ° and then was completely gelatinized at 75 °. But the corn starches could not be completely gelatinized even at 80 ° for 1 h. The high-strength green bodies (10.6 MPa) with the complex shapes were produced. The green bodies were sintered without any binder burnout procedure at 1 700 ° and a relative density of 95.3% was obtained for the sintered bodies, which is similar to that of the sintered sample formed by conventional slip casting. In addition, the effect of temperature on the apparent viscosity of the starch/alumina slurry in the process was investigated, and the corresponding mechanism for the starch consolidation was discussed.
9 citations
TL;DR: In this article, an electrically pumped silicon light-emitting device with a thin multilayer stacked amorphous silicon (alpha-Si, in thickness of 3-7 nm)/silicon nitride (~10 nm) structure was reported.
Abstract: This letter reports for the first time on an electrically pumped silicon light-emitting device with a thin multilayer stacked amorphous silicon (alpha-Si, in thickness of 3-7 nm)/silicon nitride (~10 nm) structure. The observed photoluminescence (PL) is tunable from ~700 to ~670 nm, and intensity increases by decreasing the alpha-Si thickness. The PL intensity can be enhanced through postdeposition annealing at relatively low temperatures and a short annealing time (e.g., as optimized at 700degC/10min). Electroluminescence from devices that are built upon the proposed structure originates from electron-hole pair recombination, and the carrier injection mechanism is through Frenkel-Poole tunneling. Our proposed structure, being highly complimentary metal-oxide-semiconductor compatible, benefits from a low thermal budget process coupled with an accurate layer thickness control.
4 citations
TL;DR: In this article, a simple reproducible and low-cost synthesis method for the preparation of s-tricalcium phosphate (s-TCP) was developed via wet mechanochemical treatment using calcium oxide and calcium hydrogen phosphate as raw materials.
Abstract: In this work, a simple, reproducible and low-cost synthesis method for the preparation of s-tricalcium phosphate (s-TCP) was developed. s-TCP was prepared via wet mechanochemical treatment using calcium oxide and calcium hydrogen phosphate as raw materials. XRD and FTIR analysis indicated that the as-treated precursor was non-stoichiometric, poorly-crystallized carbonated hydroxyapatite (CHA) resulting from the mechanochemical reaction, and the crystalline s-TCP powder was obtained by calcining the precursor at 800°C for 2 hours. SEM observation showed that the addition of surfactants could eliminate the agglomeration of the powder and well-dispersive s-TCP powder with a particle diameter between 0.1 and 2.0 2m can be obtained.
2 citations
TL;DR: In this article, a calcium phosphate cement (CPC) was prepared by mixing partially crystallized calcium phosphate (PCCP) containing carbonate and dicalcium phosphate anhydrous (DCPA) in order to study the effects of carbonate content on the phase composition, strength, prosity and degradation of the set bodies.
Abstract: A novel calcium phosphate cement (CPC) was prepared by mixing partially crystallized calcium phosphate (PCCP) containing carbonate and dicalcium phosphate anhydrous (DCPA) in this work. The effects of the carbonate content on the phase composition, strength, prosity, and degradation of the set bodies were studied. The results showed that the cement formed into hydroxyapatite (HAp) after setting, in which carbonate doped into the HAp crystal lattice. With the increase of the carbonate to phosphate ratio in PCCP, the compressive strength of the cement declined and the setting of the cement accelerated. Furthermore, the calcium phosphate cement formed a more porous structure with the increase of the carbonate to phosphate ratio in PCCP. The results also indicated that the degradation of CPC may be speeded up by introducing carbonate to the cement.
TL;DR: In this paper, a modified starch was employed to be the pore former in the in-situ consolidation forming process of porous alumina ceramic slurry, and the results indicated that the viscosity of the slurry increased with the modified starch content, dispersant content, alumina solid volume loading and ball milling time.
Abstract: A modified starch was employed to be the pore former in the in-situ consolidation forming process of porous alumina ceramic. In order to prepare ceramic slurry with high dispersion, high stabilization and high solid volume loading, the effects of modified starch content, dispersant content, alumina solid volume loading, pH value of the slurry and ball milling time on the rheological behavior of alumina ceramic slurry were investigated. The results indicated that the viscosity of the slurry increased with the modified starch content, alumina solid volume loading and ball milling time. When the pH value of the slurry was 9.0, the modified starch-alumina slurry exhibited high fluidity. The modified starch-alumina slurry was a pseudoplastic fluid exhibiting shear thinning behavior. The slurry possessed a desirable plasticity to enable shape forming when adding 50 vol% modified starch and 1.0 wt% dispersant to the alumina slurry at pH 9.0 after 14 h ball milling treatment.