115 research outputs found
Microfluidic production of porous chitosan/silica hybrid microspheres and its Cu(II) adsorption performance
AbstractWaste water with heavy metal ions has been of great concern because of its increased discharge, toxic and some other bad effects on human beings or the environment. In this article, monodispersed chitosan/silica hybrid microspheres with porous structure and large specific surface area were successfully prepared by using microfluidic technology and they have advantages in mechanical property and adsorption of heavy metal ions such as Cu(II). In the optimum condition, porous chitosan/silica hybrid microspheres with 1.0wt.% TEOS in the dispersed phase and pre-solidified for 3h have enhanced mechanical intensity, faster adsorption kinetic and larger equilibrium adsorption amount of Cu(II) compared to the porous chitosan microspheres. The mechanical intensity and adsorption rate of the porous hybrid microspheres were 1.5 times and two times of porous chitosan microspheres, respectively. Meantime, the adsorption capacity was increased by 25%. The porous hybrid microspheres have good potentials in the applications of removing heavy metal ions from waste water
Preparation and Characteristic of PC/PLA/TPU Blends by Reactive Extrusion
To overcome the poor toughness of PC/PLA blends due to the intrinsic properties of materials and poor compatibility, thermoplastic urethane (TPU) was added to PC/PLA blends as a toughener; meantime, catalyst di-n-butyltin oxide (DBTO) was also added for catalyzing transesterification of components in order to modify the compatibility of blends. The mechanical, thermal, and rheological properties of blends were investigated systematically. The results showed that the addition of TPU improves the toughness of PC/PLA blends significantly, with the increase of TPU, the elongation at break increases considerably, and the impact strength increases firstly and then falls, while the tensile strength decreases significantly and the blends exhibit a typical plastic fracture behavior. Meantime, TPU is conducive to the crystallinity of PLA in blends which is inhibited seriously by PC and damages the thermal stability of blends slightly. Moreover, the increased TPU makes the apparent viscosity of blends melt decrease due to the well melt fluidity of TPU; the melt is closer to the pseudoplasticity melt. Remarkably, the transesterification between the components improves the compatibility of blends significantly, and more uniform structure results in a higher crystallinity and better mechanical properties
Controllable Hydrothermal Conversion from Ni-Co-Mn Carbonate Nanoparticles to Microspheres
Starting from Ni-Co-Mn carbonate nanoparticles prepared by microreaction technology, uniform spherical particles of Ni1/3Co1/3Mn1/3CO3 with a size of 3–4 μm were obtained by a controllable hydrothermal conversion with the addition of (NH4)2CO3. Based on characterizations on the evolution of morphology and composition with hydrothermal treatment time, we clarified the mechanism of this novel method as a dissolution-recrystallization process, as well as the effects of (NH4)2CO3 concentration on the morphology and composition of particles. By changing concentrations and the ratio of the starting materials for nano-precipitation preparation, we achieved monotonic regulation on the size of the spherical particles, and the synthesis of Ni0.4Co0.2Mn0.4CO3 and Ni0.5Co0.2Mn0.3CO3, respectively. In addition, the spherical particles with a core-shell structure were preliminarily verified to be available by introducing nano-precipitates with different compositions in the hydrothermal treatment in sequence
Mean Field inference of CRFs based on GAT
In this paper we propose an improved mean-field inference algorithm for the
fully connected paired CRFs model. The improved method Message Passing
operation is changed from the original linear convolution to the present graph
attention operation, while the process of the inference algorithm is turned
into the forward process of the GAT model. Combined with the mean-field
inferred label distribution, it is equivalent to the output of a classifier
with only unary potential. To this end, we propose a graph attention network
model with residual structure, and the model approach is applicable to all
sequence annotation tasks, such as pixel-level image semantic segmentation
tasks as well as text annotation tasks
The large-scale production of carbon nanotubes in a nano-agglomerate fluidized-bed reactor
Abstract Carbon nanotubes (CNTs) produced by catalytic chemical vapor deposition (CCVD) can be formed into loose agglomerates that can be fluidized during the growth process. This provides a way to prepare high-quality CNTs on a large scale at low cost in a nano-agglomerate fluidized-bed reactor (NAFBR). With the present fluidized-bed reactor design and catalyst preparation, 50 kg/day of carbon materials was synthesized, and a high yield of 70-80% CNTs was obtained. Fluidization characteristics distinctive to CNT growth in a fluidized-bed reactor are discussed
Synthesis of Hierarchical Iron Hydrogen Phosphate Crystal as a Robust Peroxidase Mimic for Stable H<sub>2</sub>O<sub>2</sub> Detection
To develop a green, cost-efficient
and robust peroxidase mimic,
micro/nano hierarchical morphology (for ease of separation and reuse),
relative chemically stable composition (for ease of storage) and stable
crystal structure (for long-term stability) are highly desired. Herein,
using phosphoric acid as a chelating ligand to control the release
of iron ions, hierarchical ironÂ(III) hydrogen phosphate hydrate crystals
are successfully prepared by nanosheets formation and following self-assembling
in a facile low-temperature hydrothermal process. They are first found
to have peroxidase-like activity and showed higher affinity for H<sub>2</sub>O<sub>2</sub> and lower affinity for 3,3′,5,5′-tetramethylbenzidine
compared with horseradish peroxidase. The affinity feature is used
for quantitative detection of H<sub>2</sub>O<sub>2</sub> and shows
a wide linear detection range from 57.4 to 525.8 μM (<i>R</i><sup>2</sup> = 0.994) with a low detection limit of 1 μM.
Benefited from chemical stability of hierarchical ironÂ(III) salt crystals,
they own good reproducibility (relative standard deviation = 1.95%
for 10 independent measurements), long-term stability (no activity
loss after 10 cycles), and ease of recovery (by simple centrifugation).
Because the method is easily accessible, iron hydrogen phosphate hierarchical
crystals have great potential for practical use of H<sub>2</sub>O<sub>2</sub> sensing and detection under harsh conditions
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