AgBiSe
and AgSbSe
, two typical examples of Te-free I-V-VI
chalcogenides, are drawing much attention due to their promising thermoelectric performance. Both compounds were synthesized
melting and ...consolidated by spark plasma sintering. The role of annealing on the transport properties of polymorphous AgBiSe
and monophase AgSbSe
was studied. Annealing has a greater impact on AgBiSe
than AgSbSe
, which is ascribed to the temperature dependent phase transition of AgBiSe
. Unannealed AgBiSe
shows p-n switching, but annealed AgBiSe
exhibits n-type semiconducting behavior over the whole measurement temperature range. By performing high-temperature Hall measurements, we attribute this intriguing variation to the change in the amount of Ag vacancies and mid-temperature rhombohedral phase after annealing. Both AgBiSe
and AgSbSe
exhibit low thermal conductivity values, which are ∼0.40-0.50 W m
K
for AgSbSe
and ∼0.45-0.70 W m
K
for AgBiSe
, respectively. The maximum
value of AgBiSe
is enhanced from 0.18 to 0.21 after annealing. Pristine AgSbSe
presents a
value as high as 0.60 at 623 K, although slight deterioration emerges after annealing.
Cu 12 Sb 4 S 13 tetrahedrite with intrinsically low lattice thermal conductivity has been identified as a promising thermoelectric material with earth-abundant and environmental-friendly resource, ...but as a natural mineral its synthesis process has not been established. This work studied a powder metallurgical process combining mechanical alloying (MA) and spark plasma sintering (SPS) to synthesize Cu 12 Sb 4 S 13−x ( x = 0, 0.1, 0.2, 0.3 and 0.4) compounds. It is found that single-phased Cu 12 Sb 4 S 13−x bulks could be synthesized by the MA-SPS process, but tended to become powdered naturally in air at room temperature. Interestingly, this weathering-like phenomenon could be effectively suppressed when the MA-SPS process was repeated. Consequently, a high ZT value of up to 0.65 at 723 K was achieved at a nominal composition of Cu 12 Sb 4 S 12.7 , which is close to the best value of 0.70 obtained in Cu 12 Sb 4 S 13 tetrahedrites prepared by the melting method, although the present process is more simple and cost-effective. In addition, in this study temperature-dependent phase transitions were investigated to explore the reasons for the weathering-like phenomenon observed in synthetic Cu 12 Sb 4 S 13 tetrahedrites.
Cu 3 SbSe 3 , a compound with an ultralow thermal conductivity, has been predicted as a promising thermoelectric material, but relevant experimental results are inadequate. In this work we studied ...the high-temperature thermoelectric properties of this ternary chalcogenide. An extremely low thermal conductivity was observed and a glass-like behavior was seen above an order–disorder transition. Possible mechanisms causing such an ultralow thermal conductivity were discussed concerning the disorder of Cu atoms. With a large band gap of ∼0.95 eV obtained by an optical absorption edge measurement, Cu 3 SbSe 3 was found to be a nondegenerate p-type semiconductor, different from previous reports. A maximum zT of ∼0.25 was obtained at 650 K for Cu 3 SbSe 3 , which is much higher than the previously reported values, but this compound was considered inferior to Cu 3 SbSe 4 in its thermoelectric performance by comparing some key physical parameters.
Lead-free p-type AgSn sub()mbTe sub()m2(m = 2, 4, 10, 18) compound thermo-electric materials were fabricated by a process combining mechanical alloys and spark plasma sintering. The electrical and ...thermal transport properties of samples with different m values in a wide range were investigated for compositional optimization with the most enhanced thermoelectric performance. It was found that both electrical and thermal conductivity increase with increasing m value, but the Seebeck coefficient shows a maximum at m = 4, resulting in an optimal composition with a relatively high thermoelectric figure of merit up to ZT approximately 0.8 at 723 K. This work also confirmed that MA-SPS processing could be applied to the synthesis of AgSn sub()mbTe sub()m2compound thermoelectric materials.
Summary
We describe a novel strategy to produce vaccine antigens using a plant cell‐suspension culture system in lieu of the conventional bacterial or animal cell‐culture systems. We generated ...transgenic cell‐suspension cultures from
N
icotiana benthamiana
leaves carrying wild‐type or chimeric
B
amboo mosaic virus
(
B
a
MV
) expression constructs encoding the viral protein 1 (
VP
1) epitope of
foot‐and‐mouth disease virus
(
FMDV
). Antigens accumulated to high levels in
B
dT38 and
B
dT19 transgenic cell lines co‐expressing silencing suppressor protein P38 or P19. Ba
MV
chimeric virus particles (
CVP
s) were subsequently purified from the respective cell lines (1.5 and 2.1 mg
CVP
s/20 g fresh weight of suspended biomass, respectively), and the resulting
CVP
s displayed
VP
1 epitope on the surfaces. Guinea pigs vaccinated with purified
CVP
s produced humoral antibodies. This study represents an important advance in the large‐scale production of immunopeptide vaccines in a cost‐effective manner using a plant cell‐suspension culture system.
Rod-shaped SnS nanocrystals were synthesized by a facile solvothermal method, which were then compacted by a cold isostatic pressing and rapid annealing process. Two-order higher carrier mobility was ...achieved in the corresponding bulk samples, leading to over 200% enhancement of thermoelectric figure of merit.
Rod-shaped SnS nanocrystals synthesized by solvothermal method enhances thermoelectric figure of merit due to higher carrier mobility.
AgBiSe
2
and AgSbSe
2
, two typical examples of Te-free I-V-VI
2
chalcogenides, are drawing much attention due to their promising thermoelectric performance. Both compounds were synthesized
via
...melting and consolidated by spark plasma sintering. The role of annealing on the transport properties of polymorphous AgBiSe
2
and monophase AgSbSe
2
was studied. Annealing has a greater impact on AgBiSe
2
than AgSbSe
2
, which is ascribed to the temperature dependent phase transition of AgBiSe
2
. Unannealed AgBiSe
2
shows p-n switching, but annealed AgBiSe
2
exhibits n-type semiconducting behavior over the whole measurement temperature range. By performing high-temperature Hall measurements, we attribute this intriguing variation to the change in the amount of Ag vacancies and mid-temperature rhombohedral phase after annealing. Both AgBiSe
2
and AgSbSe
2
exhibit low thermal conductivity values, which are ∼0.40-0.50 W m
−1
K
−1
for AgSbSe
2
and ∼0.45-0.70 W m
−1
K
−1
for AgBiSe
2
, respectively. The maximum
ZT
value of AgBiSe
2
is enhanced from 0.18 to 0.21 after annealing. Pristine AgSbSe
2
presents a
ZT
value as high as 0.60 at 623 K, although slight deterioration emerges after annealing.
Annealing treatment has different impact on the transport properties of polymorphous AgBiSe
2
and monophase AgSbSe
2
.
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