We study the process e^{+}e^{-}→Λ_{c}^{+}Λover ¯_{c}^{-} at twelve center-of-mass energies from 4.6119 to 4.9509 GeV using data samples collected by the BESIII detector at the BEPCII collider. The ...Born cross sections and effective form factors (|G_{eff}|) are determined with unprecedented precision after combining the single and double-tag methods based on the decay process Λ_{c}^{+}→pK^{-}π^{+}. Flat cross sections around 4.63 GeV are obtained and no indication of the resonant structure Y(4630), as reported by Belle, is found. In addition, no oscillatory behavior is discerned in the |G_{eff}| energy dependence of Λ_{c}^{+}, in contrast to what is seen for the proton and neutron cases. Analyzing the cross section together with the polar-angle distribution of the Λ_{c}^{+} baryon at each energy point, the moduli of electric and magnetic form factors (|G_{E}| and |G_{M}|) are extracted and separated. For the first time, the energy dependence of the form factor ratio |G_{E}/G_{M}| is observed, which can be well described by an oscillatory function.
The effects of spongy graphene on the latent heat and thermal conductivity of the phase change material consisting of docosane and spongy graphene were studied. The latent heat and thermal ...conductivity of docosane/graphene composites were simultaneously enhanced in contrast to that of pure docosane. The latent heat increased from 256.1J/g to 262.8J/g, and the thermal conductivity increased more than 2 times in a low graphene concentration of ~3mg/cm3. X-ray diffractometer, scanning electron microscopy, and Fourier-transform infrared spectrometer were used to characterize the microstructure of docosane and docosane/graphene composite. It is found that the crystallinity of layered docosane was enhanced in the presence of spongy graphene sheets acting as a nucleating agent, which resulted in the increase of latent heat. The enhancement of thermal conductivity for docosane/graphene composite is attributed to the high thermal conductivity of graphene.
Display omitted The simultaneous enhancement of latent heat and thermal conductivity of docosane/graphene composite is attributed to the formation of layered docosane with higher crystallinity in the presence of spongy graphene sheets acting as a nucleating agent.
•The PCM composite consisting of docosane and spongy graphene (G22) is prepared.•The latent heat and thermal conductivity of G22 are simultaneously increased.•The latent heat increase is due to formation of docosane with higher crystallinity.•Graphene sheets act as a nucleating agent to enhance the docosane crystallinity.
The existing mathematical analysis approaches for the management of product manufacturing process cannot satisfy the global optimization and high feasibility required for product manufacturing. ...Neither do they reflect the actual production situation accurately and comprehensively. Therefore, this paper explores the simulation and modelling of management decisions in multi-variety small-batch product manufacturing process in discrete production environment. Firstly, the management knowledge in product manufacturing process was expressed mathematically, and the product manufacturing system was modelled in discrete production environment. Then, the flow of the interactive simulation model was explained, along with the realization steps of the model. Taking a real multi-variety small-batch production unit as the engineering background, an empirical analysis was carried out to detail the interactive simulation of the line change management for the production lines in the management system of the product manufacturing process, and to build a simulation model for the product manufacturing system. The simulation model was proved effective through simulations.
A
bstract
Using (27
.
12 ± 0
.
14) × 10
8
ψ
(3686) events collected by the BESIII detector at the center-of-mass energy of
s
= 3
.
686 GeV, we search for the first time for two nonleptonic hyperon ...decays that change strangeness by two units, Ω
−
→ Σ
0
π
−
and Ω
−
→
nK
−
. No significant signal is observed. The upper limits on their decay branching fractions are determined to be
B
(Ω
−
→ Σ
0
π
−
)
<
5
.
4 × 10
−
4
and
B
(Ω
−
→
nK
−
)
<
2
.
4 × 10
−
4
at the 90% confidence level.
Observation of ψ(3686) →Ω−K+Ξ¯0 + c.c Ai, X. C.; Bakina, O.; Balossino, I. ...
The journal of high energy physics,
04/2024, Volume:
2024, Issue:
4
Journal Article
Peer reviewed
Open access
A
bstract
Using (27
.
12
±
0
.
14)
×
10
8
ψ
(3686) events collected with the BESIII detector at BEPCII, the decay of
ψ
(3686)
→
Ω
−
K
+
Ξ
¯
0
+ c
.
c
.
is observed for the first time. The branching ...fraction of this decay is measured to be
B
ψ
3686
→
Ω
−
K
+
Ξ
¯
0
+
c
.
c
.
= (2
.
78 ± 0
.
40 ± 0
.
18) × 10
−
6
, where the first uncertainty is statistical and the second is systematic. Possible baryon excited states are searched for in this decay, but no evident intermediate state is observed with the current sample size.
The overflow of the flame plume from the window is the main cause of the vertical spread of the fire on the facade of the building. This paper considers the geometry of the window by taking measures ...to prevent the flame from propagating along the vertical wall. In this paper, a residential building is taken as an example to evaluate the flame plume characteristics through experimental tests and numerical simulations. The objective of the present study is to study the flame plume characteristics under the air blow on the outer window side of the building. The theoretical equations of the flame tilt angle, non-dimensional temperature and non-dimensional velocity are derived. A series of experimental tests were carried out in a reduced-scale building model corresponding to the changes of lateral blow ventilation velocity. Reduced scale numerical simulations were conducted to verify the experiments. Results showed that the flame tilt angle increases with ventilation velocity increases. Meanwhile, the experimental results were compared with the reduced-scale tests and numerical simulations. These showed a good agreement between experimental results and numerical simulations. All these findings provide theoretical basis for building fire prevention outside window.
To improve the wear resistance of ?-TiAl alloy, Ta alloy layer was prepared on surface by double glow plasma surface alloying technique. The tribology behavior of Ta alloy layer against Si3N4 at 25?, ...350? and 500? were comparatively studied. The results showed that Ta alloy layer comprised a deposition layer and a diffusion layer. The deposition layer played a role in protection as a soft film. With the increase of temperature, the wear mechanism of ?-TiAl changed from abrasive wear to coexistence of abrasive wear and oxidation wear. Ta alloy layer?s wear mechanism changed from adhesive wear to coexistence of adhesive wear and oxidation wear. Surface Ta alloying process significantly reduced the wear volume, the specific wear rate and the friction coefficient of ?-TiAl and improved the wear resistance properties of ?-TiAl.
The geological research and exploration evaluation of marine-continental transitional shale gas are lagging behind the rapid development of marine and continental shale-gas resources in China. To ...investigate the shale-gas potential of the lower Permian Shanxi and Taiyuan formations in the southern North China Basin, a series of measurements on representative core samples were conducted to characterise shale features, including sedimentary environment, organic geochemistry, mineral composition, pore structure and gas-bearing capacity. The average total organic carbon (TOC) content of the Shanxi and Taiyuan shales reaches 1.68 and 2.26 wt%, respectively, and deposition took place in environments of rapidly changing depositional conditions, where predominantly gas-generating type III kerogen was preserved in the sediments. Regarding the sedimentary environments, different microfacies can affect effective thickness, abundance of organic matter, mineral composition and gas content in the Shanxi and Taiyuan formations. In addition, TOC content, inertinite, chlorite, thermal maturity and pyrite have significant impacts on gas contents. Although the Shanxi-Taiyuan shales are not comparable with gas-producing shales in the USA, there are some similarities in shale reservoir parameters such as the relatively higher organic richness (>2.0 wt% TOC) and gas content (∼2.0 m
3
/t) than in the well-developed Longmaxi and Yanchang shales. Consequently, the Shanxi-Taiyuan shales could be classified as potential shale-gas targets owing to their relatively favourable reservoir properties and gas accumulation. However, some complex geological conditions, such as the greater burial depth (>3500 m), higher clay content (>45%), deficiency of organic-matter hosted pores but other well-developed types of pore-microfracture, extremely high thermal maturity (>3.0% R
o
), several large unsealed faults, etc. may impact gas production in the study areas. Therefore, local geological conditions should be fully considered for the exploration and development of transitional shale gas in the southern North China Basin.
KEY POINTS
Main controlling factors of shale-gas content in transitional Shanxi-Taiyuan shales.
Influence of sedimentary microfacies on shale reservoir parameters.
Detailed investigation of transitional shale-gas potential in southern North China Basin, China.
In this review article, recent advances in the development of the direct borohydride fuel cell (DBFC) technology are reviewed. Based on the reported results, it is concluded that the BH
4
− ...electro-oxidation is determined by the catalyst used and BH
4
− concentration at the catalytic sites. Hydrogen evolution during the DBFC operation can be suppressed by: (1) using a composite catalyst or a hydrogen storage alloy as the anode catalyst via a quasi 8-electron reaction; (2) using metals with high hydrogen over-potential, such as Au and Ag as the anode catalyst via an intrinsic 8-electron reaction; and/or (3) modifying and optimizing fuel composition.
The single cell and stack performance of DBFC is mainly influenced by the hydrogen evolution, the BH
4
− cross-over, and the BH
4
− tolerance of cathode catalyst. The development of non-platinum cathode catalysts and stacking technology is on the way. The reported results are encouraging but some problems still remain to be further investigated and solved.
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