2,826 research outputs found
Research on the infiltration of environmental protection consciousness in the teaching of chemistry teachers' specialty
As a chemistry teacher, this paper studies the recycling of experimental drugs and the treatment of three wastes in the middle school chemical demonstration experiment from the perspective of environmental protection. The concept of experimental environment-friendly was emphasized, and the concept of environmentally friendly chemistry and green chemistry education was established, and this concept into the future chemistry teaching of middle school was put. In this way, it achieves the training goal of chemists and environmental education functions, and also achieves the penetration of environmental protection awareness in middle school chemistry teaching. Keywords Environmental protection awareness; chemistry teacher major; environmentally sound chemical education; three waste treatment DOI: 10.7176/JEP/10-6-1
Alterations in intestinal microbiota and enzyme activities under cold-humid stress: implications for diarrhea in cold-dampness trapped spleen syndrome
IntroductionCold and humid environments alter the intestinal microbiota, and the role of the intestinal microbiota in the development of diarrhea associated with cold-dampness trapped spleen syndrome in Chinese medicine is unclear.MethodsThe 30 mice were randomly divided into normal and model groups, with the model group being exposed to cold and humid environmental stresses for 7 days. Then, mouse intestinal contents were collected and analyzed their intestinal microbiota and digestive enzymes.ResultsOur findings revealed significant increases in sucrase and lactase activities, as well as microbial activity, in the model group (p < 0.05). β-diversity analysis highlighted distinct intestinal microbiota compositions between the two groups. Specifically, the experimental group showed a unique dominance of the genera and strains Clostridium sensu stricto 1 and Clostridium sp. ND2. LEfSe analysis identified Helicobacter, Roseburia, and Eubacterium plexicaudatum ASF492 as differentially abundant species in them model group. Network analysis demonstrated that rare bacterial species mostly governed the microbial interactions, exhibiting increased mutual promotion. On the other hand, abundant species like Lactobacillus johnsonii and Lactobacillus reuteri showed mutual inhibitory relationships.DiscussionIn summary, exposure to cold and humid conditions led to increased intestinal enzyme activities and a shift in microbial composition, favoring the growth of rare bacterial species. These changes suggest that rare bacteria in the intestinal microbiota play a critical role in the pathology of diarrhea associated with cold-dampness trapped spleen syndrome, revealing unique survival strategies among bacterial populations under stressful conditions
Observation of prolonged coherence time of the collective spin wave of atomic ensemble in a paraffin coated Rb vapor cell
We report a prolonged coherence time of the collective spin wave of a thermal
87Rb atomic ensemble in a paraffin coated cell. The spin wave is prepared
through a stimulated Raman Process. The long coherence time time is achieved by
prolonging the lifetime of the spins with paraffin coating and minimize
dephasing with optimal experimental configuration. The observation of the long
time delayed-stimulated Stokes signal in the writing process suggests the
prolonged lifetime of the prepared spins; a direct measurement of the decay of
anti-Stokes signal in the reading process shows the coherence time is up to 300
us after minimizing dephasing. This is one hundred times longer than the
reported coherence time in the similar experiments in thermal atomic ensembles
based on the Duan-Lukin-Cirac-Zoller (DLCZ) and its improved protocols. This
prolonged coherence time sets the upper limit of the memory time in quantum
repeaters based on such protocols, which is crucial for the realization of
long-distance quantum communication. The previous reported fluorescence
background in the writing process due to collision in a sample cell with buffer
gas is also reduced in a cell without buffer gas.Comment: 4 pages, 4 figure
Towards Better Query Classification with Multi-Expert Knowledge Condensation in JD Ads Search
Search query classification, as an effective way to understand user intents,
is of great importance in real-world online ads systems. To ensure a lower
latency, a shallow model (e.g. FastText) is widely used for efficient online
inference. However, the representation ability of the FastText model is
insufficient, resulting in poor classification performance, especially on some
low-frequency queries and tailed categories. Using a deeper and more complex
model (e.g. BERT) is an effective solution, but it will cause a higher online
inference latency and more expensive computing costs. Thus, how to juggle both
inference efficiency and classification performance is obviously of great
practical importance. To overcome this challenge, in this paper, we propose
knowledge condensation (KC), a simple yet effective knowledge distillation
framework to boost the classification performance of the online FastText model
under strict low latency constraints. Specifically, we propose to train an
offline BERT model to retrieve more potentially relevant data. Benefiting from
its powerful semantic representation, more relevant labels not exposed in the
historical data will be added into the training set for better FastText model
training. Moreover, a novel distribution-diverse multi-expert learning strategy
is proposed to further improve the mining ability of relevant data. By training
multiple BERT models from different data distributions, it can respectively
perform better at high, middle, and low-frequency search queries. The model
ensemble from multi-distribution makes its retrieval ability more powerful. We
have deployed two versions of this framework in JD search, and both offline
experiments and online A/B testing from multiple datasets have validated the
effectiveness of the proposed approach
2-(4-Fluorophenyl)quinoxaline
In the title compound, C14H9FN2, the dihedral angle between the benzene ring and the quinoxaline ring system is 22.2 (3)°. Any aromatic π–π stacking in the crystal must be very weak, with a minimum centroid–centroid separation of 3.995 (2) Å
Polytypism and Unexpected Strong Interlayer Coupling of two-Dimensional Layered ReS2
The anisotropic two-dimensional (2D) van der Waals (vdW) layered materials,
with both scientific interest and potential application, have one more
dimension to tune the properties than the isotropic 2D materials. The
interlayer vdW coupling determines the properties of 2D multi-layer materials
by varying stacking orders. As an important representative anisotropic 2D
materials, multilayer rhenium disulfide (ReS2) was expected to be random
stacking and lack of interlayer coupling. Here, we demonstrate two stable
stacking orders (aa and a-b) of N layer (NL, N>1) ReS2 from ultralow-frequency
and high-frequency Raman spectroscopy, photoluminescence spectroscopy and
first-principles density functional theory calculation. Two interlayer shear
modes are observed in aa-stacked NL-ReS2 while only one interlayer shear mode
appears in a-b-stacked NL-ReS2, suggesting anisotropic-like and isotropic-like
stacking orders in aa- and a-b-stacked NL-ReS2, respectively. The frequency of
the interlayer shear and breathing modes reveals unexpected strong interlayer
coupling in aa- and a-b-NL-ReS2, the force constants of which are 55-90% to
those of multilayer MoS2. The observation of strong interlayer coupling and
polytypism in multi-layer ReS2 stimulate future studies on the structure,
electronic and optical properties of other 2D anisotropic materials
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