Doping influence of spin dynamics and magnetoelectric effect in hexagonal Y0.7_{0.7}Lu0.3_{0.3}MnO3_{3}

We use inelastic neutron scattering to study spin waves and their correlation with the magnetoelectric effect in Y$_{0.7}$Lu$_{0.3}$MnO$_3$. In the undoped YMnO$_3$ and LuMnO$_3$, the Mn trimerization distortion has been suggested to play a key role in determining the magnetic structure and the magnetoelectric effect. In Y$_{0.7}$Lu$_{0.3}$MnO$_3$, we find a much smaller in-plane (hexagonal $ab$-plane) single ion anisotropy gap that coincides with a weaker in-plane dielectric anomaly at $T_N$. Since both the smaller in-plane anisotropy gap and the weaker in-plane dielectric anomaly are coupled to a weaker Mn trimerization distortion in Y$_{0.7}$Lu$_{0.3}$MnO$_3$ comparing to YMnO$_3$ and LuMnO$_3$, we conclude that the Mn trimerization is responsible for the magnetoelectric effect and multiferroic phenomenon in Y$_{1-y}$Lu$_{y}$MnO$_{3}$.Comment: 5 pages, 5 figure

Fine-grained Audible Video Description

We explore a new task for audio-visual-language modeling called fine-grained audible video description (FAVD). It aims to provide detailed textual descriptions for the given audible videos, including the appearance and spatial locations of each object, the actions of moving objects, and the sounds in videos. Existing visual-language modeling tasks often concentrate on visual cues in videos while undervaluing the language and audio modalities. On the other hand, FAVD requires not only audio-visual-language modeling skills but also paragraph-level language generation abilities. We construct the first fine-grained audible video description benchmark (FAVDBench) to facilitate this research. For each video clip, we first provide a one-sentence summary of the video, ie, the caption, followed by 4-6 sentences describing the visual details and 1-2 audio-related descriptions at the end. The descriptions are provided in both English and Chinese. We create two new metrics for this task: an EntityScore to gauge the completeness of entities in the visual descriptions, and an AudioScore to assess the audio descriptions. As a preliminary approach to this task, we propose an audio-visual-language transformer that extends existing video captioning model with an additional audio branch. We combine the masked language modeling and auto-regressive language modeling losses to optimize our model so that it can produce paragraph-level descriptions. We illustrate the efficiency of our model in audio-visual-language modeling by evaluating it against the proposed benchmark using both conventional captioning metrics and our proposed metrics. We further put our benchmark to the test in video generation models, demonstrating that employing fine-grained video descriptions can create more intricate videos than using captions.Comment: accpeted to CVPR 2023, Xuyang Shen, Dong Li and Jinxing Zhou contribute equally, code link: github.com/OpenNLPLab/FAVDBench, dataset link: www.avlbench.opennlplab.c

Suggestions on the development strategy of shale gas in China

AbstractFrom the aspects of shale gas resource condition, main exploration and development progress, important breakthrough in key technologies and equipment, this paper systematically summarized and analyzed current situation of shale gas development in China and pointed out five big challenges such as misunderstandings, lower implementation degree and higher economic uncertainty of shale gas resource, and still no breakthrough in exploration and development core technologies and equipment for shale gas buried depth more than 3500 m, higher cost and other non-technical factors that restrict the development pace. Aiming at the above challenges, we put forward five suggestions to promote the shale gas development in China: (1) Make strategies and set goals according to our national conditions and exploration and development stages. That is, make sure to realize shale gas annual production of 20 × 109 m3, and strives to reach 30 × 109 m3. (2) Attach importance to the research of accumulation and enrichment geological theory and exploration & development key engineering technologies for lower production and lower pressure marine shale gas reservoir, and at the same time orderly promote the construction of non-marine shale gas exploration & development demonstration areas. (3) The government should introduce further policies and set special innovation funds to support the companies to carry out research and development of related technologies and equipment, especially to strengthen the research and development of technology, equipment and process for shale gas bellow 3500 m in order to achieve breakthrough in deep shale gas. (4) Continue to promote the geological theory, innovation in technology and management, and strengthen cost control on drilling, fracturing and the whole process in order to realize efficient, economic and scale development of China's shale gas. (5) Reform the mining rights management system, establish information platform of shale gas exploration and development data, and correctly guide the non-oil and gas companies to participate in shale gas exploration and development

Tight gas in China and its significance in exploration and exploitation

Tight gas reservoirs refer to the tight sandstone fields or traps accumulating natural gas of commercial values. According to reservoir characteristics, reserves, and structural height, they can be divided into two types, continuous-type and trap-type: the former are located at the lower part of the structure and have indistinct trap boundaries, inconsistent gas-water boundaries and reversal of gas and water, and their reservoirs are the same as or near the source; the latter are located at the higher part of the structure, with gas above water in traps, low reserves, and relatively high production. Tight gas in China is all coal-derived, dominantly alkane gases (C1–4), in which the amount of methane is greatest and the alkane gases have positive carbon isotopic series. The content of non-hydrocarbon gases (mainly CO2 and N2) is low. At the end of 2010, the reserves and annual production of tight gas in China accounted for 39.2% and 24.6% of the total natural gas, respectively, and the proportions are expected to increase. Compared to the shale gas and coalbed gas, tight gas should be considered in priority in the exploration and exploitation of unconventional gas in China. Key words: China, large tight gas field, geochemical characteristics, gas source, coal-derived gas, exploration and exploitation, priorit

Discussion on the gas source of the Triassic Xujiahe Formation tight sandstone gas reservoirs in Yuanba and Tongnanba, Sichuan Basin: An answer to Yin Feng et al.

Gas-source correlation is generally focused on the genetic type of the main gas components, dominantly oil-associated gas or coal-derived gas. Gases from the Yuanba and Tongnanba gas reservoirs are dominated by methane with an average content of 95.36%. The average contents of ethane, propane, butane are 1.60%, 0.29% and 0.09%, respectively. In general, for the Yuanba and Tongnanba gas reservoirs, alkane gas has an average content of 97.34%, and CO2 has an average content of 0.63%, which only accounts for 6.5‰ of the methane. According to the discrimination criteria that δ13C2 value is greater than −28‰ for coal-derived gas and lower than −28.5‰ for the oil-associated gas, Yin et al. suggested that the gases from the Yuanba gas reservoir be a mixture of coal-derived and oil-associated gases, and the gases from the Tongnanba gas reservoir be oil-associated gas. However, the discrimination criteria of δ13C2 for coal-derived and oil-associated gases are only valid when the alkane gases have not undergone secondary alteration and have positive carbon isotopic series among C1–C4 alkanes. Hence, it is concluded that gases from the Yuanba and Tongnanba gas reservoirs are coal-derived gases due to their high content and heavy carbon isotopic values of methane (−31.3‰), which is typical for high mature coal-derived gases in the world. Though Yin et al. suggested that abiogenic CO2 of these two reservoirs is originated from metamorphism or hydrolysis of deep carbonate rocks, we proposed that these CO2 gases are self-generated and self-accumulated under the corrosion of calcarenaceous sandstone of the Triassic Xujiahe Formation. Key words: Yuanba gas reservoir, Tongnanba gas reservoir, tight sandstone gas, Triassic Xujiahe Formation, carbon isotopic composition, coal-derived ga

Exploration and development of large gas fields in China since 2000

Fifty-one large gas fields had been proved in China until 2013. Specifically, exploration characteristics of those discovered since 2000 are as follows: (1) Large gas fields are only found in basins with sedimentary area larger than 10 × 104 km2; (2) Large gas fields have been proved in 9 basins, with total proved reserves of 27085.88 × 108 m3 before 2005, much less than that after 2005, which reached 81683.77 × 108 m3 by the end of 2013; (3) The reserve abundance of large gas fields varies a lot. The Kela2 gas field has the largest reserve abundance of 59.05 × 108 m3/km2, which is 86 times that of the smallest reserve abundance, i.e. 0.684 × 108 m3/km2 of the Jingbian gas field; and (4) The reservoirs of large gas fields between 3000 m and 4500 m share a large proportion of proved reserves, accounting for 46.11% of the total. Development characteristics of the large gas fields in China are as follows: (1) The yield of large gas fields is essential to the natural gas industry of China. In 2013, the total yield was 922.72 × 108 m3, accounting for 76.3% of the nation’s total natural gas yield; (2) The yield is dominated by coal-derived gas, which reached 710.13 × 108 m3 in 2013, accounting for 77.0% of the total yield of large gas fields in China; and (3) The yield of key large gas fields (Sulige, Jingbian, Daniudi, Puguang, and Kela2) is fundamental in making China a major gas producer