139 research outputs found
Threshold Characteristics of Slow-Light Photonic Crystal Lasers
The threshold properties of photonic crystal quantum dot lasers operating in
the slow-light regime are investigated experimentally and theoretically.
Measurements show that, in contrast to conventional lasers, the threshold gain
attains a minimum value for a specific cavity length. The experimental results
are explained by an analytical theory for the laser threshold that takes into
account the effects of slow-light and random disorder due to unavoidable
fabrication imperfections. Longer lasers are found to operate deeper into the
slow-light region, leading to a trade-off between slow-light induced reduction
of the mirror loss and slow-light enhancement of disorder-induced losses.Comment: 5 pages, 7 figure
Long-Term Rhythmic Video Soundtracker
We consider the problem of generating musical soundtracks in sync with
rhythmic visual cues. Most existing works rely on pre-defined music
representations, leading to the incompetence of generative flexibility and
complexity. Other methods directly generating video-conditioned waveforms
suffer from limited scenarios, short lengths, and unstable generation quality.
To this end, we present Long-Term Rhythmic Video Soundtracker (LORIS), a novel
framework to synthesize long-term conditional waveforms. Specifically, our
framework consists of a latent conditional diffusion probabilistic model to
perform waveform synthesis. Furthermore, a series of context-aware conditioning
encoders are proposed to take temporal information into consideration for a
long-term generation. Notably, we extend our model's applicability from dances
to multiple sports scenarios such as floor exercise and figure skating. To
perform comprehensive evaluations, we establish a benchmark for rhythmic video
soundtracks including the pre-processed dataset, improved evaluation metrics,
and robust generative baselines. Extensive experiments show that our model
generates long-term soundtracks with state-of-the-art musical quality and
rhythmic correspondence. Codes are available at
\url{https://github.com/OpenGVLab/LORIS}.Comment: ICML202
All-trans retinoic acid restores gap junctional intercellular communication between oral cancer cells with upregulation of Cx32 and Cx43 expressions in vitro
Objective: All-trans retinoic acid (ATRA) has been demonstrated to inhibit tumor growth by restoration of gap
junctional intercellular communication (GJIC) via upregulation of connexin (Cx) expression in some solid tumors.
However, the relationship between ATRA and GJIC remains unclear in oral squamous cell carcinoma (OSCC).
The aim of this study was to investigate the effect of ATRA on the GJIC function of OSCC.
Study design: We measured the effects of ATRA on the viability and cell cycle distribution of SCC9 and Tca8113
OSCC cells. The GJIC function was observed using the scrape-loading dye transfer technique, and the mRNA and
protein levels of Cx32 and Cx43 were detected by qRT-PCR, Western blot, and immunofluorescence assays.
Results: ATRA inhibited the growth of OSCC cells in a dose- and time-dependent manner (P <0.05) and caused
cell cycle arrest. ATRA-treated cells showed a 2.69-fold and 2.06-fold enhancement of GJIC in SCC9 and Tca8113
cells, respectively (P <0.05). Moreover, ATRA induced upregulation of Cx32 and Cx43 at both the mRNA and
protein levels in OSCC cells.
Conclusion: Our results indicated that restoration of GJIC via enhanced Cx32 and Cx43 expression might serve as
a novel mechanism for the anti-tumor effect of ATRA in OSCC
Asymmetric gradient coil design for use in a short, open bore magnetic resonance imaging scanner
A conventional cylindrical whole-body MRI scanner has a long bore that may cause claustrophobia for some patients in addition to being inconvenient for healthcare workers accessing the patient. A short-bore scanner usually offers a small sized imaging area, which is impractical for imaging some body parts, such as the torso. This work proposes a novel asymmetric gradient coil design that offers a full-sized imaging area close to one end of the coil. In the new design, the primary and shielding coils are connected at one end whilst separated at the other, allowing the installation of the cooling system and shim trays. The proposed coils have a larger wire gap, higher efficiency, lower inductance, less resistance and a higher figure of merit than the non-connected coils. This half-connected coil structure not only improves the coils’ electromagnetic performance, but also slightly attenuates acoustic radiation at most frequencies when compared to a non-connected gradient coil. It is also quieter in some frequency bands than a conventional symmetric gradient coil
The metacognitive experience of time passing in Chinese college students: scale development, structure verification, and influencing factors
The experience of time passing (ETP) is also the consciousness of the progress of life. ETP contributes to time regulation and life management, which basically conforms to the metacognitive theory. Also, the traditional Chinese cultural approach to time emphasizes ETP. It is an indispensable part of Chinese education and culture to strengthen one’s appreciation of time by emphasizing the passage of time. In combination with the above two points, ETP equals metacognitive experience of time passing (METP) to a certain extent. However, we currently know little about the connotations of METP. To better understand traditional Chinese time culture, and referring to the concept of metacognition and model of time experience as proposed by Western scholars, the current study combined the results of open and semi-structured interviews, to explore the structure of METP in Chinese college students and developed a questionnaire with which to measure it. Using convenience sampling, 2,876 college students were recruited, the interview, and the reliability and validity tests were carried out. Five hundred and seventy-nine college students were tested a second time to investigate the correlation validity between METP and Ruminative Responses, time attitude, and meaning in life. The results led to the development of the METP Scale which contains 15 items and assesses two factors: ruminative and emotional experience of time passing. The two-factor model was well fitted, and invariable in measurements across gender, grade, and major. The internal consistency coefficients of the scale and its two factors ranged from 0.82 to 0.89, the half-point reliability between 0.76 and 0.88, and the retest reliability ranged from 0.77 to 0.78. METP Scale has good correlation validity, meanwhile, the results of regression analysis showed that symptom rumination, positive past, negative present, positive future, and searching for meaning in life significantly predict the intensity of METP
InternVid: A Large-scale Video-Text Dataset for Multimodal Understanding and Generation
This paper introduces InternVid, a large-scale video-centric multimodal
dataset that enables learning powerful and transferable video-text
representations for multimodal understanding and generation. The InternVid
dataset contains over 7 million videos lasting nearly 760K hours, yielding 234M
video clips accompanied by detailed descriptions of total 4.1B words. Our core
contribution is to develop a scalable approach to autonomously build a
high-quality video-text dataset with large language models (LLM), thereby
showcasing its efficacy in learning video-language representation at scale.
Specifically, we utilize a multi-scale approach to generate video-related
descriptions. Furthermore, we introduce ViCLIP, a video-text representation
learning model based on ViT-L. Learned on InternVid via contrastive learning,
this model demonstrates leading zero-shot action recognition and competitive
video retrieval performance. Beyond basic video understanding tasks like
recognition and retrieval, our dataset and model have broad applications. They
are particularly beneficial for generating interleaved video-text data for
learning a video-centric dialogue system, advancing video-to-text and
text-to-video generation research. These proposed resources provide a tool for
researchers and practitioners interested in multimodal video understanding and
generation.Comment: Data and Code:
https://github.com/OpenGVLab/InternVideo/tree/main/Data/InternVi
SinSR: Diffusion-Based Image Super-Resolution in a Single Step
While super-resolution (SR) methods based on diffusion models exhibit
promising results, their practical application is hindered by the substantial
number of required inference steps. Recent methods utilize degraded images in
the initial state, thereby shortening the Markov chain. Nevertheless, these
solutions either rely on a precise formulation of the degradation process or
still necessitate a relatively lengthy generation path (e.g., 15 iterations).
To enhance inference speed, we propose a simple yet effective method for
achieving single-step SR generation, named SinSR. Specifically, we first derive
a deterministic sampling process from the most recent state-of-the-art (SOTA)
method for accelerating diffusion-based SR. This allows the mapping between the
input random noise and the generated high-resolution image to be obtained in a
reduced and acceptable number of inference steps during training. We show that
this deterministic mapping can be distilled into a student model that performs
SR within only one inference step. Additionally, we propose a novel
consistency-preserving loss to simultaneously leverage the ground-truth image
during the distillation process, ensuring that the performance of the student
model is not solely bound by the feature manifold of the teacher model,
resulting in further performance improvement. Extensive experiments conducted
on synthetic and real-world datasets demonstrate that the proposed method can
achieve comparable or even superior performance compared to both previous SOTA
methods and the teacher model, in just one sampling step, resulting in a
remarkable up to x10 speedup for inference. Our code will be released at
https://github.com/wyf0912/SinS
Acidochromic organic photovoltaic integrated device
Tremendous efforts have been devoted to boosting the power conversion efficiency (PCE) of organic solar cells (OSCs) via the introduction of cathode interlayers (CILs). However, CIL materials have limited diversity and the development of multifunctional devices is largely neglected. Herein, an acidochromic organic photovoltaic integrated device is firstly proposed by introducing an acid-sensitive stimulating-reaction organic molecule as both the CIL of OSCs and the sensor of monitoring environmental acidity. The oxazolidine unit of acidochromic molecule can form a ring-opening structure after acid treatment, resulting in the remarkable color change with the direct reflection of pH value of ecological environment. The additive-free PM6:Y6 OSCs using the acidochromic molecule as the CIL achieve an excellent PCE of above 15.29 %, which is 47 % higher than that of the control device. The PCE can even maintain above 92 % after treating CIL with various strong acids (pH = 1). Moreover, the color of acidified films and the degraded performance of acidified OSCs can be easily restored by alkaline treatment. The successful application of CIL in other highly efficient photovoltaic systems proves its good universality. This work triggers the promising application of acidochromic molecules in solar cells as CIL with the additional function of recognition of acid environment
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