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As optoelectronic products continue to advance rapidly, the need for effective heat dissipation has become increasingly crucial due to the emphasis on miniaturization and high integration. The vapor chamber is widely used for cooling electronic systems as a passive liquid–gas two-phase high-efficiency heat exchange device. In this paper, we designed and manufactured a new kind of vapor chamber using cotton yarn as the wick material, combined with a fractal pattern layout of leaf veins. A comprehensive investigation was conducted to analyze the performance of the vapor chamber under natural convection circumstances. SEM showed that many tiny pores and capillaries were formed between the cotton yarn fibers, which are very suitable as the wick material of the vapor chamber. Additionally, experimental findings demonstrated the favorable flow and heat transfer characteristics of the cotton yarn wick within the vapor chamber, which makes the vapor chamber have significant heat dissipation capability, compared to the other two vapor chambers; this vapor chamber has a thermal resistance of only 0.43 °C/W at a thermal load of 8.7 W. In addition, the vapor chamber showed good antigravity capability, and its performance did not show significant changes between horizontal and vertical positions; the maximum difference in thermal resistance at four tilt angles is only 0.06 °C/W. This paper also studied the influence of vacuum degree and filling amount on the performance of the vapor chamber. These findings indicate that the proposed vapor chamber provides a promising thermal management solution for some mobile electronic devices and provides a new idea for selecting wick materials for vapor chambers.

A broad range of imaging and sensing technologies in the infrared require large Field-of-View (FoV) operation. To achieve this, traditional refractive systems often employ multiple elements to compensate for aberrations, which leads to excess size, weight, and cost. For many applications, including night vision eye-wear, air-borne surveillance, and autonomous navigation for unmanned aerial vehicles, size and weight are highly constrained. Sub-wavelength diffractive optics, also known as meta-optics, can dramatically reduce the size, weight, and cost of these imaging systems, as meta-optics are significantly thinner and lighter than traditional refractive lenses. Here, we demonstrate 80$^\circ$ FoV thermal imaging in the long-wavelength infrared regime (8-12 $\mu$m) using an all-silicon meta-optic with an entrance aperture and lens focal length of 1 cm., Comment: 9 pages, 5 figures

Background Lymph node metastasis (LNM) status is an important prognostic factor that strongly influences the treatment decision of early gastric cancer (EGC). This study aimed to evaluate the pattern and clinical significance of LNM in EGC. Methods A total of 354 patients with carcinoma in situ (n = 42), EGC (n = 312) who underwent radical gastrectomy were enrolled. Their clinicopathological features, pathological reports, and prognostic data were collected and analyzed. Results The incidence of LNM in all patients was 18.36% (65/354). The rates of D1 and D2 station metastases were 12.10% (43/354) and 6.21% (22/354), respectively. The rates of LNM in absolute indication of endoscopic resection and expanded indication were 3.27% (2/61) and 28.55% (4/14), respectively. Skip LNM was observed in 3.67% (13/354) of patients. For those with middle-third tumor, the metastasis rate of the No. 5 lymph node was 3.05% (5/164). The independent risk factors for LNM were tumors measuring > 30 mm, poorly differentiated tumors, and lymphovascular invasion (all P P = 0.011). Tumors measuring > 20 mm and LNM were independent predictive factors for poor survival outcome in all patients. Conclusions Patients with EGC conforming to expanded indications have a relatively high risk of LNM and may not be suitable for endoscopic submucosal dissection. Pylorus-preserving gastrectomy for patients with middle-third EGC remains controversial due to the high metastasis rate of the No. 5 lymph node.

Objective To compare the safety and efficacy of transurethral laser and transurethral resection for treatment of non-muscle invasive bladder cancer (NMIBC). Methods Randomized controlled trials, cohort studies and case-control studies comparing transurethral laser and transurethral resection of NMIBC were retrieved from PubMed, Medline, Embase, Cochrane Library, Web of Science, Social Science Citation Index, China Journal Full-text Database (CNKI), Chinese Biomedical Literature Database and VIP medical database. RevMan 5.3 software was used for meta-analysis of the data extracted from the eligible studies. Results We retrieved 16 eligible studies involving a total of 2 570 patients from the databases. Meta-analysis of the data from these studies showed no significant difference between the 2 surgical modalities in terms of the operation time (MD=-0.70, 95%CI: -2.78~1.38, P=0.51) or the occurrence of postoperative urethral stricture (OR=0.70, 95%CI: 0.24~2.06, P=0.52). Compared with transurethral resection, transurethral laser surgery was associated with significantly lower incidences of intraoperative obturator nerve reflex (OR=0.05, 95%CI: 0.02~0.10; P < 0.001) and bladder perforation (OR=0.11, 95%CI: 0.04~0.29, P < 0.001), shorter postoperative catheterization time (MD=-1.08, 95%CI: -1.46~-0.71, P < 0.001) and length of hospital stay (OR=0.05, 95%CI: 0.02~0.10, P < 0.001), and lower rates of bladder irrigation (OR=0.21, 95%CI: 0.13~0.35, P < 0.001) and postoperative recurrence at 12 months (OR=0.67, 95%CI: 0.48~0.93, P=0.02) and 24 months (OR=0.60, 95%CI: 0.41~0.86, P=0.005). Conclusion Transurethral laser surgery for NMIBC, as compared with transurethral resection, is associated with lower incidences of intraoperative complications (obsessive nerve reflex and bladder perforation), a lower postoperative recurrence rate, and faster postoperative recovery.

Abbe's resolution limit, one of the best-known physical limitations, poses a great challenge for any wave systems in imaging, wave transport, and dynamics. Originally formulated in linear optics, this Abbe's limit can be broken using nonlinear optical interactions. Here we extend the Abbe theory into a nonlinear regime and experimentally demonstrate a far-field, label-free, and scan-free super-resolution imaging technique based on nonlinear four-wave mixing to retrieve near-field scattered evanescent waves, achieving sub-wavelength resolution of $\lambda/15.6$. This method paves the way for application in biomedical imaging, semiconductor metrology, and photolithography.

The scalability of optical addressing is one of the key challenges for the large-scale trapped-ion quantum computing (QC). Metasurfaces is a promising solution due to excellent optical performance, integration, and miniaturization. Here, we propose and numerically demonstrate a design of integrated scalable metalens array (ISMA) working in the UV 350nm range for optical addressing. These ISMAs can focus the collimated individual addressing beams array into diffraction-limited spots array, featuring crosstalk below 0.82%, focusing efficiency as high as 36.90%. For various applications, the x-polarized, polarization-insensitive and right-handed circularly polarized ISMA are designed. The design proposed in this paper can also find applications in optical trapping., Comment: 7 pages,3 figures

Stainless reinforcement is desirably corrosion-resistant, making structures safe, reliable and durable. In this paper, the constitutive model of stainless steel rebar including nonlinear buckling was presented. Consisting of four hardening rules such as kinematic rule, isotropic rule, saturation rule and memory rule, the Monti-Nuti Model could adopt the Menegotto-Pinto backbone curve to simulate accurately the monotonie and cyclic behaviour of the stainless reinforcing steel including buckling. Comparisons between the numerical results and experimental results were shown to demonstrate the validity.

Proper steel model for reinforcing bar incorporating inelastic buckling is essential for precise seismic analysis of reinforced concrete structures. Steel model without considering inelastic buckling will obviously overestimate the corresponding stress if the rebar is under cyclic loading and the inelastic buckling emerges in compressive loading. In this paper, a modified version of the Monti-Nuti steel model that includes the inelastic buckling for reinforcing bar is proposed. This modified model considers the effect of the yielding stress on the critical slenderness and the behavioral anisotropy in tension and compression of some type of stainless steel rebars. A parameter identification is carried out to calibrate the main parameters of the modified model. The identified parameters are robust. The effectiveness of the modified model is verified comparing the numerical stress-strain curves of carbon steel and stainless steel rebar with the experimental ones.