Photon statistics and bunching of a chaotic semiconductor laser

The photon statistics and bunching of a semiconductor laser with external optical feedback are investigated experimentally and theoretically. In a chaotic regime, the photon number distribution is measured and undergoes a transition from Bose-Einstein distribution to Poisson distribution with increasing the mean photon number. The second order degree of coherence decreases gradually from 2 to 1. Based on Hanbury Brown-Twiss scheme, pronounced photon bunching is observed experimentally for various injection currents and feedback strengths, which indicates the randomness of the associated emission light. Near-threshold injection currents and strong feedback strengths modify exactly the laser performance to be more bunched. The macroscopic chaotic dynamics is confirmed simultaneously by high-speed analog detection. The theoretical results qualitatively agree with the experimental results. It is potentially useful to extract randomness and achieve desired entropy source for random number generator and imaging science by quantifying the control parameters.Comment: 10 pages,7 figures, accepted by Optics Expres

Poly[[μ2-1,3-bis­(imidazol-1-ylmeth­yl)benzene][μ2-2,2′-dihy­droxy-1,1′-methyl­enebis(naphthalene-3-carboxyl­ato)]zinc]

In the title compound, [Zn(C23H14O6)(C14H14N4)]n, the ZnII ion is four-coordinated in a distorted tetra­hedral geometry. The 1,3-bis­(imidazol-1-ylmeth­yl)benzene and 2,2′-dihy­droxy-1,1′-methyl­enebis(naphthalene-3-carboxy­l­ate) ligands con­nect the ZnII ions alternately in different directions, forming a layered structure parallel to the ac plane. Topological analysis reveals that the whole structure is a (4,4) network. The layers are further assembled into a three-dimensional supra­molecular structure via C—H⋯O and C—H⋯π inter­actions

Double band inversion in the topological phase transition of Ge1-xSnx alloys

We use first-principles simulation and virtual crystal approximation to reveal the unique double band inversion and topological phase transition in Ge1-xSnx alloys. Wavefunction parity, spatial charge distribution and surface state spectrum analyses suggest that the band inversion in Ge1-xSnx is relayed by its first valence band. As the system evolves from Ge to {\alpha}-Sn, its conduction band moves down, and inverts with the first and the second valence bands consecutively. The first band inversion makes the system nontrivial, while the second one does not change the topological invariant of the system. Both the band inversions yield surface modes spanning the individual inverted gaps, but only the surface mode in the upper gap associates with the nontrivial nature of tensile-strained {\alpha}-Sn.Comment: 5 pages, 6 figure

Single-Incision Laparoscopic Splenectomy in Children With Massive Splenomegaly: A Prospective, Monocentric Pilot Study

BACKGROUND: Single-incision laparoscopic splenectomy (SILS) remains a challenging procedure because of the technical difficulty. In this prospective study, we aimed to evaluate the efficacy and safety of SILS in children with massive splenomegaly. METHODS: Pediatric patients with massive splenomegaly were recruited for SILS in a university-affiliated hospital. The data on patient demographics, clinical features, operative variables, and perioperative outcomes were collected prospectively and analyzed. According to the different surgical instruments, the patients were randomly assigned into two groups: the SILS with straight surgical instrument (SILS-S) group and the SILS with curved surgical instrument (SILS-C) group. A two-group comparative analysis was conducted using perioperative data from the different surgical instrumentation systems. RESULTS: A total of 120 patients were included, of which 103 patients (success group, 85.83%) had complete SILS, the other 17 (failure group, 14.17%) patients were converted to open ( CONCLUSION: SILS is a safe and feasible treatment in pediatric patients with massive splenomegaly, and curved surgical instrumentation has contributed to developing surgical manipulation

Selection of Surgical Modality for Massive Splenomegaly in Children

BACKGROUND: Laparoscopic splenectomy (LS), a treatment for both benign and malignant splenic diseases, can prove technically challenging in patients with massive splenomegaly. In particular, the optimal surgical modality for treating massive splenomegaly in children remains controversial. METHODS: The clinicopathologic data of 289 pediatric patients undergoing splenectomy for massive splenomegaly were studied in a retrospective analysis. Accordingly, the patients were classified into the LS surgery group and open splenectomy (OS) surgery group. In the laparoscopy cohort, they were separated into two subgroups according to the method of surgery: the multi-incision laparoscopic splenectomy (MILS) and the single-incision laparoscopic splenectomy (SILS) surgery groups, respectively. Patient demographics, clinical data, surgery, complications, and postoperative recovery underwent analysis. Concurrently, we compared the risk of adverse laparoscopic splenectomy outcomes utilizing univariable and multivariable logistic regression. RESULTS: The total operation time proved remarkably shorter in the OS group in contrast to the LS group (149.87 ± 61.44 versus 188.20 ± 52.51 min, P \u3c 0.001). Relative to the OS group, the LS group exhibited lowered postoperative pain scores, bowel recovery time, and postoperative hospitalization time (P \u3c 0.001). No remarkable difference existed in post-operation complications or mortality (P \u3e 0.05). Nevertheless, the operation duration was remarkably longer in the SILS surgery group than in the MILS surgery group (200 ± 46.11 versus 171.39 ± 40.30 min, P = 0.02). Meanwhile, the operative duration of MILS and SILS displayed a remarkable positive association with splenic length. Moreover, the operative duration of SILS displayed a remarkable positive association with the age, weight, and height of the sick children. Splenic length proved an independent risk factor of adverse outcomes (P \u3c 0.001, OR 1.378). CONCLUSIONS: For pediatric patients with massive splenomegaly who can tolerate prolonged anesthesia and operative procedures, LS surgery proves the optimal treatment regimen. SILS remains a novel surgery therapy which may be deemed a substitutional surgery approach for treating massive splenomegaly

Duckweed: a starch-hyperaccumulating plant under cultivation with a combination of nutrient limitation and elevated CO2

IntroductionThe increasing global demand for starch has created an urgent need to identify more efficient and sustainable production methods. However, traditional starch sources, such as crop-based options, experience significant bottlenecks due to limitations in land use, water consumption, and the impacts of climate change. Therefore, there is a pressing need to explore and develop new sources of starch.MethodsWe develop a novel duckweed cultivation technology that combines nutrients limitation and CO2 supplementation to achieve very high starch content. In this study, we integrated whole-genome sequencing, epigenomics, transcriptomics, enzyme activity, and composition variation to elucidate the mechanisms of efficient starch accumulation in duckweed in terms of starch accumulation and carbon partitioning, regulation of the expression of genes in the starch metabolic pathway, and sucrose biosynthesis and transportation.Results and discussionAlthough Landoltia punctata exhibits dramatic gene family contraction, its starch content and productivity reached 72.2% (dry basis) and 10.4 g m-2 d-1, respectively, in 10 days, equivalent to a yield of 38.0 t ha-1 y-1, under nutrient limitation treatment with elevated CO2 levels. We also examined the mechanism of high starch accumulation in duckweed. This phenomenon is associated with the regulation of DNA methylation and transcription factors as well as the significantly upregulated transcription levels and the increased activities of key enzymes involved in starch biosynthesis. Moreover, while nitrogen redistribution was increased, sucrose biosynthesis and transportation and lignocellulose biosynthesis were reduced. These alterations led to a reduction in lignocellulose and protein contents and ultimately an increase in the accumulation of starch in the chloroplasts.ConclusionThis work demonstrates the potential of duckweed as a highly efficient starch producer

LASER-INDUCED THERMAL–MECHANICAL DAMAGE CHARACTERISTICS OF CLEARTRAN MULTISPECTRAL ZINC SULFIDE WITH TEMPERATURE-DEPENDENT PROPERTIES

Laser-induced thermal–mechanical damage characteristics of window materials are the focus problems in laser weapon and anti-radiation reinforcement technology. Thermal–mechanical effects and damage characteristics are investigated for cleartran multispectral zinc sulfide ( ZnS ) thin film window materials irradiated by continuous laser using three-dimensional (3D) thermal–mechanical model. Some temperature-dependent parameters are introduced into the model. The temporal-spatial distributions of temperature and thermal stress are exhibited. The damage mechanism is analyzed. The influences of temperature effect of material parameters and laser intensity on the development of thermal stress and the damage characteristics are examined. The results show, the von Mises equivalent stress along the thickness direction is fluctuant, which originates from the transformation of principal stresses from compressive stress to tensile stress with the increase of depth from irradiated surface. The damage originates from the thermal stress but not the melting. The thermal stress is increased and the damage is accelerated by introducing the temperature effect of parameters or the increasing laser intensity. </jats:p

Effect of the Deformation Degree on the Microstructure Evolution of an Austenite Reverted Transformation-Annealed Medium Manganese Steel

An Fe-0.15C-1.2Si-5Mn-0.09Nb-0.08V-0.07Mo (wt.%) medium manganese steel that was subjected to a novel austenite reverted transformation (ART) annealing process. This paper is based on the conventional ART annealing process, and a deformation and ART annealing process is proposed. The influence of the deformation degree on the microstructure and grain size of the medium manganese steel was determined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron backscatter diffraction (EBSD) and X-ray diffraction (XRD). The results show that the deformation had a great effect on the microstructure evolution and grain size. The microstructure of the medium manganese steel after the deformation and ART annealing process was consistent with the theory of austenite reverse transformation, i.e., the martensite reverse transformation into austenite occurred during the deformation and ART annealing process. The final microstructure was a mixture of martensite and austenite. As the deformation degree increases, the martensite gradually refines, and carbides precipitate in the lath martensite. The retained austenite is gradually transformed from very large to small and is distributed between the martensite laths. The results show that when deformation occurs in the austenite region, a small deformation can obtain more retained austenite