Ultra-low-loss all-fiber orbital angular momentum mode-division multiplexer based on cascaded fused-biconical mode selective couplers

Mode-division multiplexers(MDMUXs)play a pivotal role in enabling the manipulation of an arbitrary optical state within few-mode fibers,offering extensive utility in the fields of mode-division multiplexing and structured optical field engineering.The exploration of MDMUXs employing cascaded resonant couplers has garnered significant attention owing to their scalability,exceptional integration capabilities,and the anticipated low insertion loss.In this work,we present the successful realization of high-quality orbital angular momentum MDMUX corresponding to topological charges 0,±1,and±2,achieved through the utilization of cascaded fused-biconical tapered couplers.Notably,the measured insertion losses at 1550 nm exhibit remarkable minimal values:0.31,0.10,and 0.64 dB,respectively.Furthermore,the 80%efficiency bandwidths exceed 106,174,and 174 nm for these respective modes.The MDMUX is composed of precisionmanufactured high-quality mode selective couplers(MSCs).Utilizing a proposed supermode propagation method based on mode composition analysis,we precisely describe the operational characteristics of MSCs.Building upon this comprehensive understanding,we embark on a pioneering analysis elucidating the influence of MSC cascading order on the performance of MDMUXs.Our theoretical investigation substantiates that when constructing MDMUXs,MSCs should adhere to a specific cascading sequence.

人工智能助力:Orbital Materials公司加速清洁技术材料的开发

随着全球对环境保护意识的增强,探寻能够有效减少碳排放并促进可持续发展的新材料成为了科研领域的热点。一家成立于2022年的初创公司Orbital Materials,正利用人工智能(AI)技术在这一领域取得突破。

OrbitMI的数字化解决方案

近日,劳氏日报揭晓了2024年度十大科技领袖榜单,OrbitMI公司的首席执行官Ali Riaz以其卓越的领导力成功上榜,位列第6。OrbitMI的前身是被誉为极具创新精神的瑞典油轮公司Stena Bulk的一个部门。Stena Bulk的全球开发团队与海事和能源专家、麻省理工学院的工程师合作,采用创新方法创建了基于实际使用案例的解决方案,建立了名为Orbit的运营平台,旨在提高效率,使公司更加灵活,增加与客户之间的透明度,并加强市场信息收集。很快,Orbit便无缝融入了Stena Bluk的日常工作。

ORBIT评分与HAS-BLED评分对心脏瓣膜置换术后华法林抗凝出血风险的预测价值比较

目的比较ORBIT评分与HAS-BLED评分对心脏瓣膜置换术后华法林抗凝出血风险的预测价值。方法回顾性分析304例心脏瓣膜置换术后需行华法林抗凝治疗患者的病例资料,分别根据ORBIT评分和HAS-BLED评分对患者进行风险分层和分组,分析基于不同评分的风险分层与术后华法林抗凝出血事件的相关性,比较2种评分方法风险分层的一致性及其对出血事件的预测价值。结果304例患者中,出血患者32例、未出血患者272例,出血患者的术后ORBIT评分、HAS-BLED评分均高于未出血患者,差异有统计学意义(P<0.05)。基于ORBIT评分划分的中危、高危患者的出血风险分别为低危患者的6.092(95%CI:2.694~13.775)倍、9.373(95%CI:1.465~59.943)倍,基于HAS-BLED评分划分的中危、高危患者的出血风险分别为低危患者的3.750(95%CI:1.383~10.166)倍、14.250(95%CI:5.489~36.995)倍。受试者工作特征曲线分析结果显示,ORBIT评分预测华法林抗凝出血风险的曲线下面积(AUC)为0.646(95%CI:0.589~0.699),敏感度为46.88%,特异度为87.87%,最佳截断值为3分;HAS-BLED评分预测华法林抗凝出血风险的AUC为0.768(95%CI:0.717~0.814),敏感度为75.00%,特异度为69.85%,最佳截断值为2分;Delong检验结果显示,2种评分的AUC差异有统计学意义(D=0.122,95%CI:0.001~0.245,Z=1.962,P<0.05)。结论ORBIT评分和HAS-BLED评分对心脏瓣膜置换术后华法林抗凝出血风险均具有一定预测价值,其中HAS-BLED评分的预测效能更优。

Theory for Charge Density Wave and Orbital-Flux State in Antiferromagnetic Kagome Metal FeGe

We theoretically study the charge order and orbital magnetic properties of a new type of antiferromagnetic kagome metal FeGe.Based on first-principles density functional theory calculations,we study the electronic structures,Fermi-surface quantum fluctuations,as well as phonon properties of the antiferromagnetic kagome metal FeGe.It is found that charge density wave emerges in such a system due to a subtle cooperation between electron-electron interactions and electron–phonon couplings,which gives rise to an unusual scenario of interaction-triggered phonon instabilities,and eventually yields a charge density wave(CDW)state.We further show that,in the CDW phase,the ground-state current density distribution exhibits an intriguing star-of-David pattern,leading to flux density modulation.The orbital fluxes(or current loops)in this system emerge as a result of the subtle interplay between magnetism,lattice geometries,charge order,and spin-orbit coupling(SOC),which can be described by a simple,yet universal,tight-binding theory including a Kane-Mele-type SOC term and a magnetic exchange interaction.We further study the origin of the peculiar step-edge states in FeGe,which sheds light on the topological properties and correlation effects in this new type of kagome antiferromagnetic material.

p-d Orbital Hybridization Engineered Single-Atom Catalyst for Electrocatalytic Ammonia Synthesis

The rational design of metal single-atom catalysts(SACs)for electrochemical nitrogen reduction reaction(NRR)is challenging.Two-dimensional metal-organic frameworks(2DMOFs)is a unique class of promising SACs.Up to now,the roles of individual metals,coordination atoms,and their synergy effect on the electroanalytic performance remain unclear.Therefore,in this work,a series of 2DMOFs with different metals and coordinating atoms are systematically investigated as electrocatalysts for ammonia synthesis using density functional theory calculations.For a specific metal,a proper metal-intermediate atoms p-d orbital hybridization interaction strength is found to be a key indicator for their NRR catalytic activities.The hybridization interaction strength can be quantitatively described with the p-/d-band center energy difference(Δd-p),which is found to be a sufficient descriptor for both the p-d hybridization strength and the NRR performance.The maximum free energy change(ΔG_(max))andΔd-p have a volcanic relationship with OsC_(4)(Se)_(4)located at the apex of the volcanic curve,showing the best NRR performance.The asymmetrical coordination environment could regulate the band structure subtly in terms of band overlap and positions.This work may shed new light on the application of orbital engineering in electrocatalytic NRR activity and especially promotes the rational design for SACs.

Manipulating d-d orbital hybridization induced by Mo-doped Co_(9)S_(8) nanorod arrays for high-efficiency water electrolysis

Precisely refining the electronic structure of electrocatalysts represents a powerful approach to further optimize the electrocatalytic performance.Herein,we demonstrate an ingenious d-d orbital hybridization concept to construct Mo-doped Co_(9)S_(8) nanorod arrays aligned on carbon cloth(CC)substrate(abbreviated as Mo-Co_(9)S_(8)@CC hereafter)as a high-efficiency bifunctional electrocatalyst toward water electrolysis.It has experimentally and theoretically validated that the 4d-3d orbital coupling between Mo dopant and Co site can effectively optimize the H_(2)O activation energy and lower H^(*)adsorption energy barrier,thereby leading to enhanced hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)activities.Thanks to the unique electronic and geometrical advantages,the optimized Mo-Co_(9)S_(8)@CC with appropriate Mo content exhibits outstanding bifunctional performance in alkaline solution,with the overpotentials of 75 and 234 mV for the delivery of a current density of 10 mA cm^(-2),small Tafel slopes of 53.8 and 39.9 mV dec~(-1)and long-term stabilities for at least 32 and 30 h for HER and OER,respectively.More impressively,a water splitting electrolylzer assembled by the self-supported Mo-Co_(9)S_(8)@CC electrode requires a low cell voltage of 1.53 V at 10 mA cm^(-2)and shows excellent stability and splendid reversibility,demonstrating a huge potential for affordable and scalable electrochemical H_(2) production.The innovational orbital hybridization strategy for electronic regulation herein provides an inspirable avenue for developing progressive electrocatalysts toward new energy systems.

Fast solution to the free return orbit's reachable domain of the manned lunar mission by deep neural network

It is important to calculate the reachable domain(RD)of the manned lunar mission to evaluate whether a lunar landing site could be reached by the spacecraft. In this paper, the RD of free return orbits is quickly evaluated and calculated via the classification and regression neural networks. An efficient databasegeneration method is developed for obtaining eight types of free return orbits and then the RD is defined by the orbit’s inclination and right ascension of ascending node(RAAN) at the perilune. A classify neural network and a regression network are trained respectively. The former is built for classifying the type of the RD, and the latter is built for calculating the inclination and RAAN of the RD. The simulation results show that two neural networks are well trained. The classification model has an accuracy of more than 99% and the mean square error of the regression model is less than 0.01°on the test set. Moreover, a serial strategy is proposed to combine the two surrogate models and a recognition tool is built to evaluate whether a lunar site could be reached. The proposed deep learning method shows the superiority in computation efficiency compared with the traditional double two-body model.

Comparison between local-made and imported porous polyethylene orbital implant:a randomized controlled equivalence trial and multicenter study

AIM:To compare the exposure rate,infection rate,percentage of enhancement,and success rate between Medpor and the three-dimensional printed polyethylene(3DP-PE)orbital implant in a preliminary report.METHODS:This prospective,randomized,equivalence,controlled trial was conducted at two institutes.The equivalent margin was±10%.The sample size for the equivalence trial was 174 participants per group.Patients who were eligible for enucleations received either Medpor or 3DP-PE implants based on a randomized block of six.The surgeries were performed by five oculoplastic surgeons.The assessor and patients were masked.The magnetic resonance imaging(MRI)of the orbit was performed at least 6mo after operation and the fibrovascular ingrowth was analyzed using the Image J software.Follow-up continued at least 1y after surgery.The intention to treat and per protocol approaches were used.RESULTS:Totally 128 patients met the criteria in the report.Fifty Medpor and 553DP-PE cases completed the trial.The most common cause of blindness was trauma.The mean follow-up times of Medpor and 3DP-PE were 33 and 40mo respectively.The exposure rate was not statistically significant between two groups(6.0%and 7.3%),P<0.05,95%CI(-9.8%,+12.0%).The success rates were 94%(Medpor)and 92.7%(3DP-PE).No postoperative infection was reported.Nine patients had MRI tests and two had implant exposures with 66.3% enhancement at 75mo(Medpor)and 58% enhancement at 57mo(3DP-PE)postoperatively.CONCLUSION:There is no statistically significant difference in exposure rate and success rate between Medpor and 3DP-PE in enucleation in the report.However,we cannot conclude that they are equivalent in terms of the exposure rate and success rate because the 95%CI is wider than±10%.The infection rate is equivalent in both groups.

Secure optical interconnects using orbital angular momentum beams multiplexing/multicasting

Orbital angular momentum(OAM),described by an azimuthal phase term expej lθT,has unbound orthogonal states with different topological charges l.Therefore,with the explosive growth of global communication capacity,especially for short-distance optical interconnects,light-carrying OAM has proved its great potential to improve transmission capacity and spectral efficiency in the space-division multiplexing system due to its orthogonality,security,and compatibility with other techniques.Meanwhile,100-m freespace optical interconnects become an alternative solution for the“last mile”problem and provide interbuilding communication.We experimentally demonstrate a 260-m secure optical interconnect using OAM multiplexing and 16-ary quadrature amplitude modulation(16-QAM)signals.We study the beam wandering,power fluctuation,channel cross talk,bit-error-rate performance,and link security.Additionally,we also investigate the link performance for 1-to-9 multicasting at the range of 260 m.Considering that the power distribution may be affected by atmospheric turbulence,we introduce an offline feedback process to make it flexibly controllable.

Experimental study of the influencing factors and mechanisms of the pressure-reduction and augmented injection effect by nanoparticles in ultra-low permeability reservoirs

Nanoparticles(NPs)have gained significant attention as a functional material due to their ability to effectively enhance pressure reduction in injection processes in ultra-low permeability reservoirs.NPs are typically studied in controlled laboratory conditions,and their behavior in real-world,complex environments such as ultra-low permeability reservoirs,is not well understood due to the limited scope of their applications.This study investigates the efficacy and underlying mechanisms of NPs in decreasing injection pressure under various injection conditions(25—85℃,10—25 MPa).The results reveal that under optimal injection conditions,NPs effectively reduce injection pressure by a maximum of 22.77%in core experiment.The pressure reduction rate is found to be positively correlated with oil saturation and permeability,and negatively correlated with temperature and salinity.Furthermore,particle image velocimetry(PIV)experiments(25℃,atmospheric pressure)indicate that the pressure reduction is achieved by NPs through the reduction of wall shear resistance and wettability change.This work has important implications for the design of water injection strategies in ultra-low permeability reservoirs.

Late infection after peri-orbital autologous micro-fat graft:a case presentation and literature review

Citation:Pakdel F,Asadigandomani H,Arab Bafrani M,Nozarian Z,Abedinifar Z,Pirmarzdashti N,Jafari B,Siami Z.Late infection after peri-orbital autologous micro-fat graft:a case presentation and literature review.Int J Ophthalmol 2024;17(3):603-606.

High-Resolution Recognition of Orbital Angular Momentum Modes in Asymmetric Bessel Beams Assisted by Deep Learning

Fractional orbital angular momentum(OAM) vortex beams present a promising way to increase the data throughput in optical communication systems. Nevertheless, high-precision recognition of fractional OAM with different propagation distances remains a significant challenge. We develop a convolutional neural network(CNN)method to realize high-resolution recognition of OAM modalities, leveraging asymmetric Bessel beams imbued with fractional OAM. Experimental results prove that our method achieves a recognition accuracy exceeding 94.3% for OAM modes, with an interval of 0.05, and maintains a high recognition accuracy above 92% across varying propagation distances. The findings of our research will be poised to significantly contribute to the deployment of fractional OAM beams within the domain of optical communications.

Bone destruction of orbital wall in idiopathic orbital inflammatory pseudotumor:does it always imply malignancy?

AIM:To assess the clinical presentations and outcomes of idiopathic orbital inflammatory pseudotumor(IOIP)patients with orbital wall bone destruction(OWBD)and to propose an expanded classification system that includes bone destruction.METHODS:The study retrospectively reviewed clinical presentations,imaging findings,treatment modalities,and outcomes of six patients diagnosed histopathologically with IOIP and OWBD at the Beijing Tongren Hospital,Capital Medical University between October 2018 and June 2021.RESULTS:Over two years,6(10%)of 60 IOIP patients at our hospital exhibited OWBD,but this may overrepresent severe cases.The cohort consisted of three men and three women,aged 17 to 60y(mean 35.5±16.1y).Presenting symptoms included proptosis,eyelid swelling,decreased visual acuity with pain,and palpable mass.Imaging revealed multiple anatomical structures involved with the medial wall being the most common site of bone destruction.Histopathological examination showed classic type in five patients and sclerosing type in one patient.All patients underwent surgical resection followed by methylprednisolone treatment.Follow-up(mean 30.3±3.1mo)indicated three patients had no recurrence,while others had varying degrees of symptom persistence or recurrence.CONCLUSION:IOIP with bone destruction is a rare but significant subtype that mimics malignancy,leading to potential diagnostic and therapeutic challenges.Our findings suggest that complete surgical resection combined with adjunctive glucocorticoid therapy can yield favorable outcomes.However,larger-scale studies are needed to further optimize therapeutic approaches.

Orbital-Ordering Driven Simultaneous Tunability of Magnetism and Electric Polarization in Strained Monolayer VCl_(3)

Two-dimensional(2D)van der Waals magnetic materials have promising and versatile electronic and magnetic properties in the 2D limit,indicating a considerable potential to advance spintronic applications.Theoretical predictions thus far have not ascertained whether monolayer VCl_(3) is a ferromagnetic(FM)or anti-FM monolayer;this also remains to be experimentally verified.We theoretically investigate the influence of potential factors,including C_(3) symmetry breaking,orbital ordering,epitaxial strain,and charge doping,on the magnetic ground state.Utilizing first-principles calculations,we predict a collinear type-Ⅲ FM ground state in monolayer VCl_(3) with a broken C_(3) symmetry,wherein only the former two of three t_(2g)orbitals(a_(1g),e_(g2)^(π)and e_(g1)^(π))are occupied.The atomic layer thickness and bond angles of monolayer VCl_(3) undergo abrupt changes driven by an orbital ordering switch,resulting in concomitant structural and magnetic phase transitions.Introducing doping to the underlying Cl atoms of monolayer VCl_(3) without C_(3) symmetry simultaneously induces in-and out-of-plane polarizations.This can achieve a multiferroic phase transition if combined with the discovered adjustments of magnetic ground state and polarization magnitude under strain.The establishment of an orbital-ordering driven regulatory mechanism can facilitate deeper exploration and comprehension of magnetic properties of strongly correlated systems in monolayer VCl_(3).

The super-connectivity of graphs with two orbits

A graph G is said to be super-connected or simply super-κ, if each minimum vertex cut of G isolates a vertex. A graph G is said to be a k-vertex-orbit graph if there are k vertex orbits when Aut(G) acts on V(G). A graph G is said to be a k-edge-orbit graph if there are k edge orbits when Aut(G) acts on edge set E(G). In this paper, we give a necessary and sufficient condition for connected bipartite 2-vertex-orbit graphs to be super-κ. For 2-edge-orbit graphs,we give a sufficient condition for connected 2-edge-orbit graphs to be super-κ. In addition, we show that if G is a k-regular connected irreducible Ⅱ-kind 2-edge-orbit graph with k ≤ 6 and girth g(G) ≥ 6, or G is a k-regular connected irreducible Ⅲ-kind 2-edge-orbit graph with k ≤ 6and girth g(G) ≥ 8, then G is super-connected.

Guidelines for the standardized diagnosis and treatment of non-specific orbital inflammation(2024)

Non-specific orbital inflammation(NSOI)is a noninfectious orbital inflammation.Although it is often considered the most common diagnosis in orbital biopsies,it is an exclusionary diagnosis that requires ruling out systemic disease or other possible causes.Its characteristics include acute orbital signs and symptoms,including pain,proptosis,periorbital edema,chemosis,diplopia,and visual impairment.The clinical manifestations and histological findings of NSOI are heterogeneous,without specific diagnostic criteria or treatment guidelines,which poses significant challenges for diagnosis and treatment.This guideline provides a detailed description of the definition,classification,diagnosis,and treatment of NSOI.

Prognostic factors and clinical features of rhino-orbitalmucormycosis cases:an update for patient and visual survivals

AIM:To determine the frequency of patients’vision survival and prognostic factors and evaluate clinical features in rhino-orbital mucormycosis.METHODS:Forty-three eyes of 43 patients followed up with orbital mucormycosis infections were included in the study.Demographic characteristics of the patients,symptoms at admission,ophthalmologic and non-ophthalmologic examination findings,clinical findings during follow-up,medical and surgical procedures,and complications were recorded.Patient survival was determined by assessing the incidence of mortality,and vision survival was defined as achieving a final visual acuity of at least light perception.RESULTS:Twenty-seven(62.8%)patients were male,and 16(37.2%)were female.When the underlying disease status of the patients was examined,it was observed that all patients had an underlying disease and diabetes constituted the majority(65.2%).Periorbital swelling(69.8%)and ophthalmoplegia(53.5%)were the most common symptoms and findings at the admission of patients with mucormycosis infection.The disease resulted in death in 22(51.2%)patients.The presence of fever and shorter duration of antifungal therapy were associated with lower patient survival.Exenteration surgery was not found to be associated with the survival of the patients.Frozen eye,loss of pupillary light reflex,and development of central retinal artery occlusion were associated with lower vision survival.CONCLUSION:This study presents one of the most extensive patient series in the literature on rhino-orbital mucormycosis.Knowing the patients’symptoms at the time of admission and the clinical findings during the infection process will increase awareness about the disease.

Adult Neuromuscular Choristoma in the Intraconal Region of the Orbital Muscle: A Case Report

Background: Neuromuscular choristoma is a rare benign peripheral neuropathy composed of ectopic mature muscle fibers and nerve bundles, usually involving large nerve roots or trunks, such as brachial plexus and sciatic nerve. NMC usually occurs in childhood, and some cases are congenital. Here, we report a case of adult orbital intraconal NMC. The resected specimens were fish-like and tough. Histological pathology suggested that the specimen was composed of mature skeletal muscle tissue interspersed with peripheral nerve bundles. Histopathological examination revealed that the left orbital mass was composed of mature skeletal muscle tissue interspersed with surrounding nerve fascicles. Immunohistochemistry: S-100 protein was positive. In general, postoperative histopathological examination ultimately determined the diagnosis of NMC in the intraconal region of the orbital muscle. Case Presentation: A 51-year-old female patient was admitted to the hospital due to periocular pain for 2 weeks. Orbital CT scan showed an irregular soft tissue density in the left orbital muscle cone area, and the boundary between the local and the left lateral rectus muscle was unclear. Magnetic resonance imaging showed that there was an oval abnormal signal in the posterior lateral space of the left eyeball, with a clear edge and a size of about 22 mm × 8 mm. The boundary between the local area and the left lateral rectus muscle was unclear, and the optic nerve was compressed to the right side. The T1 WI showed low signal, T2-FS showed high and low mixed signal, and the enhanced scan showed continuous obvious enhancement. Eventually, the patient underwent surgical resection of the lesion. Conclusions: NMC is a rare benign peripheral neuropathy, especially NMC in the orbital muscle cone. There is no specificity in clinical and imaging examinations. Accurate diagnosis before surgical resection is very challenging for clinicians and radiologists. Importantly, we can differentiate orbital NMC from other types of orbital tumors.

Optimization of Gas-Flooding Fracturing Development in Ultra-Low Permeability Reservoirs

Ultra-low permeability reservoirs are characterized by small pore throats and poor physical properties, which areat the root of well-known problems related to injection and production. In this study, a gas injection floodingapproach is analyzed in the framework of numerical simulations. In particular, the sequence and timing of fracturechanneling and the related impact on production are considered for horizontal wells with different fracturemorphologies. Useful data and information are provided about the regulation of gas channeling and possible strategiesto delay gas channeling and optimize the gas injection volume and fracture parameters. It is shown that inorder to mitigate gas channeling and ensure high production, fracture length on the sides can be controlled andlonger fractures can be created in the middle by which full gas flooding is obtained at the fracture location in themiddle of the horizontal well. A Differential Evolution (DE) algorithm is provided by which the gas injectionvolume and the fracture parameters of gas injection flooding can be optimized. It is shown that an improvedoil recovery factor as high as 6% can be obtained.