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This study describes thermal transmission features across a gravity-driven bioconvection flow of the viscoplastic-type Casson nanofluid caused by a vertically rotating cylinder under gyrotactic microorganisms. The research further quantifies the impact of nonlinear thermal radiations, heat source/sink and convective interface on the temperature and heat transmission rate of a nanofluid rotating on a cylindrical surface. The Buongiorno two-phase model characterizing Brownian diffusion and thermophoretic properties is utilized to examine the nanoparticle's effect on the Casson nanofluid. A system of strongly nonlinear PDEs is converted into a system of ODEs by using the appropriate variables. The MATLAB technique is used to build a numerical solution for nonlinear flow equations. The influences of various parameters on the volumetric concentration of nanoparticles, velocities, thermal fields, and microorganism profiles are examined. The finding indicates that an upsurge in the bioconvection Lewis parameter causes declines in the microorganism profile. The thermal and solutal distribution of species increases with an increase in thermophoresis parameter estimations. Significant thermal transport is acquired with greater radiation impacts. The microorganism's distribution is improved with a larger Peclet number. [ABSTRACT FROM AUTHOR]

Surface plasmon resonance (SPR) sensing methods enable highly sensitive, fast response, and label-free analysis of biomolecular interactions. For SPR sensors, sensitivity and full width at half maximum (FWHM) are two incompatible performance parameters. We propose a refractive index (RI) sensor using a dual-core photonic crystal fiber (PCF) and SPR effects to achieve high sensitivity and a narrow FWHM simultaneously. The air holes of the sensor appear in a hexagonal arrangement, and polishing technology introduces two polishing planes into the cladding. A gold film is deposited on one side of the polished plane to form a highly sensitive RI sensing channel. Five gold nanowires are deposited on the other side of the polished plane to form a RI sensing channel with a narrow FWHM. We analyzed and optimized its structural parameters using the finite element method and determined the optimal structural parameters. The numerical results demonstrate that the maximum sensitivity of the sensor is 21,000 nm/RIU with the narrowest FWHM of 31 nm. Therefore, measuring the refractive index simultaneously with two sensing channels increases the detection accuracy of the measurement. In addition, the findings further indicate that variations in structural parameters do not significantly impact the sensing performance of the sensor, which makes the production of the sensor relatively simple. In conclusion, our work provides a new research method for realizing high sensitivity and a narrow FWHM simultaneously. [ABSTRACT FROM AUTHOR]

Lie similarity transformations for unsteady flow in a thin film under the influence of internal heating and thermal radiation have been deduced earlier. These transformations have been employed to reduce the partial differential equations of the fluid flow and heat transfer to ordinary differential equations. Fluid velocity and temperature profiles were presented by constructing homotopic solutions for the obtained system of equations. Here we apply a general linear combination of all the Lie point symmetries associated with the equations describing the flow and heat transfer with internal heating and thermal radiation, to construct the general Lie similarity transformations. By applying these transformations to the flow, we map them to ordinary differential equations. The reduced system of differential equations contains the arbitrary constants used to construct the generalised Lie similarity transformations through the linear combination of all the Lie symmetries of the flow equations. Further, we determine analytic solutions using the homotopy analysis method for the reduced system of equations. We show that the presence of arbitrary constants in the reduced system of differential equations enables control of the deduced homotopic analytic solutions, i.e., these constants serve as control parameters. We illustrate the effects of these control parameters on the temperature profiles graphically. [ABSTRACT FROM AUTHOR]

The heat transfer phenomenon in the flow of non-Newtonian fluids is important in the manufacturing processes of plastic products, cooling systems polymer solutions and extrusion and injection phenomena, etc. The motivation behind this study is to explore the thermal aspects of Burger non-Newtonian fluids by applying exponential heat source–sink, mixed convection phenomenon and thermal radiation. The analysis was done for different values of fluid viscosity. The numerical methodology is based on the implementation of a variational iteration technique. It is concluded that consideration of variable fluid viscosity is important to improve the heat transfer phenomenon more precisely. It is seen that the temperature profile increases with exponential heat source parameters. [ABSTRACT FROM AUTHOR]

In a wide variety of mechanical and industrial applications, e.g., space cooling, nuclear reactor cooling, medicinal utilizations (magnetic drug targeting), energy generation, and heat conduction in tissues, the heat transfer phenomenon is involved. Fourier's law of heat conduction has been used as the foundation for predicting the heat transfer behavior in a variety of real-world contexts. This model's production of a parabolic energy expression, which means that an initial disturbance would immediately affect the system under investigation, is one of its main drawbacks. Therefore, numerous researchers worked on such problem to resolve this issue. At last, this problem was resolved by Cattaneo by adding relaxation time for heat flux in Fourier's law, which was defined as the time required to establish steady heat conduction once a temperature gradient is imposed. Christov offered a material invariant version of Cattaneo's model by taking into account the upper-connected derivative of the Oldroyd model. Nowadays, both models are combinedly known as the Cattaneo-Christov (CC) model. In this attempt, the mixed convective MHD Falkner-Skan Sutterby nanofluid flow is addressed towards a wedge surface in the presence of the variable external magnetic field. The CC model is incorporated instead of Fourier's law for the examination of heat transfer features in the energy expression. A two-phase nanofluid model is utilized for the implementation of nano-concept. The nonlinear system of equations is tackled through the bvp4c technique in the MATLAB software 2016. The influence of pertinent flow parameters is discussed and displayed through different sketches. Major and important results are summarized in the conclusion section. Furthermore, in both cases of wall-through flow (i.e., suction and injection effects), the porosity parameters increase the flow speed, and decrease the heat transport and the influence of drag forces. [ABSTRACT FROM AUTHOR]

In this work, a novel compact difference scheme for the generalized Rosenau-KdV-RLW equation is investigated, which preserves some conservative properties of the original equation. The proposed numerical scheme is three-level and nonlinear implicit, which adopts a novel approximation 1 4 (U j n + 1 + 2 U j n + U j n - 1) of u (x j , t n) in the temporal direction and a direct compact discretization method for the higher-order derivatives u xxx and u xxxx in the spatial direction. The discrete conservation laws are given, and a priori estimates of the difference solution in maximum norm are obtained by applying mathematical induction. The solvability of the proposed numerical scheme is proved by the well-known Brouwer's fixed point theorem. The convergence with O (τ 2 + h 4) convergence order and stability of the novel difference scheme in L ∞ norm are proved. A linearized iterative algorithm for solving nonlinear algebraic systems generated by the compact scheme is proposed and its convergence is proved. Some numerical experimental results validate the theoretical results and demonstrate that the proposed compact scheme is efficient and reliable. [ABSTRACT FROM AUTHOR]

The impact of chemical reaction and activation energy plays a vital role in the analysis of fluid dynamics and its thermal properties. The application of the flow of fluid is significantly considered in nuclear reactors, automobiles, manufacturing setups, electronic appliances etc. This study explores the impacts of activation energy and chemical reaction on the magnetohydrodynamic Darcy–Forchheimer squeezed Casson fluid flow through a porous material across the horizontal channel where the two parallel plates are assumed to be in motion. By using similarity variables, partial differential equations are converted to ordinary differential equations. Numerical method is applied using MATLAB to solve the problems and acquire the data for velocity field, thermal distribution, and concentration distribution. The graphs indicate that fluid velocity and temperature increases as the plates are brought closer. In addition, there was a correlation between a rise in the Hartmann number and a decrease in the fluid's velocity because of the existence of strong Lorentz forces. The temperature and the concentration of the liquid will increase due to the Brownian motion. When the Darcy–Forchheimer and activation energy parameters are both increased, the velocity and concentration decreases. [ABSTRACT FROM AUTHOR]

In this article, the flow of ternary nanofluid is analysed past a stretching sheet subjected to Thomson and Troian slip condition along with the temperature jump. The ternary nanofluid is formed by suspending three different types of nanoparticles namely TiO 2 , Cu and Ag into water which acts as a base fluid and leads to the motion of nanoparticles. The high thermal conductivity and chemical stability of silver was the main cause for its suspension as the third nanoparticle into the hybrid nanofluid Cu-TiO 2 / H 2 O . Thus, forming the ternary nanofluid Ag-Cu-TiO 2 / H 2 O . The sheet is assumed to be vertically stretching where the gravitational force will have its impact in the form of free convection. Furthermore, the presence of radiation and heat source/sink is assumed so that the energy equation thus formed will be similar to most of the real life applications. The assumption mentioned here leads to the mathematical model framed using partial differential equations (PDE) which are further transformed to ordinary differential equations (ODE) using suitable similarity transformations. Thus, obtained system of equations is solved by incorporating the RKF-45 numerical technique. The results indicated that the increase in the suspension of silver nanoparticles enhanced the temperature and due to density, the velocity of the flow is reduced. The slip in the velocity decreased the flow speed while the temperature of the nanofluid was observed to be increasing. [ABSTRACT FROM AUTHOR]

Novel materials with high thermal conductivity are urgently needed to solve the problem of thermal diffusion with the rapid development of science and technology. Experiments have been conducted to join polydopamine (PDA) with graphene (G) and carbon fibers (CF) using electrophoresis to form a G/PDA@CF material with ultrahigh thermal conductivity. The thermal conductivity has been improved by a factor of 6, which has ultrahigh thermally conductive properties. The composite doubled the tensile strength relative to the original material. Experiments were designed to test the thermal conductivity of G/PDA@CF. Scanning electron microscopy (SEM), X-ray diffraction pattern (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) analyses of the material were carried out to obtain the formation mechanism of G/PDA@CF. The SEM image shows that PDA and G formed a layered self-assembled structure on the CF surface. The XRD image shows the existence of G in G/PDA@CF. The XPS analysis obtained the bonding species between the G and PDA, CF and PDA. The phonon spectra were then calculated by microcanonical ensembles (NVE). The PDA has ultrahigh thermal conductivity due to the high overlap of its phonon spectrum with G, which leads to its high strength thermal conductivity of G/PDA@CF. G/PDA@CF material can be used for flexible screens, housings for wearable devices, and thermally conductive devices. [ABSTRACT FROM AUTHOR]

This paper presents a dual-core two-parameter optical fiber sensor based on the surface plasmonic resonance (SPR) effect. It is analyzed by the finite element method. The proposed sensor is a dual-channel structure designed with photonic crystal fiber (PCF) as the base material: one channel is coated with a gold film to measure the refractive index (RI) of the solution to be measured, and the other channel is coated with a gold film and polydimethylsiloxane to measure the temperature of the solution to be measured. The exposed microslot structure on both sides reduces the complexity of sensing measurements. The results show that the maximum RI sensitivity of the sensor is 19,900 nm/RIU, and the maximum sensitivity to temperature is 8.7 nm/℃. This work is conducive to realizing a PCF sensor with high sensitivity, large measurement range, real-time monitoring, and easy preparation. As a result, the sensor is expected to be widely used in fields such as biology and chemicals. [ABSTRACT FROM AUTHOR]

Sulfur dioxide (SO2) belongs to the highly reactive group of gases familiar as “Oxides of Sulfur”. SO2 has lots of adverse effects on plants, respiratory system and many other environmental issues. Sulfur dioxide is a primary pollutant which is regulated worldwide, due to the combustion of fuel. Different approaches are adopted to economically control the SO2 in the environment which causes the production of sulfuric acid that is reflected in acid rain. The aim of this study is to investigate the invariant regions and solution pathways for the formation of H2SO4 in a multi-step reaction mechanism. The employed Model Reduction Techniques (MRTs) such as Spectral Quasi Equilibrium Manifold (SQEM) and Intrinsic Low Dimensional Manifold (ILDM) give the solution curves, which functions as a primary approximation to invariant manifold. It is achieved that each chemical specie can be assessed rather than taking the overall mechanism. The new discovery suggests that we could achieve the invariant regions for SO2 and H2SO4. SO2 emissions, along with emission norms, will be disclosed. The comparison of MRTs is depicted through tabular and graphical representations, while theoretical results are demonstrated through computer simulations using MATLAB. [ABSTRACT FROM AUTHOR]

Long-term exposure to chemical solutions can change the mineral composition and microstructure and may seriously affect the physical and mechanical properties of rocks. Therefore, to clarify the effects of long-term exposure and types of acids on the mechanical properties of rocks, and to develop the constitutive model of acid-immersed rocks, uniaxial compression tests were carried out on acid-immersed sandstone specimens. The sample weakened, and the brittle failure behavior became more ductile by the acid immersion to the aqueous solution of hydrochloric or sulfuric acids. The duration of the compaction stage of the stress–strain curve increased, that of the elastic stage decreased; the peak stress, elastic modulus, and Poisson's ratio decreased, and the peak point strains increased with the acidity and the immersion duration. The brittle shear failure of the untreated specimen became more axial splitting type failure with acidity. The damage variable of the combined effects of chemical and stress was introduced, and a statistical damage model considering the compaction stage of the stress–strain curve was established based on the damage variable. The model well-simulated the experimentally obtained stress–strain curves of the acid-immersed specimens. Finite element models reflecting the characteristics of the acid-immersed sandstone were established based on CT images. [ABSTRACT FROM AUTHOR]

A single-mode single-polarization photonic crystal fiber (SMSP-PCF) filter at the wavelengths of 1.125 and 1.31 μm based on surface plasmon resonance is proposed and studied by the finite element method. Numerical results indicate that compared with the filter with the same size of holes near the core, the filter with four small holes near the core makes its extinction ratio (ER) at the wavelengths of 1.125 and 1.31 μm twice as large. That is, when the fiber length is 500 μm, the ER at 1.125 μm increases from 33.43 to 58.62 dB, and the ER at 1.31 μm increases from 129.41 to 244.85 dB. Furthermore, the designed SMSP-PCF filter also has a good structural tolerance. The proposed optical fiber filter has excellent performance of compact structure, high ER and good structural tolerance, and can be used in an integrated communication transmission system. [ABSTRACT FROM AUTHOR]

In this paper, we demonstrate a high sensitivity refractive index (RI) sensor with D-shaped structure covered with gold and graphene film. Specifically, the effect of structural parameters on the stability of fiber sensor is analyzed. In our research, it have been found that the sensor we proposed is not very sensitive to the change of structure parameters on the premise of ensuring the sensing precision. This advantage means that the requirements for machining errors are reduced. Further probing shows that the proposed sensor shows a maximum wavelength interrogation sensitivity of 4391nm/RIU with the dynamic refractive index range from 1.33 to 1.39 and a maximum amplitude sensitivity of 1139RIU− 1 with the analyte RI = 1.38 in the visible region. The corresponding resolution are 2.28 × 10− 5 and 8.78 × 10− 6 based on the methods of wavelength interrogation and amplitude-(or phase-) based method. These characteristics of compact sensing architectures, simple to fabricate, and high sensitivity open the possibility of using this type of sensor in biological applications. [ABSTRACT FROM AUTHOR]

A negative curvature hollow core fiber (NCHCF) refractive index (RI) sensor based on localized surface plasmon resonance (LSPR) is proposed. The gold nanowires are deposited in four cladding tubes in the y-direction, with the core region serving as the analyte channel. The full vector finite element method (FEM) is used to analyze the influence of various structural parameters on this sensor, and the structural parameters are optimized and selected. Ultimately, an average sensitivity of 9356.59 nm/RIU is accomplished within a spacious refractive index detection scope of RI = 1.28–1.43. The sensor attained a maximum sensitivity of 10,220 nm/RIU at RI = 1.36. In the bargain, there is an excellent linear correlation between the resonance wavelength and the refractive index of the analyte, with a value of 0.99901 and a factor of merit (FOM) range of 119.9563–155.9432 RIU−1, achieving a resolution of 10−6 RIU. The sensor has potential applications in various fields such as environmental protection, food safety, and medical diagnostics due to its high sensitivity, spacious detection scope, and positive linear response. [ABSTRACT FROM AUTHOR]

High-resolution P wave tomography shows that the subducting Pacific slab is stagnant in the mantle transition zone and forms a big mantle wedge beneath eastern China. The Mg isotopic investigation of large numbers of mantle-derived volcanic rocks from eastern China has revealed that carbonates carried by the subducted slab have been recycled into the upper mantle and formed carbonated peridotite overlying the mantle transition zone, which becomes the sources of various basalts. These basalts display light Mg isotopic compositions (δ26Mg =-0.60‰ to -0.30‰) and relatively low 87Sr/86Sr ratios (0.70314-0.70564) with ages ranging from 106 Ma to Quaternary, suggesting that their mantle source had been hybridized by recycled magnesite with minor dolomite and their initial melting occurred at 300−360 km in depth. Therefore, the carbonate metasomatism of their mantle source should have occurred at the depth larger than 360 km, which means that the subducted slab should be stagnant in the mantle transition zone forming the big mantle wedge before 106 Ma. This timing supports the rollback model of subducting slab to form the big mantle wedge. Based on high P-T experiment results, when carbonated silicate melts produced by partial melting of carbonated peridotite was raising and reached the bottom (180-120 km in depth) of cratonic lithosphere in North China, the carbonated silicate melts should have 25-18 wt% CO2 contents, with lower SiO2 and Al2O3 contents, and higher CaO/Al2O3 values, similar to those of nephelinites and basanites, and have higher εNd values (2 to 6). The carbonatited silicate melts migrated upward and metasomatized the overlying lithospheric mantle, resulting in carbonated peridotite in the bottom of continental lithosphere beneath eastern China. As the craton lithospheric geotherm intersects the solidus of carbonated peridotite at 130 km in depth, the carbonated peridotite in the bottom of cratonic lithosphere should be partially melted, thus its physical characters are similar to the asthenosphere and it could be easily replaced by convective mantle. The newly formed carbonated silicate melts will migrate upward and metasomatize the overlying lithospheric mantle. Similarly, such metasomatism and partial melting processes repeat, and as a result the cratonic lithosphere in North China would be thinning and the carbonated silicate partial melts will be transformed to high-SiO2 alkali basalts with lower εNd values (to −2). As the lithospheric thinning goes on, initial melting depth of carbonated peridotite must decrease from 130 km to close 70 km, because the craton geotherm changed to approach oceanic lithosphere geotherm along with lithospheric thinning of the North China craton. Consequently, the interaction between carbonated silicate melt and cratonic lithosphere is a possible mechanism for lithosphere thinning of the North China craton during the late Cretaceous and Cenozoic. Based on the age statistics of low δ26Mg basalts in eastern China, the lithospheric thinning processes caused by carbonated metasomatism and partial melting in eastern China are limited in a timespan from 106 to 25 Ma, but increased quickly after 25 Ma. Therefore, there are two peak times for the lithospheric thinning of the North China craton: the first peak in 135−115 Ma simultaneously with the cratonic destruction, and the second peak caused by interaction between carbonated silicate melt and lithosphere mainly after 25 Ma. The later decreased the lithospheric thickness to about 70 km in the eastern part of North China craton. [ABSTRACT FROM AUTHOR]

A broad bandwidth polarization filter based on photonic crystal fiber (PCF) coated with gold layer is proposed and simulated by the full vector finite element method. The surface plasmon resonance coupling theory is studied, and the factors that affect the polarization filtering effect are analyzed. By changing the structural parameters of the PCF, we realize polarization filter at 1.55 and 1.48 μm. In the designed polarization filter, the maximum loss of the unwanted y-polarization at 1.55 μm is 803.56 dB/cm and at 1.48 μm is 732.69 dB/cm. Besides, a broad bandwidth of 1000 nm with the crosstalk better than 20 dB is obtained. The suggested PCF is competitive for polarization device. [ABSTRACT FROM AUTHOR]

Key message: The RTM-GWAS was chosen among five procedures to identify DTF QTL-allele constitution in a soybean NAM population; 139 QTLs with 496 alleles accounting for 81.7% of phenotypic variance were detected. Abstract: Flowering date (days to flowering, DTF) is an ecological trait in soybean, closely related to its ability to adapt to areas. A nested association mapping (NAM) population consisting of four RIL populations (LM, ZM, MT and MW with M8206 as their common parent) was established and tested for their DTF under five environments. Using restriction-site-associated DNA sequencing the population was genotyped with SNP markers. The restricted two-stage multi-locus (RTM) genome-wide association study (GWAS) (RTM-GWAS) with SNP linkage disequilibrium block (SNPLDB) as multi-allele genomic markers performed the best among the five mapping procedures with software publicly available. It identified the greatest number of quantitative trait loci (QTLs) (139) and alleles (496) on 20 chromosomes covering almost all of the QTLs detected by four other mapping procedures. The RTM-GWAS provided the detected QTLs with highest genetic contribution but without overflowing and missing heritability problems (81.7% genetic contribution vs. heritability of 97.6%), while SNPLDB markers matched the NAM population property of multiple alleles per locus. The 139 QTLs with 496 alleles were organized into a QTL-allele matrix, showing the corresponding DTF genetic architecture of the five parents and the NAM population. All lines and parents comprised both positive and negative alleles, implying a great potential of recombination for early and late DTF improvement. From the detected QTL-allele system, 126 candidate genes were annotated and χ tested as a DTF candidate gene system involving nine biological processes, indicating the trait a complex, involving several biological processes rather than only a handful of major genes. [ABSTRACT FROM AUTHOR]

We design a single-polarization single-mode photonic crystal fiber filter based on surface plasmon resonance. The finite element method is employed to evaluate the characteristics of the filter. The proposed fiber is devised such that there is a great discrepant confinement loss between two polarizations of x and y by varying two air holes in the cladding region, which is composed of hexagonal structural air holes in pure silica selectively filling with gold wires. Numerical simulations show that single-polarization single-mode operation waveband can be tuned by adjusting the parameters of the photonic crystal fiber. The confinement losses of the unwanted polarization can reach to 126.10 and 326.30 dB/cm in the wavelengths of 1.31 and 1.55 μm, while the corresponding confinement losses of the wanted polarized mode are only 0.08 and 1.20 dB/cm, respectively. Furthermore, the crosstalk can come to a maximum of 120.34 and 310.41 dB in the two communication bands. The bandwidths of the fiber designed for 1.31 and 1.55 μm are, respectively, 20 and 60 nm, which may be found useful applications for fiber polarizer. [ABSTRACT FROM AUTHOR]

A kind of polarized filtering photonic crystal fiber (PCF) with nanoscale gold film is studied by using the finite element method. The cross-section structure of the PCF is composed of a hexagonal lattice of air holes in which an air hole is gold coated, and the air-hole layout is modified. By our structure, the loss of x-polarized mode is further larger than the loss of y-polarized mode and the loss peak appears at the wavelength 1.31 μm. The corresponding loss in x-polarized can reach a value of 85,780 dB/m at the resonance wavelength. It can be used for the communication windows of 1.31 μm which can be used for carrying data/voice. When the length of fiber is longer than 30 μm, the extinction ratio is better than 20 dB at the wavelength 1.31 μm. When the length of fiber is longer than 210 μm, the extinction ratio is better than 20 dB with the wavelength ranging from 1.26 to 2 μm. The broadband polarized filtering PCF covering 740 nm is achieved. [ABSTRACT FROM AUTHOR]

We propose and investigate a photonic crystal fiber (PCF) refractive index sensor with triangular lattice and four large-size channels based on surface plasmon resonance. In such sensor, two gold wires obtained by chemical reaction are filled in two air holes between the upper and lower channels. Numerical results show that the refractive indexes of the analytes can be detected from 1.30 to 1.79. It's a very broad detection range that is rarely seen in the field of photonic crystal fiber sensor based on surface plasmon resonance. The average sensitivity of this photonic crystal fiber could be 100 nm/refractive index unit (RIU) in the dynamic index range from 1.30 to 1.63. In the range from 1.63 to 1.79, the highest sensitivity could reach to 3233 nm/RIU. The ability to integrate four large-size microfluidic channels for efficient analyte flow in is attractive for the development of integrated highly sensitive PCF-SPR sensors. [ABSTRACT FROM AUTHOR]

A high-sensitivity magnetic field sensor based on photonic crystal fiber (PCF) Sagnac interferometer is proposed by finite element method (FEM). The elliptical-hole PCF is injected with water-based magnetic fluid. The fiber core is introduced in an elliptical hole to act as a defected core. The sensitivities are 13.25 and −14.32 nm/Oe at the wavelength of 1750 and 1780 nm, respectively, as the magnetic field H is 100 Oe. The simulation result shows that the sensitivity is extremely high near the wavelength of 1765 nm, because the group birefringence Bg is about zero at that wavelength. The above theory is examined in a different configuration by the transmission mode. The average sensitivities are 0.265, 1.63 and −1.915 nm/Oe, respectively, for the dip wavelength A, B and C as the fiber length is 5 cm. The detecting window is 60Oe. We also demonstrate that the sensitivity can be greatly enhanced by 1-2 orders of magnitude by introducing a defected core. [ABSTRACT FROM AUTHOR]

A polarization splitter based on dual-core photonic crystal fiber filled with tellurite glass in the central hole is proposed. The characteristics are studied by finite element method. The influences of the parameters $$d_{1}, d_{2}, \varLambda$$ on the coupling length and coupling length ratio (CLR) are analyzed. The curves of coupling lengths of X-polarization, Y-polarization light dependence on the operable wavelength $$\lambda$$ are flat under the optimized structural parameters which is helpful to realize broadband polarization splitter. The simulation results indicate that the CLR could reach to 2.006 at the wavelength of $$1.55\,\upmu {\hbox {m}}$$ . The fiber length is only 510 $$\upmu {\hbox {m}}$$ and the bandwidth of extinction ratio greater than 20 dB is 284 nm, i.e., from 1461 to 1745 nm which could be widely used in the large-capacity, broad-bandwidth and integrated optical communication systems. As the fiber length decreases, we find the bandwidth increases. But the extinction ratio at 1.55 $$\upmu {\hbox {m}}$$ is lower than 20 dB as the fiber length is less than 510 $$\upmu {\hbox {m}}$$ . [ABSTRACT FROM AUTHOR]

We design two kinds of plasmonic broadband polarization splitters based on dual-core photonic crystal fiber (DC-PCF) with elliptical Au or Ag nanowire in this paper. It is analyzed for the polarization independent characterestics of the designed DC-PCF by the finite element method (FEM). In order to excite the surface plasmon resonance (SPR), the metal Au and Ag are filled into elliptical central air hole. The resonance coupling between the fourth- or fifth-order surface plasmon modes (SPMs) and core-guided modes (CGMs) are founded by this numerical simulation. The device lengths of the designed splitters with Au nanowire are 2937 and 827 μm at the wavelength of 1.31 and 1.55 μm, respectively. As the extinction ratios are better than −20 dB, its bandwidths are better than 94 and 103 nm. For the designed Ag nanowire splitter, the device lengths are 3066 or 809 μm at 1.31 or 1.55 μm, respectively. The bandwidths with the extinction ratio better than −20 dB are 66 and 104 nm, respectively. [ABSTRACT FROM AUTHOR]

The Au film and glycerin selectively infilling photonic crystal fibers are analyzed by the finite element method. One cladding air hole is coated with Au film and infiltrated with glycerin to form a defect core. The simulation results show that both of the defect core modes formed on the glycerin and Au film can inspire resonance with core modes. The maximum sensitivity can reach to 2.50 nm/ C in x polarized direction and 2.00 nm/ C in y polarized direction for the temperature sensor, respectively. Furthermore, we obtain that the confinement losses of the photonic crystal fibers (PCFs) can meet with 321.442 dB/cm and 445.958 dB/cm at a short wavelength band (1460 ∼1530 nm) and an extended wavelengths band (1360 ∼1460 nm) for x polarized direction and y polarized direction respectively, which can be applied in many polarization filter devices as well. The compatibility of temperature sensor and polarization filter based on an identical structure can be realized at different wavelengths. [ABSTRACT FROM AUTHOR]

A polarization filter at the two communication windows of 1.31 and 1.55 μm based on photonic crystal fiber (PCF) coated by nanoscale gold film is proposed. The effects of geometrical parameters of the PCF on the performances of polarization filter are evaluated by finite element method (FEM). Numerical simulations reveal that the polarization filter possesses ultra-short length of 400 μm and high extinction ratios of 41 and −150 dB at the communication wavelengths of 1.31 and 1.55 μm respectively. The bandwidth of extinction ratio (ER) better than 20 dB is 58 nm at the communication window of 1.31 μm. Moreover, the bandwidth of ER better than −20 dB is 164 nm at the communication window of 1.55 μm. [ABSTRACT FROM AUTHOR]

The polarization filter characteristics of Au wires and liquid crystal infiltrated photonic crystal fibers are investigated by using the finite element method. The nematic liquid crystal of E7 being injected into cladding air holes is benefit to induce large birefringence under controllable electrical field. The simulation results show that the surface plasmon resonance is strongly inspired by core modes in y-polarized direction. Meanwhile, the coupling between core modes in x-polarized direction and surface plasmon polaritons modes is faint. The confinement losses can achieve 446 dB/cm in y-polarized direction and 0.8 dB/cm in x-polarized direction at wavelength of 1550 nm in one of our designed fiber. The effects of fiber structural parameters and temperature are investigated with a view of tuning and optimizing the confinement loss spectrum. Own to the large contrast of confinement losses in two orthogonal directions, the designed Au wires and liquid crystal infiltrated photonic crystal fibers promise candidate for tunable polarization filter devices. [ABSTRACT FROM AUTHOR]

We propose a modified design for a photonic crystal fiber (PCF) filter based on surface plasmon resonance(SPR). The air holes are arrayed in rectangular lattices, while the size and the pitches of holes around the gold-coated holes are different. That can separate the x-polarization and y-polarization of second-order surface plasmon polariton (SPP). The resonance strength of the surface plasmon mode and import of structural parameters of the PCF on the filter characteristics are studied through using the finite element method (FEM). Numerical simulations demonstrate that the thickness of the gold layer, the gold-coated or gold-filled, and the asymmetry around the gold-coated holes have a great effect on the filter characteristics. It is certain to obtain a resonance strength as high as 873 and 771.5 dB/cm at the communication wavelength of 1050 and 1310 nm in x-polarization by adjusting the size and the place of the gold-coated holes, while the loss is extremely low in y-polarization. [ABSTRACT FROM AUTHOR]

A polarization filter at the two communication windows of 1310 and 1550 nm based on photonic crystal fiber (PCF) with two large-diameter gold-coated air holes is proposed. The effects of geometrical parameters of the PCF on the performances of polarization filter are evaluated by finite element method (FEM). Numerical simulations reveal that the polarization filter possesses ultra-short length of 1 mm and high extinction ratios of 396 and −292 dB at the communication wavelengths of 1310 and 1550 nm, respectively. The bandwidth of extinction ratio (ER) better than 20 dB is 181 nm at the communication window of 1310 nm. Moreover, the bandwidth of ER better than −20 dB is 423 nm at the communication window of 1550 nm. [ABSTRACT FROM AUTHOR]

In this paper, two kinds of novel plasmonic polarization beam splitters based on dual-core photonic crystal fiber (DC-PCF) have been designed and analyzed through the full-vector finite element method. The metallic gold is used as the surface plasmon resonance (SPR) active metal. The coupling characteristics of the designed DC-PCF can be enhanced by the resonant coupling between the second-order surface plasmon polariton (SPP) mode and the core-guided modes. A gold layer in the designed DC-PCF is introduced to achieve an perfect splitting performance and an ultra-bandwidth compared to the designed DC-PCF with gold wire. Numerical results show the ultra-bandwidth of core A and B of the polarization beam splitter with gold layer can reach 210 and 220 nm, as the extinction ratio better than -20 dB, covering the E, S, C, and L optical communication bands. The extinction ratios of core A and B can reach to -84 and -46 dB at the wavelength of 1.55 μm, respectively, and the length of splitter is 0.542 mm. [ABSTRACT FROM AUTHOR]

The polarization filter characters of a square lattice photonic crystal fiber with a large diameter gold-coated air hole are studied by finite element method. Results show that the resonance strength of y-pol direction is far stronger than x-pol direction. It can achieve 517 and 375 dB/cm, respectively, in y-pol direction at the communication wavelengths of 1310 and 1550 nm by adjusting structural parameters. If a second large hole is added in the opposite corner of the lattice, the resonance strength of y-pol direction can increases to 701 dB/cm at 1310 nm. At the same time, the influence for polarization filter characters is studied by changing the fiber length, the thickness of gold layer, the diameter of large air hole, and the diameters of small air holes. [ABSTRACT FROM AUTHOR]

An ultrabroad bandwidth polarization filter based on D-shaped photonic crystal fibers with gold film is proposed. The design of gold film deposited on the polished plane of the D-shaped photonic crystal fibers is benefit to generate multiple resonances between surface plasmon polaritons and photons. In our designed polarization filter, the resonant intensity in y-polarization direction is much stronger than in x-polarization direction. An ultrabroad bandwidth of exceeding 1 μm with extinction ratio better than -20 dB is obtained. The performance characteristics of the filter can be improved further by optimizing the structure parameters of the D-shaped photonic crystal fibers. [ABSTRACT FROM AUTHOR]

A broadband single-polarization photonic crystal fiber polarized filter based on surface plasmon resonance is proposed based on finite element method. Numerical simulations show the confinement loss of y-PCM (y-polarized core mode) is much higher than that of x-PCM (x-polarized core mode) in the wavelength range 1.20-1.63 μm. The confinement loss of y-polarized mode is 45,240 and 10,200 dB/m at the communication wavelength 1.31 and 1.55 um, respectively, and the corresponding loss of x-polarized mode is just 90 and 80 dB/m. When the fiber length is 3 mm, the bandwidth of extinction ratio better than -20 dB is greater than 430 nm covering almost all the communication wavelength. To our best knowledge, the bandwidth is the widest. The impacts of structural parameters on the resonance characteristics are also discussed. The structure could be further optimized for better result. [ABSTRACT FROM AUTHOR]

A D-shaped photonic crystal fiber (PCF) surface plasmon resonance (SPR) sensor is proposed to measure the refractive index in visible and near-infrared regions. Compared with traditional PCF, the use of D-shaped PCF can avoid filling materials and coatings in the hole. The plasma material of sensors is silver, and graphene is coated on the surface of the silver film. Graphene layer can not only prevent the oxidation of the silver but also improve the performance of the sensor. Then the influence of structural parameters on the sensor performance is studied by the finite element method (FEM). Results show that the performance of the sensor is not sensitive to the structural parameters, which makes the sensor has a good manufacturing tolerance. Moreover, when the refractive index (RI) of the analyte is 1.33 ~ 1.41, the maximum wavelength sensitivity is 13,750 nm/RIU, and the corresponding RI resolution is 7.27 × 10−6 RIU−1. In addition, the maximum figure of merit is 201 RIU−1. The proposed sensor is advanced with high sensitivity, simple structure and big fabrication tolerance, which could become a competitive candidate for water pollution monitoring, medical diagnosis, biochemical analysis, and detection fields. [ABSTRACT FROM AUTHOR]

In this paper, a novel D-shaped photonic crystal fiber (D-PCF) based on surface plasmon resonance (SPR) is designed, and gold nanowire is used as the SPR active metal. A full-vector finite element method is applied to analyze the polarization filter characteristics. Phase matching between the second-order surface plasmon polariton (SPP) mode and the core-guided modes of x- and y-polarization can be met in two different wavelengths. By adjusting the diameters of the large air holes and the gold nanowire, this designed D-PCF can be used to the polarization filter in two communication bands. The loss of unwanted y-polarization mode can reach 244.9 and 292.8 dB/cm at the wavelength of 1.31 and 1.55 μm, respectively. With a length of 1 mm of the designed D-PCF, the bandwidths with the crosstalk better than 30 dB can reach to 88 and 150 nm, and the crosstalks are 208.4 and 249.5 dB the wavelength of 1.31 and 1.55 μm, respectively. [ABSTRACT FROM AUTHOR]

A kind of elliptical structure photonic crystal fiber with diameter increasing air holes is proposed. In this structure all the circular air holes are arranged in six elliptical rings. And the diameter of each rings increase from the inner to the outer. Moreover, we have choose some air holes to coating the metal Au and filling the liquid of the purified water. Properties, just like the confinement loss, of these structures with different diameters of the holes and thickness of the gold layer are numerical analyzed by using the finite element method. Numerical results show that the resonance strength in x-direction is much stronger than in y-polarized direction, and filling the liquid and changing the thickness of the gold film can significantly increase the loss of core mode polarized in the x-polarized direction. [ABSTRACT FROM AUTHOR]

A novel polarization splitter based on d-shaped dual-core photonic crystal fiber with gold film is proposed and analyzed by the finite element method. The designed polarization splitter involves side-polishing of photonic crystal fiber and depositing of gold film. The numerical results reveal that the separate length is 0.782 mm and the extinction ratios are -151 and -55 dB for the x- and y-polarized modes at the communication wavelength of 1,550 nm. The bandwidths of the polarization splitter are 40 and 65 nm for the x- and y-polarized modes with extinction ratios better than -20 dB and insertion losses lower than 0.3 dB. This d-shaped dual-core photonic crystal fiber is competitive for polarization splitter. [ABSTRACT FROM AUTHOR]

We propose and investigate a D-shaped photonic fiber refractive index sensor with rectangular lattice based on surface plasmon resonance. In such sensor, the nanoscale gold metal film is deposited on the flat surface where it is side polished. Numerical results show that the average sensitivity of Au-metalized surface plasmon resonance (SPR) sensor could reach as high as 8,129 nm/refractive index unit (RIU) in the dynamic index range from 1.35 to 1.41 as well as 2,000 nm/RIU from 1.33 to 1.35. Compared to conventional Au-metalized SPR sensors, the performance of our device is obviously better, and the production process is greatly simplified. [ABSTRACT FROM AUTHOR]

Systematical studies of post-collisional igneous rocks in the Dabie orogen suggest that the thickened mafic lower crust of the orogen was partially melted to form low-Mg # adakitic rocks at 143-131 Ma. Delamination and foundering of the thickened mafic lower crust occurred at 130 Ma, which caused the mantle upwelling and following mafic and granitic magmatic intrusions. Migmatite in the North Dabie zone, coeval with the formation of low-Mg # adakitic intrusions in the Dabie orogen, was formed by partial melting of exhumed ultrahigh-pressure metamorphic rocks at middle crustal level. This paper argues that the partial melting of thickened lower and middle crust before mountain-root collapse needs lithospheric thinning. Based on the geothermal gradient of 6.6°C/km for lithospheric mantle and initial partial melting temperature of ∼1000°C for the lower mafic crust, it can be estimated that the thickness of lithospheric mantle beneath thickened lower crust has been thinned to <45 km when the thickened lower crust was melting. Thus, a two-stage model for mountain-root removal is proposed. First, the lithospheric mantle keel was partially removal by mantle convection at 145 Ma. Loss of the lower lithosphere would increase heat flow into the base of the crust and would cause middle-lower crustal melting. Second, partial melting of the thickened lower crust has weakened the lower crust and increased its gravity instability, thus triggering delamination and foundering of the thickened mafic lower crust or mountain-root collapse. Therefore, convective removal and delamination of the thickened lower crust as two mechanisms of lithospheric thinning are related to causality. [ABSTRACT FROM AUTHOR]

Deep carbon recycling is an essential part of the global carbon cycle. The carbonates at the bottom of the ocean are brought to the mantle by subduction. Subsequently, deep carbon is released to the atmosphere in the form of CO through volcanism. At present, research on deep carbon recycling is still at its early stage. The proportion of subduction-related carbon and primary mantle-derived carbon in CO released by volcano is an important issue. Carbon isotopes can easily distinguish organic carbon from inorganic carbon. However, ∼95% of subduction-related and primary mantle-derived carbon released by volcano is inorganic, which carbon isotopes find difficult to distinguish. Recently, Ca and Mg isotope geochemistry has provided important tools for tracing crust-derived material recycling. Here we focus on this topic by introducing the principles of C, Ca, and Mg isotopes in tracing deep carbon recycling and previous research results. We also summarize the research progress on the total storage and phases of deep carbon, CO fluxes which depend on the release via volcanism, the partial melting of the carbon-bearing mantle, and carbon behaviour during oceanic subduction. [ABSTRACT FROM AUTHOR]

Leucogranites have a relatively narrow variation in SiO[sub2] content (70.5%-75.5%). Giving similar SiO[sub2] content, leucogranites have relatively higher Al[sub2]O[sub3] (>13.5%) and lower TFeO + MgO (<2.5%) contents than those of normal granites. These petrochemical characteristics suggest that leucogranites are derived from partial melting at relatively low temperature and are not significantly affected by fractional crystallization. In the present study, we propose that the Al[sub2]O[sub3] vs SiO[sub2] and TFeO + MgO vs SiO[sub2] diagrams can be used to distinguish leucogranites from normal granites. In addition, we report the major element compositions of the Jurassic granitic intrusions from Jingshan-Tushan-Mayishan in the Bengbu area, east-central China. Using the Al[sub2]O[sub3] vs SiO[sub2] and TFeO + MgO vs SiO[sub2] diagrams and the comparison with the High Himalayan leucogranites in mineralogical and petrochemical characteristics, we suggest that the Jingshan-Tushan-Mayishan intrusions belong to a leucogranite belt. Similar to those of the High Himalayan leucogranites, the Bengbu leucogranites have low Mg[sup#] values, indicating that they resulted from low temperature dehydration partial melting of the subducted continental crust of the South China Block at the crustal depth. [ABSTRACT FROM AUTHOR]

Zircon SHRIMP U-Pb dating was per- formed for olivine gabbro at Wangmuguan in the Beihuaiyang zone of the Dabie orogen and its country rock (garnet-bearing epidote-mica-quartz schist). The results show that the gabbro was crystallized at 635 ± 5 Ma, in the late Neoproterozoic rather than in the late Paleozoic as previously suggested; its country rocks formed at 464±7 Ma, younger than the enclosed gabbro. The U-Pb age for the gabbro is in good agreement with ages for tuff interbedded with sediments from the Doushantuo Formation in the South China Block and late-Neoproterozoic basic dyke swarms distributed on a large scale over areas of Suizhou to Zaoyang of Hubei Province in the northern margin of the South China Block. This suggests a large-scale magmatic activity occurred at the late Neoproterozoic in the South China Block, so that the gabbro at Wangmuguan in the western segment of the Beihuaiyang zone is geotectonic affinity to the northern margin of the South China Block. Since the olivine gabbro occurs within the schist of Ordovician protolith with tectonic contact between them but forming in different tectonic settings, it is concluded that the late-Neoproterozoic gabbro was detached from the Precambrian basement of the South China Block during the Triassic subduction of the South China Block, and tectonically thrusted over the metamorphosed rocks in the southern margin of the North China Block. [ABSTRACT FROM AUTHOR]

Methods recently advanced for discrimination on the genesis of metamorphic zircon, such as analysis of mineral inclusions and trace elements, provide us powerful means to distinguish zircon overgrowth during high-pressure metamorphism. Zircons in ultrahigh-pressure eclogite from Qinglongshan in the Sulu terrane were studied by the SHRIMP U-Pb method in combining with trace element and mineral inclusion analyses. No inherited core was identified in the analyzed zircons by means of cathodoluminescence images. The occurrence of high-pressure metamorphic mineral inclusions in zircon, such as garnet, omphacite, rutile, and the flat HREE pattern in zircon indicate that the zircon formed at high-pressure metamorphic conditions. Therefore, a weighted average U-Pb age of 227.4 ± 3.5 Ma obtained from such a kind of zircon is interpreted to represent the timing of peak metamorphism for the Qinglongshan eclogite. [ABSTRACT FROM AUTHOR]

Methods recently advanced for discrimination on the genesis of metamorphic zircon, such as analysis of mineral inclusions and trace elements, provide us powerful means to distinguish zircon overgrowth during high-pressure metamorphism. Zircons in ultrahigh-pressure eclogite from Qinglongshan in the Sulu terrane were studied by the SHRIMP U-Pb method in combining with trace element and mineral inclusion analyses. No inherited core was identified in the analyzed zircons by means of cathodoluminescence images. The occurrence of high-pressure metamorphic mineral inclusions in zircon, such as garnet, omphacite, rutile, and the flat HREE pattern in zircon indicate that the zircon formed at high-pressure metamorphic conditions. Therefore, a weighted average U-Pb age of 227.4 ± 3.5 Ma obtained from such a kind of zircon is interpreted to represent the timing of peak metamorphism for the Qinglongshan eclogite. [ABSTRACT FROM AUTHOR]

Reports on the decoupling of surface and subsurface sutures in the Dabie orogen and a continent-collisional lithospheric-wedging model. Differences of neodymium (Nd) and lead (Pb) isotopic compositions between Mesozoic mafic igneous rocks from the North China Block (NCB) and the South China Block (SCB); Subsurface suture between the NCB and SCB; Southward movement of subsurface suture in the Dabie-Sulu orogen.

Focuses on the lithosphere delamination of the Dabie Sulu orogen in China. Formation of syncollisional granites; Geological relationship between the mafic-ultramafic intrusions and granites; Dynamic causes of the mantle upwelling and underplating.

Examines the uranium-lead isotope composition of rutile, omphacite and garnets in the eclogite in China. Determination of the cooling ages of minerals in ultrahigh-pressure metamorphic rocks; Performance of magnetic and heavy liquid separations; Completion of the chemical and mass-spectrometric analyses.

Reports on a group of rubidium-strontium (Rb-Sr) ages for one pyroxenite sample from Renjiawan in North Dabie Terrane. Rb-Sr chronology; Discussion.

Examines the characteristics of pyroxenite-gabbro intrusions in the Dabie Mountains in China. Geology of the Dabie Mountains; Isochron age of the intrusions; Mechanics of development of syncollisional granites.

A double-clad single-mode tellurite optical fiber (DC-SMTOF) with a loss of 0.5 dB/m @1545.1 nm was fabricated based on the TeO2–ZnO–Li2O–Bi2O3 (TZLB) material. During the fiber drawing process, a low level of residual birefringence was produced, which gave a chance for the investigation of the polarization modulation instability (PMI). With a nanosecond laser operated at 1545.1 nm as the pump source, the PMI effect in the DC-SMTOF was investigated using different fiber length and different average pump power. This investigation of the PMI generation in non-silica optical fibers may provide guidance for the generation of the highly repetitive optical pulse train. [ABSTRACT FROM AUTHOR]