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Because of the viscous properties of rock, a viscoelastic model is closer to the real situation of rock media than an elastic model is. Cracks in the media are common geophysical phenomena. In particular, horizontal cracks are widely developed in the thin interbeds of sedimentary rock. Taking a Cole—Cole viscoelastic medium as the background medium, we compute the frequency-dependent velocities, quality factors, anisotropy coefficients, crack densities, and crack aspect ratios of P- and S-waves based on Hudson's theory. We give the velocity-stress staggered finite-difference equations of the elastic wave propagation in a cylindrical coordinate system for a viscoelastic medium with horizontal cracks and numerically simulate acoustic propagation in the cracked medium with different crack densities and aspect ratios. The simulation results indicate that as the crack density increases outside a borehole the P- and S-wave velocities decrease and their amplitudes increase, in a borehole the P- and S—wave velocities and amplitudes decrease; as the crack aspect ratios increases outside a borehole the P-wave velocities decrease, its amplitudes change little and the S-wave amplitudes and velocities change little, in a borehole the P-wave velocities and amplitudes decrease and the S-wave velocities in a borehole change little, and the S-wave amplitudes decrease. [ABSTRACT FROM AUTHOR]

The roles of angiotensin II (Ang II) AT1 (AT1a) receptors and its downstream target Na+/H+ exchanger 3 (NHE3) in the proximal tubules in the development of two-kidney, 1-clip (2K1C) Goldblatt hypertension have not been investigated previously. The present study tested the hypothesis that deletion of the AT1a receptor or NHE3 selectively in the proximal tubules of the kidney attenuates the development of 2K1C hypertension using novel mouse models with proximal tubule-specific deletion of AT1a receptors or NHE3. 2K1C Goldblatt hypertension was induced by placing a silver clip (0.12 mm) on the left renal artery for 4 weeks in adult male wild-type (WT), global Agtr1a−/−, proximal tubule (PT)-specific PT-Agtr1a−/− or PT-Nhe3−/− mice, respectively. As expected, telemetry blood pressure increased in a time-dependent manner in WT mice, reaching a maximal response by Week 3 (p < 0.01). 2K1C hypertension in WT mice was associated with increases in renin expression in the clipped kidney and decreases in the nonclipped kidney (p < 0.05). Plasma and kidney Ang II were significantly increased in WT mice with 2K1C hypertension (p < 0.05). Tubulointerstitial fibrotic responses were significantly increased in the clipped kidney (p < 0.01). Whole-body deletion of AT1a receptors completely blocked the development of 2K1C hypertension in Agtr1a−/− mice (p < 0.01 vs. WT). Likewise, proximal tubule-specific deletion of Agtr1a in PT-Agtr1a−/− mice or NHE3 in PT-Nhe3−/− mice also blocked the development of 2K1C hypertension (p < 0.01 vs. WT). Taken together, the present study provides new evidence for a critical role of proximal tubule Ang II/AT1 (AT1a)/NHE3 axis in the development of 2K1C Goldblatt hypertension. [ABSTRACT FROM AUTHOR]

In order to understand the effect of fluid-induced alteration on the Sm-Nd isotope systematic in apatite, a series of fluid/apatite reaction experiments, which involve reacting the well-characterized Durango fluorapatite with CO 2 ± CaCO 3 -, NaF- or HCl ± CaCl 2 -bearing solutions with a known 143Nd/144Nd ratio, were conducted at 800 or 600 °C at 200 MPa. In experiments involving CO 2 -H 2 O ± CaCO 3 , the fluorapatite grains did not react with the solution, such that the Sm-Nd isotopic system was undisturbed. In experiments involving NaF, the fluorapatite grains were partially to completely altered. During the alteration process, REE mobilization was retarded via the coupled substitution Na+ + REE3+ = 2Ca2+ due to the high activity of Na in the fluid. Because the REE were not mobilized, the 147Sm/144Nd ratios remained constant. However, the 143Nd/144Nd ratios were slightly altered due to small degrees of Nd isotopic exchange between the fluid and fluorapatite. In experiments involving HCl ± CaCl 2 , the fluorapatite grains were partially altered, and the REE were variably leached from the altered fluorapatite. Leaching of REE was accompanied by an increase in the 147Sm/144Nd ratio, which is related to the higher compatibility of Sm in the fluorapatite structure and the lower mobility of Sm in Cl-bearing fluids. Although the 147Sm/144Nd ratios were strongly affected, the 143Nd/144Nd ratios experienced only a small change, which is related to the slow rate of transport for Nd between reaction-front fluid and bulk fluid. In general, the experimental results indicate that fluid chemistry is the main factor controlling the response of the Sm-Nd isotopic system to fluid-induced alteration. The 147Sm/144Nd ratio of apatite can be highly modified, and in turn the Sm-Nd isotopic system is disturbed when the fluids are rich in ligands that are able to facilitate REE mobilization and fractionation. Therefore, a thorough evaluation of the fluid-rock history, along with the conjectured fluid chemistry, is necessary before using apatite Sm-Nd isotopes as geological indicators. [ABSTRACT FROM AUTHOR]

The ridged substrate integrated coaxial line (RSICL) supports transverse electromagnetic (TEM) wave with small size, broadband, and good shielding performance. This article presents a two-material RSICL, which has two different dielectric materials filled in its substrate layers. Compared with the conventional RSICL with only one dielectric material, the two-material RSICL shows a higher cutoff frequency of the first higher order mode. Hence, the monomode bandwidth of the two-material RSICL can be improved accordingly. Based on the printed circuit board (PCB) process, the two-material RSICL with feeding structures is designed and fabricated. In the experiment, the first two-order modes of the two-material RSICL are excited with two types of transitions. The measured monomode bandwidth of the two-material RSICL is from dc to 44 GHz, which is 14.9% wider than that of the one-material RSICL. [ABSTRACT FROM AUTHOR]

• The proposed polarizer enables independent, tunable phase modulation without altering the structure size. • The proposed DBS can switch the types of scattered beams through the phase-transition of VO 2. • The proposed AZM can switch the function between achromatic metalens and zoom metalens through the phase-transition of VO 2. • The proposed MFOVG can switch the function between metalens and FOAM generator through the phase-transition of VO 2. Metasurfaces, especially coded ones, have gained significant attention for their excellent ability to control electromagnetic (EM) waves, opening up possibilities for a new generation of miniaturized devices. However, integrating multiple functionalities into a single metasurface while endowing tunable performance remains a challenge. In this study, we propose a strategy to design switchable and multifunctional terahertz (THz) photonic devices using complementary Gold-VO 2 split resonant ring (GV-SRR) and complementary Gold-VO 2 split resonant oblong (GV-SRO) structures. The designed devices can convert right-handed circularly polarized (RCP) light into left-handed circularly polarized (LCP) light in three frequency bands, corresponding to center frequencies fre. 1 = 0.34 THz (narrowband), fre. 2 = 0.50 THz (narrowband), and fre. 3 = 0.80 THz (broadband). The phases of the reflected LCP wave can be independently modulated across different frequency bands by rotating the in-plane orientation of GV-SRR and GV-SRO separately. In addition, the overall phase reconstruction can be achieved through the state change of VO 2. By arranging GV-SRR and GV-SRO in a defined encoding form, the engineered photonic devices can exhibit distinct and switchable capabilities in modulating EM wavefronts across various frequency ranges. As proof-of-concept examples, we have designed three encoded photonic devices, namely, a dynamic beam splitter (DBS), an achromatic and zoom metalens (AZM), and a switchable device between metalens and focusing orbital angular momentum (OAM) generator (MFOAM). These devices have potential applications in wireless communication, AR holographic displays, and information processing. [ABSTRACT FROM AUTHOR]

The mode-selective transmission line (MSTL) has excellent transmission performance due to its wide bandwidth and low loss, which is characterized by the mode-selective effect. In this article, a skew-symmetric slotted waveguide (SSSW) is proposed, whose dominant mode also exhibits the interesting mode-selective effect and transmission performance is similar to that of the MSTL. It is investigated that the dominant mode of the SSSW performs quasi-transverse electromagnetic (TEM) mode at low frequency and quasi-TE10 mode at high frequency. Then, for fast design, a characteristic impedance formula of the SSSW is derived by the conformal mapping, which has the error less than 3% compared with the finite-element method (FEM). In addition, a microstrip line (MSL) to grounded coplanar waveguide (GCPW) transition is designed to excite the dominant mode of the SSSW, with good transmission of the dominant mode and significant suppression of higher order modes. Finally, the SSSWs with the transitions are fabricated under printed circuit board (PCB) technology and measured with the S21 larger than −2.1 dB and the S11 less than −12.7 dB from dc to 67 GHz, and the attenuation of the SSSW is less than 0.065 dB/mm below 65 GHz. Good eye diagram is obtained with bit error rate (BER) less than $10^{-12}$ for the 32-Gb/s data rate. [ABSTRACT FROM AUTHOR]

In this article, a compact unconditionally stable two-dimensional (2-D) stochastic weighted Laguerre polynomial finite-difference time-domain (S-WLP-FDTD) method for geometric uncertainty in superconducting transmission lines is proposed. It calculates both the Maxwell equations and the London equations and uses a weighted Laguerre polynomial (WLP) scheme to eliminate the stability constraint. The mean and the standard deviation of electromagnetic fields, voltages, and currents are calculated. Compared with the Monte Carlo method and 2-D S-FDTD method, the proposed method has the same accuracy but much higher efficiency. The runtime of the proposed S-WLP-FDTD method is only 2.4% of that of the S-FDTD method. Thus, the proposed method is suitable for predicting the influence of geometric uncertainty on superconducting transmission lines. [ABSTRACT FROM AUTHOR]

Apatite is a ubiquitous accessory mineral in crustal rocks. The Sr-isotope record of apatite has a wide range of applications in earth science studies. However, apatite has been documented to be easily altered by certain fluids. Currently, the impact of metasomatic alteration on Sr-isotopic abundances in apatite is not well known. In order to better understand this issue, well-characterized fluorapatite grains have been metasomatized experimentally at a temperature of 800 or 600 °C and a pressure of 200 MPa. Fluids used included a CO 2 -H 2 O mixture and NaF-, CaCl 2 -, and HCl-bearing solutions, all of which were doped with a standard solution with a known 87Sr/86Sr ratio. In the fluorapatite + CO 2 -H 2 O experiments, the fluorapatite grains were not altered by the fluids; thus, their Sr isotope compositions were generally kept unchanged. However, the other fluids induced partial to complete alteration of fluorapatite. In experiments involving the NaF- or HCl-bearing solutions, the Sr content remained constant or was increased in altered areas of the fluorapatite, and the Sr isotopes underwent changes with partial isotopic signature of the reacting solutions. In experiments involving CaCl 2 , the Sr content was decreased in the altered fluorapatite because high Ca activity in the solution caused Ca to replace Sr on the Ca site. Notably, the Sr isotopic ratios are still changed, although to a relatively small extent. The efficient Sr isotopic exchange between fluid and apatite is attributed to the rapid transport rate of Sr between the reaction-interface fluid and bulk fluid surrounding the apatite. This experimental study demonstrates that the response of apatite Sr isotopes to metasomatic alteration is mainly controlled by the chemistry of fluids. Overall, Sr isotopes become susceptible to hydrothermal alteration once the apatite is chemically reactive with the fluids. Therefore, it is important to evaluate the fluid-rock history, especially the conjectured fluid composition before using Sr isotopes from apatite as a geochemical tracer. [ABSTRACT FROM AUTHOR]

In this study, molecular dynamics (MD) simulations were used to systematically investigate the behaviour of hydrogen (H) and helium (He) around 1/2<111> screw dislocations (SDs) and 1/2<111>{110} edge dislocations (EDs) in tungsten (W). The binding energy distributions of H and He around these two dislocations were obtained by molecular statics methods. The results revealed that both types of dislocation cores strongly attracted H and He atoms, and capture strengths were stronger for EDs than SDs. The simulations predicted that two factors influenced the interaction: strain fields of dislocations (effects of dislocations on H/He atoms) and residual stresses of H/He atoms (influences of H/He atoms on dislocations), which were validated. In the selection of trapping sites, H was synergistically affected by hydrostatic compressive and shear stress fields, and He was influenced only by shear stress fields. Conversely, the insertion of H atoms reduced the local lattice distortion of the SDs and induced the EDs to glide. He atoms repelled neighbouring atoms to increase the free volume of the trapping site. The diffusion behaviour of H/He atoms around dislocation cores was studied through nudged elastic band (NEB) and MD methods. Both H and He atoms tended to diffuse along screw channels around SD lines and one-dimensional channels inclined to ED lines, preferentially migrating along the dislocation line. The results of this study provide new insight into the retention and diffusion of H and He atoms in W. However, we have not been able to determine the clear influence of dislocations on the retention amount and diffusion tendency of H or He atom. [ABSTRACT FROM AUTHOR]

In this article, an ultrawideband magnetic probe with high electric field suppression ratio (EFSR) is proposed. The probe has three parts: the loop part, the transmission part, and the head part. Shield metal sheets are designed in the loop part to enhance EFSR. The tapered transmission line in the transmission part and the quasi coaxial transition in the head part are adopted for impedance matching between the induction loop and the grounded coplanar waveguide (GCPW) in the head part. Then, segmented resistance–inductance–capacitance (RLC) equivalent circuit models of the probe are proposed for magnetic field coupling and electric field coupling, which are suitable for accurate modeling and efficient optimization of the magnetic probe. In addition, the coupling capacitors between the shield metal sheets and the device under test (DUT) are extracted utilizing the conformal transforming method with analytical formulas. Finally, this magnetic probe is fabricated under printed circuit board (PCB) technology and used in measuring the magnetic field distribution. The measurement and simulation results agree well. The probe has a bandwidth of 100 MHz–30 GHz and an EFSR of higher than 21 dB. Compared with the conventional probe with similar bandwidth, the proposed probe can improve the EFSR by 9 dB. [ABSTRACT FROM AUTHOR]

Isotopic dating studies have revealed that many carbonatite-related REE ore systems have protracted and complex temporal evolution histories. The mechanisms that cause these complex dating results remain poorly understood. Here, we present an in-situ Sm-Nd and Th-Pb isotopic investigation of monazite and bastnäsite from a geologically-complicated deposit, the world-class Bayan Obo REE deposit of China, with the aim of defining the general mechanisms accounting for the protracted age spread observed in this and many other REE deposits. Monazite and bastnäsite are two principle REE ore minerals in the Bayan Obo deposit. Most of the studied monazite and bastnäsite grains have experienced fluid-aided modification. The modified grains have generally homogeneous Sm and Nd contents and Sm-Nd isotopic compositions, implying low mobility of Sm and Nd during the modification process. Thus, the Sm-Nd chronometer can be used to constrain the primary crystallization timing of the REE minerals at 1293 ± 48 Ma. However, altered REE minerals have apparent 208Pb-232Th ages (1248–261 Ma) that are variably younger than the primary crystallization age. In most samples, Th contents have no correlations with 208Pb-232Th ages, while Pb contents tend to decrease along with the younging trend of 208Pb-232Th ages. NanoSIMS mapping shows that 208Pb and 208Pb/232Th are heterogeneous, and irregularly distributed in the altered grains. Such results are indicative of variable Pb loss during the fluid-aided modification process. Thus, many Th-Pb ages represent partial isotopic resetting and, hence, are geologically meaningless. Completely reset ages cluster at 450–400 Ma or 280–260 Ma, representing two discrete episodes of post-ore hydrothermal activity. Small amounts of monazite and bastnäsite that were newly crystallized during these two overprinting episodes have initial Nd isotopic signatures approaching the time-evolved isotopic compositions of primary ores, which suggests insignificant REE input to the primary ores during these events. This study provides critical evidence to resolve complex dating results and disparate ore genesis models for the giant Bayan Obo deposit. Moreover, our results indicate the resistance of Sm-Nd isotopes, but the susceptibility of Th-(U)-Pb isotopes, to fluid-aided modification. Therefore, younger Th-U-Pb dates in geologically-complicated deposits should be treated with caution as they may represent partial resetting results and/or may not represent events of increased metal tenor. [ABSTRACT FROM AUTHOR]

Magnetic‐field probes can be used for electromagnetic interference measurement of high‐speed circuits. The main magnetic probe performance includes sensitivity, spatial resolution, electric‐field suppression ratio (EFSR), and measurement accuracy. In this article, a pair of differential magnetic‐field probes is proposed to improve measurement accuracy without reducing sensitivity. The proposed differential probes consist of two asymmetric loop probes, which are designed in the same plane and separated by a row of periodic vias. The proposed differential probes are fabricated under PCB process. High accuracy can be achieved by measuring difference between outputs of the two probes. In addition, EFSR can be improved by size optimization of the differential magnetic‐field probes. Simulation and measurement results show the operating bandwidth is from 100 MHz to 12 GHz, the measurement error is 3.4% and the EFSR is about 40 dB. The proposed probes have higher measurement accuracy and higher EFSR than the conventional single probe, and larger operation bandwidth than the stacked differential probes. [ABSTRACT FROM AUTHOR]

In this article, a stochastic finite-difference time-domain (S-FDTD) method is proposed for analyzing the influence of physical size uncertainty on the time-domain response of superconducting transmission lines. The formulations of the proposed method are, in detail, derived with the two-fluid model and London equation. A typical superconducting microstrip line is simulated to verify the effectiveness of the proposed algorithm. Compared with the Monte Carlo simulation, the proposed method has the same accuracy but much higher efficiency. The computation time of the proposed S-FDTD method is only about 3% of that of the Monte Carlo simulation. Therefore, the proposed method shows a promising prospect on predicting the variability in transmission line's performance caused by variation in superconducting manufacturing. [ABSTRACT FROM AUTHOR]

In this article, a half-mode substrate integrated waveguide (HMSIW) combined with 2.5-D spoof surface plasmon polaritons (SPPs) structure is proposed to tailor the dispersion features and cutoff frequency of the HMSIW. The proposed HMSIW-SPP structure has a smaller longitudinal dimension since the dispersion of the proposed structure can be tailored by adjusting the geometric parameters of the 2.5-D spoof SPP arbitrary. Simultaneously, the proposed structure has a smaller lateral width than that of the classical HMSIW because the 2.5-D spoof SPP introduces extra capacitance in the waveguide. Moreover, an equivalent circuit model is proposed and used to analyze the design principles. The structure exhibiting the cutoff frequency of 6.0 GHz is designed and fabricated under the printed circuit board process. Measurement and simulation results show that the proposed HMSIW-SPP structure decreases the longitudinal dimension by more than 50% and the lateral width by 25% without sacrificing its transmission performance. Due to the reduced cutoff frequency and effective wavelength, the proposed structure enables extreme miniaturization and can be applied in the design of miniaturized microwave circuits. [ABSTRACT FROM AUTHOR]

With the development of rapid single-flux-quantum (RSFQ) circuits, signal integrity issues of interconnects, such as signal distortion and crosstalk, become critical. Josephson junctions, as driver and receiver of interconnects, also affect signal integrity. Hence, it is significant to coanalyze time-domain responses of multicoupled passive transmission lines (PTLs) and Josephson junctions in RSFQ circuits. In this article, an accurate numerical method based on finite-difference time-domain (FDTD) is proposed to coanalyze multicoupled PTLs and Josephson junctions. The FDTD method is used to solve the telegraph equations of PTLs, and an iteration algorithm based on the contractive mapping theorem is proposed to solve the nonlinear equations generated by the Josephson junctions. In addition, the existence and uniqueness conditions of the nonlinear equations are also provided. The numerical and simulation results show that the proposed coanalysis method has the same accuracy as but higher efficiency than WRspice. [ABSTRACT FROM AUTHOR]

Tungsten (W) and W alloys are regarded as the most promising candidates for plasma facing materials (PFMs), which will be widely used in the next generation of fusion reactors. However, blistering in W-PFM induced by extremely high fluxes of low-energy hydrogen (H) and helium (He) ions irradiation will seriously influence the plasma stability and limits the lifetime of PFM. We systematically investigate the interaction between H and He interaction in W using molecular dynamics (MD) calculations. The vacancy clusters can capture a large amount of H/He, and the H-He-vacancy clusters have much higher binding energy to He than to H. The binding energy of H-He-vacancy clusters to vacancy/W is positive, and H-He-vacancy clusters have strong trapping of W atoms and vacancies. He will strongly affect the H behavior in W, He atoms and He cluster will trap H atoms, thereby preventing the diffusion of H in W. [ABSTRACT FROM AUTHOR]

The Khetri Copper Belt (KCB) in northwestern India contains several economically important hydrothermal Cu–(Au) deposits. Orebodies in these deposits are locally rich in monazite-(Ce). In this study, in situ U–Pb ages and Sm–Nd isotopic compositions of monazite-(Ce) are used to constrain the timing of mineralization and to better understand the genesis of the Cu–(Au) deposits. Monazite-(Ce) crystals were identified in the Madhan-Kudhan and Kolihan deposits in the KCB. Most monazite-(Ce) crystals in the two deposits show close textural associations with hydrothermal minerals (biotite, chlorite, and sulfide) and have low contents of ThO2 (mostly < 2 wt.%), indicating a hydrothermal origin. The hydrothermal monazite-(Ce) crystals have U–Pb ages of 833 ± 5 to 840 ± 6 Ma, which are interpreted to represent the timing of the mineralization in the KCB. Another set of monazite-(Ce) crystals in the Kolihan deposit has relatively high contents of ThO2 (4.72 wt.% on average) and commonly shows concentric zonation with respect to Th. They have a weighted average 207Pb/206Pb age of 1362 ± 29 Ma, which may record a pre-ore metamorphic event in the KCB. Hydrothermal monazite-(Ce) crystals from the Madhan-Kudhan deposit have εNd(t = 835 Ma) values ranging from − 4.3 to − 16.8 (− 9.6 on average), indicating that isotopically heterogeneous materials were in the metal sources or along the flow paths of hydrothermal fluids. The ages of Cu–(Au) deposits in the KCB fall within the age range of the regional Ca–Na metasomatism (~ 830 to ~ 850 Ma). Combining this temporal association with relevant geochemical and isotopic data, we propose that circulation of hydrothermal fluids caused widespread Ca–Na metasomatism, mobilized certain ore-metals, and thus facilitated the formation of Cu–(Au) deposits. [ABSTRACT FROM AUTHOR]

The Neoproterozoic (840 Ma) Sin Quyen deposit in northwestern Vietnam contains replacement Cu-LREE-Au orebodies in Proterozoic metasedimentary rocks. In this deposit, LREE-bearing minerals include allanite-(Ce), monazite-(Ce), chevkinite-(Ce), and fluorapatite. Fluorapatite from orebodies has undergone variable degrees of metasomatic alteration. Samarium-neodymium isotopic analyses were conducted on altered fluorapatite, and also on allanite-(Ce) and monazite-(Ce), to investigate whether such metasomatism can affect the Sm-Nd isotope system. Allanite-(Ce) and monazite-(Ce) have 147Sm/144Nd ratios ranging from 0.0359 to 0.0549, and 143Nd/144Nd ratios from 0.51147 to 0.51172. Their initial 143Nd/144Nd values at the time of mineralization range from 0.51126 to 0.51148, but mostly cluster between 0.51135 and 0.51145. Thus, the primary ore-forming fluids were relatively homogeneous in their Sm-Nd isotopic compositions. In the 147Sm/144Nd vs. 143Nd/144Nd diagram, the compositions of allanite-(Ce) and monazite-(Ce) generally plot along a Sm-Nd isochron of 840 Ma, implying that the Sm-Nd isotopic systems of these minerals were either closed or only slightly modified. In contrast, altered fluorapatite crystals have 147Sm/144Nd ratios varying from 0.0667 to 0.1348, and 143Nd/144Nd ratios from 0.51160 to 0.51199. The calculated initial 143Nd/144Nd ratios range widely from 0.51114 to 0.51141, with most values lower than those of the allanite-(Ce) and monazite-(Ce). In the 147Sm/144Nd vs. 143Nd/144Nd diagram, their compositions mostly plot below the 840-Ma Sm-Nd isochron. Petrographic observations and trace elemental analyses show that metasomatic modification of fluorapatite grains led to increases of their Sm/Nd ratios. The unaltered domains in the grains have Sm/Nd ratios varying from 0.114 to 0.200, with an average value of 0.161; whereas the altered domains have Sm/Nd ratios varying from 0.111 to 0.254, with an average value of 0.183. The increased Sm/Nd ratios can cause the calculated initial 143Nd/144Nd ratios to be lower than actual initial isotopic ratios, and can also result in compositional deviations from the reference Sm-Nd isochron. This study demonstrates that the traditionally assumed inert Sm-Nd isotopic system can be metasomatically disturbed due to changes in the Sm/Nd ratio. Therefore, care must be taken when interpreting the Sm-Nd isotopic data from apatite/apatite-rich rocks that have undergone metasomatic alteration. [ABSTRACT FROM AUTHOR]

The Longbohe Fe-Cu-(LREE) deposit in the Longbohe–Sin Quyen (LSQ) Fe-Cu belt in the border zone of South China and northern Vietnam has a resource of > 1 million tonnes Cu, and was once speculated to be a potentially important subduction-related deposit of Precambrian age, but with poor constraints. Our study reveals that the major Fe-, Cu-, and LREE mineralization comprises three stages and are comparable to typical IOCG deposits worldwide. Stage I is characterized by pervasive Na alteration, followed by Fe mineralization stage (Stage II) consisting of Ti-poor magnetite associated with Ca-Na alteration forming amphibole and albite. Stage III, the Cu-LREE mineralization stage, is composed mainly of chalcopyrite and REE-rich allanite with minor pyrrhotite and pyrite. Stages I and II formed at broadly comparable temperatures of 515 to 670 ºC, and have δ18O fluid values of 4.3 to 11.7 ‰, indicating dominantly magmatic fluids. Furthermore, they have hydrothermal zircon with εHf(t) values (7.5 to 12.7) similar to coeval mafic intrusions in the region, likely indicating a mafic magma-source for the fluids. Stage III fluids have lower temperatures (332 to 402 ºC) but exhibit magmatic-like δ34S values (1.2 to 3.7 ‰) similarly suggestive of a major magmatic source. However, they have distinctly lower εHf(t) and εNd(t) values comparable to those of coeval regional felsic intrusions, suggesting that an additional component of REE-rich external fluid from felsic magmas was involved during the Cu-REE mineralization. Hydrothermal zircons from Stages II and III have similar U–Pb ages of ~ 850 Ma, providing tight constraints on the timing of Fe-Cu mineralization. The new U–Pb ages indicate that the Longbohe deposit is coeval with the Sin Quyen IOCG deposit in northern Vietnam, and with the regional subduction-related magmatism, indicating that the Longbohe–Sin Quyen belt is of Neoproterozoic age and formed in a convergent setting. [ABSTRACT FROM AUTHOR]

[Display omitted] • Four types of HREE-rich minerals are identified in the giant Bayan Obo deposit. • The identified HREE-minerals were mainly precipitated from carbonatite-relate fluids. • A local physiochemical environment that facilitated the formation of niobium oxides is significant for efficient HREE deposition. The carbonatite-related Bayan Obo deposit, China is the largest REE resource in the world. This deposit has long been a major light REE (LREE) producer, with heavy REE (HREE) rarely exploited. In order to better understand the occurrence of HREE in the deposit, this paper conducts a study of HREE-rich minerals at Bayan Obo. Overall, four types of HREE-rich minerals are identified, including fergusonite-group mineral [(Y, REE)(Nb, Ta, Ti)O 4 ], samarskite-group mineral [(Y, REE, Fe) 2 (Nb, Ta, Ti) 2 O 8 ], aeschynite-group mineral [(Y, REE, Ca, Th, U)(Nb, Ta, Ti) 2 O 6 ], and a type of unknown Pb-rich mineral. These minerals have HREE contents varying from 3.4 wt% to 46.4 wt%, mostly between 19.7 wt% and 34.3 wt%. Yttrium, Dy and Gd are the major REE constitute. Textual relations indicate that the HREE-rich minerals were mainly precipitated from carbonatite-related fluids, with small amounts of grains crystallized from the carbonatitic magma or deposited from post-ore modification fluids. The HREE-rich minerals occur in close temporal and/or spatial association with LREE minerals (e.g., monazite and bastnäsite), so formation of these HREE-minerals does not mean strong LREE-HREE fractionation during the ore-formation or post-ore modification process. Given that certain niobium oxides strongly prefer HREE relative to LREE in the mineral structure, a local physiochemical environment that allowed for the deposition of niobium oxides may be significant for efficient HREE deposition. Although HREE-rich minerals are not widely present in the deposit, they tend to occur as clusters in places. To determine what proportions of HREE can be hosted in the HREE-rich minerals, the weight proportions and REE contents of major REE-bearing minerals were measured in three representative ore samples. The results show that ∼ 25–57 % HREE can be hosted in fergusonite, samarskite, and/or aeschynite. Therefore, the newly identified HREE-rich minerals are non-negligible targets for future exploitation of HREE in the Bayan Obo deposit. [ABSTRACT FROM AUTHOR]

Several Neoproterozoic granitic intrusions, including the Phin Ngan intrusion and some smaller ones from the Sin Quyen Cu mine, have been identified in the Phan Si Pan belt, Northwest Vietnam. Whole-rock geochemical and Sm-Nd isotopic data and zircon U-Pb age and Hf-O isotopes have been determined for these intrusions in order to constrain their ages, petrogenesis and tectonic implications. The Phin Ngan intrusion, mainly composed of syenogranite, was emplaced at 824 ± 4 Ma. Rocks from this intrusion have high SiO 2 (72.1–73.5 wt.%), and K 2 O (5.14–5.52 wt.%), with A/CNK values ranging from 1.02 to 1.06. They have negative whole-rock ε Nd ( t ) (−8.4 to −5.2) and zircon ε Hf ( t ) values (−8.1 to −5.5), and high zircon δ 18 O values (9.7–10.9‰). These geochemical features suggest that the Phin Ngan intrusion was derived from ancient, K-rich crustal sources. Granitic intrusions from the Sin Quyen mine occur as stocks or dykes intruding ores and ore-hosting rocks. They are composed of monzogranite and granodiorite, emplaced between 736 ± 8 and 758 ± 6 Ma. They have high SiO 2 (68.2–76.7 wt.%) and (K 2 O + Na 2 O) (6.93–8.54 wt.%), and low MgO (0.19–0.87), with A/CNK values ranging from 0.91 to 1.14. Their whole-rock ε Nd ( t ) values range from −6.6 to 0, mostly clustered between −6.6 and −4.3. Their zircon ε Hf ( t ) values vary from −6.7 to +11.1, mostly lower than −2.0. Such geochemical data indicate that these intrusions were produced mainly through partial melting of ancient crustal materials, coupled with subordinate involvement of mantle-/juvenile crust-derived components. The Phin Ngan intrusion and intrusions from the Sin Quyen mine are sub-alkaline in nature, and have arc-like trace-element compositions. Compiled with other broadly synchronous igneous rocks with arc-like affinities in the region, the Neoproterozoic magmatism in the Phan Si Pan belt was generated in a subduction-related setting. The Neoproterozoic intrusions in the Phan Si Pan belt are geochronologically and geochemically correlated with the Neoproterozoic subduction-related igneous rocks along the western Yangtze Block. Thus, the Phan Si Pan belt represents the southern most part of the giant arc system of the western Yangtze Block. [ABSTRACT FROM AUTHOR]

The Sin Quyen deposit in northwestern Vietnam contains economic concentrations of Cu, Au and LREE, and sub-economic concentration of U. In this deposit, massive and banded replacement ores are hosted in Neoproterozoic metapelite. The paragenetic sequence includes sodic alteration (stage I), calcic-potassic alteration and associated Fe-REE-(U) mineralization (stage II), Cu-Au mineralization (stage III), and sulfide-(quartz-carbonate) veins (stage IV). The Sin Quyen deposit experienced an extensive post-ore metamorphic overprint, which makes it difficult to precisely determine the mineralization age. In this study, zircon and monazite U-Pb geochronometers and the Rb-Sr isochron method are used to constrain the timing of mineralization. Zircon grains in the ore are closely intergrown or texturally associated with hydrothermal minerals of stage II (e.g., garnet, allanite, and hedenbergite). They may contain primary fluid inclusions and display irregular zoning in cathodoluminescence (CL) images. Zircon grains are rich in U (688 to 2902 ppm) and poor in Th (0.2 to 2.9 ppm). Their δ18OV-SMOW values range from 11.9 to 14.0‰, higher than those of typical magmatic zircon. These textural and compositional features imply that zircon precipitated from 18O- and U-rich hydrothermal fluids, coeval with the minerals of stage II. Monazite occurs in close association with stage II magnetite and allanite and has low contents of Th (<2700 ppm), indicative of a hydrothermal origin. Hydrothermal zircon and monazite have indistinguishable U-Pb ages of 841 ± 12 and 836 ± 18 Ma, respectively, representing the timing of Fe-REE mineralization. There is no direct isotopic constraint on the timing of the Cu-Au mineralization, but geological observations suggest that the Cu-Au and Fe-REE ores most likely formed within a single evolved hydrothermal process. In the plot of 87Rb/86Sr vs. 87Sr/86Sr, the composition of bulk-ore and biotite separates from ore lie along a reference line for 30 Ma, which is consistent with the timing of metamorphism in the region. The mineralization age of the Sin Quyen deposit falls within the overall age range (740 to 860 Ma) of the regional Neoproterozoic igneous rocks. This temporal linkage, in combination with the magmatic-like sulfur isotopes of sulfide minerals (δ34SV-CDT = −0.8 to 3.1), indicates that the mineralization may have a close genetic association with the Neoproterozoic igneous activity. [ABSTRACT FROM AUTHOR]

In this paper, Quadrature Phase Shift Keying (QPSK) modulation and demodulation system based on a Substrate Integrated Waveguide (SIW) is designed and implemented for high-speed data transmission. The technique of orthogonal multiplexing allows two independent channels to transmit data simultaneously through one waveguide structure. For this proof-of-principle study, a fabricated SIW prototype with bandwidth of 14-28 GHz is designed and optimized through full-wave simulations. The QPSK system prototype is verified with different data rates and bit patterns. Experimental results demonstrate that the bit error rates (BERs) of the received data in channel I/Q are less than 10-12 and the transmission rate can reach up to 15 Gb/s for 27-1 Pseudo Random Binary Sequence (PRBS). The transmission data rate of the proposed QPSK system is two times higher than that of the conventional mixing system. [ABSTRACT FROM AUTHOR]

Functional components extracted from algal biomass are widely used as dietary and health supplements with a variety of applications in food science and technology. In contrast, the applications of algae in dermal-related products have received much less attention, despite that algae also possess high potential for the uses in anti-infection, anti-aging, skin-whitening, and skin tumor treatments. This review, therefore, focuses on integrating studies on algae pertinent to human skin care, health and therapy. The active compounds in algae related to human skin treatments are mentioned and the possible mechanisms involved are described. The main purpose of this review is to identify serviceable algae functions in skin treatments to facilitate practical applications in this high-potential area. [ABSTRACT FROM AUTHOR]

Substrate integrated coaxial line (SICL) is a kind of planar transmission line, which can guarantee the propagation of transverse electromagnetic mode wave within a wide band. In this paper, a multichannel SICL array with coaxial lines placed in both vertical and horizontal directions is proposed for high-speed parallel data transmission. The adjacent channels of the SICL array share outer conductors for high-density integration. Moreover, the outer conductor is enhanced by metal fence to suppress the crosstalk between adjacent channels of the SICL array. In addition, a quasi-coaxial transition is designed for the proposed SICL array. A systematical design procedure is given to determine the physical dimensions of SICL array with transitions. The SICL array has flat group delay so that data can be transmitted without significant phase distortion. It is suitable for high-density integration and high-speed data transmission due to the low crosstalk and high bandwidth. To verify the advantage of the proposed SICL array, a $15 \times 3$ channel prototype is designed and fabricated in low temperature co-fired ceramic. The measured S-parameters agree well with the simulated results. The maximum bandwidth of a single channel of the SICL array is up to 56 GHz and the coupling of adjacent channels in the SICL array is less than −30 dB. Data rate of 30 Gb/s is measured for each channel with good eye diagram and low bit error rate, and hence, a total 1.35-Tb/s data rate can be achieved with the proposed $15 \times 3$ channel SICL array. [ABSTRACT FROM PUBLISHER]

First-principles theory is applied to identify the structure of γ-Al 2 O 3 first. Then, hydrogen dissolution and diffusion behavior was further studied to reveal the reason that permeation reduction factor (PRF) of γ-Al 2 O 3 is lower than that of α-Al 2 O 3. Our calculations show that the formation energy for Al vacancy at the octahedral interstitial site (V Al − OIS − 3) is lower than that at the tetrahedral interstitial site (V Al − TIS − 3), and are far lower than those of other defects in both defective spinel and non-spinel γ-Al 2 O 3. Thus, the stability of V Al − OIS − 3 is higher than that of V Al − TIS − 3 in both Al-rich and O-rich environments. However, when hydrogen atoms are introduced into γ-Al 2 O 3 , the stability of [V Al-TIS -H]−2 is higher than that of [V Al-OIS -H]−2 in the defective spinel γ-Al 2 O 3 structure, while the opposite is true for the non-spinel γ-Al 2 O 3 structure. The vibrational frequencies for OH− in [V Al-TIS -H]−2 and [V Al-OIS -H]−2 for defective γ-Al 2 O 3 are calculated to be 3608 cm−1 and 3374 cm−1, respectively, which is in excellent agreement with the infrared (IR) absorption peaks observed at ∼3500 and ∼3300 cm−1. The defective spinel model is more suitable for describing the γ-Al 2 O 3 structure. In defective spinel γ-Al 2 O 3 , there are many native Al vacancies, which are arranged in a straight line along the [ 2 1 ¯ 1 ¯ 0 ] direction. The migration barrier for H diffusion along these native Al vacancies is so low that these Al vacancies can provide a rapid diffusion channel for H. Thus, the permeability of H in γ-Al 2 O 3 is much higher than that in α-Al 2 O 3 leading to a lower permeation reduction factor (PRF). Our results can provide not only a sound theoretical explanation for the low PRF of γ-Al 2 O 3 but also a direction to improve the efficiency in preventing H permeation through FeAl/Al 2 O 3 tritium permeation barriers (TPBs). [ABSTRACT FROM AUTHOR]

The Sin Quyen deposit in northwestern Vietnam is composed of Fe-Cu-LREE-Au ore bodies hosted in Proterozoic metapelite. There are massive and banded replacement ores with variable amounts of monazite-(Ce) and chevkinite-(Ce) crystals, which have undergone fluid-induced alteration. Monazite-(Ce) and chevkinite-(Ce) were deposited from high-temperature fluids in the early ore-forming stage, but became thermodynamically unstable, and thus were altered to other phases in later ore-forming stages. The alteration of monazite-(Ce) formed a three-layered corona texture, which commonly has relict monazite-(Ce) in the core, newly formed fluorapatite in the mantle, and newly formed allanite-(Ce) in the rim. In some cases, the original monazite-(Ce) was completely consumed, forming a core of polygonal fluorapatite crystals rimmed by allanite-(Ce) crystals. The formation of allanite-(Ce) and fluorapatite at the expense of monazite-(Ce) indicates that the later-stage fluids had high Ca/Na ratios and relatively low temperatures. Chevkinite-(Ce) was variably replaced by an assemblage of allanite-(Ce) + aeschynite-(Ce) ± bastnäsite-(Ce) ± columbite-(Fe) ± ilmenite. The replacement of chevkinite-(Ce) by mainly allanite-(Ce) and aeschynite-(Ce) required low-temperature, Ca-, LREE-, and Nb-rich metasomatic fluids, probably with relatively low fO2. Mass-balance calculations were made to investigate the hydrothermal element mobility. It is assumed that Th was immobile during the alteration process of monazite-(Ce). Light (and middle) REE from La to Tb, U, As, and Ge were variably lost relative to Th, while heavy REE from Dy to Lu, HFSE (e.g., Nb, Ta, Zr, and Hf) and Sr were variably gained relative to Th. Regarding the alteration of chevkinite-(Ce), some major elements in chevkinite-(Ce), such as Ti, La, and Ce, were obviously removed from the system during alteration, whereas Ca, Al, Nb, U, and HREE were needed to be variably supplied by the metasomatic fluids. Concerning the hydrothermal mobility of trace elements, previous studies demonstrated that REE and HFSE can be commonly reserved in the system during alteration, consistent with the traditionally assumed immobile nature of these elements. In contrast, this study shows that REE and HFSE can be mobilized on at least the hundreds of micrometers scale. This may be related to the high flux and strong chemical reactivity of the metasomatic fluids. [ABSTRACT FROM AUTHOR]

In this paper, a numerical approach based on weighted Laguerre polynomials finite-difference time-domain (WLP-FDTD) method is proposed to analyze noise coupling in power/ground planes between package and printed circuit board (PCB). Compared to the traditional finite-difference time-domain (FDTD) method, which is limited by Courant–Friedrich–Lecy stability condition, the proposed method has the unconditionally stable characteristic. Examples of a ball grid array package mounted on a PCB were simulated, and the numerical results show that the computation time of the proposed WLP-FDTD method can be 4.4% of that of the FDTD method at the same accuracy condition. Therefore, the proposed method has higher efficiency than the conventional FDTD method without sacrificing precision. [ABSTRACT FROM AUTHOR]

The mechanism of sputtering due to cluster impacting which has been widely studied is an important but unsolved problem. In present research, we discuss the effect of the landing point on the sputtering with the method of molecular dynamics. The results show that the landing points play significant roles on sputter yield when the temperature of target is low. Specific landing points can cause particular sputtering patterns which lead to different sputtering yield and moving directions of sputtered atoms. The mechanism of this phenomenon is that specific landing keeps symmetries and anisotropies of target lattice, which influence the sputtering yield. [ABSTRACT FROM AUTHOR]

There remains a challenge for elegantly designing structurally simple but multi-signal fluorescence probes to visualize simultaneously various intracellular redox species and microenvironmental parameters. Herein we present such a design in the small probe COU-Mito featuring the graft of a strong electron-withdrawing 4-pyridiniumylacrylonitrile unit to an electron-donating diethylamino coumarin. The introduction of the cyano group destroys the coplanarity of the total push-pull π-conjugation system, thus the probe exhibits very weak background red fluorescence but a turn-on response to increased viscosity which restricts the rotation of the molecular rotor between the push and pull parts around a single bond. More importantly, the introduction of the cyano group together with the 4-pyridinium moiety improves significantly the electrophilicity of the carbon-carbon double bond in the probe that allows selective oxidative cleavage and nucleophilic addition on the double bond by peroxynitrite (ONOO-) and sulfur dioxide (SO 2), respectively. Hence the probe, whilst superficially simple, is in fact a multifunctional probe capable of simultaneously discriminating viscosity, ONOO- and SO 2 in a fashion of three sets of distinct signals: red for viscosity, green for ONOO-, and blue for SO 2. The probe was successfully employed to visualize the change of mitochondrial viscosity and the fluctuation of mitochondrial ONOO- and SO 2 levels in living cells and zebrafish, and to probe into their roles in the hepatotoxicity induced by acetaminophen, a widely used analgesic and antipyretic drug. [Display omitted] • Imaging of viscosity, ONOO- and SO 2 in red, green and blue channels, respectively. • Excellent sensitivity and fast response toward ONOO-. • Imaging of mitochondrial ONOO-, SO 2 and viscosity in living cells and zebrafish. • Visualizing the toxicity mechanism of acetaminophen. [ABSTRACT FROM AUTHOR]

The interactions between dust and plasma-facing material (PFM) relate to the lifetime of PFM and impurity production. Series results have been obtained theoretically and experimentally but more detailed studies are needed. In present research, we investigate the evolution of kinetic, potential and total energy of plasma-facing material (PFM) in order to understand the dust/PFM interaction process. Three typical impacting energy are selected, i.e., 1, 10 and 100 keV/dust for low-, high- and hyper-energy impacting cases. For low impacting energy, dust particles stick on PFM surface without damaging it. Two typical time points exist and the temperature of PFM grows all the time but PFM structure experience a modifying process. Under high energy case, three typical points appear. The temperature curve fluctuates in the whole interaction process which indicates there are dust/PFM and kinetic/potential energy exchanges. In the hyper-energy case in present simulation, the violence dust/PFM interactions cause sputtering and crater investigating on energy evolution curves. We further propose the statistics of energy distribution. Results show that about half of impacting energy consumes on heating plasma-facing material meanwhile the other half on PFM structure deformation. Only a small proportion becomes kinetic energy of interstitial or sputtering atoms. [ABSTRACT FROM AUTHOR]

The biochemical and enzymatic properties of four highly similar rice oxalate oxidase proteins (OsOxO1–4) were compared after their purification from the leaves of transgenic plants each overexpressing the respective OsOxO1–4 genes. Although alignment of their amino acid sequences has revealed divergence mainly in the signal peptides and they catalyze the same enzymic (oxalate oxidase) reaction, divergence in apparent molecular mass, K m , optimum pH, stability and responses to inhibitors and activators was uncovered by biochemical characterization of the purified OsOxO1–4 proteins. The apparent molecular mass of oligomer OsOxO1 was found to be similar to that of OsOxO3 but lower than the other two. The molecular mass of the subunit of OsOxO1 was lower than that of OsOxO3. The K m value of OsOxO3 was higher than the other three which had similar K m . OsOxO1 and OsOxO4 possessed peak activity at pH 8.5 which was close to that at the optimum pH 4.0. The activity of OsOxO2 at pH 8.5 was only 65% of that at its optimum pH 3.5, while the activity of OsOxO3 did not vary much at pH 6–9 and was also much lower than that at its optimum pH 3. OsOxO2 and OsOxO3 still maintained all their activities after being heated at 70 °C for 1 h while OsOxO1 and OsOxO4 lost about 30% of their activities. Pyruvate and oxaloacetic acid inhibited the activity of OsOxO3 more strongly than the other three. Interestingly, glucose 6-phosphate, fructose 6-phosphate and fructose 1,6-biphosphate related to photosynthetic assimilation of triose phosphate greatly increased the activities of OsOxO3 and OsOxO4. In addition to the differences in the biochemical properties of the four OsOxO proteins, an intriguing finding is that the purified OsOxO1–4 exhibited substrate inhibition, which is a typical of the classical Michaelis–Menten enzyme kinetics exhibited by a majority of other enzymes. [ABSTRACT FROM AUTHOR]

Seeking for an available thermal runaway solution is becoming one important and challenging issue in current nanometer ICs. Thermoelectric coolers (TECs) may give a solution. In this paper, a simplified power model of circuits closely associated with temperature with and without repeaters is derived. Based on the surface temperature difference and heat-flow density, an equivalent thermal resistance model for powered TECs is proposed. According to the thermal profile model, the steady-state temperature is calculated for the same chip with two different package forms. Finally, optimizations of p-n couples are performed with the purpose of obtaining the maximum coefficient of performance (COP) and minimum TECs power. As compared with the traditional flip-flop controlled-collapse-chip-connection package, the results reveal desirable conclusions that a 15.8% decrease of the chip stability temperature with the COP optimization at $I =2.5$ A and 11.4% steady-state power savings with the 13.2 W TEC power consumption are obtained in a 50-nm technology node. Analysis demonstrates that the maximum COP and minimum power consumed by TECs can be obtained at different optimum numbers of p-n couples, which is independent of electrical current across by TECs. [ABSTRACT FROM AUTHOR]

In present research, the sputtering and reflection yield of self-bombardment of tungsten are investigated with the aid of molecular dynamics simulations. The source of sputtered and reflected atoms is detected by traced the original locations of sputtered and reflected atoms. Results show that for the reflected atoms no specific region exists which means cluster atoms are randomly reflected. But almost all of sputtered atoms are from a conical region under the landing point of cluster. So we can determine the sputtering yield by study the dimension of the sputtering region. Molecular dynamics shows the depth and radius of the conical are power functions of impacting energy. The effects of cluster size and temperature of target on sputtering and reflection rate are also preformed in present study. Both sputtering and reflection yield are proportion to cluster size in present cluster size, i.e. 66–2647 atoms. Higher target temperature can increase sputtering yield and deduce sputtering threshold energy, but little effect on reflection rate. [ABSTRACT FROM AUTHOR]

Molecular dynamics (MD) simulations have been performed to investigate the diffusion behavior of helium (He) clusters in tungsten (W), because their diffusion properties provide basic knowledge in understanding the He bubble formation. The binding energy between He and He cluster is shown to be positive, and thus, He is easy to form bubbles by self-trapping. The mean squared displacements (MSDs) were employed to determine the diffusivities of He clusters with different sizes at different temperatures. The He bubble formation at different temperatures with 1% He was also investigated. It is revealed that the formation of He bubbles is strongly associated with the temperature and the diffusivities of the He clusters in W. The results demonstrate the initial stage of the He bubble formation and growth in W. [ABSTRACT FROM AUTHOR]

Abstract: Molecular dynamics simulations have been performed to investigate the interactions between helium (He) and defects in tungsten (W). The binding energy between He and He cluster is shown to be positive, which increases with increasing He cluster size. Both the W self-interstitial atoms (SIAs) and the vacancy can promote the He cluster formation. The binding energies of a He, a vacancy and an SIA W to a He–vacancy cluster (He nVm ) in W are also investigated, which depend on the n/m ratio. According to these results, we propose the formation and growth mechanism of He bubbles, which involves the procedures of He–vacancy cluster formation, the capturing of vacancies, then He atoms, and vacancies again. The mechanism provides a good reference to understand the initial stage of the He bubble formation and growth in W. [Copyright &y& Elsevier]

The development of modern industry puts forward higher and higher re quire me nts to engine e rs ' comprehensive practical ability. Engineering training is indispensable in training qualified talents. In order to improve the quality of the engineering training courses and foster the students ' ability of engineering practice, this paper considers the innovative consciousness, and the teamwork spirit. It summarizes achievements of Engineering Training center of Jilin University in the practice of teaching reform, and points out problems in engineering training of the engineering students. This paper puts forward some measures and suggestions from changing concept, talent reserves, constructing cascade engineering training system, reforming teaching methods and other aspects that for the reform of the practice teaching. It promotes the development of teaching quality of engineering training. [ABSTRACT FROM AUTHOR]

A new dinuclear manganese complex, [Mn2L2(N3)2], was prepared by reaction of bis-Schiff baseN,N'-bis(5-fluoro-2-hydroxybenzylidene)ethane-1,2-diamine (H2L) with manganese acetate and sodium azide in methanol. Both the Schiff base and the complex were characterized by physico-chemical methods and single crystal X-ray determination. The Schiff base crystallized in the orthorhombic space groupPbcawith unit cell dimensionsa?=?7.3191(7)?Å,b?=?6.0948(6)?Å,c?=?35.382(3)?Å,V?=?1578.3(3)?Å3,Z?=?4,R1?=?0.0481,wR2?=?0.1488. The manganese complex crystallized in the monoclinic space groupP21/cwith unit cell dimensionsa?=?8.802(1)?Å,b?=?14.928(2)?Å,c?=?14.478(2)?Å,??=?105.517(2)°,V?=?1833.0(4)?Å3,Z?=?2,R1?=?0.0768,wR2?=?0.1640. There are crystallographic inversion centers in both the ligand and the complex. The ligand coordinates to Mn through all the phenolate oxygens and imino nitrogens. The two Mn in the complex are bridged by two phenolate oxygens with separation of 3.549(1)?Å. Each Mn is octahedral with four donors of the Schiff base ligand defining the equatorial plane, and with one azido nitrogen and one phenolate oxygen of an adjacent Schiff base ligand occupying the axial positions. The Schiff base and the complex were testedin vitrofor their antibacterial activities. [ABSTRACT FROM AUTHOR]

Abstract: The Sanshandao gold deposit (reserves of more than 200t Au and average grade of 3.96g/t), located at northwestern edge of the Jiaodong Peninsula, eastern North China Craton, is one of the largest gold deposits in the Jiaodong gold province. In this deposit, disseminated- and stockwork-style ores are hosted in Mesozoic granitoids; mineralization and alteration are largely controlled by the regional Sanshandao–Cangshang fault. Host granitic rocks for the deposit display a complex paragenetic sequence of alteration and mineralization. Activities of the Sanshandao–Cangshang fault created structurally controlled permeability allowing for infiltration of hydrothermal fluids, leading to diffusive K-feldspar alteration on the two fault planes. Later, large scale diffusive sericitization symmetrically developed across the main fault, and partially overprinted the earlier K-feldspar alteration. Following the sericitization, relatively small scale silicification occurred, but now it is only retained in the hanging wall of the main fault. Subsequently, the fault gouge formed as a “barrier layer”, which is impermeable for later fluids to move upward. After that, strong pyrite–sericite–quartz alteration occurred only in the footwall of the main fault, and was accompanied by gold precipitation. The last stage carbonation and quartz-carbonate veins marked the waning of gold-related hydrothermal activity. Mass-balance calculations indicate complex behaviors of different types of elements during fluid–rock interaction. Most major elements were affected by intensive mineral replacement reactions. As expected, the fluid-mobile elements, LILE and LREE, generally show moderate to high mobility. It is notable that even the commonly assumed fluid-immobile elements, such as HREE and HFSE, tend to be changed to various degrees. In addition, Y–Ho, Zr–Hf and Nb–Ta fractionations are observed in altered domains. Studies on alteration assemblages and fluid inclusions suggest that the ore-forming fluids were characterized by low salinity (≤8.4wt.% NaCl equiv.), moderate temperature (300–400°C), weakly acidic (pH: 3–5), and relatively reducing (log f O2: ~–28) characteristics. In this type of fluids, gold was most likely transported as Au(HS)2 − complex. With alteration going on, log (a K +/a H +) of fluids generally decreased due to significant formation of secondary K-bearing minerals. In addition, there might be a decrease of f O2 from pre-gold alteration stage to the main gold mineralization stage, and decrease of f O2 was probably one of the factors controlling gold precipitation. The Sr and Nd isotopic compositions of hydrothermal minerals, combined with previous H–O and He–Ar isotopic studies, indicate that the hydrothermal fluids were mainly derived from crustal sources (e.g., degassing of felsic magmas and meteoric water), but with involvement of mantle derived components. The gold mineralization event just coincided with reactivation of the North China Craton, as marked by asthenosphere upwelling, voluminous igneous rocks, and high crustal heat flow, which may have provided sufficient heat energy and fluid input required for the formation of the gold deposits. [Copyright &y& Elsevier]

[Display omitted] • Hydrothermal zircon is identified in the Bayan Obo REE deposit for the first time. • Dating of hydrothermal zircon yielded an age of ~1.3Ga for the Bayan Obo deposit. • Substantial LREE depletion and Th/U fractionation are two discriminative features for hydrothermal zircon. The Bayan Obo deposit in China hosts the largest REE resource in the world. However, the genesis of this deposit is still highly debated, largely due to a lack of consensus on the mineralization age. The Banyan Obo deposit has experienced intensive post-ore metamorphic and metasomatic overprints, so it is crucial to choose robust chronometers to determine the primary mineralization age. In this study, zircon is identified in the REE ore of the Bayan Obo deposit. The zircon grains are in contact with or contain inclusions of hydrothermal minerals (e.g., magnetite, biotite, monazite, allanite, apatite and ilmenorutile). They have variable Th contents (14 to 1139 ppm) and are poor in U (<0.8 ppm), consistent with the Th-rich and U-poor feature of the Bayan Obo REE ore. Moreover, they have substantially low contents of light REE (La to Nd; LREE), which may be due to zircon coprecipitation with LREE-rich monazite and allanite. The combined textural and compositional features imply a hydrothermal origin of the zircon grains. The hydrothermal zircon grains have a weighted mean 208Pb-232Th age of 1297 ± 13 Ma, which places a direct constraint on the timing of REE mineralization at Bayan Obo. Notably, substantial LREE depletion and Th/U fractionation have not been documented before for hydrothermal zircon from other environments, and thus they could be taken as discriminative features for hydrothermal zircon from carbonatite-related REE deposits. Thorium-lead dating was also conducted on monazite from the zircon-bearing sample, yielding 208Pb-232Th ages (993 to 319 Ma) variably younger than that of zircon. The younger monazite Th-Pb ages could have resulted from disturbance of the Th-Pb isotopic system during post-ore modification process. Similarly, monazite has younger Th-U-Pb dates than zircon in many other geologically-complicated carbonatites or REE deposits. Such a phenomenon implies that the zircon Th-U-Pb chronometer is robust even if the host-rocks have experienced intensive modification, whereas monazite Th-U-Pb chronometer is more susceptible to modification. Therefore, younger Th-U-Pb dates of monazite should be interpreted with caution as they may record the timing of post-ore modification event or represent partial resetting, and hence geologically meaningless results. [ABSTRACT FROM AUTHOR]

It has been suggested to use LiNbO3:Fe, Mn crystal for solving the problem of information volatility during the read-out process with all-optical facilities, but the minute order response time is far from the requirements for the real-time information processing. We present the nonvolatile holographic storage properties of LiNbO3:Hf, Fe, Mn. The response time is shortened to 5.0 s, and the sensitivity S' is enhanced to 0.22 cm/J in this triply doped crystal. The experimental results show that the HfO2 doping threshold is 5.0 mol.%. Thus it seems that we have found a useful tetravalent dopant for LiNbO3:Fe, Mn that can obviously improve the nonvolatile holographic recording sensitivity. [ABSTRACT FROM AUTHOR]

Abstract: We have constructed W–He and H–He analytical bond-order potentials for a W–H–He system. In combination with the previously self-developed W–H potential [X.-C. Li, X. Shu, Y.-N. Liu, F. Gao, G.-H. Lu, J. Nucl. Mater. 408 (2011) 12] and the Hartree–Fock-dispersion pair potential (Aziz-potential) for He−He interactions, we demonstrate that such potentials behave well for reproducing various properties of the W–H–He system such as defect formation energies, structural properties, and diffusion barriers. Such potentials can be employed to model both the He behaviours and the H–He synergetic effects in the W–H–He system. [Copyright &y& Elsevier]

Abstract: The Gushan granite, located in the Jiaobei terrane of the eastern North China Craton, carries mafic microgranular enclaves (MMEs) and zoned K-feldspar phenocrysts, and is a typical example of magma generation and evolution in an extensional setting. Here we present whole rock major and trace element geochemistry, Sr–Nd isotopes and zircon U–Pb and Hf isotope data on the granite and its enclaves. The granite was emplaced at ∼120Ma. It is high in SiO2, K2O+Na2O, LILE and LREE, but low in MgO and HFSE. The granite are also marked by high initial 87Sr/86Sr (0.7103) and low ε Nd(t) (−18.5 to −18.9) and zircon ε Hf(t) (−16.6 to −22.0) values. These features indicate that the host granite was mainly derived from ancient North China Craton lower crust. Field, petrographic and compositional studies indicate that MMEs are products of mafic–felsic magma interactions in the generation of the granite in the relatively late magmatic history. Available data suggest that enriched lithospheric mantle was a suitable candidate for the mafic magma end-member involved in the magma interaction process. Internal Sr–Nd isotopic variations within K-feldspar phenocrysts are also evaluated to decipher the magmatic history. In spite of a protracted cooling history and evidence of subsolidus alteration, the K-feldspar phenocrysts preserve marked primary Sr–Nd isotopic variations: initial 87Sr/86Sr ratios increase from the cores (0.7100–0.7102) to rims (0.7105–0.7110), whereas ε Nd(t) values show decrease from the cores (−17.7 to −20.5) to rims (−21.1 to −27.0). The overall isotopic profiles across the K-feldspar phenocrysts are consistent with a continuous magma contamination process. Highly negative Nd isotopic values of some K-feldspar rims suggest that the Precambrian basement rocks in the upper crust are potential candidates for the contaminant. These results indicate that isotopic heterogeneity could be preserved within single crystal from much older, slower cooled plutonic rocks, and those isotopically zoned minerals are effective recorders of open magma system. Based on petrographic, geochemical and isotopic studies, we envisage multiple magmatic pulses, mafic–felsic magma interaction, and continuous assimilation during the formation of the Gushan granite. A model involving lithospheric thinning and mantle–crust interaction in an extensional setting is proposed to account for the generation of the Gushan granite and its enclaves. [Copyright &y& Elsevier]

As the feature size of integrated circuits shrinking in deep submicron technologies, time delay, and crosstalk noise of complementary metal-oxide-semiconductor (CMOS)-gate-driven interconnects become critical issues. Traditionally, CMOS driver is simplified as a linear circuit in which a constant resistance is used to approximate the nonlinear and time-varying MOS resistance, which is inaccurate for signal integrity analysis in high-speed interconnect systems. This paper proposes a finite-difference time-domain (FDTD)-based method for transient analysis of lossy transmission lines in the presence of the nonlinear behavior of CMOS gates. The conventional FDTD with second-order accuracy is used for interconnect analysis and the parameters with frequency-dependent losses are also included. The nonlinear behavior of CMOS gates is represented by alpha-power law model, with the drain current described by piecewise linear function of the drain voltage and discretized in time domain for the FDTD implementation. Explicit forms of the boundary conditions are derived from the implicit interface equations and hence the stability is strictly constrained by Courant condition. Experimental results show that the proposed method has good accuracy and high efficiency with respect to HSPICE. Therefore, it is useful for accurate prediction of time delay and crosstalk noise in high-speed interconnect systems. [ABSTRACT FROM PUBLISHER]

Abstract: We construct modified W–H and W–W analytical bond-order potentials for a W–H system. In combination with Brenner’s H–H potential, we demonstrate that such potentials can reproduce energetics and structural properties of W and W–H systems, including defect formation energies, surface energies and diffusion barriers as well as melting point determined from first-principles or experiments. The present potentials can be employed for modelling the behaviour of H in W containing defects such as vacancies and surfaces. [Copyright &y& Elsevier]

Abstract: The influence of uniform flow on the pattern formation is investigated in a two-dimensional reaction–diffusion system. It is found that the convective flow plays a key role on pattern modulation. Both traveling and stationary periodic patterns are obtained. At moderate flow rates, the perfect hexagon, phase-shifted hexagon and stable square, which are essentially unstable in unperturbed reaction–diffusion systems, are obtained. These patterns move downstream. If the flow rate is increased further, the stationary flow-oriented stripes develop and compete with the spots. If the flow rate exceeds some critical value, the system is convectively unstable and the stationary stripes prevail against the traveling spots. The above patterns all have the same critical wavenumber associated with Turing bifurcation, which indicates that Turing instability produces the patterns while the flow induces the symmetry reduction, i.e., from six-fold symmetry to four-fold one, and to two-fold one ultimately. [Copyright &y& Elsevier]

In this article, a discontinuous Galerkin time-domain (DGTD) method hybridized with Robin transmission condition (RTC-DGTD) is proposed for the transient thermal analysis of 3-D integrated circuits (ICs). As a kind of domain decomposition method (DDM), the DGTD method employs a term named numerical flux for the information exchange of solutions between neighboring subdomains. The numerical flux is a function of both temperature $T$ and heat flux q, and thus for the heat equation, apart from $T$ , the variable q has to be solved as well. To reach this, the traditional DGTD method decomposes the second-order partial-differential thermal equation into two first-order ones, which results that both $T$ and q need to be solved in the whole computational domain, thereby the computational cost is extremely expensive. In this work, to get this trouble-treated, the proposed DGTD method is directly applied to discretize the second-order heat equation. An RTC is established at the interfaces of subdomains, which serves as the second governing equation and meanwhile bridges another connection of solutions in adjacent subdomains. In this way, the new variable q is now only present at the interfaces of subdomains. Consequently, the total number of unknowns is significantly reduced compared with that in the traditional DGTD method. To further speed up the time-marching scheme, an adaptive time-stepping method in terms of the proportional–integral–derivative (PID) control algorithm is employed. Besides, by introducing a restriction operator, the globally coupled matrix equation is torn into a number of small matrix equations pertinent to each subdomain, which is later solved via a finite-element tearing and interconnecting (FETI)-like method. To validate and verify the accuracy and efficiency of the proposed algorithm, several representative examples are studied and compared with COMSOL simulations. [ABSTRACT FROM AUTHOR]

The destruction of the North China Craton (NCC) is a well‐known dynamic event in the Mesozoic, but the western NCC, with only few magmatic activities, has lacked studies so far. The Zijinshan alkaline complex, tectonically located at the western part of the NCC and the eastern edge of Ordos Block/Basin, is one of the most typical alkaline intrusions during the NCC destruction, and consists of monzonite, aegirine–augite syenite, nepheline syenite, pseudoleucite phonolite and trachyte porphyry. Geochronological, geochemical and in situ Sr–Nd–Hf isotopic analyses were performed on the various lithologies, in order to reveal the magma sources, petrogenesis and possible geodynamic processes. Zircon and titanite U–Pb dating shows that the Zijinshan complex was emplaced at ~130 Ma. The main rocks are enriched in light rare earth elements (LREEs) and large‐ion lithophile elements (LILEs; such as Rb, Ba, K, Sr), and depleted in heavy rare earth elements (HREEs) and high‐field‐strength elements (HFSEs; such as Th, U, Nb, Ta, Ti), without negative Eu anomaly. In addition, the obviously enriched and inhomogeneous Sr–Nd isotopic components occurred among the various lithologies, implying the primary magma of Zijinshan complex may originate from a deep mixed source. Specifically, the monzonites of Zijinshan complex come from the partial melting of the enriched lithospheric mantle with participation of crustal materials. Meanwhile, the nepheline syenites and alkaline volcanics originated from the enriched lithospheric mantle mixing with the depleted asthenosphere‐derived compositions. During the NCC destruction, continuous asthenospheric upwelling resulted in several times of mixing of melts from asthenospheric mantle, lithospheric mantle and lower crust in different proportions, and then the mixed magma of each episode migrated upward to the shallow part to form the Zijinshan pluton. [ABSTRACT FROM AUTHOR]

Abstract: Molecular dynamics simulations were performed to investigate the interaction between H and vacancy in W using an analytical bond-order potential to describe the interactions between W–W, W–H and H–H. The most stable configuration for H in W is the tetrahedron interstitial site. We calculated the binding energies of an H and a vacancy to an H-vacancy cluster (H n V m ) in W, respectively, where n and m ranged from 0 to 10. The binding energy was almost unchanged. The binding energy of a vacancy to H-vacancy cluster is about 0.4eV, which is higher than the binding energy of an H to H-vacancy cluster. Vacancy is much easier to bond with H-vacancy cluster than H. And H is easier to stay in the tetrahedron interstitial site or octahedron interstitial site in bcc W. [Copyright &y& Elsevier]

In this study, we applied historical matching and self-analogism methods, as well as laboratory physical-mechanics tests, to study the evolution mechanism of the collapse-slide-flow slide at the waste dump on the slope of the chair-shaped gully, as well as the evolution mechanism of the subsequent debris flow. Our analyses indicate that (1) an excessive fine particle content results in a relatively large specific surface area and further enhances water retention performance, (2) rainfall infiltration was concentrated at the contact surface between chair-shaped valley and bottom of the bulk, and (3) with high-intensity continuous rock discharge during the snow and ice period, a mixed frozen body of ice waste stone particles forms, such that ice melting in the spring leads to a sudden change in the shear strength near the contact interface between the waste rock pile foundation and the bulk. Dual effects, essential internal factors, i.e., shear strength and water retention, induced external factors, i.e., ice-freezing skeleton-melting structure collapse, and the chimney effect drive the slope toe of the waste dump. The weak interface of the Quaternary base gradually penetrates the interior of the dumping body, beginning to form from a single-stage traction landslide and evolving into a multi-stage rotary landslide. The sliding surface is characterized by the shear outlet at the front edge of the slope toe, quaternary base interface, and nearly vertical and steep trailing edge. During this movement, gasification on the sliding surface and particle rotation lead to long run-out sliding, which magnifies the scope of disaster. [ABSTRACT FROM AUTHOR]