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Radio astronomy plays a very important role in promoting scientific progress and unraveling the mysteries of the universe. However, radio telescopes are inevitably affected by radio frequency interference (RFI) when receiving radio signals, which leads to a reduction in data quality and has a serious impact on the formation of correct scientific conclusions. Therefore, it is essential to identify the RFI present in the observational data. In order to effectively identify RFI, improve the existing RFI identification methods that suffer from missed detections, and enhance the performance of RFI identification, this paper proposes a novel method that combines a dual cross-attention mechanism with multi-scale feature fusion. Experimental studies were conducted using the observational data from the 40-meter radio telescope at the Yunnan Astronomical Observatory of the Chinese Academy of Sciences. The proposed method achieved scores of 92.49%, 83.90%, and 87.99% in terms of precision, recall, and F1−score, respectively. It outperformed existing methods (U-Net, RFI-Net, R-Net6, RFI-GAN, EMSCA-UNet) in recalland F1−score, effectively reducing the occurrence of missed detections and improving the overall performance of radio frequency interference identification.

Abstract

Multiphase flow through porous media is important in a wide range of environmental applications such as enhanced oil recovery and geologic storage of CO2. Recent in situ observations of the three-phase contact line between immiscible fluid phases and solid surfaces suggest that existing models may not fully capture the effects of nanoscale surface textures, impacting flow prediction. To better characterize the role of surface roughness in these systems, spontaneous and forced imbibition experiments were carried out using glass capillaries with modified surface roughness or wettability. Dynamic contact angle and interfacial speed deviation, both resulting from stick-slip flow conditions, were measured to understand the impact these microscale dynamics would have on macroscale flow processes. A 2kfactorial experimental design was used to test the ways in which the dynamic contact angle was impacted by the solid surface properties (e.g., wettability, roughness), ionic strength in the aqueous phase, nonaqueous fluid type (water/Fluorinert and water/dodecane), and the presence/absence of a wetting film prior to the imbibition of the wetting phase. The analysis of variance of spontaneous imbibition results suggests that surface roughness and ionic strength play important roles in controlling dynamic contact angle in porous media, more than other factors tested here. The presence of a water film alone does not affect dynamic contact angle, but its interactions with surface roughness and aqueous chemistry have a statistically significant effect. Both forced imbibition and spontaneous imbibition experiments suggest that nanoscale textures can have a larger impact on flow dynamics than chemical wettability. These experimental results are used to extend the Joos and Wenzel equations relating apparent static and dynamic contact angles to roughness, presence of a water film, and water chemistry. The new empirical equation improves prediction accuracy by taking water film and aqueous chemistry into account, reducing error by up to 50%.

LTCBDE combined with or without modified techniques is safe and efficacious for the management of gallstones and concomitant, even large, common bile duct (CBD) stones. To describe the surgical indications and procedure strategies of laparoscopic transcystic common bile duct exploration (LTCBDE), a retrospective analysis of 205 patients with concomitant gallstones and CBD stones treated using LTCBDE between June 2008 and June 2015 was performed. Clinical data on disease characteristics, methods for cystic duct incision and CBD stone extraction (with or without laser lithotripsy), and surgical outcomes were collected and reviewed. CBD stones were successfully cleared in all patients. No patient was converted to choledochotomy or laparotomy. The cystic duct diameter ranged 3–8 mm, and 85 patients with cystic duct diameter ≥ 5 mm. The mean time for CBD stone extraction was 25.3 min, with the operative time ranged from 63 to 170 min. Lithotripsy was used in 74 (36.1%) patients among which 26 patients with cystic duct diameter ≥ 5 mm. Estimated blood loss during surgery was 10–120 ml per patient, and no intra-operative blood transfusions were needed. The mean postoperative hospital stay was 5.1 (range 3–7) days, and postoperative complications developed in seven patients. No bile duct injury, stricture, remnant, recurrent stones, or other adverse events were observed during the mean follow-up of 8 months. Based on preoperative MRCP and intra-operative IOC findings about cystic duct diameter, the diameter of CBD, CBD stone size, we summarized and proposed the surgical indications and suitable techniques and strategies during LTCBDE.

Abstract

A field campaign (29 May to 14 June 2018) was conducted at a mountain site in central China. The chemical composition of non‐refractory submicron particulate matter (NR‐PM1) and the particle number size distribution (PNSD) were measured, respectively. The mean NR‐PM1mass concentration was 20.94 ± 10.14 μg m−3, among which organics (47%) was the most abundant component, followed by sulfate (37%), ammonium (11%), nitrate (4%), and chloride (1%). Notably, sulfate accounted for more than 70% of the secondary inorganic aerosols. Positive matrix factorization (PMF) analysis of the composition data resulted in three organic aerosol (OA) factors: hydrocarbon‐like OA (HOA), oxygenated OA I (OOA‐I), and oxygenated OA II (OOA‐II). The secondary organic aerosol (SOA) composed of the latter two factors (SOA: OOA‐I + OOA‐II) was dominant in OA (80.7%). The PMF analysis of the PNSD data yielded three factors: new particle formation related mode, growth mode, and accumulation mode, among which the last factor dominated both number and volume ratios. The sulfate formation was characterized by the sulfur oxidation ratio (SOR), heterogeneous sulfate production rate (Phet), and gaseous sulfuric acid concentration, representing secondary sulfate transformation, heterogeneous reactions, and gas phase reactions, respectively. The results showed that Phetwas well correlated with both sulfate concentrations and SOR, especially during the polluted periods. Our study demonstrates that photochemically‐driven heterogeneous reactions contribute dominantly to the sulfate formation and SOA is formed predominantly by photochemical oxidation of volatile organic compounds under high temperatures and ultraviolet (UV) intensities, and NOXconcentrations on Mt. Wudang during the campaign period. In this study, the chemical composition and size distribution of submicron aerosols were measured at a mountain site in central China (Mt. Wudang), and the sources as well as controlling factors were further investigated. Our results reveal that photochemical reactions play an important role in both sulfate and secondary organic aerosol formation. For sulfate, heterogeneous reactions were dominant during the polluted periods, whereas gas‐phase reactions are more pronounced during the clean periods. Organics and sulfate account for more than 80% mass concentration of submicron aerosols on Mt. WudangHeterogenous reactions lead to sulfate formation on Mt. Wudang during the polluted periodsSecondary organic aerosol was mainly formed by photochemical reactions on Mt. Wudang Organics and sulfate account for more than 80% mass concentration of submicron aerosols on Mt. Wudang Heterogenous reactions lead to sulfate formation on Mt. Wudang during the polluted periods Secondary organic aerosol was mainly formed by photochemical reactions on Mt. Wudang

Genome-wide association studies have revealed a large number of genetic-risk loci for many autoimmune diseases. One clear finding emerging from the published genetic studies of autoimmunity is that different autoimmune diseases share susceptibility loci. Recent evidence has demonstrated that UBASH3Agene was associated with multiple autoimmune diseases. The aim of this study was to explore the association between UBASH3Asingle-nucleotide polymorphisms (SNPs) and atopic dermatitis (AD) in a Chinese Han population. In total, three UBASH3ASNPs (rs11203203, rs3788013 and rs1893592) were genotyped using TaqMan genotyping assays in a Chinese Han population (1012 cases and 1362 controls). Among these SNPs, we selected the SNP rs1893592 with association values of P<5 × 10−2for AD in the TaqMan genotyping assay data for further replication in the independent Chinese replication samples (1080 cases and 1367 controls) using a Sequenom MassARRAY system. We combined the association results in two stages using meta-analysis. We found that rs1893592 in UBASH3Ashowed association with AD (P=1.29 × 10−3, odds ratio=1.16). These results showed that UBASH3Agene SNP is associated with susceptibility to AD. Further fine mapping and functional studies will be required to identify true causal variant in the UBASH3Agene and its exact role in the pathogenesis of AD.

The purpose of this paper is to discuss the application of mSOFCs to mobile robots. A typical robotic device for consumer applications contains a 1kWh battery which runs down with time. This battery requires swapping or lengthy recharging after each shift. The purpose of this paper is to discuss battery extension by adding an mSOFC generator running on propane. This keeps the battery at a high voltage, removing deep discharge problems, while giving a factor 5 longer running time with rapid turnaround because the on-board propane tank can be changed or refilled in 1 minute. An international research project was initiated in 2016 to develop these ideas under the heading PERT (PODS: Extending Robot Traction). This paper describes results from the project and shows that mSOFCs operating on small mobile robots can give substantial benefits in several applications.

ABSTRACTSquash is a non-climacteric fruit, so the release of ethylene plays a limited role in the ripening process; however, there is a large accumulation of abscisic acid (ABA) during fruit maturation and ripening. To investigate the contribution of ABA in squash fruit development, the CpNCED1gene, which encodes the key enzyme in ABA biosynthesis (9-cis-epoxycarotenoid dioxygenase [NCED]), was cloned from squash fruit, and its transcriptional regulation during fruit development, dehydration and pollination was analysed using a quantitative reverse transcription polymerase chain reaction (qRT-PCR). The expression of CpNCED1peaked 20 days after full bloom (DAFB) in the pulp and seed, and 25 DAFB in the peel, all of which corresponded with the accumulation of ABA. The application of exogenous ABA increased the expression of CpNCED1and the release of ethylene, thereby promoting fruit ripening. The expression of CpNCED1was also induced by dehydration stress and pollination. These findings show that ABA plays important roles in squash fruit ripening, and in the plant’s response to dehydration stress and early fruit set via the transcriptional regulation of CpNCED1.

The Mingantu Ultrawide Spectral Radioheliograph (MUSER) is a synthetic-aperture radio interferometer built in Ming'antu, Inner Mongolia, China. As a solar-dedicated interferometric array, the MUSER can produce high-quality radio images in a frequency range of 400 MHz-15 GHz with high temporal, spatial, and spectral resolution. Implementing of the data processing system for the MUSER is a major challenge to performing high-cadence imaging in wideband and obtaining more than two orders of higher multiple frequencies. There is an urgent need to build a pipeline for processing the massive amount of MUSER data generated each day. In this article, we present a high-performance distributed data processing pipeline (DDPP) built on the OpenCluster infrastructure for processing MUSER observational data, including data storage, preprocessing, image reconstruction, deconvolution, archiving, and real-time monitoring. We comprehensively elaborate the system architecture of the pipeline and the implementation of each subsystem. The DDPP is automatic, robust, scalable, and manageable. The processing performance under a parallel CPU/GPU hybrid system meets the requirements of MUSER data processing.

The propagation characteristics of a focused laser beam in a SBN:75 photorefractive crystal strongly depend on the signal-to-background intensity ratio (R=I_s/I_b) under reverse external electric field. In the range 20>R>0.05, the laser beam shows enhanced self-defocusing behavior with increasing external electric field, while it shows self-focusing in the range 0.03>R>0.01. Spatial solitons are observed under a suitable reverse external electric field for R=0.025. A theoretical model is proposed to explain the experimental observations, which suggest a new type of soliton formation due to “enhancement” not “screening” of the external electrical field.

Non-halogen flame retarded polyethylene (PE) can be prepared by filling metallic hydroxides magnesium hydroxide (MH) or aluminium hydroxide (ATH), the mechanical properties of polymer composites will decline greatly when filling much more inorganic particles. Selecting microencapsulating particles, suitable synergistic agents or compatibilizers are good methods for improving the combination performance of composites. In this study, microencapsulated red phosphorous (MRP) was synthesized by using melamine-formaldehyde resin through in-situ polymerization, and used as a synergistic agent of MH and ATH, and the best proportion of three flame retardants was studied in detail. Results showed that flame retarded PE had a better combination performance when filling with 45 wt% compound flame retardants of MRP, MH and ATH under the weight ratio of 46/46/8. In order to improve the mechanical performance of composite, two polymeric compatibilizers POE-g-MAH and EPDM-g-MAH were selected to toughen the flame retarded PE composite. Results showed the flame resistance and mechanical properties of composites improved greatly with an increase of compatibilizer content, under the same condition, POE-g-MAH has a better contribution on the flame resistance and EPDM-g-MAH has a better toughening effect. The best flame retarded PE composite can be obtained by filling with 45 wt% compound flame retardants and 10 wt% EPDM-g-MAH.

The main contribution of this article is the proposal of a path-following method for fixed-wing unmanned aerial vehicles. This path-following method employs the multi-loop framework that consists of an outer guidance loop and an inner control loop. The guidance loop relies on the idea of tracking a virtual target. The virtual target is assumed to travel along the defined path and its speed is explicitly specified. This guidance law guarantees the asymptotic convergence to the desired path and can anticipate the transition of the flight path in advance, which reduces the command for the inner control loop. In the inner control loop, the flight control law based on dynamic surface control is derived to overcome the ‘explosion of complexity’ problem in the backstepping design. The numerical simulation result illustrates the effectiveness of the proposed method.

OBJECTIVE: To explore the relationships between serum concentrations of tissue inhibitor of metalloproteinase-2 (TIMP-2) and matrix metalloproteinase-2 (MMP-2), and severity of liver fibrosis in chronic hepatitis B. METHODS: A total of 101 patients with hepatitis B and 54 healthy control subjects were consecutively enrolled. Serum MMP-2 and TIMP-2 were quantified by enzyme-linked immunosorbent assay. RESULTS: Serum MMP-2 concentrations in patients with stage F2 – F4 fibrosis were significantly higher than in patients with stage F0 – F1 fibrosis and control subjects, but no significant difference was found between patients with stage F0 – F1 fibrosis and control subjects. Significant differences in serum TIMP-2 concentrations were found between patients with stages F2 – F4 and F0 – F1 fibrosis, and between stages F0 – F1 fibrosis and healthy control subjects. Areas under the receiver operating characteristic curves of serum TIMP-2 and MMP-2 for predicting clinically significant fibrosis (stage F2 – F4) were 0.899 and 0.770, respectively. CONCLUSION: Serum TIMP-2 and MMP-2 assessment may represent a valuable noninvasive diagnostic test for liver fibrosis in hepatitis B.

Knowledge on the C:N ratio of crop residues is of great importance for modelling carbon (C) and nitrogen (N) dynamics of agricultural systems. This study determined (i) the C:N ratios in the seed, straw, and roots of selected broadleaf crops and (ii) the root C and N distribution in the 0–100cm rooting zone. Three oilseed (Brassica napus canola, Brassica juncea mustard, Linum usitatissimum flax), three pulse crops (Cicer arietinum chickpea, Pisum sativum dry pea, Lens culinaris lentil), and spring wheat (Triticum aestivum L.) were grown under field conditions with low- (rainfall only) and high-water (rainfall plus irrigation) availability. Root C mass decreased substantially with rooting depth, with ~58% of root C mass in the top 20cm of the soil, 78% in the top 40cm, and 94% in the top 60cm. Significant differences in root C mass between crop species occurred in the top 20cm with canola, mustard, and wheat allocating 66% of their root C total, compared with 55% for dry pea, lentil, and flax, and 41% for chickpea. Root N mass followed a similar response to root C. Seed C:N ratios ranged between 6 and 17, whereas straw C:N ranged between 14 and 55, and root C:N between 17 and 75. Under low-water conditions, canola and mustard had a straw C:N of 33, lower than that of flax (38) and wheat (41). Under higher-water availability, however, mustard and wheat had straw C:N ratios at 55, greater than canola, mustard and flax (47). Three pulses had an average straw C:N ratio of 17, significantly lower than 41 for the oilseeds and 32 for wheat. On average, canola, mustard and wheat had greater root C:N ratios (44) than chickpea (33) and lentil (29), with dry pea having a smallest root C:N ratio (18). Root C:N ratios did not change with soil depth. These detailed measurements on the vertical distribution of root C and N as well as C:N ratios for various crops will assist in improving estimates of inputs for C and N cycling studies.

The Square Kilometre Array (SKA) project is an international cooperation project to build the largest radio telescope worldwide. Data processing is one of the biggest challenges of building the SKA telescope. As a distributed execution framework, the Data Activated Liu Graph Engine (DALiuGE) was proposed to be one of the candidates for addressing the massive data of the SKA. DALiuGE has many distinctive features, but its actual ability to handle scientific data is still not clear. In this paper, we perform an objective evaluation of the usability of DALiuGE for the execution performance, developer workload, and implementation difficulty of porting the SAGECal to DALiuGE. The evaluation results show that the DALiuGE enables fast integration of astronomical software, but there are significant differences in the efficiency of different parallel granularities. Even with the deep optimization of the program, there is still a gap between the current DALiuGE and the traditional MPI in execution performance. Therefore, we come to a preliminary conclusion that the DALiuGE has no performance advantage in batch processing of massive data. At the same time, it may be more suitable for application scenarios with more customized computational tasks, such as SKA science regional centers.

A series of 1‐phenylisoquinoline derivatives encapsulated with peripheral arylamines as dendrons are synthesized by using the Ullmann reaction and palladium‐catalyzed aromatic carbon–carbon Suzuki‐coupling reactions. Red‐emitting dendritic iridium complexes (called G1‐1, G1‐2, and G2) are synthesized using the following derivatives: N,N‐diphenyl‐3′‐isoquinolin‐4‐biphenylaniline, N,N‐di(9,9‐dimethylfluorenyl‐3′‐isoquinolin‐4‐biphenylaniline, N,N‐di(4′‐di(2′‐(9′,9′‐dimethylfluorenyl)amine)biphenyl‐3′‐isoquinolin‐4‐biphenylaniline as the first ligands and 5‐methyl‐3‐(pyridin‐2′‐yl)‐1H‐1,2,4‐triazole as an ancillary ligand. The obtained dendrimers are soluble in common organic solvents, and uniform thin films can be spin‐coated from such solutions. Devices fabricated from dendritic iridium complexes G1‐2and G2 with a small molecule host are fabricated by spin‐coating from chloroform solution in different device configurations. G1‐2and G2show similar device performances with maximum external quantum efficiencies (EQEs) of 12.8 % and 11.8 % (photons/electron) and luminous efficiency of 9.2 cd A–1and 8.5 cd A–1at 0.1 mA cm–2, respectively. Devices based on polymer host poly(9,9‐dioctylfluorene)(PFO) (30 % PBD (2‐(4‐biphenyl)‐5‐(4‐tert‐butylphenyl‐1,3,4‐oxadiazole)) show a slightly higher efficiency for G1‐2, with a maximum EQE of 13.9 % at a much higher current density of 6.4 mA cm–2and luminance of 601 cd m–2.

Black Carbon (BC) may significantly affect nutrient retention and play a key role in a wide range of biogeochemical processes in soils, especially for nutrient cycling. Anthrosols from the Brazilian Amazon (ages between 600 and 8700 yr BP) with high contents of biomass‐derived BC had greater potential cation exchange capacity (CEC measured at pH 7) per unit organic C than adjacent soils with low BC contents. Synchrotron‐based near edge X‐ray absorption fine structure (NEXAFS) spectroscopy coupled with scanning transmission X‐ray microscopy (STXM) techniques explained the source of the higher surface charge of BC compared with non‐BC by mapping cross‐sectional areas of BC particles with diameters of 10 to 50 μm for C forms. The largest cross‐sectional areas consisted of highly aromatic or only slightly oxidized organic C most likely originating from the BC itself with a characteristic peak at 286.1 eV, which could not be found in humic substance extracts, bacteria or fungi. Oxidation significantly increased from the core of BC particles to their surfaces as shown by the ratio of carboxyl‐C/aromatic‐C. Spotted and non‐continuous distribution patterns of highly oxidized C functional groups with distinctly different chemical signatures on BC particle surfaces (peak shift at 286.1 eV to a higher energy of 286.7 eV) indicated that non‐BC may be adsorbed on the surfaces of BC particles creating highly oxidized surface. As a consequence of both oxidation of the BC particles themselves and adsorption of organic matter to BC surfaces, the charge density (potential CEC per unit surface area) was greater in BC‐rich Anthrosols than adjacent soils. Additionally, a high specific surface area was attributable to the presence of BC, which may contribute to the high CEC found in soils that are rich in BC.

One of the difficulties in understanding energy transfer in bilayer quantum dot structures is the complex role of carrier tunneling. This limitation is due to the fact that, for most studies to date, QDs in each layer have only one confined energy level making it difficult to study resonant tunneling effects. In this work, we have investigated the low growth-rate technique to produce dislocation-free very large QDs in the second layer that are characterized by several confined energy levels. The high quality surface morphology and optical behavior of these structures were demonstrated by AFM and PL measurements. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

With a cleaving technique and Ar-ion etching, we make ultra-thin bridges from Bi2Sr2CaCu2O8+xsingle crystals. Superconductivity can be observed in the bridges only a few unit cells thick. A superconductor-insulator transition occurs when the thickness is lower than 4.5 nm. The two-dimensional nature of the superconducting transition is examined in these ultra-thin samples. We see deviations from the usual Kosterlitz-Thouless-type behaviour and discuss a possible explanation.

Silicate is polymerized in the presence of chitosan to form novel silica−chitosan nanoparticles in weakly acidic solution under ambient conditions. Both the turbidity of the silica solution and the average hydrodynamic diameter of the silica nanoparticles increased dramatically after the addition of chitosan. The initial stage of silica formation closely observed fourth-order kinetics. The latter transformation of colloidal nanoparticles approximated an exponential growth pattern during slow aggregation. Chitosan did not significantly change the rate of silica synthesis and the size of the individual nanoparticles, but it facilitated an aggregation of the composite nanoparticles by 1 order of magnitude faster than for pure silica nanoparticles. Scanning electron microscopy revealed that the composite nanoparticles grew in three dimensions and became clusters and aggregates within a shorter time. Atomic force microscopy demonstrated that the composite nanoparticles increased from as small as 1 nm to 32 nm after a reaction time of 1 and 24 h, respectively. X-ray diffraction, infrared spectroscopy, and elemental analysis confirmed that these nanoparticles were amorphous composites of silica and chitosan. Synthesis of silica with chitosan provided a facile way of preparing composite silica nanoparticles with improved functional properties.

Summer fallow (fallow) is still widely used on the North American Great Plains to replenish soil moisture between crops. Our objective was to examine how fallowing affects soil organic carbon (SOC) in various agronomic and climate settings by reviewing long‐term studies in the midwestern USA (five sites) and the Canadian prairies (17 sites). In most soils, SOC increased with cropping frequency though not usually in a linear fashion. In the Canadian studies, SOC response to tillage and cropping frequency varied with climate—in semiarid conditions, SOC gains under no‐till were about 250 kg ha−1yr−1greater than for tilled systems regardless of cropping frequency; in subhumid environments, the advantage was about 50 kg ha−1yr−1for rotations with fallow but 250 kg ha−1yr−1with continuous cropping. Specific crops also influenced SOC: Replacing wheat (Triticum aestivumL.) with lentil (Lens culinarisMedikus) had little effect; replacing wheat with lower‐yielding flax (Linum usitatismumL.) reduced SOC gains; and replacing wheat with erosion‐preventing fall rye (Secale cerealeL.) increased SOC gains. In unfertilized systems, cropping frequency did not affect SOC gains, but in fertilized systems, SOC gains often increased with cropping frequency. In a Colorado study (three sites each with three slope positions), SOC gains increased with cropping frequency, but the response tended to be highest at the lowest potential evaporation site (where residue C inputs were greatest) and least in the toeslope positions (despite their high residue C inputs). The Century and the Campbell et al. SOC models satisfactorily simulated the relative responses of SOC although they underestimated gains by about one‐third.

The fate of fertilizer P in soil during crop production has to be determined to evaluate the long‐term economic value and sustainability of fertilizer practices. We assessed changes in soil test P and soil P fractions with continuous P fertilization and soil P depletion under continuous corn (Zea maysL.) in a Ste. Rosalie clay soil (humic Gleysol; fine, mixed, frigid, Typic Humaquept). Soil samples were analyzed for Mehlich‐3 P (M‐3 P) and P fractions using a modified Hedley's procedure. Soil M‐3 P values remained constant in spite of crop removal in soil not receiving fertilizer for 10 yr. Continuous P fertilization at rates from 44 to 132 P ha−1yr−1increased linearly soil M‐3 P, with 6.3 kg P ha−1of net P addition required to increase M‐3 P by 1 mg P kg−1Residual fertilizer P in soil resulted from the continuous P addition were found predominately in labile inorganic P (LPi) (NaHCO3–Pi) and moderately labile Pi(MLPi) (NaOH‐Pi). Increased P rates favored soil P transformation from LPito MLPi, indicating enhanced soil P retention. With P depletion, soil M‐3 P declined in plots previously receiving 132 kg P ha−1yr−1, with 4.2 kg P ha−1crop P removal decreasing soil M‐3 P by 1 mg P kg−1Continuous crop removal of soil residual P (Res‐P) resulted in decreases in soil LPiand increases in MLPi, an indication of increased retention of Res‐P with time. However, moderately stable Pi(HCl‐Pi) remained constant, both with continuous P addition and P depletion. Conversion of residual fertilizer P to less available P forms in soil was a slow process and thus the fate of the Res‐P should be taken into consideration when developing soil nutrient management plans.

A novel thiourea-based C2-symmetric ligand was synthesized, and its application in the palladium-catalyzed Heck and Suzuki coupling reactions of arenediazonium salts was evaluated. The reactions, which were performed at room temperature, without added base, and under aerobic conditions, produced product in 4 h with good yield. The corresponding arenediazonium salts were easily generated in one step from anilines.

Si/(Pt/Co/Pt) modulated multilayers (MLs) have been prepared by magnetic sputtering method with Si layer thickness dSi varying from 0 to 16 Å. We found that the intercalating of Si between Pt layers in Pt/Co MLs could cause a strong interdiffusion of Si atoms into Pt layer, Pt–Co interfaces and Co layers. The effective saturation magnetization Ms of the Pt/Co MLs changes slightly when Si thickness is less than about ~7 Å. When the Si layer thickness is larger than ~7 Å, formation of Co silicides at interfaces and in the Co layers leads to sharp decrease of the effective saturation magnetization Ms of the multilayers. The effective perpendicular magnetic anisotropy constant Ku eff is more sensitive to the interface structure and it drops monotonically with increasing Si thickness due to the intermixing of the atoms at the interfaces. The coercivity Hc also decreases with increasing the Si layer thickness due to the decrease of the perpendicular magnetic anisotropy. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Fluorescent analogues (DB1 and TA1) of the secondary metabolites didemnin B (DB) and tamandarin A (TA) were synthesized to investigate the potential chemical defense mechanisms of tunicates in the family Didemnidae. These compounds were found to alter predator−prey relations. Five species of freshwater fish and one marine fish, the damselfish Amphiprion ocellaris, were acclimated to a diet of mosquito larvae. Fish showed an immediate, negative reaction to mosquito larvae treated with ≥5 ng of DB1 or TA1, with consumption of larvae resulting in regurgitation. Both freshwater and marine fish learned to avoid tainted prey by associating species of larvae with “distaste”. Distaste for a given organism also arose when depsipeptides DB1 or TA1 were transferred to the fish from the surrounding medium. Fluorescence microscopy in fish indicated that a similar processing and localization followed ingestion and absorption of DB1 or TA1. Fluorescent labeling of DB or TA provided an ideal tool to conduct short-term studies of predator−prey relationships between fish and marine invertebrate larvae.

It is well known that railway vehicles with conventional rigid wheelsets can experience problems of unstable running which in extreme circumstances may lead to derailment. Uncoupling the two wheels across each axle dramatically reduces the instability known as hunting but can lead to an impairment in the natural curving ability of the wheelset. However if wheels on the same axle are driven independently through a suitable control system, improved curving performance as well as good stability may be achieved.

Computer simulation of electric motor operation is particularly useful for gaining an insight into their dynamic behaviour and electro-mechanical interaction. A suitable model enables motor faults to be simulated and the change in corresponding parameters to be predicted without physical experimentation. This paper presents both a theoretical and experimental analysis of asymmetric stator and rotor faults in induction machines. A three-phase induction motor was simulated and operated under normal healthy operation, with one broken rotor bar and with voltage imbalances between phases of supply. The results illustrate good agreement between both simulated and experimental results. [Copyright &y& Elsevier]

Laser-ablated chromium, molybdenum, and tungsten atoms react with discharged sulfur vapor during cocondensation in excess argon. On the basis of the metal isotopic splittings, ³⁴S isotopic substitution, and mixed ³²S + ³⁴S experiments, the primary reaction product MS2 molecules are identified. The S−M−S bond angles in the MS2 molecules are determined from isotopic frequencies as 115° ± 4°, 114° ± 3°, and 114° ± 8° for M = Cr, Mo, and W, respectively. Other reaction products, including CrS, CrS3, and WS3, are also characterized. DFT calculations using both B3LYP and BPW91 functionals produce consistent results for the Mo and W compounds and are in excellent agreement with experimental frequencies. For chromium sulfides, the BPW91 functional calculations give satisfactory results.

Laser-ablated titanium, zirconium, and hafnium atoms react with discharged sulfur vapor during co-condensation in excess argon. The primary reaction product MS2 molecules are identified for the first time, and evidence for metal monosulfides is also presented. The ν1 and ν3 modes for TiS2, ZrS2, and HfS2 absorb at 533.5 and 577.8 cm^-1, 502.9 and 504.6 cm^-1, and 492.2 and 483.2 cm^-1, respectively, in solid argon. On the basis of the isotopic frequencies for the ν3 modes, the bond angles of TiS2, ZrS2, and HfS2 are determined as 113 ± 4°, 107 ± 4°, and 108 ± 4°. DFT/B3LYP calculations predict ¹A1 ground states and bond angles of 113.3°, 108.5°, and 109.5°, for the MS2 molecules, M = Ti, Zr, and Hf, respectively, and frequencies in excellent agreement with the observed values. The same calculation also predicts ³Δ ground states for TiS and ZrS, the ¹Σ⁺ ground state for HfS, and frequencies in agreement with the observed values.

Laser-ablated vanadium, niobium, and tantalum atoms react with discharged sulfur vapor during co-condensation in excess argon. The primary reaction products are metal disulfides, while evidence for metal monosulfides is found. The ν1 and ν3 modes for VS2, NbS2, and TaS2 in argon matrices are observed at 527.8 and 583.5 cm^-1, 525.1 and 531.0 cm^-1, 523.4 and 516.5 cm^-1, respectively. On the bases of the isotopic ν3 vibrations, the bond angles of VS2, NbS2, and TaS2 are estimated to be 113 ± 3°, 107 ± 3°, and 107 ± 3°. DFT calculations have been performed on the metal sulfides and disulfides, and excellent agreement between the observed and calculated frequencies supports the product identifications.

Laser-ablated Os and Ru atoms react with CO2 molecules upon cocondensation in excess argon at 7 K and neon at 4 K. Besides the dominant neutral products [OMCO, O2MCO (M = Os, Ru), O2Os(CO)2, and OCRu(O2)CO], anionic species [OMCO^- (M = Os, Ru)] are also formed and identified through annealing, ultraviolet irradiation, isotopic substitution, and CCl4-doping experiments. DFT calculations have been performed on possible products, and the overall agreement between the calculated and observed vibrational absorptions supports the product identifications.

Laser-ablated thorium atoms react with discharged sulfur vapor during co-condensation in excess argon at 7 K. The ThS fundamental is observed at 474.7 cm^-1, and the ν1 and ν3 modes for ThS2 are observed at 451.4 and 431.5 cm^-1, respectively, based on sulfur-34 substitution and infrared spectra of sulfur 32, 34 mixtures. Sulfur isotopic ν3 vibrational frequencies for ThS2 indicate a 112 ± 5° upper limit for the S−Th−S bond angle. Quasirelativistic DFT calculations performed on ThS and ThS2 find that ThS has the ¹Σ⁺ ground state, and ThS2 has the ¹A1 ground state with a bond angle of 111.6°. Calculated vibrational frequencies are in excellent agreement with the observed values, and support this first identification of molecular thorium sulfides.

The growth kinetics of the bacterium Thiobacillus thiooxidans (HSS) was investigated and its metabolic acidic solution was used to bioleach phosphate rock. The bacterium HSS adsorbs on the surface of elemental sulfur particle and oxidizes sulfur to sulfuric acid to provide itself energy. The equilibrium between attached cells on sulfur surface and unattached cells in solution can be described with the Langmuir isotherm equation. The maximum adsorption capacity XAM is 7.310 × 10¹² cells/kg of sulfur and the equilibrium constant KA is 2.9110 × 10^-14 M³/cell. In a batch growth process, the specific growth rate of the bacteria on sulfur, μA, and the growth yield, YA, are 2.874 day^-1 and 8.455 × 10¹⁴ cells/kg of S, respectively. The bacterium shows the highest activity to oxidize sulfur at 30 °C. The dilute microbiological acid solutions produced by HSS were used to dissolve fluorapatite ore. The digestion conversions of phosphorus ranged from 24% to 100%. Fluorine ion contained in fluorapatite ore shows a significant effect on the biological activity of HSS.

Previous studies of people's perceptions of intergenerational communication in many countries around the Pacific Rim suggest that aspects of intergenerational communication in some East Asian nations may be more problematic than in some Western ones. This study extends the earlier work by considering similarities and differences between Taiwanese and American young adults' perceptions of communication with same-age peers and adults 65 years of age and older. As well, in an attempt to discover how the acculturation process may affect intergenerational relations, the perceptions of young Chinese-Americans were also examined. Two-hundred and three participants (including 98 Taiwanese, 47 Euro-Americans, and 59 Chinese-Americans) completed a questionnaire that assessed their perceptions of accommodation and nonaccommodation from members of the two age groups. Also assessed was the extent to which the participants felt deferential towards and avoidant of communication with these two age groups, as well as the experience of positive emotions in these interactions. Consistent with earlier work, young adults were more positive with regards to communication with other younger adults than with older adults, and Euro-Americans generally perceived interactions more positively than people in Taiwan. The Chinese-Americans were similar to the Taiwanese in some respects and similar to the Euro-Americans in others.

Co-deposition of laser-ablated metals with NO in excess neon at 4 K produced new 1060.8 ± 0.4 and 1052.6 ± 0.2 cm^-1 absorptions, which almost disappear on annealing to 9 K and reappear in part on ultraviolet irradiation. These absorptions shift with ¹⁵N¹⁶O and ¹⁵N¹⁸O substitution as fundamental N−O vibrations and exhibit 1:2:1 triplet bands with ¹⁴N¹⁶O + ¹⁵N¹⁶O and ¹⁵N¹⁶O + ¹⁵N¹⁸O mixtures, which demonstrates the involvement of two equivalent NO oscillators. The above absorptions are assigned to N2O2^2- isolated and insulated from metal stabilizing cations in two solid neon matrix configurations. The blue shift from the 1028.5 cm^-1 solid argon band position for this species is larger than found for most small molecules and anions, which is consistent with a dianion. The photochemistry in laser-ablated gold experiments suggests the involvement of N2O2^- in electron-transfer processes to form N2O2^2-.

Laser-ablated rhenium atoms react with CO2 molecules upon co-condensation in excess argon at 7 K and neon at 4 K. Besides neutral products [OReCO, O2ReCO, ORe(CO)2, and O2Re(CO)2], anionic species [OReCO^-, ORe(CO)2^-] are formed and identified through annealing, ultraviolet irradiation, isotopic substitution, and CCl4 doping experiments. DFT calculations have been performed on all product species, and the very good overall agreement between the calculated and the observed vibrational frequencies supports the product identifications.

Adenosine A3 receptors are of interest in the treatment of cardiac ischemia, inflammation, and neurodegenerative diseases. In an effort to create a unique receptor mutant that would be activated by tailor-made synthetic ligands, we mutated the human A3 receptor at the site of a critical His residue in TM7, previously proposed to be involved in ligand recognition through interaction with the ribose moiety. The H272E mutant receptor displayed reduced affinity for most of the uncharged A3 receptor agonists and antagonists examined. For example, the nonselective agonist 1a was 19-fold less potent at the mutant receptor than at the wild-type receptor. The introduction of an amino group on the ribose moiety of adenosine resulted in either equipotency or enhanced binding affinity at the H272E mutant relative to wild-type A3 receptors, depending on the position of the amino group. 3‘-Amino-3‘-deoxyadenosine proved to be 7-fold more potent at the H272E mutant receptor than at the wild-type receptor, while the corresponding 2‘- and 5‘-amino analogues did not display significantly enhanced affinities. An 3‘-amino-N⁶-iodobenzyl analogue showed only a small enhancement at the mutant (Ki = 320 nM) vs wild-type receptors. The 3‘-amino group was intended for a direct electrostatic interaction with the negatively charged ribose-binding region of the mutant receptor, yet molecular modeling did not support this notion. This design approach is an example of engineering the structure of mutant receptors to recognize synthetic ligands for which they are selectively matched on the basis of molecular complementarity between the mutant receptor and the ligand. We have termed such engineered receptors “neoceptors”, since the ligand recognition profile of such mutant receptors need not correspond to the profile of the parent, native receptor.

As it is known, track transportation can be divided into track system above and track system below. While the train is moving, the parts above and below are subject to interaction and influence. The shortcoming of dynamic analysis in the past cannot usually reflect how the substructure of track including subgrade affects the running train. The analysis mentioned above indicates that the track damage involves not only the failure in strength of components but also the overdeformation or intolerable settlement of the system below track. So, in connection with the train running, taking track–subgrade as a part of vibration structure of the vehicle model, a vehicle–subgrade model of vertical coupled system has been presented. In this paper, the interactions between the vehicle running quality and the subgrade design parameters have been investigated in systematic concept and from the viewpoint of systematic matching.

During the total synthesis of the novel cyclic depsipeptide callipeltin A (1), the unit (3S,4R)-3,4-dimethylglutamine, was successfully synthesized by asymmetric Michael addition and subsequent electrophilic azidation. The key feature of this approach is the generation of three adjacent stereogenic centers using the same camphorsultam chiral auxiliary.