Search

The gas tungsten arc welding (GTAW) is a classic traditional welding method for aluminum alloys. However, the strong reflection of the welding area illuminated by arc light and the weld pool surface of aluminum alloy work piece determines the difficulty of making the visual sensor disturbed and sensitive during the welding process. The high sensitivity of aluminum alloys to heat input is the difficulty in determining the real-time and stability control of heat input adjustment. Online defect detection in aluminum alloy welding is significantly more difficult compared to materials like low-carbon steel. This paper focuses on intelligent technology in GTAW for aluminum alloys, specifically highlighting multi-information acquisition, defect prediction and quality control of weld formation, penetration state, and pore generation. Firstly, the paper reviews and discusses the development and application of multi-information sensing technology in aluminum alloy GTAW. Subsequently, different modeling methods for defect prediction related to penetration, weld formation, and porosity defects are summarized and compared. Additionally, the application of intelligent control methods in the aluminum alloy welding process is categorized. Finally, existing scientific and technical issues and further research directions are proposed.

Sarcopenia and frailty are both age‐related declines in functional reserve that are linked to adverse health outcomes. It is critical to know about the outcomes of a combination of these conditions. The study aimed to investigate the effects of sarcopenia and frailty on postoperative recovery in elderly patients and to explore risk factors. This prospective cohort study was conducted among 608 patients aged ≥60 years, American Society of Anesthesiologists I‐III, who were scheduled to undergo thoracic (non‐cardiac) and abdominal surgery from 1 March 2022 to 31 October 2022 at the Affiliated Hospital of Xuzhou Medical University. Frailty was measured by the 28‐item frailty index, and sarcopenia was assessed sarcopenia was assessed by skeletal muscle index in computed tomographic scan, handgrip strength and 6‐m walk. Participants were classified as follows: Group A: both sarcopenia and frailty; Group B: sarcopenia only; Group C: frailty only; and Group D: neither frailty nor sarcopenia. The primary outcome was 90‐day morbidity. Multivariable logistic regression model was used to estimate the association between sarcopenia, frailty and 90‐day morbidity. The median (interquartile range) age of participants was 68 (64–72) years, and 62.7% were men. The prevalence rates of sarcopenia and frailty were 32.8% and 47.6%, respectively. The 90‐day morbidity in Group A was 58.5%, in Group B was 46.2%, in Group C was 42.0% and in Group D was 28.8%, and the difference was significant (P< 0.001). In the multivariable analysis, both sarcopenia and frailty [odds ratio (OR), 2.21; 95% confidence interval (CI), 1.26–3.89], sarcopenia only (OR, 1.84; 95% CI, 1.01–3.36), frailty only (OR, 1.77; 95% CI, 1.03–3.03), women (OR, 0.67; 95% CI, 0.45–0.99), body mass index (OR, 0.94; 95% CI, 0.88–0.99), pre‐operative albumin (OR, 0.96; 95% CI, 0.91–1.00) and operative stress score (OSS) [OSS 3 (OR, 2.09; 95% CI, 1.21–3.67); OSS 4–5 (OR, 3.81; 95% CI, 2.31–6.42)] were independently associated with 90‐day morbidity. In the multivariable analysis with inverse probability weighting adjusted cohort, sarcopenia and frailty were also significantly associated with 90‐day morbidity. Sarcopenia and frailty were associated with higher risks of postoperative 90‐day morbidity in elderly patients alone and in combination. Sex, body mass index, pre‐operative albumin and operative stress were also independent factors for postoperative morbidity within 90 days.

Wireless signal recognition driven by artificial intelligence (AI) plays a pivotal role in 6G ultrareliable wireless communications, facilitating spectrum surveillance to impede illegal radio interference. As a promising wireless technique, multicarrier waveform recognition (MWR) has been explored to enhance the reliability of wireless data transmission. However, existing works fail to achieve reliable recognition accuracy under strong noise. It remains a daunting task for MWR in signal-to-noise ratio (SNR) regimes. To deal with this issue, we propose a denoised cyclic autocorrelation-based multimodality fusion network (DCA-MFNet). Specifically, we first leverage the cyclic autocorrelation (CA) transformation to convert intercepted signals into CA features in cyclic frequency domains, which have the robust property of being insensitive to low SNR. Next, the singular value decomposition method is employed to weaken the strong noise effects on useful CA peak values. Based on the denoised CA matrix (DCAM), the projection accumulation strategy is proposed to generate the time delay accumulation vector (TDV) and cyclic frequency accumulation vector (CFV), which can enlarge the discrimination among multicarrier signals. Finally, we fed the multimodality features of DCAM, TDV, and CFV into the developed DCA-MFNet to perform hierarchical learning, feature aggregation training, and multicarrier type prediction. Experimental results demonstrate that the proposed DCA-MFNet obtains better recognition performance than existing algorithms. Moreover, DCA-MFNet can effectively identify six multicarrier signals with a recognition accuracy of 100% at a low SNR of even −2 dB.

Introduction: The effects of deep neuromuscular block (DNMB) on chronic postsurgical pain (CPSP) have not been conclusively determined. Moreover, a limited number of studies have examined the impact of DNMB on long-term recovery quality after spinal surgery. We investigated the impact of DNMB on CPSP and the quality of long-term recovery in patients who had been subjected to spinal surgery. Methods: This was a randomized, controlled, double-blind, single-center study performed from May 2022 to November 2022. A total of 220 patients who underwent spinal surgery under general anesthesia were randomly assigned to receive either DNMB (post-tetanic count at 1–2) (the D group) or moderate NMB (MNMB) (train-of-four at 1–3) (the M group). The primary endpoint was the incidence of CPSP. The secondary endpoints included the visual analogue scale (VAS) score in the post-anesthesia recovery unit (PACU), at 12, 24, 48 h and 3 months after surgery; postoperative opioid consumption; quality of recovery-15 (QoR-15) scores on the second postoperative day, before discharge, and 3 months after surgery. Results: The incidence of CPSP was significantly lower in the D group (30/104, 28.85%) than in the M group (45/105, 42.86%) (p= 0.035). Besides, VAS scores were significantly reduced at the third month in the D group (p= 0.016). In the PACU and 12 h after surgery, VAS scores were also significantly lower in the D group than in the M group (p&lt; 0.001, p= 0.004, respectively). The total amount of postoperative opioid consumption (expressed in total oral morphine equivalents) was significantly less in D group than M group (p= 0.027). At 3 months after surgery, QoR-15 scores were significantly higher in D group than M group (p= 0.003). Conclusions: Compared with MNMB, DNMB significantly reduced CPSP and postoperative opioid consumption in spinal surgery patients. Moreover, DNMB improved the long-term recovery of patients. Trial Registration: Chinese Clinical Trial Registry (ChiCTR2200058454).

Incorporating inorganic components into organic molecular devices offers one novel alternative to address challenges existing in the fabrication and integration of nanoscale devices. In this study, using a theoretical method of density functional theory combined with the nonequilibrium Green’s function, a series of benzene-based molecules with group III and V substitutions, including borazine molecule and XnB3–nN3H6(X = Al or Ga, n= 1–3) molecules/clusters, are constructed and investigated. An analysis of electronic structures reveals that the introduction of inorganic components effectively reduces the energy gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital, albeit at the cost of reduced aromaticity in these molecules/clusters. Simulated electronic transport characteristics demonstrate that XnB3–nN3H6molecules/clusters coupled between metal electrodes exhibit lower conductance compared to prototypical benzene molecule. Additionally, the choice of metal electrode materials significantly impacts the electronic transport properties, with platinum electrode devices displaying distinct behavior compared to silver, copper, and gold electrode devices. This distinction arises from the amount of transferred charge, which modulates the alignment between molecular orbitals and the Fermi level of the metal electrodes by shifting the molecular orbitals in energy. These findings provide valuable theoretical insights for the future design of molecular devices incorporating inorganic substitutions.

BackgroundLow-pass genome sequencing (LP GS) is an alternative to chromosomal microarray analysis (CMA). However, validations of LP GS as a prenatal diagnostic test for amniotic fluid are rare. Moreover, sequencing depth of LP GS in prenatal diagnosis has not been evaluated.ObjectiveThe diagnostic performance of LP GS was compared with CMA using 375 amniotic fluid samples. Then, sequencing depth was evaluated by downsampling.ResultsCMA and LP GS had the same diagnostic yield (8.3%, 31/375). LP GS showed all copy number variations (CNVs) detected by CMA and six additional variant of uncertain significance CNVs (>100 kb) in samples with negative CMA results; CNV size influenced LP GS detection sensitivity. CNV detection was greatly influenced by sequencing depth when the CNV size was small or the CNV was located in the azoospermia factor c(AZFc) region of the Y chromosome. Large CNVs were less affected by sequencing depth and more stably detected. There were 155 CNVs detected by LP GS with at least a 50% reciprocal overlap with CNVs detected by CMA. With 25 M uniquely aligned high-quality reads (UAHRs), the detection sensitivity for the 155 CNVs was 99.14%. LP GS using samples with 25 M UAHRs showed the same performance as LP GS using total UAHRs. Considering the detection sensitivity, cost and interpretation workload, 25 M UAHRs are optimal for detecting most aneuploidies and microdeletions/microduplications.ConclusionLP GS is a promising, robust alternative to CMA in clinical settings. A total of 25 M UAHRs are sufficient for detecting aneuploidies and most microdeletions/microduplications.

Intracellular pH plays a crucial role in many cellular processes, and abnormal intracellular pH has been linked to common diseases such as cancer and Alzheimer's. To address this issue, a water-soluble fluorescent pH probe was designed based on the protonation/deprotonation of the 4-methylpiperazin-1-yl group, using dicyanoisophorone as the fluorophore. In the neutral form of the probe, fluorescence is quenched due to charge transfer from the 4-methylpiperazin-1-yl group to the fluorophore upon excitation. Under acidic conditions, protonation of the 4-methylpiperazin-1-yl group inhibits the photoinduced electron transfer process, leading to an increase in fluorescence intensity. Density-functional theory calculations also verified the fluorescence OFF–ON mechanism. The probe exhibits high selectivity, photostability, fast response to pH changes, and low cytotoxicity to cells. Additionally, the probe selectively accumulates in lysosomes, with a high Pearson coefficient (0.95) using LysoTracker Green DND-26 as a reference. Notably, the probe can monitor lysosomal pH changes in living cells and track pH changes stimulated by chloroquine. We anticipate that the probe has potential for diagnosing pH-related diseases.

A dual-regulation strategy of adopting B/N codoped carbon nanotube-encapsulated nickel nanoparticles (Ni@BNCNT) as a sulfur host and separator coating is proposed for high-performance Li-S batteries. On the cathode side, the 3D conductive network structure of Ni@BNCNT is favorable for high sulfur utilization, and the collaboration between polar metal Ni nanoparticles (NPs) and doped B/N elements facilitates the chemical adsorption of Li polysulfides (LiPSs). In addition, these metal Ni NPs exhibit a satisfactory catalytic effect on the polysulfide conversion. Moreover, using the Ni@BNCNT interlayer can further capture the soluble LiPSs, make them convert quickly, and prevent them from diffusing toward the anode side. The Li-S batteries simultaneously equipped with a S/Ni@BNCNT cathode and Ni@BNCNT interlayer show high reversible capacity and good cycle stability. Additionally, even at a sulfur loading of 3.5 mg cm−2and an electrolyte/sulfur ratio of 3 μL mg−1, excellent battery performance can be achieved. We believe that this work offers a new strategy based on combining a catalytic host and separator coating to construct high efficiency Li S batteries.

The transfer of excitation energy in photosynthetic light-harvesting complexes has inspired growing interest for its scientific and engineering significance. Recent experimental findings have suggested that spatially correlated environmental fluctuations may account for the existence of long-lived quantum coherent energy transfer observed even at physiological temperature. In this paper, we investigate the effects of spatial correlations on the excitation energy transfer dynamics by including a nonequilibrium initial bath in a simulated donor–acceptor model. The initial bath state, which is assumed to be either equilibrium or nonequilibrium, is expanded in powers of coupling strength within the polaron formalism of a quantum master equation. The spatial correlations of bath fluctuations strongly influence the decay of coherence in the dynamics. The role of a nonequilibrium initial bath is also influenced by spatial correlations and becomes the most conspicuous for certain degrees of spatial correlations from which we propose a picture that the spatial correlations of bath fluctuations open up new energy transfer pathways, playing a role of protecting coherence. Besides, we apply the polaron master equation approach to study the dynamics in a two-site subsystem of the FMO complex and provide a practical example that shows the versatility of this approach.

The shuttle effect of lithium–sulfur batteries (LSBs) caused by the dissolution and migration of lithium polysulfides (LiPSs) leads to rapid capacity decay of sulfur cathodes. Modifying the separator with a catalytic layer becomes an effective strategy to inhibit LiPS shuttling and promote the conversion kinetics of sulfur active materials. Herein, we propose a carbon nanotube (CNT)-encapsulation strategy to fabricate a composite of CoSe nanoparticles encapsulated in N-doped CNT (CoSe@NCNT). The as-prepared CoSe@NCNT is endowed with a full sulfiphilic surface to trap LiPSs by Co–S and Se–Li bonds and catalyze sulfur redox reactions (SRRs) of the discharge/charge processes. In addition, the encapsulated structure effectively inhibits the aggregation of CoSe nanoparticles and enables its persistent adsorption–catalysis ability on regulating the kinetics of SRRs. When equipped with a CoSe@NCNT catalytic interlayer, the LSB shows a high specific capacity of 768.3 mAh g–1at 2 C and superior cycle stability with the capacity decay rate of 0.06% per cycle over 1000 cycles at 1 C. In addition, when operated with an electrolyte/sulfur ratio of 5 μL mg–1, the modified battery with a sulfur loading of 4.0 mg cm–2delivers a specific capacity of 746.9 mAh g–1at 0.2 C. Our studies provide a CNT-encapsulation strategy to develop transition metal-based catalytic materials for high-performance LSBs.

To address the issues of poor electrical conductivity and volume expansion of SiO2, the composite SiO2/Co encapsulated in N-doped Carbon nanofibers is prepared in situ using an electrostatic spinning method followed a high-temperature treatment. Co nanoparticles exist as an elementary substance in the composite and improve the electrical conductivity of the composite, resulting in enhanced electrochemical performance. In addition, the N-doped carbon nanofibers wrap around the outside of SiO2/Co to form a conductive network, which improves the conductivity of the composite and alleviates the volumetric effects during the charge-discharge process. As expected, the prepared SiO2/Co@N-doped carbon nanofibers exhibit excellent rate performance, which can provide a very high discharge specific capacity of 1276 mA h g−1and 493 mA h g−1at current densities of 0.1 A g−1and 2 A g−1, respectively. The composite also has a long cycle life, with a reversible discharge capacity of 659 mA h g−1at 0.5 A g−1after 400 cycles, and 552 mA h g−1at 1 A g−1after 1000 cycles. Furthermore, a full-cell LiFePO4||SiO2|Co@N-doped carbon nanofibers can release a reversible capacity of 119 mA h g−1at 0.1C.

Background: Giant cell arteritis (GCA) is primarily treated with glucocorticoids (GCs), which have substantial toxicity. Tocilizumab, an interleukin-6-receptor inhibitor (IL-6Ri), showed beneficial effects in GCA, leading to its approval. This study investigated the efficacy and safety of sarilumab (another IL-6Ri) in GCA. Methods: This Phase 3, double-blind study comprised a 52-week treatment period and a 24-week follow-up phase. Eligible GCA patients were randomized to receive sarilumab 200 mg (SAR200 + 26W) or 150 mg (SAR150 + 26W) with a 26-week GC taper, or placebo with a 52-week (PBO + 52W) or 26-week (PBO + 26W) GC taper. The primary efficacy endpoint was sustained remission (SR) at week 52. Additional endpoints were SR at week 24, cumulative GC dose, and safety. The study was discontinued prematurely due to protracted recruitment timelines, because of the impact of COVID-19. Therefore, only descriptive statistics were summarized. Results: Of the planned 360 subjects, only 83 were randomized and 36 were included in the week 52 analysis. At week 52, 46% (n= 6/13) of patients in SAR200 + 26W, 43% (n= 3/7) in SAR150 + 26W, 30% (n= 3/10) in PBO + 52W, and 0 (n= 0/6) in PBO + 26W taper groups achieved SR. Sensitivity analyses, excluding acute-phase reactants from the SR definition, showed similar results for SAR groups, but 60% (n= 6/10) in PBO + 52W and 17% (n= 1/6) in PBO + 26W taper groups achieved SR at week 52. Similar findings were noted at week 24. The proportions of patients who adhered to GC taper from week 12 through week 52 in each group were as follows: 46% (n= 6/13, SAR200 + 26W), 43% (n= 3/7, SAR150 + 26W), 60% (n= 6/10, PBO + 52W), and 33% (n= 2/6, PBO + 26W). The median actual cumulative GC dose received in the SAR200 + 26W group was lower than other groups. Most patients (80–100%) experienced treatment-emergent adverse events, with similar incidences reported across groups. Conclusions: Owing to the small sample size due to the early termination, it is difficult to draw clear conclusions from this study. There were no unexpected safety findings. Trial registration: ClinicalTrials.gov NCT03600805. Registered on July 26, 2018.

The aliphatic Claisen rearrangement of allyl vinyl ether has attracted great interest for its broad applications in chemical synthesis and biosynthesis. Although it is well agreed that this reaction proceeds viaa concerted, “chair-like” transition state, certain inconsistencies of kinetic isotope effect (KIE) data between experimental measurements and theoretical simulations or between independent experiments indicate that the nature and mechanism of this important reaction need to be investigated in more detail. In order to verify two independent sets of experimental data, we present theoretical calculations on heavy-atom KIE values of alipahtic Claisen rearrangement, using our recently developed path-integral method with the second-order Kleinert’s variational perturbation theory, which goes beyond the traditional method for computing KIE values by employing the Bigeleisen equation. Amazingly, the results demonstrate that both sets of experimental measurements are correct, while the inconsistency originates from the fact that the aliphatic Claisen rearrangement undergoes similar but different mechanisms in gas and solution phases. Different experimental conditions will alter the actual reactant state by tuning the population distribution of reactant conformers. According to the comparison between experimental and theoretical results, a more clear reaction mechanism of aliphatic Claisen rearrangement is revealed.

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related deaths worldwide. Chemoresistance remains the major factor for limited efficacy of the HCC treatment. Thus, exploring the mechanisms underlying drug resistance is of great importance. Secretory clusterin (sCLU), a stressactivated and ATP-independent molecular chaperone, is up-regulated in numerous tumors and correlated with malignant phenotypes. For HCC, the implication of sCLU was previously addressed in tumor growth, metastasis, as well as early diagnosis and poor prognosis. Notably, accumulating studies have emphasized its vital role in drug resistance of HCC. Depletion of sCLU synergistically could enhance the sensitivity of HCC cells to a variety of chemotherapy agents. Herein, we summarized the potential mechanisms accounting for the sCLU-induced chemoresistance, including promoting apoptosis evasion, facilitating epithelial-mesenchymal transition (EMT), maintaining the viability of cancer stem cell (CSC), enhancing drug efflux capacity, and regulating autophagic activities. The current evidence suggest that targeting sCLU might be a promising approach in overcoming chemoresistance of HCC.

•Water Cycleprovides a type of Smart Articleentitled Novel Terms & Concepts.•Novel Terms & Conceptsfocus on defining novel or easily confused terms and concepts in the field of water .•A dedicated editorial team provide “butler service” to facilitate the writing process.

Here, we report a highly water‐soluble colorimetric and fluorescent pH probe that works in the pH range 0.2–3.0. The probe showed a rapid response, high stability, and excellent reversibility to acidity. Moreover, the fluorescence of probe was not influenced by the existence of high concentration of cations. The pKaof probe was calculated to be 2.25 ± 0.06. Furthermore, the pH test papers coated with the probe exhibited a distinct color change in acidic conditions. A highly water‐soluble colorimetric and fluorescent pH probe that works in the pH range 0.2–3.0 has been designed and investigated. The probe showed a rapid response, high stability, and excellent reversibility to acidity, and the probe has been successfully applied for the preparation of pH test paper.

RNA strand cleavage by 2′-O-transphosphorylation is catalyzed not only by numerous nucleolytic RNA enzymes (ribozymes) but also by hydroxide or hydronium ions. In experiments, both cleavage of the 5′-linked nucleoside and isomerization between 3′,5′- and 2′,5′-phosphodiesters occur under acidic conditions, while only the cleavage reaction is observed under basic conditions. An ab initiopath-integral approach for simulating kinetic isotope effects is used to reveal the reaction mechanisms for RNA cleavage and isomerization reactions under acidic conditions. Moreover, the proposed mechanisms can also be combined through the experimental pH-rate profiles.

High-performance piezoresistive sensors have the potential for human health monitoring applications. However, the conductive ink should add adhesive to ensure the hydrophobic carbon-based conductive material uniformly, which decrease the sensitivity. We fabricated a piezoresistive sensor without any adhesive polymer by introduced multi-walled carbon nanotubes (MWCNTs) and carbon black (CB) into the skeletons of the melamine sponge (MS) via a simple hydrothermal method. Due to the crosslinking effect, the microporous structure and strong adsorption of the of conductive MWCNTs and CB, the MWCNTs@CB sensor exhibits excellent performance: a sensitivity of 48.26 kPa−1in the working range of 12.5 kPa–20 kPa, a response time of 15 ms, an low detection limit of 20 Pa, and performance stability (>250,000 loading cycles). This MWCNTs@CB flexible pressure sensor can detect physiological motions.

Optimizing the characteristics of granular activated carbon (GAC) can improve the performance of biologically activated carbon (BAC) filters, and iodine value has always been the principal index for GAC selection. However, in this study, among three types of GAC treating the same humic acid-contaminated water, one had an iodine value 35% lower than the other two, but the dissolved organic carbon removal efficiency of its BAC was less than 5% away from the others. Iodine value was found to influence the removal of different organic fractions instead of the total removal efficiency. Based on the removal and biological characteristics, two possible mechanisms of organic matter removal during steady-state were suggested. For GAC with poor micropore volume and iodine value, high molecular weight substances (3500–9000 Da) were removed mainly through degradation by microorganisms, and the biodegraded organics (soluble microbial by-products, < 3500 Da) were released because of the low adsorption capacity of activated carbon. For GAC with higher micropore volume and iodine value, organics with low molecular weight (< 3500 Da) were more easily removed, first being adsorbed by micropores and then biodegraded by the biofilm. The biomass was determined by the pore volume with pore diameters greater than 100 µm, but did not correspond to the removal efficiency. Nevertheless, the microbial community structure was coordinate with both the pore structure and the organic removal characteristics. The findings provide a theoretical basis for selecting GAC for the BAC process based on its pore structure.

Based on the annual production data collected by the Statistic Center of the Ministry of Railways of the People’s Republic of China, we calculated the energy saving and direct emission reductions of CO2, soot, SO2, CO, NOxand CnHmof electrified railways, and analyzed their dynamic characteristics during the period of 1975–2007. The results show that during this period, the annual mean values of energy saving is 1.23×106tce, and direct emission reduction of CO2, soot, SO2, CO, NOxand CnHm are 4.267×106t, 20.5×103t, 3.0×103t, 9.6×103t, 67.9×103t, and 6.9×103t per year, respectively. The annual average increasing rates of energy saving is 139×103tce, and direct emission reduction of CO2, soot, SO2, CO, NOxand CnHm are 483×103t, 2.3×103t, 0.34×103t, 1.1×103t, 7.7×103t and 0.78×103t per year, respectively. The electrified railways have played an important role in decreasing the energy consumption and air pollutant emissions of China’s railway system. The results of this study could provide some reference knowledge for future reductions of energy consumption and waste gas emission in China’s railway transportation.

(Mn,Sb) co-doped Pb(Zr, Ti)O3 (PMSZT) pyroelectric films were successfully deposited on polycrystalline La0.5Sr0.5CoO3 (LSCO) films on amorphous-glass-substrates in the low temperature range of 470°C to 550°C by pulsed laser deposition (PLD). Polycrystalline PMSZT films with preferred (110) surface normal orientation, but no in-plane order were grown on polycrystalline LSCO/silica substrates. For comparison, epitaxial PMSZT(001) films were grown under the same deposition conditions on epitaxial LSCO(001) films grown on LaAlO3 (LAO) (001) crystal substrates. Both polycrystalline and epitaxial PMSZT films on LSCO had leakage currents lower than 4×10-10 A/cm2 at 10V applied voltage. The polycrystalline PMSZT films on the LSCO/glass substrate unexpectedly showed superior ferroelectric and pyroelectric properties than the counterpart PMSZT(001) epitaxial films on LSCO(001)/LAO(001) substrates. Remnant polarization of 2Pr=62 μC/cm2 and IR photocurrent responsivity of Ri ∼2.0 mA/W at 50-60Hz were obtained for polycrystalline PMSZT films deposited on silica at 500°C, compared with 2Pr=37μC/cm2 and Ri ∼0.5 mA/W for the epitaxial PMSZT films.

Ni(0)-complex promoted dehalogenation polymerization of 1,2-bis(4-bromophenyl)ethylene derivatives gave poly(p-biphenylene vinylene) type polymers, [—C6H2R¹2—CR² = CR²—C6H2R¹2—)n (P(R¹,H) and P(H,R²)], having substituents (R¹ = Me, Et, CHMe2, and n-C8H17, R² = Me, Et, n-C6H13, n-C11H23, and Ph) at the benzene ring or vinylene group in 90–99% yields. The polymers were soluble in organic solvents such as CHCl3, dimethylformamide, and tetrahydrofuran, and gave Mn of 2.4–5.3 × 10³ in gel permeation chromatography analysis. The absorption peak of the polymers appeared at a longer wavelength than that of the corresponding monomers by about 30 nm due to the expansion of the π-conjugation system. The polymers were photoluminescent in solutions and in their films, emitting blue or green light. P(R¹,H)s gave higher quantum yields (Φ = 0.35–0.51) than P(H,R²)s in CHCl3. P(H,R²)s showed a large Stokes shift (9600–13,500 cm⁻¹) in their photoluminescence. Single-layer and multilayer light emitting diodes using vacuum deposited thin film of P(H,Ph) were prepared. Polymers with long alkyl substituents formed an ordered structure in the solid state as judged from their XRD patterns. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1493–1504, 2000

No abstract.

AbstractA planar multi target sputtering approach was used to deposit self polarized PZT films on TiO2/Pt bottom electrodes for the use in thin film pyroelectric IR detector arrays. By using elevated substrate temperatures of about 450°C “in situ” growth of tetragonal PZT could be achieved. The films exhibited pyroelectric currents without poling. The pyroelectric coefficient was 2×10−4C/m2K, the dielectric constant was 300 and dielectric loss tan δ was 0.01. The self polarization disappears after heating the sample to 600°C.Stresses were studied in the thin film processing for the bottom electrode and the PZT film. The TiO2/Pt electrode is under high tensile stress of 900 MPa after preparation. PZT has a small compressive stress of -60 MPa, the whole TiO2/Pt/PZT stack has a tensile stress of +80 MPa. This low stress level together with the self polarization and the good electrical properties makes the films suitable for the use in pyroelectric detector arrays.

AbstractFerroelectric Pb(Zr,Ti)O3(PZT) and Mn and Sb-doped PbZrTiO3(PMSZT) thin films were integrated to high Tc superconducting YB2Cu3O7-x(YBCO) thin films on LaAlO3(100) and YSZ/Si (100) substrates by the pulsed laser deposition technique. The YBCO layer in the heterostructure was used as an atomic template for the epitaxial growth of the PZT and PMSZT thin films, as well as a nonsuperconducting electrode and IR reflector in the IR detector applications. Mn and Sb doping was used to tune the Pb(Zr,Ti)O3transition temperature to a lower value, and to modify the pyroelectric and dielectric properties of the pyroelectric material. The PZT/YBCO and PMSZT/YBCO IR detectors were examined as to their IR photon induced pyroelectric response to the source temperature, detector temperature, and IR wavelength, as well as their high temperature retention behavior. A YBCO air-bridge has been fabricated for lower thermal mass of the heterostructure detector.

The construction of ecological civilization needs to take both environmental protection and socio-economic development into consideration. Climate is one of the important environmental resources; it is also a foundation which human and society development depend on. Climate changes have exerted significant global impacts, which will continue in the future and affect population, livelihoods, economy, resources, ecosystems and many other aspects. In the future development planning, we need to coordinate the change of climate system and its impacts, fully follow and abide by climatic rules, take into consideration climatic carrying capacity, define the natural ecosystem and the intensity and scale of human socio-economic activities which the climatic resources can carry. This article introduces some related research background about the carrying capacities of environment and resources, and brings out the concept of climatic carrying capacity. In addition, the article summarizes general approaches of climatic carrying capacity assessment and introduces two case studies of climatic carrying capacity to clarify the urgency and importance of climatic carrying capacity assessment, as well as its practical significance to socio-economic development. The assessment of climatic carrying capacity has just got off the ground, and is faced with many challenges. We suggest that the priority lies in constructing and improving the theoretical foundation and assessment framework of climatic carrying capacity; secondly, the assessment should be focused on practicality and operability in accordance with local conditions; thirdly, the assessment on climatic carrying capacity needs to be integrated with other disciplines, and the application areas and service objects should be broadened; and finally, carrying out the assessment of climatic carrying capacity, especially quantitative assessment, requires continuous innovation and further involvement of new technological methods.

Poly(p-phenylene vinylene) type polymers having biphenyl-4,4′-diyl units have been prepared by organometallic polycondensation. They are photoluminescent and electrochemically active, and are considered to take a stacked and liquid crystalline structure depending on the substituent.