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Two new Zn(II)/Co(II) coordination polymers, [Zn1.5(pmda)(OH)(bipy)]2n·2nH2O (1) and [Co(pmda)(bib)]n (2) (H2pmda = 4,4′-[1,2-phenylenebis(methyleneoxy)]dibenzoic acid, bipy = 4,4′-bipyridine, bib = 1,4-bis(imidazol-1-yl)-butane), have been prepared under hydrothermal conditions. Their structure were determined by single-crystal X-ray diffraction analysis, and further characterized by elemental analysis, IR spectra TG, and powder X-ray diffraction analysis. Complexes 1 and 2 both exhibit two-dimensional network structures and the intermolecular hydrogen bonding, π-π stacking interactions extend them into 3D supramolecular architectures, which play an important role in stabilizing them. The solid-state luminescent property of 1 and 2 were characterized and the results revealed that they exhibit fascinating photoluminescence properties. In addition, the sensing property of only 1 has been examined briefly. The quantum-chemical calculations of complex 1 have been performed on ‘molecular fragments’ extracted from the crystal structure using the PBE0/LANL2DZ method built in Gaussian 16 Program.

Two new Zn(II) coordination polymers based on bis(imidazol), namely, [Zn(hba)2(bib)]n(1) and [Zn(NAA)(bib)1.5]n·nNO3−·3nH2O (2) (Hhba = 3-hydroxybenzoic acid, HNAA = 1-naphthyl acetic acid, bib = 1,4-bis(imidazol-1-yl)-butane) have been successfully synthesized under hydrothermal conditions. Their structures have been determined by single crystal X-ray diffraction analyses, elemental analyses, IR, TG and fluorescence spectrums. Complex 1 shows a one-dimensional zigzag chain structure. Complex 2 exhibits two-dimensional network structure. The intermolecular hydrogen bonding and π–π stacking interactions extend the complexes 1 and 2 into supramolecular architectures and play an important role in stabilizing complexes 1 and 2. Furthermore, complex 1 exhibits intense blue luminescence and appears to be a good candidate for novel hybrid inorganic–organic photoactive materials, while no photoluminescent response was observed for complex 2. In addition, we analyzed the Natural Bond Orbitals (NBO) of 1 and 2 using the PBE0/LANL2DZ method in the Gaussian 09 Program. The calculations showed the obvious covalent interaction between the coordinated atoms and Zn(II) ion. Two new Zn(II) coordination polymers based on bis(imidazol), namely, [Zn(hba)2(bib)]n(1) and [Zn(NAA)(bib)1.5]n·nNO3−·3nH2O (2) have been successfully synthesized under hydrothermal conditions. Their structures have been determined by single crystal X-ray diffraction analyses, elemental analyses, IR, TG and fluorescence spectrum. Complex 1 shows a one-dimensional zigzag chain structure. Complex 2 exhibits two-dimensional network structure. The intermolecular hydrogen bonding and π–π stacking interactions extend the complex 1 and 2 into supramolecular architectures and play an important role in stabilizing complex 1 and 2. In addition, we analyzed Natural Bond Orbital (NBO) of 1 and 2 in using the PBE0/LANL2DZ method built in Gaussian 09 Program. The calculation results showed the obvious covalent interaction between the coordinated atoms and Zn(II) ion.

Two new complexes [Ni(4-nph)(bix)(H2O)]n(1) and [Zn(4-nph)(mbix)]n·nH2O (2) (4-H2nph = 4-nitrophthalic acid, bix = 1,4-bis(imidazol-1-yl)-benzene, mbix = 1,3-bis(imidazol-1-yl)-benzene) have been hydrothermally synthesized and structurally characterized by elemental analysis, IR spectroscopy, TG, fluorescence spectroscopy, single-crystal and powder X-ray diffraction. Complex 1 exhibits two dimensional (2D) network structure contain 42-number ring and complex 2 shows one-dimensional ribbon, which were further extended into three-dimensional supramolecular structure through hydrogen bonds and π–π stacking interactions. Moreover, we analyzed the natural bond orbital using the PBE0/LANL2DZ method in the Gaussian 03 program of complexes 1 and 2. The calculation results indicated the obvious covalent interactions between the coordinated atoms and the NiII, ZnII ion respectively.

The complexity and uncertainty of forest regeneration is crucial for predicting forest ecosystem dynamics. A natural regeneration model of pine-oak forests in Qinling Mountains was constructed with competition, climate and topography factors using Bayesian statistics and global sensitivity analysis (GSA). The alternative models were based on Poisson, negative binomial (NB), zero-inflated Poisson (ZIP), and zero-inflated negative binomial (ZINB) models. According to the uncertainty of model parameter transfer, the analysis results were quantified, and the dominant factors of small probability events affecting forest regeneration were explained. The results showed that the ZINB model was the best one in the simulation of森林天然更新的复杂性和不确定性是森林生态系统动态预测中的关键问题。本研究引入贝叶斯技术和全局敏感性分析,构建基于竞争、气候和地形3类因子的秦岭松栎林天然更新模型。备选模型形式以泊松(Poisson)模型、负二项(negative binomial,NB)模型、零膨胀泊松(zero-inflated Poisson,ZIP)模型和零膨胀负二项(zero-inflated negative binomial,ZINB)模型为基础。同时,根据模型参数传递的不确定性量化分析结果,阐释影响森林更新小概率事件的主导因子。结果表明: ZINB模型在油松和锐齿栎更新模拟中均优于其他模型。林分总断面积、光截留、坡位和生长季最低温是影响松栎林中油松天然更新的最关键因子;而林分总断面积、坡向与海拔的组合、年均温和最热季节降水量则是影响松栎林中锐齿栎天然更新的关键因子。油松更新模拟中,各类因子对模型输出的不确定性贡献率从小到大依次为: 竞争因子(25%)＜气候因子(29%)＜地形因子(46%);锐齿栎更新模拟中为: 气候因子(12%)＜竞争因子(24%)＜地形因子(64%)。油松天然更新数量对生长季最低温和最干季节降水量为正响应,对最干季节均温为负响应;锐齿栎天然更新数量对年均温、生长季最低温和最热季节降水量为正响应,对最干季节均温为负响应。基于贝叶斯技术的ZINB模型可以量化森林更新的影响因子,并解释参数传递的不确定性,是预测森林天然更新的有力工具。.

Objective This study was performed to explore the association of the high-resolution computed tomography (HRCT) score with ventilator weaning and 28-day mortality of patients with acute respiratory distress syndrome (ARDS). Method In total, 197 patients treated for ARDS from October 2004 to December 2015 were retrospectively analyzed. Univariate analysis and multifactor regression analysis were used to determine the relationship of the HRCT score with ventilator weaning and 28-day mortality. Curve-fitting analysis and threshold analysis were further used to explore the association of the HRCT score with ventilator weaning and 28-day mortality. Results The multifactor regression analysis showed that the HRCT score was significantly associated with a lower rate of ventilator weaning and a higher risk of 28-day mortality in patients with ARDS. HRCT scores of 257.0 and 243.2 were the thresholds for ventilator weaning and 28-day mortality, respectively. When the HRCT score was below the threshold, every 1-point increase in the HRCT score was associated with a 4.6% decrease in the ventilator weaning rate and a 4.6% increase in the 28-day mortality rate. Conclusion The HRCT score was associated with ventilator weaning and 28-day mortality with a threshold of 257.0 and 243.2 points, respectively.

We devised a transverse flux linear motor (TFLM) that uses the superconductor-aluminum hybrid as the secondary to explore the potentials of integrating the propulsion with the levitation and guidance, which are generally separated in existing magnetic levitation (MAGLEV) systems. In this proposal, the hybrid secondary is made of aluminum plate and close-ended coated superconductor coils, with the latter placed over the former to achieve the stable levitation and self-propulsion. To validate the proposal, analytical formulations for describing the electromagnetic responses of such hybrid secondary were established, and the resultant magnetic forces were calculated and compared with a 3-D finite-element model, in which the actual geometry of the proposed TFLM and the nonlinear behavior of superconductor were represented. Afterward, the proposed TFLM was demonstrated and its 3-D forces were measured by a test rig developed for this paper. It was proven that the derived analytical formulations and built finite-element model are both able to reproduce the main feature of the measured results. Characteristic studies clearly display that, although the levitation capability is limited in the proof-of-concept demonstrator, the self-stability and self-propulsion could be integrated by the proposed TFLM, which provides a novel alternative to the scientific community of MAGLEV transit.

Thermal diffusion of CO adsorbed on rutile TiO2(110) was studied in the 20–110 K range using photon-stimulated desorption (PSD), temperature-programmed desorption (TPD), and scanning tunneling microscopy. During UV irradiation, CO desorbs from certain photoactive sites (e.g., oxygen vacancies). This phenomenon was exploited to study CO thermal diffusion in three steps: first, empty these sites during a first irradiation cycle, then replenish them with CO during annealing, and finally probe the active site occupancy in the second PSD cycle. The PSD and TPD experiments show that the CO diffusion rate correlates with the CO adsorption energy—stronger binding corresponds to slower diffusion. Increasing the CO coverage from 0.06 to 0.44 monolayer (ML) or hydroxylation of the surface decreases the CO binding and increases the CO diffusion rate. Relative to the reduced surface, the CO adsorption energy increases and the diffusion decreases on the oxidized surface. The CO diffusion kinetics can be modeled satisfa...

To determine the performance of chemical shift signal intensity index (CS-SII) values for distinguishing minimal-fat renal angiomyolipoma (mfAML) from renal cell carcinoma (RCC) and to assess RCC subtype characterisation. We identified eligible studies on CS magnetic resonance imaging (CS-MRI) of focal renal lesions via PubMed, Embase, and the Cochrane Library. CS-SII values were extracted by lesion type and evaluated using linear mixed model-based meta-regression. RCC subtypes were analysed. Two-sided p value

Two new complexes [Zn(NIPH)(bbib)]2n·nbbib·nH2O (1) and [Co(NIPH)(bbib)]n (2) (H2NIPH = 5-nitroisophthalic acid, bbib = 1,4-bis(1H-benzimidazolyl)butane) have been hydrothermally synthesized and structurally characterized by elemental analysis, IR spectroscopy, TG, fluorescence spectroscopy, single-crystal and powder X-ray diffraction. Complex 1 exhibits a two-dimensional network structure and complex 2 shows a three-dimensional framework, which were further extended into three-dimensional supramolecular structure through hydrogen bonds and π–π stacking interactions. Moreover, we analyzed the natural bond orbital using the PBE0/LANL2DZ method in the Gaussian 03 program of complex 1 and 2. The calculation results indicated the obvious covalent interactions between the coordinated atoms and the ZnII, CoII ion respectively.

The non-oxidative dehydrogenation of ethanol to acetaldehyde and hydrogen is an industrially relevant chemical conversion. Although Cu-based catalysts show high reactivity toward oxidative ethanol dehydrogenation, the flat Cu(111) surface is rather inactive for ethanol dehydrogenation in the absence of water, surface oxygen or defects. Herein we show, using experimental and theoretical studies of model systems, that adding 1% Pt into the surface of Cu(111) to form dilute Pt–Cu single atom alloys (SAAs) increases the activity of Cu(111) for ethanol dehydrogenation sixfold. The mechanism of ethanol dehydrogenation was investigated at the molecular level using scanning tunneling microscopy, temperature programmed experiments and density functional theory calculations. Our results demonstrate that Pt–Cu SAAs are much more active than Cu(111) for converting ethanol to acetaldehyde and hydrogen in the absence of surface oxygen and water. Specifically, the O–H bond of ethanol is activated at Pt sites below 160 K, followed by ethoxy spillover to Cu sites which results in a significant increase of the ethoxy intermediate yield. The C–H bond of ethoxy is then activated at 310 K, and the final product, acetaldehyde, desorbs from Cu(111) in a reaction rate limited process. Finally, we show that the Cu model surfaces exhibit stability with respect to poisoning as well as 100% selectivity in the alcohol dehydrogenation to acetaldehyde and hydrogen.

The adsorption and photochemistry of CO on rutile TiO2(110) are studied with scanning tunneling microscopy (STM), temperature-programmed desorption, and angle-resolved photon-stimulated desorption (PSD) at low temperatures. Site occupancies, when weighted by the concentration of each kind of adsorption site on the reduced surface, show that the adsorption probability is the highest for the bridging oxygen vacancies (VO). The probability distribution for the different adsorption sites corresponds to very small differences in CO adsorption energies (

The non-oxidative dehydrogenation of alcohols is considered as an important method to produce aldehydes for the chemical industry and hydrogen gas. However, current industrial processes are oxidative, meaning that the aldehydes are formed along with water, which, in addition to being less energy efficient, poses separation problems. Herein the production of aldehydes from methanol and ethanol on clean and dry Cu(111) and Cu(110) surfaces was investigated in order to understand the catalytic anhydrous dehydrogenation of alcohols. Both ethanol and methanol preferentially react under ultrahigh vacuum conditions at surface defects to yield acetaldehyde and formaldehyde, respectively, in the absence of surface oxygen and water. The amount of alkoxide reaction intermediates measured by scanning tunneling microscopy, and aldehyde and hydrogen products detected by temperature programmed reaction, are increased by inducing more defects in the Cu substrates with Ar ion sputtering. This work also reveals that the Cu...

A high temperature superconducting (HTS) linear synchronous motor that uses REBCO-coated conductor as the secondary excitation system was recently demonstrated. Four series-connected REBCO-coated conductor coils were fabricated via the epoxy impregnation technique and the critical current of each coil can be retained by a percent of over 75% at 77 K after winding. Meanwhile, a three-dimensional (3-D) finite-element model was established to describe the coated superconductor coils subject to the traveling magnetic fields of a conventional copper-based stator. The comparison between experiment and simulation in terms of thrust has verified the developed 3-D numerical model, allowing the complex studies of HTS linear motor prior to fabrication. Our preliminary testing has shown that, when the coated superconductor coils were placed over a three-phase stator, the transport dc current in the coated conductor coils will exhibit a significant variation, depending on its magnitude and the operating frequency of stator current as well as the electromagnetic gap.

We devised a linear induction motor (LIM) that uses the close-ended coated superconductor coils as the secondary to explore the potential solutions of enhancing the thrust performance at large clearance, which is generally required for the linear propulsion of transit systems. In this proposal, the coated superconductor coils are embedded into a ferromagnetic yoke whose function is to guide and concentrate the travelling fields generated by the three-phase conventional stator. To make a preliminary study before the laboratory demonstration, we built a numerical model of this proposal by resorting to the finite-element software of MagNet, a recognized professional tool to simulate the electrical machines in the scientific community. Through a treatment of the power law, the developed numerical model has included the nonlinear constitutive law of superconductor, which is currently thought to be difficult in the MagNet environment. This general treatment takes a step forward toward the use of the professional software to perform complex simulations of the superconducting machines. Based on the numerical model, we carried out a set of transient studies on the proposed LIM to observe the distributions of travelling flux, the starting characteristics, and the time evolutions of thrust and speed. The achieved results clearly display that the proposed LIM has advantages over the conventional type and could be thereby regarded as a candidate for developing high thrust linear LIM with large clearance.

Understanding adsorbed water and its dissociation to surface hydroxyls on oxide surfaces is key to unraveling many physical and chemical processes, yet the barrier for its deprotonation has never been measured. In this study, we present direct evidence for water dissociation equilibrium on rutile-TiO2(110) by combining supersonic molecular beam, scanning tunneling microscopy (STM), and ab initio molecular dynamics. We measure the deprotonation/protonation barriers of 0.36 eV and find that molecularly bound water is preferred over the surface-bound hydroxyls by only 0.035 eV. We demonstrate that long-range electrostatic fields emanating from the oxide lead to steering and reorientation of the molecules approaching the surface, activating the O–H bonds and inducing deprotonation. The developed methodology for studying metastable reaction intermediates prepared with a high-energy molecular beam in the STM can be readily extended to other systems to clarify a wide range of important bond activation processes.

International audience; Hydrothermal Synthesis and Crystal Structure of Three-dimensional Supramolecular Zinc, Manganese Coordination Polymers Zhi-Tao Wang • Valentin Valtchev • Qian-Rong Fang • Xiu-Mei Li • Ya-Ru Pan Two new complexes [Zn 2 (pzdc)(L) 2 (H 2 O)] 2n •2nH 2 O (1) and [Mn(µ 2-O)(H 2 O) 2-(HL)] 2n •2nNIPH (2) (H 2 pzdc = pyrazine-2,3-dicarboxylic acid, HL = 3-(2-Pyridyl) pyrazole, H 2 NIPH = 5-nitroisophthalic acid) have been hydrothermally synthesized and structurally characterized by elemental analysis, IR spectrum, UV spectrum, TG, fluorescence spectrum and single-crystal X-ray diffraction. Complex 1 shows two-dimensional (2D) network, which was stabilized by O-H•••O, C-H•••O hydrogen bonding and π-π interactions and extended into 3D supramolecular architecture. Complex 2 is zero-dimensional structure, which was further extended into 3D supramolecular framework through N-H•••O, O-H•••O, C-H•••O hydrogen bonds and π-π interactions.

To compare clinical effect of modified anterolateral approach combined with modified posteromedial approach and conventional posterolateral approach combined with medial-aided in treating trimalleolar fractures.From January 2015 to August 2017, 108 patients with trimalleolar fractures were enrolled and randomly divided into modified approaches (experimental group) and conventional approaches(control group). There were 53 patients in experimental group including 31 males and 22 females aged from 18 to 67 years old with an average of(40.2±16.4) years old; 19 patients on the left side and 34 patients on the right side; 39 patients were supination external rotation and 14 patients were pronation-external rotation; preoperative waiting time ranged from 6 to 14 d with an average of(9.6±3.1) d; performed operation through modified anterolateral approach combined with modified posteromedial approach. There were 55 patients in control group, including 34 males and 21 females aged from 19 to 69 years old with an average of (42.1±15.3) years old; 18 patients on the left side and 37 patients on the right side; 42 patients were supination external rotation and 13 patients were pronation-external rotation; preoperative waiting time ranged from 7 to 16 d with an average of (10.3±3.4) d; performed operation through conventional posterolateral approach combined with medial-aided. Operation time, intraoperative blood loss, postoperative drainage volume, cases of incision complications and excellent-good reduction, fracture healing time, cases of nerve injury and muscular flexor contracture, cases of incision complications between two groups were compared; AOFAS score were used to evaluate clinical efficacy at 1 year after operation.All patients were followed up from 12 to 24 months with an average of (16.4 ±7.5) months. Operation time, intraoperative blood loss, postoperative drainage volume and incision complication in experimental group were (95.3±22.6) min, (114.7±68.7) ml, (127.5±87.8) ml and 1 case, respectively; while in control group were (112.5±53.8) min, (155.2±79.6) ml, (178.4±73.8) ml and 3 cases respectively; the data in experimental group were better than that of control group. In experimental group, 36 cases got excellent results, 14 good and 3 poor on the quality of reduction, while 30 patients got excellent results, 15 good and 10 poor in control group; the experimental group was better than control group. Fracture healing time in experimental group were(5.5±1.6) months, 2 patients occurred incision complications, while(6.7±2.1) months, 12 patients in control group; the experiment group were better than control group. Postoperative AOFAS score at 12 months in experimental group was 92.9±18.4, and better than control group 80.3±38.3; 32 patients got excellent results, 17 good, 3 moderate and 1 poor in experimental group; 25 patients got excellent results, 18 good, 8 moderate and 4 poor in control group; there was statistical difference between two groups.Both of modified anterolateral approach combined with modified posteromedial approach and conventional posterolateral approach combined with medial-aided in treating trimalleolar fractures could receive good clinical effect. While compared with conventional posterolateral approach combined with medial-aided, modified anterolateral approach combined with modified posteromedial approach is more fit for blood supply of local soft tissue, and has advantages of less trauma, safety operation and clearly exposure.

Ni/Au is an alloy combination that while, immiscible in the bulk, exhibits a rich array of surface geometries that may offer improved catalytic properties. It has been demonstrated that the addition of small amounts of Au to Ni tempers its reactivity and reduces coking during the steam reforming of methane. Herein, we report the first successful preparation of dilute Ni–Au alloys (up to 0.04 ML) in which small amounts of Ni are deposited on, and alloyed into, Au(111) using physical vapor deposition. We find that the surface structure can be tuned during deposition via control of the substrate temperature. By adjusting the surface temperature in the 300–650 K range, we are able to produce first Ni islands, then mixtures of Ni islands and Ni–Au surface alloys, and finally, when above 550 K, predominantly island-free Ni–Au single atom alloys (SAAs). Low-temperature scanning tunneling microscopy (STM) combined with density functional theory calculations confirm that the Ni–Au SAAs formed at high temperature c...

We have devised a magnetic circuit for improved transport of quasistatic magnetic fields from a transmitter to a receiver in order to increase the transfer efficiency of electromagnetic devices such as transformers. This novel structure is made by coating a superconductor-ferromagnet heterostructure on a traditionally used magnetic core. We tested the transfer efficiency of the proposed magnetic circuit in transporting ac current from the primary to the secondary coils, which could be regarded as a proof-of-principle demonstration of the current transformer. The measured and calculated results clearly show that the proposed current transformer could transport current to the secondary coil with much higher efficiency than a conventional naked magnetic core. Characterization of the current transformer shows a dependence of transfer efficiency on the amplitude and frequency of the primary current. The results could also be applied to enhance the efficiency of voltage transformers, which rely on the same principle as the current transformer.

The influence of reactant coverage on photochemical activity was explored using scanning tunneling microscopy (STM) and ultraviolet photoelectron spectroscopy (UPS). We observed diminished reactivity of carboxylate species (trimethyl acetate, TMA) on TiO2(110) as a function of increasing coverage. This effect was not linked to intermolecular interactions of TMA but to the accumulation of the coadsorbed bridging hydroxyls (HOb) deposited during (thermal) dissociative adsorption of the parent, trimethylacetic acid (TMAA). Confirmation of the hindering influence of HOb groups was obtained by the observation that HOb species originated from H2O dissociation at O-vacancy sites have a similar hindering effect on TMA photochemistry. Though HOb’s are photoinactive on TiO2(110) under ultrahigh vacuum conditions, UPS results show that these sites trap photoexcited electrons, which in turn likely (electrostatically) attract and neutralize photoexcited holes, thus suppressing the hole-mediated photoreactivity of TMA....

Purpose To compare hysterosalpingo-contrast-sonography (HyCoSy) and magnetic resonance-hysterosalpingography (MR-HSG) in the diagnosis of fallopian tubal patency. Materials and methods The databases of PubMed, Embase, and the Cochrane Library were searched for records up to November 30, 2019. Studies involved in the diagnostic detection of HyCoSy or MR-HSG for fallopian tubal patency using conventional HSG or laparoscopy as the reference test were included. Data was analyzed by meta-analysis. We compared sensitivity, specificity, positive and negative likelihood ratios (PLR and NLR), diagnostic odds ratio (DOR), and summary receiver operating characteristic (sROC) plots of both HyCoSy and MR-HSG. Quality was assessed using the QUADAS-2 tool. Results The analysis included 24 articles involving 1340 patients. HyCoSy was studied in 17 studies, and MR-HSG was studied in seven studies. For HyCoSy in diagnosis of fallopian tubal patency, pooled sensitivity was 89 % (95 % confidence interval [CI], 87 %–91 %), and specificity was 93 % (95 % CI, 91 %–94 %). For MR-HSG in diagnosis of fallopian tubal patency, pooled sensitivity was 100 % (95 % CI, 98 %–100 %), and specificity was 82 % (95 % CI, 74 %–89 %). The sROC showed similar diagnostic accuracy for MR-HSG and HyCoSy. 3D/4D HyCoSy with ultrasound microbubbles had equal sensitivity (95 % vs. 100 %, P = 0.186) and significantly higher specificity (94 % vs. 82 %, P = 0.005) compared with MR-HSG. Conclusions HyCoSy and MR-HSG showed similar overall diagnostic performance for diagnosing fallopian tubal patency. 3D/4D HyCoSy with ultrasound microbubbles could significantly improve the diagnostic specificity of HyCoSy.

High-performance YBa2Cu3O7−z (YBCO) super conducting films have been prepared on single-crystal substrate by fluorine-free polymer-assisted metal organic deposition (PA-MOD) method. The introduction of polymers into the precursor solution can make the coating solution more homogeneous and stable. And, the novel high temperature partial melting process can enhance the epitaxial growth of the precursor films. The influence of partial melting time on the texture, microstructure, and properties was thoroughly investigated. The results indicate YBCO film melting for 5 min has biaxial texture, smooth and dense microstructures, as well as high critical current density (77 K, 0 T) over 3 MA/cm2.

SmBa2Cu3O7−z (SmBCO) films with different metal cation concentrations (MCCs) were prepared on (00l) LaAlO3 substrate by self-developed non-fluorine chemical solution deposition (CSD) method. The influence of MCC on structure and performance of SmBCO films was investigated. The film with MCC of 1.0 mol/L shows better c-axis texture and smoother as well as denser surface microstructure than other films. With increasing the MCC, the superconducting transition temperature (Tc) of the films has a peak value of 91.2 K at MCC of 1.0 mol/L. And the films with MCC of 0.8 mol/L and 1.0 mol/L show higher current carrying capabilities in the magnetic fields according to the Jc−H behaviors.

The formation and coupling of methylene upon dissociation of formaldehyde on reduced TiO2(110) are studied using variable temperature scanning tunneling microscopy (STM). In agreement with prior studies, formaldehyde preferably adsorbs on the bridging-bonded oxygen vacancy (VO) defect site. VO-bound formaldehyde couples with Ti-bound formaldehyde forming a diolate species, which appears as the majority species on the surface at 300 K. Here, STM images directly visualize a low-temperature coupling reaction channel. Two VO-bound formaldehyde molecules can couple and form Ti-bound species, which desorbs above ∼215 K. This coupling reaction heals both VO sites indicating the formation and the desorption of ethylene. We also directly observed the diffusion of methylene groups to nearby empty VO sites upon dissociation of the C–O bond in VO-bound formaldehyde, which suggests that the ethylene formation occurs via coupling of the methylene groups. Statistical analysis shows that the sum of visible reaction produ...

Direct imaging of site-specific reactions of individual molecules as a function of temperature has been a long-sought goal in molecular science. Here, we report the direct visualization of molecular coupling of formaldehyde on reduced rutile TiO2(110) surfaces as we track the same set of molecules using scanning tunneling microscopy (STM) when the temperature is increased from 75 to 170 K. Our previous study showed that formaldehyde preferably adsorbs at bridging-bonded oxygen (Ob) vacancy (VO) defect site. Herein, images from the same area as the temperature is increased show that VO-bound formaldehyde couples with Ti-bound formaldehyde forming a diolate intermediate. Consequently, exposure of formaldehyde at room temperature leads to diolate as the majority species on the surface, and no VO-bound formaldehyde is observed. The diolate species are the key reaction intermediates in the formation of ethylene reported in previous ensemble-averaged studies.

Surface reactions of formaldehyde with reduced TiO2(110) surfaces have been studied using variable-temperature scanning tunneling microscopy (STM) and density functional theory (DFT). STM images taken from a same area at various temperatures clearly show that formaldehyde preferentially adsorbs on the bridge-bonded oxygen (Ob) vacancy (VO) defect sites. Bias-dependent STM images show that the STM features corresponding to both the Ti-bound CH2O and the VO-bound CH2O are positioned between the Ob row and the Ti row. While the VO-bound formaldehyde rotates at 95 K, the Ti-bound CH2O does not. The VO-bound CH2O starts to diffuse along the Ob row as –CH2– at ~170 K and starts to diffuse along the Ti row as an intact molecule at ~215 K. However, the stabilities and the configurations of the Ti-bound and VO-bound formaldehyde calculated using DFT are not in line with the experimental results. The discrepancy between the experiment and theory indicates the presence of a complex charge distribution related to the surface defects.

Due to the fact that the low speed pump similarity theory is only applicable to incompressible fluid, this theory cannot be used for extrapolation of compressor performance curve. Considering the compressibility of working medium; therefore, this paper has modified the similarity theory and put forward a new index relationship equation. The two low speed performance lines which are already known were used to get the similar working points and extrapolate the performance lines through the optimization method. Compared with the existing performance lines, the results show that the method is simple, convenient and qualified with practicability and accuracy. This method plays an important role on studying startup process of a gas turbine and improving the accuracy of the simulation of startup process.