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Fe doping is acknowledged as an extremely efficient strategy for enhancing the catalytic performance in oxygen evolution reaction (OER).

The electrocatalytic reduction of nitrobenzene to aniline normally faces high overpotential and poor selectivity because of its six-electron redox nature. Herein, a Ag nanoparticles/laser-induced-graphene (LIG) heterointerface was fabricated on polyimide films and employed as an electrode material for an efficient nitrobenzene reduction reaction (NBRR) via a one-step laser direct writing technology. The first-principles calculations reveal that Ag/LIG shows the lowest activation barriers for the NBRR, which could be attributed to the optimum adsorption of the H atom realized by the appropriate interaction between Ag/LIG heterointerfaces and nitrobenzene. As a result, the overpotential of the NBRR is reduced by 217 mV after silver loading, and Ag/LIG shows a high aniline selectivity of 93%. Furthermore, an electrochemical reduction of nitrobenzene in tandem with an electrochemical oxidative polymerization of aniline was designed to serve as an alternative method to remove nitrobenzene from the aqueous solution. This strategy highlights the significance of heterointerfaces for efficient electrocatalysts, which may stimulate the development of novel electrocatalysts to boost the electrocatalytic activity.

Highly efficient La/Sr-based perovskites with surface Fe sites and Sr vacancies were developed for the active lattice oxygen mechanism (LOM) of the oxygen evolution reaction (OER), and a relationship between the LOM and dynamic surface structure was established.

Metal-organic frameworks (MOFs) with carboxylate ligands as co-catalysts are very efficient for the oxygen evolution reaction (OER). However, the role of local adsorbed carboxylate ligands around the in-situ-transformed metal (oxy)hydroxides during OER is often overlooked. We reveal the extraordinary role and mechanism of surface-adsorbed carboxylate ligands on bi/trimetallic layered double hydroxides (LDHs)/MOFs for OER electrocatalytic activity enhancement. The results of X-ray photoelectron spectroscopy (XPS), synchrotron X-ray absorption spectroscopy, and density functional theory (DFT) calculations show that the carboxylic groups around metal (oxy)hydroxides can efficiently induce interfacial electron redistribution, facilitate an abundant high-valence state of nickel species with a partially distorted octahedral structure, and optimize the d-band center together with the beneficial Gibbs free energy of the intermediate. Furthermore, the results of in situ Raman and FTIR spectra reveal that the surface-adsorbed carboxylate ligands as Lewis base can promote sluggish OER kinetics by accelerating proton transfer and facilitating adsorption, activation, and dissociation of hydroxyl ions (OH- ).

Electrocatalytic water splitting is considered as a promising route to use renewable energy for hydrogen production; however, its industrial application is limited by the anodic reaction, oxygen ev...

Ultra-high temperature ceramics have been considered as good candidates for plasma facing materials due to their combination of high melting point, high strength and hardness, high thermal conductivity as well as good chemical inertness. In this study, zirconium diboride has been chosen to investigate its irradiation damage behavior. Irradiated by 4 MeV Au2+ with a total fluence of 2.5 × 1016 cm−2, zirconium diboride ceramic shows substantial resilience to irradiation-induced damage with its structural integrity well maintained but mild damage at lattice level. Grazing incident X-ray diffraction evidences no change of the hexagonal structure in the irradiated region but its lattice parameter a increased and c decreased, giving a volume shrinkage of ∼0.46%. Density functional theory calculation shows that such lattice shrinkage corresponds to a non-stoichiometric compound as ZrB1.97. Electron energy-loss spectroscopy in a transmission electron microscope revealed an increase of valence electrons in zirconium, suggesting boron vacancies were indeed developed by the irradiation. Along the irradiation depth, long dislocations were observed inside top layer with a depth of ∼750 nm where the implanted Au ions reached the peak concentration. Underneath the top layer, a high density of Frank dislocations is formed by the cascade collision down to a depth of 1150 nm. All the features show the potential of ZrB2 to be used as structural material in nuclear system.

Optimizing the coordination/surrounding environments of active metal nanoclusters to promote the catalytic performance during hydrogen evolution reaction (HER) in alkaline media is highly important but extremely challenging. Here, we demonstrate that novel S-coordinated ruthenium (Ru) nanoclusters anchored on N/S-codoped carbon nanosheets (Ru–S/N–C) can be successfully synthesized via the space-confinement pyrolysis of Ru complexes in the framework of polyaniline–ammonia persulfate supermolecules. X-ray absorption fine structure spectroscopy and X-ray photoelectron spectroscopy studies reveal the local coordination structure of Ru–S bonds, the surrounding N/S/C environments of Ru, and the synergistic electronic interactions among N, S, C and Ru atoms. Theoretical calculations further confirm that the coordination/surrounding environments could optimize the adsorption energies of intermediates on Ru through interfacial charge transfer and, thus, accelerate the reaction kinetics of hydrogen evolution. The fabricated Ru–S/N–C exhibits an ultra-small overpotential of 10 mV at 10 mA cm−2 and an extremely high turnover frequency (TOF) of 2.3 H2 s−1 at an overpotential of 50 mV for the HER, as well as a mass catalytic activity about 10 times higher than that of a commercial Pt/C catalyst.

Two-dimensional transition metal hydroxides are greatly limited in the application of the electrocatalytic oxygen evolution reaction (OER) due to its large and inert basal planes. Herein, we report a one-step in situ etching hydrothermal method to construct Co(OH)2 and Ni(OH)2 heterostructure nanomaterials, successfully activating the basal plane of Co(OH)2. The abundant lattice strains that appear at heterogeneous interfaces cause a downshift of the d-band center of Co in Co(OH)2 and promote the desorption of oxygen during the OER process, which accelerates reaction kinetics of the OER and improves catalytic activity effectively. Furthermore, the electron interaction at the Co(OH)2/Ni(OH)2 interfaces leads to charge polarization, which will regulate the adsorption and dissociation of H2O molecules and enhances mass and electron transfer. Owing to the above advantages of Co(OH)2/Ni(OH)2 interfaces, the as-prepared composite catalysts show an excellent OER catalytic performance with a low overpotential of only about 270 mV at 20 mA cm−2, maintaining long-term catalytic stability for more than 24 h at 20 mA cm−2.

PurposeThis paper investigates the current psychological state of Chinese tourism practitioners and their career resilience during the ongoing COVID-19 pandemic. It empirically examines the effects of COVID-19 on Chinese tourism practitioners' professional attitudes and their career belief in the future. The study is intended to guide enterprises and governments to design effective strategies/policies to deal with the effect of this unfavorable environment.Design/methodology/approachThe sample consists of 442 tourism practitioners in 313 tourism enterprises in China. The data were collected via a targeted online survey based on a well-structured questionnaire. The data were analyzed using statistical procedures including multilevel regression analysis.FindingsThe study results show that Chinese tourism practitioners have strong career resilience in the face of current turbulent time. After testing, the model shows that career beliefs and social support have a significant positive impact on the professional attitudes of tourism practitioners, and that career resilience has a partial mediating effect on their career beliefs, social support and professional attitude.Originality/valueThis study enriches the existing literature on career belief, social support and career resilience. It provides a new interpretation on how career belief and social support impact career resilience and thus shape tourism practitioners' professional attitudes during pandemics.

The intrinsic activity of NiFe layer double hydroxides (LDHs) for the oxygen evolution reaction (OER) suffers from its predominantly exposed (003) basal plane, which is thought to have poor activity. Herein, we construct a hierarchal structure of NiFe LDH nanosheet-arrays-on-microplates (NiFe NSAs-MPs) to elevate the electrocatalytic activity of NiFe LDHs for the OER by exposing a high-activity plane, such as the (012) edge plane. It is surprising that the NiFe NSAs-MPs show activity of 100 mA cm−2 at an overpotential (η) of 250 mV, which is five times higher than that of (003) plane-dominated NiFe LDH microsheet arrays (NiFe MSAs) at the same η, representing the excellent electrocatalytic activity for the OER in alkaline media. Besides, we analyzed the OER activities of the (003) basal plane and the (012) and (110) edge planes of NiFe LDHs by density functional theory with on-site Coulomb interactions (DFT+U), and the calculation results indicated that the (012) edge plane exhibits the best catalytic performance among the various crystal planes because of the oxygen coordination of the Fe site, which is responsible for the high catalytic activity of NiFe NSAs-MPs., The (012) edge plane of NiFe layer double hydroxides (LDHs) has been proven to be a highly active plane for water oxidation.

We report a success in synthesizing high entropy silicides (HES) compounds and manufacturing well-densified HES ceramics through spark plasma sintering. For a designed chemical formula as (Ti0.2Zr0.2Nb0.2Mo0.2W0.2)Si2, the as-synthesized HES showed a formula as (Ti0.22Zr0.06Nb0.29Mo0.22W0.21)Si2 with zirconium partially oxidized into zirconia. Doping with aluminum resulted in a HES with the same composition, promoted formation of ZrSi2 and Al2O3. XRD analysis of as-synthesized HES is well supported by the calculated diffraction data based on a 2 × 3 × 1 supercell with HCP crystal structure and experimental chemical composition. The cations in this HES crystal structure can occupy their positions randomly with little change of its lattice parameters and formation enthalpy.

The hydrogen evolution reaction (HER) is key half reaction in the electrochemical water splitting. Metal oxides as electrocatalysts have attracted much interest because of their application potenti...

A stable pillared-layer metal-organic framework (MOF) was obtained through post-synthesis modification from an unstable fence-like MOF for the first time. By virtue of high exposure of active sites on the layers, the evolved MOF with Fe doping exhibits an ultralow overpotential of 238 mV at 10 mA cm-2 during the oxygen evolution reaction (OER). Moreover, it shows a superior electrocatalytic stability with almost no attenuation for more than 168 h.

Here, we report the successful fabrication of highly dispersed ultrafine Ni nanoparticles (NPs) embraced into the partially carbonized Ni-MOF-74 (Ni NPs/C@Ni-MOF-74) microrod arrays by the heat treatment of the rod-like Ni-MOF-74 arrays grown on Ni foam. The partial carbonization is an effective strategy to realize the homogeneous dispersion of ultrafine Ni NPs and carbon in the skeleton of rod-like Ni-MOF-74. This can prevent the encapsulated Ni NPs and carbon from aggregation and oxidation, allowing them to serve as highly efficient electrocatalysts. The fabricated Ni NPs/C@Ni-MOF-74 not only provide high specific surface area and high conductivity, but also provide good hydrophilicity and synergetic effects among Ni NPs, carbon and Ni-MOF-74 for the adsorption and activation of H2O molecules. The HER electrocatalytic performance of Ni NPs/C@Ni-MOF-74 arrays can be optimized by the control of the carbonization time and temperature. The optimized Ni NPs/C@Ni-MOF-74/NF shows outstanding HER catalytic performance, with a low overpotential of 131 mV at 10 mA cm−2 and excellent durability, and it is superior to most of the recently reported MOF-based HER electrocatalysts.

The integration of Fe dopant and interfacial FeOOH into Ni-MOFs [Fe-doped-(Ni-MOFs)/FeOOH] to construct Fe-O-Ni-O-Fe bonding is demonstrated and the origin of remarkable electrocatalytic performance of Ni-MOFs is elucidated. X-ray absorption/photoelectron spectroscopy and theoretical calculation results indicate that Fe-O-Ni-O-Fe bonding can facilitate the distorted coordinated structure of the Ni site with a short nickel-oxygen bond and low coordination number, and can promote the redistribution of Ni/Fe charge density to efficiently regulate the adsorption behavior of key intermediates with a near-optimal d-band center. Here the Fe-doped-(Ni-MOFs)/FeOOH with interfacial Fe-O-Ni-O-Fe bonding shows superior catalytic performance for OER with a low overpotential of 210 mV at 15 mA cm

Background: We aimed to assess the utility of the poisoning severity score (PSS) as early prognostic predictors in patients with wasp stings, and to explore a reliable and simple predictive tool for short-term outcomes.Methods: From January 2016 to December 2018, 363 patients with wasp stings in Suining Central Hospital were taken as research subjects. In the first 24h of hospital admission, the PSS and Chinese expert consensus on standardized diagnosis and treatment of wasp stings (CECC) were used as the criterion for severity classification, and their correlation was analyzed. The patients were divided into survival and death groups according to the state of discharge. The factors that affect outcome were analyzed by logistic regression analysis. A clinical prognostic model of death was constructed according to the risk factors, and 1000 times repeated sampling was done to include the data to verify the model internally.Results: The mortality of wasp sting patients was 3.9%. There was a correlation between PSS and CECC (r=0.435, PPConclusions: PSS is helpful in the early classification of the severity of wasp stings. Sex, age, number of stings, and PSS were independent risk factors for death in wasp sting patients. The nomogram model established in this study can accurately predict the occurrence of the risk of death.

Searching for a highly efficient electrocatalyst for the hydrogen evolution reaction (HER) in alkaline solution is still challenging. In this work, we report a HER electrocatalyst composed of Ni foam, Ni3S2, and nitrogen-doped carbon nanotubes (NF@Ni3S2@NCNTs). The good lattice matching between Ni and Ni3S2, interstitial doping of C and N atoms, and synergistic effect of NCNTs make NF@Ni3S2@NCNTs highly efficient HER electrocatalysts in alkaline solution. NF@Ni3S2@NCNTs exhibit an overpotential of 93.89 mV at a current density of 10 mA cm-2, a Tafel slope of 54 mV dec-1, and superior stability for HER in 1 M KOH solution. Our findings will promote the reasonable design and synthesis of an efficient electrocatalyst for HER in alkaline electrolytes.

The occurrence characteristics of magnetite and the methods to quickly and effectively explore are important topics for ore prospecting in the new era. Taking northeast of Hebei Province of China as an example, this article aimed at an important strategic mineral of magnetite, then discussed its distribution characteristics and aeromagnetic exploration methods of it. First of all, we discuss the occurrence characteristics of sedimentary metamorphic and magmatic magnetite. Then, using the latest high-precision aeromagnetic data, combined with the geological outcrops, known iron deposits, ground magnetic surveys, and verification, we studied the relationship between the aeromagnetic anomalies and iron deposits through potential field conversion processing of the reduction to the pole, vertical derivative, upward continuation and residual anomaly, and the forward modeling and inversion methods of 2.5 D optimization fitting. Next, we summarize the metallogenic conditions and attributes of aeromagnetic prospecting and make magnetite predictions. In addition, it has suitable magnetite prospecting potential in the Laochenjia, Dabai, Jiuwuying, Beierying, Sidaogoumen, and Wuyingzi aeromagnetic anomaly regions. In conclusion, these regions have aeromagnetic anomalies with high amplitudes, large scales, and favorable metallogenic backgrounds for magmatic rocks, strata, and structures caused by concealed magnetite. In addition, they have great prospecting potential. Eventually, we hope this research method in this article can provide a reference for magnetite exploration in other areas with similar geological conditions.

Metal-organic frameworks (MOFs) with carboxylate ligands as co-catalysts are very efficient for oxygen evolution reaction (OER). However, the role of local adsorbed carboxylate ligands around the in situ transformed metal (oxy)hydroxides during OER is often overlooked. Here we reveal the extraordinary role and mechanism of surface adsorbed carboxylate ligands on bi/trimetallic layered double hydroxides (LDHs)/MOFs for OER catalytic activity enhancement. The results of X-ray photoelectron spectroscopy (XPS), synchrotron X-ray absorption spectroscopy and theoretical calculations show that the carboxylic groups around metal (oxy)hydroxides can efficiently induce the interfacial electron redistribution, facilitate abundant high-valence state of nickel species with partial distorted octahedral structure, and optimize the d-band center together with the beneficial Gibbs free energy of intermediate. Furthermore, the results of in-situ Raman and FI-IR spectra firstly reveal that the surface adsorbed carboxylate ligands as Lewis base can promote the sluggish OER kinetics by accelerating proton transfer and facilitating adsorption/ activation/dissociation of hydroxyl ions (OH−). Our findings will offer unique insights into the reason for disclosing the origin of excellent electrocatalytic activity for MOF/NiFe-LDHs catalysts.

In this paper, the surface insulation performance of 3D-printed functionally graded material (FGM) insulators are investigated. These FGM insulators were fabricated through a self-developed 3D printing technique, which is called as Active-Mixing Fused Deposition Modeling (AM-FDM). Based on a prototypical AM-FDM platform, truncated cone insulators with heterogeneous relative permittivity were fabricated. Then, the surface flashover voltage of 3D-printed d-FGM insulators were tested under 50Hz AC voltage in both air and SF6 atmosphere. Preliminary results indicates a large increase (maximum 41%) in surface flashover voltage, which is especially significant when high pressure SF6 atmosphere $(> \mathbf{0.3\ MPa})$ is utilized. This research provides a novel and universal approach (i.e. AM-FDM 3D printing) for the fabrication of d-FGM objects, and verifies the feasibility of d-FGM in the improvement of surface insulation performance.

Background Coronavirus disease 2019 (COVID-19) is a pandemic that has affected more than 3 million patients globally. Previous data from Wuhan city showed that acute kidney injury (AKI), proteinuria and hematuria occurred frequently in patients with severe COVID-19. However, the prevalence of kidney injury in milder cases remains unclear. Methods This retrospective study included two major consecutive cohorts of COVID-19 patients in Sichuan Province. Baseline characteristics, laboratory data including renal function, proteinuria and dipstick hematuria, and other laboratory parameters were collected. A subgroup of patients was followed up for 2–4 weeks to evaluate the short-term outcome of renal impairment. Results Overall, 168 COVID-19-positive patients were included in the study. The majority of patients (79.7%) were diagnosed with mild or moderate disease. Half of patients presented with fever; however, in The Tibetan cohort, fever only occurred in 13.4% of patients. On hospital admission, proteinuria and dipstick hematuria were noted in 18.4% and 17.4% of patients, respectively, while AKI only occurred in one patient. Further analysis showed that severe or critical COVID-19 was associated with higher risk of proteinuria [relative risk (RR) 7.37, 95% confidence interval (CI) 2.45–22.18, P = 3.8 × 10−4] and dipstick hematuria (RR 8.30, 95% CI 2.69–25.56, P = 2.3 × 10−4). Proteinuria, dipstick hematuria, or the combination of proteinuria and hematuria could significantly predict severe or critical severe COVID-19. Conclusions Proteinuria and dipstick hematuria are not uncommon in patients with COVID-19 infection, especially in severe or critical cases.

Novel coronavirus 2019 (COVID-19) infection is a global public health issue, that has now affected more than 200 countries worldwide and caused a second wave of pandemic. Severe adult respiratory syndrome-CoV-2 (SARS-CoV-2) pneumonia is associated with a high risk of mortality. However, prognostic factors predicting poor clinical outcomes of individual patients with SARS-CoV-2 pneumonia remain under intensive investigation. We conducted a retrospective, multicenter study of patients with SARS-CoV-2 who were admitted to four hospitals in Wuhan, China from December 2019 to February 2020. Mortality at the end of the follow up period was the primary outcome. Factors predicting mortality were also assessed and a prognostic model was developed, calibrated and validated. The study included 492 patients with SARS-CoV-2 who were divided into three cohorts: the training cohort (n = 237), the validation cohort 1 (n = 120), and the validation cohort 2 (n = 135). Multivariate analysis showed that five clinical parameters were predictive of mortality at the end of follow up period, including advanced age [odds ratio (OR), 1.1/years increase (p p p = 0.005)], increased aspartate transaminase [OR, 2.47 (p = 0.019)], and decreased total protein [OR, 1.69 (p = 0.018)]. Furthermore, the prognostic model drawn from the training cohort was validated with validation cohorts 1 and 2 with comparable area under curves (AUC) at 0.912, 0.928, and 0.883, respectively. While individual survival probabilities were assessed, the model yielded a Harrell’s C index of 0.758 for the training cohort, 0.762 for the validation cohort 1, and 0.711 for the validation cohort 2, which were comparable among each other. A validated prognostic model was developed to assist in determining the clinical prognosis for SARS-CoV-2 pneumonia. Using this established model, individual patients categorized in the high risk group were associated with an increased risk of mortality, whereas patients predicted to be in the low risk group had a higher probability of survival.

This paper introduces an adaptive routing algorithm based on Q-learning in the SDON controller, which effectively realizes dynamic load balancing and reduces the risk of congestion in the optical transmission network. © 2020 The Author(s)

In the process of oxygen evolution reaction (OER) on perovskite, it is of great significance to accelerate the hindered lattice oxygen oxidation process to promote the slow kinetics of water oxidation. In this paper, a facile surface modification strategy of nanometer-scale iron oxyhydroxide (FeOOH) clusters depositing on the surface of LaNiO 3 (LNO) perovskite is reported, and it can obviously promote hydroxyl adsorption and weaken Ni-O bond of LNO. The above relevant evidences are well demonstrated by the experimental results and DFT calculations. The excellent hydroxyl adsorption ability of FeOOH-LaNiO 3 (Fe-LNO) can obviously optimize OH - filling barriers to promote lattice oxygen-participated OER (LOER), and the weakened Ni-O bond of LNO perovskite can obviously reduce the reaction barrier of the lattice oxygen participation mechanism (LOM). Based on the above synergistic catalysis effect, the Fe-LNO catalyst exhibits a maximum factor of 5 catalytic activity increases for OER relative to the pristine perovskite and demonstrates the fast reaction kinetics (low Tafel slope of 42 mV dec -1 ) and superior intrinsic activity (TOFs of ~40 O 2 S -1 at 1.60 V vs. RHE).

Realizing synergetic effect of multiple factors is critical to develop an optimal catalyst. Bimetallic oxides have shown great potential for catalytic hydrogen evolution from water splitting in alkaline media because their oxygen species are beneficial for water adsorption and can get unique d electron configurations to optimize the binding strength of intermediates. Here bimetallic oxide heterointerface CoMoO4/Co2Mo3O8 with rich-oxygen vacancies (Vo) incorporated by the monodisperse small-size cobalt (Co) nanoparticles (Co@CoMoO4/Co2Mo3O8-Vo) is designed for hydrogen evolution reaction (HER) in alkaline media. The charge redistribution occurs at the CoMoO4/Co2Mo3O8 interface because of incorporation of Co, and this will be helpful for H* adsorption and interfacial electron transferring. Meanwhile, the rich-oxygen vacancies can well optimize the binding energy of intermediate species on CoMoO4/Co2Mo3O8 interface and thus will facilitate the sluggish HER in alkaline media. Because of the synergistic effects of metallic Co, CoMoO4/Co2Mo3O8 interfaces and rich-oxygen vacancies, the Co@CoMoO4/Co2Mo3O8-Vo catalyst shows superior electrocatalytic activity for HER in alkaline media with a low overpotential of 60 mV at 10 mA cm-2, a small Tafel slop of 52 mV dec-1, and excellent durability with ∼2% degradation after 24 h test. This work will provide a new strategy to enhance HER catalytic performance of bimetallic oxides in alkaline media.

The tremendous works focusing on long-range ordered hydroxides have ignored the investigation of the edge/corner sites in hydroxides, which is recently believed to be crucial for electrocatalytic activity enhancement of oxygen evolution reaction (OER). In this study, by anodic galvanostatic treatment in (NH4)2Fe(SO4)2 solution, the amorphous Ni(OH)2 (am-Ni(OH)2) is transformed into a short-range ordered Fe substituted-Ni(OH)2 (so-Fe-Ni(OH)2), which contains abundant electroactive edge/corner sites. To further enhance surface area, the special tube-in-tube arrays (TTAs) are fabricated for so-Fe-Ni(OH)2 to accelerate the reaction kinetics of OER. From DFT calculation, the low-coordinated defect sites with Fe-Ni-Fe units caused by the short-range ordered structure of so-Fe-Ni(OH)2 TTAs facilitate the formation of adsorbed oxygen, which is rate-determining step for efficient OER. The so-Fe-Ni(OH)2 TTAs show higher OER performance than long-range ordered Fe substituted-Ni(OH)2 (lo-Fe-Ni(OH)2). This study will provide a new strategy for electroactive edge/corner-site engineering of hydroxide-based electrocatalysts for efficient OER.

The efficient bifunctional catalysts for hydrogen and oxygen evolution reactions (HER/OER) have attracted great interest for hydrogen production from water splitting. Herein, the doping and vacancy double control strategy for the design of bifunctional catalysts is firstly demonstrated for the significant enhancement of HER/OER catalytic performances by constructing Fe doped-Ni5P4/Fe-doped Ni(OH)2 (Fe-Ni5P4/NiFeOH) hybrid nanosheets with rich oxygen vacancies. The experimental studies and first-principle calculations both prove that the combined effects of Fe doping and oxygen vacancy can easily regulate the electronic structure and accordingly optimize the adsorptions/desorptions of intermediates. The bifunctional Fe-Ni5P4/NiFeOH-350 shows small overpotentials of 197 and 221 mV for HER and OER, respectively, along with a low cell voltage of 1.55 V at 10 mA cm−2 and excellent long-term stability for water splitting.

The oxygen reduction reaction (ORR) takes place on the surface of catalyst, and the precise control of surface component at atomic scale has been an important factor to effectively improve the performance of catalysts. Herein, a highly active and stable catalyst is designed by constructing Pt skin and controllable near-surface atomic distribution of PtNi alloy nanowires (NWs). It is found that the d-band center of Pt-skin down-shifts with Pt ratio in the surface/near-surface of PtNi alloy decreasing, and correspondingly the adsorption energy of atomic oxygen (ΔEO) on PtNi alloys weakens, confirmed by experimental results and theoretical calculations. The optimum PtNi/C-NH3 NWs exhibit the enhanced mass activity (1.02 A mgPt−1) and specific activity (3.86 mA cm−2) for ORR, which are 5.7-fold and 11.4-fold higher than those of commercial Pt/C, respectively. Moreover, the H2/air fuel cell of PtNi/C-NH3 NWs exhibits a current density of 308 mA cm−2 at 0.8 V, which is superior to that of the 2020 target of the U.S. Department of Energy (DOE). Our study provides a new perspective and approach in promoting the electrocatalysis on alloy nanomaterials for ORR.

HLA-C*07:02:83 differs from HLA-C*07:02:01:01 (387C- A, P105P).

Combining theoretical and experimental studies is one of the most optimistic strategies to synthesize high-performance electrocatalysts for water splitting. Herein Co nanoparticles (NPs)/N-doped carbon (Co/N-C) hybrid electrocatalysts with biactive sites, hierarchical porosity and high specific surface area were successfully designed and fabricated. The detail mechanism of hydrogen evolution through Co*-/N-C*-biactive sites was demonstrated by DFT calculations and was further confirmed via in situ Raman spectra. The coupled effects between the Co NPs and N-doped carbon of Co/N-C hybrids can facilitate water adsorption, activation and dissociation, and the Co/N-C hybrid electrocatalysts exhibit the superior catalytic activity with a low overpotential of only ∼84 mV at 10 mA/cm2 and excellent stability for hydrogen evolution in alkaline media. This study will provide an insight into the biactive sites nature in the Co/N-C hybrids and will offer a new strategy for the design of high-performance electrocatalysts.

Here we report the functional FeOOH as a cocatalyst to enhance excellent bifunctionality of the Ni3N catalyst, which demonstrate remarkable electrocatalytic activity for hydrogen evolution reaction (HER) and oxygen evolution reduction (OER) compared to the pristine Ni3N sample. Experimental data and theoretical calcinations demonstrate that the FeOOH facilitates surface adsorption and cleavage of OH−/H2O species and decrease the d-band center of active Ni species for optimizing the Gibbs free energy of intermediates. Furthermore, relatively vertical Ni3N nanotubes can promote the mass transport and electrons transfer as a main catalyst. The unusual synergistic effect in hybrid system with high density of heterointerface is contributed to the improvement of HER/OER catalytic performance. Specifically, the obtained FeOOH/Ni3N hybrid catalysts display excellent OER/HER performance with an overpotential of 244 mV/67 mV at 10 mA cm−2 in 1.0 M KOH, along with an applied potential of 1.58 V to boost overall water splitting at 10 mA cm−2. This simple and effective strategy may provide a new path to design the bifunctional catalysts and improve the catalytic performance for water splitting.

In 2017, our printing engineering was awarded the "first-class major" construction point of Beijing municipal universities, which laid a good foundation for consolidating the connotation of specialty construction and enhancing major popularity. This paper expounds the contribution of printing engineering to national development and capital development, analyzes the social demand for the capital, economy, society and printing industry, and confirms the indispensable role of printing engineering in the development of national economy.

To investigate the effect of loss of heterozygosity(LOH) in HLA region at initial diagnosis and remission of leukemia patient before transplantation on HLA typing.The HLA typing was performed in DNA extracted from peripheral blood obtained at diagnosis (Sample 1 and Sample 2) and remission (Sample 3) in one pretransplant male patient with mixedphenotype acute leukemia (MPAL). HLA typing for HLA-A, B, C, DQB1, DRB1 was performed by Sequence-based typing (SBT), Sequence-specific oligonucleotide probe hybridization (SSO) and Sequence-specific primers (SSP). To define more precisely a cutoff limit for the detection of a heterozygous DNA present in a fraction of the cells by the SBT technology, DNA mixing experiments were performed.SBT results showed that Sample 1 and Sample 2 were both homozygous HLA results at five loci (lost one haplotype) although the sequencing background of Sample 1 was a little high. Except HLA-C locus was homozygous, Sample 3 was heterozygous HLA results at four loci. Based on DNA mixing experiments, a cutoff limit for the detection of heterozygous DNA was 20% by SBT technology, and a detection threshold for HLA-A, B, C, DQB1, DRB1 heterozygosity in blood samples was75% blasts.Because LOH may be partial, any homozygous HLA result obtained during a blast crisis, especially ≥75% blasts, would have to be confirmed by a second typing on a buccal swab or on peripheral blood from the patient in complete remission.

Deep convolutional neural networks have achieved great success in various applications. However, training an effective DNN model for a specific task is rather challenging because it requires a prior knowledge or experience to design the network architecture, repeated trial-and-error process to tune the parameters, and a large set of labeled data to train the model. In this paper, we propose to overcome these challenges by actively adapting a pre-trained model to a new task with less labeled examples. Specifically, the pre-trained model is iteratively fine tuned based on the most useful examples. The examples are actively selected based on a novel criterion, which jointly estimates the potential contribution of an instance on optimizing the feature representation as well as improving the classification model for the target task. On one hand, the pre-trained model brings plentiful information from its original task, avoiding redesign of the network architecture or training from scratch; and on the other hand, the labeling cost can be significantly reduced by active label querying. Experiments on multiple datasets and different pre-trained models demonstrate that the proposed approach can achieve cost-effective training of DNNs., Comment: 9 pages