Adhesion strength of tetrahydrofuran hydrates is dictated by substrate stiffness

Understanding the hydrate adhesion is important to tackling hydrate accretion in petro-pipelines.Herein,the relationship between the Tetrahydrofuran(THF)hydrate adhesion strength(AS)and surface stiffness on elastic coatings is systemically examined by experimental shear force measurements and theoretical methods.The mechanical factor-elastic modulus of the coatings greatly dictates the hydrate AS,which is explained by the adhesion mechanics theory,beyond the usual factors such as wettability and structural roughness.Moreover,the hydrate AS increases with reducing the thickness of the elastic coatings,resulted from the decrease of the apparent surface elastic modulus.The effect of critical thickness for the elastic materials with variable elastic modulus on the hydrate AS is also revealed.This study provides deep perspectives on the regulation of the hydrate AS by the elastic modulus of elastic materials,which is of significance to design anti-hydrate surfaces for mitigation of hydrate accretion in petro-pipelines.

Effect of hot isostatic pressing processing parameters on microstructure and properties of Ti60 high temperature titanium alloy

Hot isostatic pressing parameters are critical to Ti60 high temperature titanium alloy castings which have wide application perspective in aerospace.In order to obtain optimal processing parameters,the effects of hot isostatic pressing parameters on defects,composition uniformity,microstructure and mechanical properties of Ti60 cast high temperature titanium alloy were investigated in detail.Results show that increasing temperature and pressure of hot isostatic pressing can reduce defects,especially,the internal defects are substantially eliminated when the temperature exceeds 920℃or the pressure exceeds 125 MPa.The higher temperature and pressure can improve the microstructure uniformity.Besides,the higher pressure can promote the composition uniformity.With the temperature increases from 880℃to 960℃,α-laths are coarsened.But with increasing pressure,the grain size of prior-βphase,the widths ofα-laths andα-colony are reduced.The tensile strength of Ti60 alloy is 949 MPa,yield strength is 827 MPa,and the elongation is 11%when the hot isostatic pressing parameters are 960℃/125 MPa/2 h,which exhibits the best match between the strength and plasticity.

全脊柱内镜下治疗极外侧型腰椎间盘突出症的疗效评价

目的评估经皮全脊柱内镜下腰椎间盘切除术(PELD)治疗极外侧型腰椎间盘突出症(FLDH)的临床疗效。方法回顾性分析2014年6月-2015年9月该科采用经皮全脊柱内镜技术治疗FLDH 27例,年龄41~64岁,平均52.3岁,通过观察手术时间、术中出血量和住院时间,采用视觉模拟评分(VAS)评估术前及术后患者腰腿痛情况,改良Mac Nab评分评估患者腰部功能恢复情况。结果单节手术时间为69 min(58~109 min)、术中出血量为18 ml(11~40 ml)、住院时间为5.0 d(3.0~10.0 d),术前VAS评分(8.12±1.25),术后第3天VAS评分(2.80±1.12),术后3个月VAS评分(1.59±1.06),末次随访VAS评分(1.31±0.89),术后VAS评分与术前相比差异均有统计学意义(P<0.05)。采用改良Mac Nab标准评估,优良率为88.9%。结论 PELD治疗FLDH具有创伤小、恢复快等优点,是一种安全、有效的微创手术。

叶根与轮槽配合间隙对压缩机叶片结构动力学特性影响

基于单向流固耦合的有限元方法,以某压缩机叶片为研究对象,计算了叶根与轮槽接触面在不同间隙时叶片的强度与振动特性,分析了不同间隙状态下叶片的静应力、动频率以及动应力的变化趋势。研究表明:叶根与轮槽在无间隙设计以及0.15mm间隙条件下,叶片静应力大小相当,峰值应力位置一致。不同间隙条件下,叶根与轮槽接触状态发生变化,叶片起振点表现出差异,且前三阶共振频率随着间隙的增大而减小,其中二阶共振频率变化最大,达28.7%。接触间隙的变化使参振尺寸和共振频率发生变化,产生不同的峰值应力,该应力随着间隙的增大而降低。

基于径向热变形的滑阀滞卡数值研究（英文）

液压滑阀常常在使用过程中伴随着黏性加热现象,这将严重影响液压滑阀的控制特性。为了揭示滑阀的热失效故障,建立带有配合间隙的滑阀热特性模型,运用COMSOL软件内置的共轭传热与粒子追踪模块通过求解滑阀热特性模型,对液压滑阀内的流动与传热过程进行数值解析。结果表明:高温主要出现在速度梯度较大的区域以及受高速油液冲击的节流槽壁面;由此导致滑阀配合边上产生不均匀径向热变形,固体颗粒物在发生变形的间隙更容易聚集,由此可知,滑阀配合边的径向热变形对颗粒物的污染卡紧有促进作用。这些研究成果为工程技术人员对液压滑阀卡紧现象提供可视化的理解。

Inhibition of RhoA/Rho-kinase pathway suppresses the expression of extracellular matrix induced by CTGF or TGF-β in ARPE-19

AIM:To investigate the role of Rho-associated protein kinase (ROCK) inhibitor, Y27632, in mediating the production of extracellular matrix (ECM) components including fibronectin, matrix metallo-proteinase-2 (MMP-2) and type I collagen as induced by connective tissue growth factor(CTGF) or transforming growth factor-β (TGF-β) in a human retinal pigment epithelial cell line, ARPE-19. METHODS:The effect of Y27632 on the CTGF or TGF-β induced phenotype in ARPE-19 cells was measured with immunocytochemistry as the change in F-actin. ARPE-19 cells were treated with CTGF (1, 10, 100ng/mL)and TGF-β (10ng/mL) in serum free media, and analyzed for fibronectin, laminin, and MMP-2 and type I collagen by RT-qPCR and immunocytochemistry. Cells were also pretreated with an ROCK inhibitor, Y27632, to analyze the signaling contributing to ECM production. ·RESULTS:Treatment of ARPE-19 cells in culture with TGF-β or CTGF induced an ECM change from a cobblestone morphology to a more elongated swirl pattern indicating a mesenchymal phenotype. RT-qPCR analysis and different gene expression analysis demonstrated an upregulation in expression of genes associated with cytoskeletal structure and motility. CTGFor TGF-β significantly increased expression of fibronectin mRNA (P =0.006, P =0.003 respectively), laminin mRNA (P =0.006, P =0.005), MMP-2 mRNA (P =0.006, P =0.001), COL1A1 mRNA (P =0.001, P =0.001), COL1A2 mRNA (P = 0.001, P =0.001). Preincubation of ARPE-19 with Y27632 (10mmol/L) significantly prevented CTGF or TGF-β induced fibronectin (P=0.005, P=0.003 respectively), MMP-2 (P = 0.003, P =0.002), COL1A1 (P =0.006, P =0.003), and COL1A2 (P =0.006, P =0.004) gene expression, but not laminin (P =0.375, P =0.516). CONCLUSION:Our study demonstrated that both TGF-β and CTGF upregulate the expression of ECM components including fibronectin, laminin, MMP-2 and type I collagen by activating the RhoA/ROCK signaling pathway. During this process, ARPE-19 cells were shown to change from an epithelial to a mesenchymal phenotype in vitro. Y27632, a ROCK inhibitor, inhibited the transcription of fibronectin, MMP-2 and type I collagen, but not laminin. The data from our work suggest a role for CTGF as a profibrotic mediator. Inhibiting the RhoA/ROCK pathway represents a potential target to prevent the fibrosis of retinal pigment epithelial (RPE) cells. This might lead to a novel therapeutic approach to preventing the onset of early proliferative vitreoretinopathy(PVR).

Neuroprotective effects of BDNF and GDNF in intravitreally transplanted mesenchymal stem cells after optic nerve crush in mice

AIM： To assess the neuro-protective effect of bone marrow mesenchymal stem cells （BMSCs） on retinal ganglion cells （RGCs） following optic nerve crush in mice. METHODS： C56BL/6J mice were treated with intravitreal injection of PBS, BMSCs, BDNF-interference BMSCs （BIM）, and GDNF-interference BMSCs （GIM） following optic nerve crush, respectively. The number of surviving RGCs was determined by whole-mount retinas and frozen sections, while certain mRNA or protein was detected by q-PCR or ELISA, respectively.RESULTS： The density （cell number/mm^2） of RGCs was 410.77±56.70 in the retina 21d after optic nerve crush without any treatment, compared to 1351.39±195.97 in the normal control （P〈0.05）. RGCs in BMSCs treated eyes was 625.07±89.64/mm^2, significantly higher than that of no or PBS treatment （P〈0.05）. While RGCs was even less in the retina with intravitreal injection of BIM （354.07±39.77） and GIM （326.67±33.37） than that without treatment （P〈0.05）. BMSCs injection improved the internal BDNF expression in retinas.CONCLUSION： Optic nerve crush caused rust loss of RGCs and intravitreally transplanted BMSCs at some extent protected RGCs from death. The effect of BMSCs and level of BDNF in retinas are both related to BDNF and GDNF expression in BMSCs.

β-Ⅲ-Tubulin: a reliable marker for retinal ganglion cell labeling in experimental models of glaucoma

·AIM: To evaluate the reliability of β-III-Tubulin protein as a retinal ganglion cell(RGC) marker in the experimental glaucoma model.·METHODS: Glaucoma mouse models were established by injecting polystyrene microbeads into the anterior chamber of C57BL/6J mice, then their retinas were obtained 14 d and 28 d after the intraocular pressure(IOP)was elevated. Retinal flat mounts and sections were double-labeled by fluorogold(FG) and β-III-Tubulin antibody or single-labeled by β-III-Tubulin antibody,then RGCs were counted and compared respectively.· RESULTS: IOP of the injected eyes were elevated significantly and reached the peak at 22.8 ±0.7 mm Hg by day 14 after injection, then dropped to 11.3 ±0.7 mm Hg by day 28. RGC numbers counted by FG labeling and β-III- Tubulin antibody labeling were 64 807 ± 4930 and64 614 ±5054 respectively in the control group, with no significant difference. By day 14, RGCs in the experimental group decreased significantly compared to the control group, but there was no significant difference between the FG labeling counting and the β-III-Tubulin antibody labeling counting either in the experimental group or in the control group. The result was similar by day 28, with further RGC loss.·CONCLUSION: Our result suggested that the β-III-Tubulin protein was not affected by IOP elevation and can be used as a reliable marker for RGC in experimental models of glaucoma.

Metal-Free Hexagonal Perovskite High-Energetic Materials with NHOH/NHNH as B-Site Cations

寻找可经由简单路线合成的高性能含能材料是发展先进实用含能材料的重要问题。文中通过合理地选择分子组分,经由易于规模放大的简单合成路线,以NH3OH^+和NH2NH3^+分别作为B位点阳离子构筑了两例无金属六方钙钛矿含能材料(H2dabco)B(ClO4)3(分别命名为DAP-6和DAP-7,其中,H2dabco2+是1,4-二氮杂双环[2.2.2]辛烷-1,4-二鎓离子)。与基于NH4^+阳离子构筑的立方钙钛矿类似物(H2dabco)(NH4)(ClO4)3相比,DAP-6和DAP-7有较高的晶体堆积密度和生成焓,从而具有更高的爆轰性能。特别地,DAP-7具有超高热稳定性(起始分解温度Td=375.3℃)、高爆速(D=8.883 km·s^-1)和高爆压(P=35.8 GPa),因此具有作为耐热炸药的应用潜力。计算表明,DAP-6不仅具有较高的热稳定性(Td=245.9℃)以及优异的爆轰性能(D=9.123 km·s^-1,P=38.1 GPa),而且其爆热值(Q=6.35 kJ·g^-1)和理论比冲值(Isp=265.3 s)均稍优于六硝基六氮杂异伍兹烷(CL-20:Q=6.23 k J·g^-1,Isp=264.8 s),在炸药和推进剂领域中具有很好的应用前景。

Novel roles of lipopolysaccharide and TLR4/NF-κB signaling pathway in inflammatory response to liver injury in Budd-Chiari syndrome

BACKGROUND Budd-Chiari syndrome(BCS)is an uncommon disorder characterized by obstruction of hepatic venous outflow.To date,the exact mechanism underlying hepatic injury derived from the hepatic venous outflow obstruction in BCS remains largely unknown.AIM To assess the role of NF-κB-mediated inflammation in BCS-induced liver injury in humans and rats.METHODS A total of 180 rats were randomly assigned into nine groups,including four BCS model groups(1,3,6 and 12 wk),four sham-operated groups(1,3,6 and 12 wk),and a control group.Lipopolysaccharide(LPS)levels in each group were detected by the Tachypleus Amebocyte Lysate assay.The mRNA and protein levels of TLR4,NF-κB,tumor necrosis factor(TNF)-α,interleukin(IL)-2 and interferon(IFN)-γwere quantified.In addition,60 patients with BCS and 30 healthy controls were enrolled,and their blood samples were analyzed.RESULTS Hepatic and plasma LPS levels were significantly increased in rats.The mRNA and protein expression levels of TLR4,NF-κB and inflammatory cytokines(TNF-α,IL-2 and IFN-γ)in liver tissues were significantly higher in the BCS model groups compared with the other two groups.In addition,the model groups(1,3,6 and 12 wk after BCS induction)showed significant differences in the levels of LPS,TLR4,NF-κB,TNF-α,IL-2 and IFN-γ.Notably,there was a significant correlation between the LPS concentrations and mRNA and protein levels of TLR4,NF-κB and inflammatory cytokines.Importantly,it was revealed that the levels of LPS,TLR4,NF-κB and inflammatory cytokines were significantly greater in chronic BCS patients than healthy controls and acute BCS patients.CONCLUSION LPS level is markedly elevated in BCS,in turn activating the TLR4/NF-κB signaling pathway,leading to induction of inflammatory cytokines(TNF-α,IL-2 and IFN-γ)in response to BCS-induced liver injury.

Adaptive optics scanning laser ophthalmoscopy in fundus imaging, a review and update

Adaptive optics scanning laser ophthalmoscopy（AOSLO） has been a promising technique in funds imaging with growing popularity. This review firstly gives a brief history of adaptive optics（AO） and AO-SLO. Then it compares AO-SLO with conventional imaging methods（fundus fluorescein angiography, fundus autofluorescence, indocyanine green angiography and optical coherence tomography） and other AO techniques（adaptive optics flood-illumination ophthalmoscopy and adaptive optics optical coherence tomography）. Furthermore, an update of current research situation in AO-SLO is made based on different fundus structures as photoreceptors（cones and rods）, fundus vessels, retinal pigment epithelium layer, retinal nerve fiber layer, ganglion cell layer and lamina cribrosa. Finally, this review indicates possible research directions of AO-SLO in future.

Effect of body position on the pathogenesis of asymmetric primary open angle glaucoma

AIM： To explore the pathogenesis of asymmetric primary open angle glaucoma（POAG） in both eyes by comparing the intraocular pressure（IOP） of patients who sleep in different positions and to investigate the relationship between IOP variations and sleep positions.METHODS： One hundred and thirty-one patients with asymmetric POAG and forty-six healthy volunteers were enrolled. All participants completed a questionnaire that provided information about their sleep laterality. The cup disc ratio（C/D） and visual field defect established binocular asymmetry. The IOP of both eyes was measured using i Care parameters after the patients were asked to change body position. The ＂worse＂ and ＂better＂ eyes were identified according to the diagnosis, whereas the ＂dependent＂ and ＂independent＂ eyes were defined according to the lateral position. RESULTS： No significant difference in sleep laterality was observed between healthy people and patients with POAG（F=3.195, P=0.362）. Among the enrolled patients, the IOP of the dependent eye was always greater than that of the independent eye in the lateral position（P〈0.05）. In the patients with binocular asymmetric POAG, the questionnaire clearly showed that 85.7% of left side preferences were found their left eyes to be the worse eyes and the right eyes of 71.4% patients with a right side preference were the more serious. When the asymmetric C/D ratio was greater than or equal to 0.2, the worse eye of patients with POAG and a preferred sleeping position was the dependent eye（χ~2=16.762, P=0.001）.CONCLUSION： A higher IOP was measured in the dependent eye in the lateral position. The long-term tendency to choose a lateral sleeping position might lead the dependent eye to manifest more severe symptoms than the independent eye. Thus, the lateral sleeping position might be one cause of asymmetric POAG.

Detecting the possibility of a type of photon number splitting attack in decoy-state quantum key distribution

The existing decoy-state quantum key distribution(QKD)beating photon-number-splitting(PNS)attack provides a more accurate method to estimate the secure key rate,while it still considers that only single-photon pulses can generate secure keys in any case.However,multiphoton pulses can also generate secure keys if we can detect the possibility of PNS attack in the channel.The ultimate goal of this line of research is to confirm the absence of all types of PNS attacks.In particular,the PNS attack mentioned and detected in this paper is only the weaker version of PNS attack which significantly changes the observed values of the legitimate users.In this paper,under the null hypothesis of no weaker version of PNS attack,we first determine whether there is an attack or not by retrieving the missing information of the existing decoy-state protocols,extract a Cauchy distribution statistic,and further provide a detection method and the type I error probability.If the result is judged to be an attack,we can use the existing decoy-state method and the GLLP formula to estimate the secure key rate.Otherwise,the pulses with the same basis received including both single-photon pulses and multiphoton pulses,can be used to generate the keys and we give the secure key rate in this case.Finally,the associated experiments we performed(i.e.,the significance level is 5%)show the correctness of our method.

Ant sting-induced whole-body pustules in an inebriated male:A case report

BACKGROUND Many ant species can harm humans;however,only a few cause life-threatening allergic reactions.Normally,reactions caused by ants occur in patients who come into contact with ant venom.Venom contains various biologically active peptides and protein components,of which acids and alkaloids tend to cause anaphylaxis.Ant venom can cause both immediate and delayed reactions.The main histopathological changes observed in ant hypersensitivity are eosinophil recruitment and Th2 cytokine production.CASE SUMMARY A 70-year-old man was bitten by a large number of ants when he was in a drunken stupor and was hospitalized at a local hospital.Five days later,because of severe symptoms,the patient was transferred to our hospital for treatment.Numerous pustules were observed interspersed throughout the body,with itching and pain reported.He had experienced fever,vomiting,hematochezia,mania,soliloquy,sleep disturbances,and elevated levels of myocardial enzymes since the onset of illness.The patient had a history of hypertension for more than 1 year,and his blood pressure was within the normal range after hypotensive drug treatment.He had no other relevant medical history.Based on the clinical history of an ant bite and its clinical manifestations,the patient was diagnosed with an ant venom allergy.The patient was treated with 60 mg methylprednisolone for 2 d,40 mg methylprednisolone for 3 d,and 20 mg methylprednisolone for 2 d.Oral antihistamines and diazepam were administered for 12 d and 8 d,respectively.Cold compresses were used to treat the swelling during the process.After 12 d of treatment,most pustules became crusts,whereas some had faded away.No symptoms of pain,itching,or psychological disturbances were reported during the follow-up visits within 6 mo.CONCLUSION This case report emphasizes the dangers of ant stings.

Using PVP/SDS Complex as a Probe to Study the Inclusion Complex of β-cyclodextrin with SDS in Aqueous Solution

PVP/SDS complex was applied as a probe to study the interaction between β-cyclodextrin （β-CD） and sodium dodecyl sulfate （SDS） in aqueous solution. It has been found that a critical concentration, namely cs, exists in the relative viscosity of solution containing PVP/SDS complex versus β-CD concentration plot. As the β-CD concentration is less than cs, the relative viscosity of solution decreases sharply by adding β-CD into solution successively. On the other hand, as the β-CD concentration is greater than cs, the relative viscosity of solution increases gradually by adding β-CD into solution. The decrease of the relative viscosity of solution containing PVP/SDS in the presence of β-CD is just due to the inclusion complex of β-CD with the guest molecule SDS. And, this inclusion interaction takes down SDS from the PVP chains in solution. The ratio of the host molecule β-CD to the guest molecule SDS can be calculated from Cs. In our experiment the inclusion ratio of β-CD to SDS is 1/1. The further experimental results indicate that cs is associated with SDS but free from PVP in PVP/SDS complex. However, the inclusion ratio of β-CD to SDS has proved to be independent of either SDS or PVP in PVP/SDS complex.

Composition formula of Al-TMs high-entropy alloys derived by cluster-plus-glue-atoms model and its experimental verification

High-entropy alloys(HEAs)are based on solid solutions which characterized by chemical short-range ordering(CSRO),but there is no accurate structural tool to address CSRO characteristic,which obstacles precise composition design for HEAs.In this study,based on the cluster-plus-glue-atoms model,the composition law of Al-TMs(TMs,transition metals)HEAs with BCC and FCC structures was revealed.In BCC structure,with five elements in equi-atomic ratio,the composition formula of Al-TMs HEAs can be expressed by a cluster formula[Al-M_(14)]Al_(3),and in non equi-atomic ratio can be expressed by[Al-M_(14)]Al,where M is the average atom of the TMs.But in FCC structure,both Al-TMs HEAs with five elements in equiatomic and non equi-atomic ratios can be expressed by a cluster formula[Al-M_(12)]Al.To confirm the effectiveness of cluster formula for Al-TMs,two alloys were designed,[Al-Ti_(4)V_(3)Nb_(4)Mo_(3)]Mo and[Al-Ti_(3)V_(3)Nb_(4)Mo_(4)]Al.Results show that the[Al-Ti_(3)V_(3)Nb_(4)Mo_(4)]Al alloy has both higher strength and higher plastic deformation at room temperature.Besides,[Al-Ti_(3)V_(3)Nb_(4)Mo_(4)]Al alloy shows slower soften effect at 800℃,contributed to its higher strength.By substituting Ta for some of Mo,the strength of[Al-Ti_(3)V_(3)Nb_(4)Mo_(3)Ta]Al at room temperature and high temperature drastically decreases,suggesting that Ta element deteriorates the properties of Al-TMs alloys.

Effects of immunosuppressants after penetrating keratoplasty:meta-analysis of randomized controlled trials

AIM: To assess the effectiveness of immunosuppressants in the prophylaxis of corneal allograft rejection after high-risk keratoplasty and normal-risk keratoplasty. METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CNKI, VIP and reference lists of articles. Date of most recent search: 18 June, 2011. All randomised controlled trials (RCTs) assessing the use of immunosupressants in the prevention of graft rejection, irrespective of publication language. Two authors assessed trial quality and extracted data independently. Only dichotomous outcomes (clear graft survival, ratio of immune reactions and side effects) were available and were expressed as relative risk (RR) and 95% confidence intervals (CI). RESULTS: Seven studies were included in this review. In the comparing of mycophenolate mofetil (MMF) with placebo, the results showed MMF could significantly reduce immune reactions compared with placebo (RR 1.08 95% Cl 0.95 to 1.21), but no effect on clear graft survival (RR 1.11 95% Cl 0.90 to 1.35). In clear graft survival and immune reactions, MMF and cyclosporine A (CsA) showed similar effect (RR 1.11 95% Cl 0.90 to 1.35, and RR 1.48, 95% Cl 0.56 to 3.93, respectively). Tacrolimus (FK506) and steroid showed similar effects on clear graft survival and immune reactions (RR 0.32, 95% CI 0.02 to 6.21, and RR 1.00, 95%CI 0.88 to 1.14, respectively). No drug relative side effect has been found. CONCLUSION: MMF may reduce immune reactions in both normal-risk and high-risk rejection of penetrating keratoplasty. CsA and FK506 showed similar effects as MMF. However, due to the lack of large clinical trials, the evidence remain weak, the quality of evidences were rated as very low to moderate. Large, properly randomised, placebo-controlled, double masked trials are needed to evaluate the effect of immunosuppressants.

构筑未来:框架化学的研究前沿与产业化展望

基于“框架化学的基础及应用研究”研讨会,本文阐述了“框架化学”的科学内涵,从框架结构的设计合成、精确表征、高性能化和产业应用四个方面综述了框架化学领域的主要研究进展,凝练了该领域的关键科学问题,并提出了面向国家需求和产业发展的重点发展方向.

Precisely Tailoring the First Coordination Shell of Metal Centers in Porous Nitrogen-Doped Carbon Promoting Electroreduction of CO^(2)Under Neutral Condition

Precise regulation of the coordination environment of a metal active center is very important but remains a challenge.Here,single-atom Ni catalysts with a combined N-and C-coordination structure(Ni-NC_(3))and N-coordination structure(Ni-N4)were prepared by modulating the side groups of organic ligands in the corresponding precursor metal–azolate frameworks.Compared with the Ni-N4 site,the d-band center of 3d orbitals of the Ni atom in Ni-NC_(3)was more significantly shifted to the Fermi energy level;thus,the Ni-NC_(3)catalytic site was superior to activating CO_(2)molecule into the*COOH intermediate.As a result,Ni-NC_(3)exhibited an exceptionally high performance for CO_(2)-to-CO conversion with a Faradaic efficiency of 98.4%,an energy efficiency of>50%,as well as an industrial current density of∼300 mA cm^(−2) in neutral electrolyte.Such high performance could be retained for at least 70 h.This work reveals the importance of modulating the coordination environment in the electrochemical CO_(2)reduction reaction and provides a possible way to rational design of electrocatalysts for highly efficient conversion of CO_(2)to target products.

Achieving excellent temperature-stable dielectric properties of Bi_(0.5)Na_(0.5)TiO_(3)-based lead-free ceramics via doping AgNbO_(3)

The lead-free ceramics(1−x)(0.94Bi0.47Na0.47Ba0.06TiO3-0.06BiAlO3)-xAgNbO3(denoted as BNBTA-xAN)were synthesized via a solid-state sintering method.The effect of AgNbO3 doping amount on dielectric properties of the ceramics was studied systematically.X-ray diffraction(XRD),scanning electron microscope(SEM)and Raman spectroscope were used to detect the structure of the ceramics.Temperature-dependent dielectric spectra,frequency-dependent dielectric constant and alternating current(ac)electric conductance at various temperatures were measured.The doping of AgNbO3 greatly reduces dielectric constant around Curie temperature and thus enhances the temperature stability of the dielectric constant.The ceramic BNBTA-0.03AN exhibits excellent temperature-stable dielectric properties with temperature coefficient of capacitance(TCC)≤±15%between 55°C and 418°C with temperature window 363°C and small changes of dielectric constant and dielectric loss from 100 Hz to 1 MHz at different temperatures.The obtained ceramics are expected to be used in high-temperature capacitors due to its excellent temperature stability.