Materials Research Bulletin最新文献

{"title":"Cation substitution strategy realizing controllable spectral shape and multiple applications in a novel blue-cyan emitting KBaScSi2O7:Bi3+ phosphor","authors":"Minliang Deng ,&nbsp;Yixin Sun ,&nbsp;Yining Wang ,&nbsp;Xiaole Xing ,&nbsp;Mengmeng Shang","doi":"10.1016/j.materresbull.2024.113125","DOIUrl":"10.1016/j.materresbull.2024.113125","url":null,"abstract":"<div><div>Controlling the emission spectrum shape and the site occupancy tendency are of great significance for designing full-visible-spectrum phosphors in pc-wLEDs application. Herein, a novel blue-cyan emitting KBaScSi₂O₇ (KBSS):Bi³⁺ phosphor is reported. Under excitation at 331 nm UV light, the KBSS:0.04Bi³⁺ exhibits a broadband blue-cyan emission, including a primary peak at 409 nm and a shoulder peak at 493 nm. The two emission peaks exhibit different thermal quenching behaviors because of the existence of defects. The implementation of Y³⁺, Lu³⁺ and Cs⁺ substitutions has successfully enhanced the luminescence intensity of the samples by factors of 1.4, 2, and 2.3, respectively, and the goal of controlling the spectral shape and site occupancy tendency is achieved. Their applications in luminescence thermometers and wLEDs are evaluated. The S_r (relative sensitivity) and S_a (absolute sensitivity) of phosphor are 0.37 % K^-1 and 0.20 % K^-1, respectively and the as-fabricated white LED device shows superior luminescence performance (CCT = 5311 K, Ra = 90).</div></div>","PeriodicalId":18265,"journal":{"name":"Materials Research Bulletin","volume":"182 ","pages":"Article 113125"},"PeriodicalIF":5.3,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Construction of heterojunction MXene/RGO/CoFe-LDH for electromagnetic wave absorption","authors":"Guoxin Ding ,&nbsp;Chenfeng Sun ,&nbsp;Meiyi Wang ,&nbsp;Yuexiang Hu ,&nbsp;Guojun Cheng ,&nbsp;Jun Liu","doi":"10.1016/j.materresbull.2024.113121","DOIUrl":"10.1016/j.materresbull.2024.113121","url":null,"abstract":"<div><div>The 2D nanomaterial has been widely used in the field of electromagnetic wave absorption because of its high specific surface area and special electrical properties. In this work, three 2D materials were integrated to form a unique ternary composite with Ti₃C₂T_x MXene as the substrate, RGO as the intercalator with additional components, and CoFe-LDH loaded on the MXene/RGO surface. The interfacial and dipole polarizations were notably enhanced due to the abundant formation of heterogeneous interfaces between the three 2D materials and their corresponding abundant functional groups and defects, and the space between the 2D lamellae enabled multiple reflections of electromagnetic waves. Compared with pure MXene, the MXene/RGO/CoFe-LDH composites exhibited excellent electromagnetic wave absorption performance due to the synergy of multiple loss mechanisms, resulting in the best reflection loss value of −58.9 dB at 13.12 GHz.</div></div>","PeriodicalId":18265,"journal":{"name":"Materials Research Bulletin","volume":"181 ","pages":"Article 113121"},"PeriodicalIF":5.3,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of Z-scheme BiVO4/g-C3N4/rGO heterojunction nanocomposite for enhanced photocatalytic degradation and antibacterial activity","authors":"Nicharee Akechatree ,&nbsp;Ranjith Rajendran ,&nbsp;Thammasak Rojviroon ,&nbsp;Priyadharsan Arumugam ,&nbsp;Vasanthakumar Vasudevan ,&nbsp;Sanya Sirivithayapakorn ,&nbsp;Arul Dhayalan ,&nbsp;Pongsakorn Wongpipun ,&nbsp;Natacha Phetyim ,&nbsp;Orawan Rojviroon","doi":"10.1016/j.materresbull.2024.113119","DOIUrl":"10.1016/j.materresbull.2024.113119","url":null,"abstract":"<div><div>In this study, we synthesized a novel BiVO₄/g-C₃N₄/rGO (BGR) heterojunction photocatalyst using the hydrothermal method. The synthesized catalysts were characterized through X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDX), Transmission Electron Microscopy (TEM), and Ultraviolet-Visible Diffuse Reflectance Spectroscopy (UV-DRS) to analyze their structural, morphological, and optical properties. The hybrid BGR nanocomposite displayed remarkable absorption characteristics, photocatalytic activity, and notable stability. Photocatalytic degradation performance was evaluated against methylene blue (MB) and indigo carmine (IC) dyes. The BGR ternary hybrid nanocomposites demonstrated significant photocatalytic degradation efficiency, achieving removal rates of 95.6 % for MB and 97.5 % for IC dyes within 120 min. The improved photocatalytic efficiency of the ternary photocatalyst is attributed to superior electron-hole pair separation and the formation of the heterojunction structure. The BGR nanocomposite exhibited excellent recyclability, maintaining its activity and crystalline characteristics over five photodegradation cycles. Additionally, the antibacterial activity of the BGR nanocomposites against <em>Staphylococcus aureus,Escherichia coli, Klebsiella pneumoniae</em>, and <em>Pseudomonas aeruginosa</em> was evaluated under UV–visible light exposure. This study provides insights for designing efficient visible-light-driven photocatalysts for environmental remediation purposes.</div></div>","PeriodicalId":18265,"journal":{"name":"Materials Research Bulletin","volume":"181 ","pages":"Article 113119"},"PeriodicalIF":5.3,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design plasmonic nanostructure of silicon dioxide and titanium dioxide loaded on a nano surface for clean water production through photocatalysis and electrochemical techniques","authors":"Rasha M. El-Gohary ,&nbsp;Nagi M. El-Shafai ,&nbsp;Ibrahim M. El-Mehasseb ,&nbsp;Heba I. Ghamry ,&nbsp;Mohammad Y. Alshahrani ,&nbsp;Amr M. Beltagi","doi":"10.1016/j.materresbull.2024.113120","DOIUrl":"10.1016/j.materresbull.2024.113120","url":null,"abstract":"<div><div>The work is targeted to rebuild the framework of a nanocatalyst (NCat) that depends on the n/p-type heterojunction through the plasmonic structure of reduced graphene oxide (rGO), silicon oxide nanoparticles (SiO₂ NPs), polyvinyl alcohol (PVA NPs), and titanium dioxide (TiO₂ NPs). The removal of medical and organic contaminants occurs via photocatalysis operation which follows through the electrochemical technique and UV-spectrophotometer under visible light with nanocatalyst (rGO@SiO₂@PVA@TiO₂) for clean water and a safe medical environment. The Z-Scheme mechanism explains the development of electron maps in fabricated nanocatalyst engineering to increase the efficiency of the photocatalytic activity. The high activity of the NCat appeared, after 160 min, and the photocatalytic efficiency for methylene blue (MB), methyl orange (MO), rhodamine B (RhB), moxifloxacin (MFX), and colchicine, was 90 %, 76 %, 88 %, 84 %, and 91 % respectively. The stability of NCat was confirmed via the recyclability process, with the efficiency at 58 % after the fifth cycle. The high stability of NCat was proved by the electrochemical technique performed after 100 cycles. The safety of the NCat for the generation of clean water was highlighted by the cytotoxicity test using normal mouse liver cells. It is suggested to use the new NCat design because of its distinctive optical characteristics, which make it a viable candidate for use as a revolutionary nanomaterial with high efficiency and safety for clean water and removal of medical contaminants.</div></div>","PeriodicalId":18265,"journal":{"name":"Materials Research Bulletin","volume":"182 ","pages":"Article 113120"},"PeriodicalIF":5.3,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unravelling charge carrier dynamics for enhancement of photocatalytic performance in Pd/MoS2 nanocomposites for water remediation of real-world pollutants","authors":"Ritu Kumari,&nbsp;Rakesh Kumar","doi":"10.1016/j.materresbull.2024.113122","DOIUrl":"10.1016/j.materresbull.2024.113122","url":null,"abstract":"<div><div>In this study, Pd/MoS₂ nanocomposites were successfully synthesized incorporating Pd nanoparticles into three-dimensional (3D) flower-like MoS₂ nanostructures. The controlled introduction of Pd was aimed to optimize the photocatalytic performance of the resulting nanocomposites, which exhibited exceptional efficiency in degrading various organic pollutants and antibiotic tetracycline (TC) under simulated solar light irradiation. The nanocomposites with an optimized Pd concentration of 2.5 % demonstrated outstanding photocatalytic efficiency, achieving the degradation of Rhodamine B (RhB), Methylene blue (MB), TC by 98 %, 98 %, and 96 %, respectively, with specific interval of 40, 30 and 60 min. The reaction rate constant of the Pd/MoS₂ nanocomposites was measured to be 0.7798 min⁻¹ using pseudo first-order rate kinetics. The value is about 19 times higher than that of pure MoS₂ (0.00414 min⁻¹) for degradation of RhB. The improved photocatalytic performance of these nanocomposites can be attributed to several factors. Firstly, the incorporation of Pd nanoparticles substantially enhanced their light absorption capabilities, leading to an overall increase in photocatalytic efficiency. Moreover, the presence of Pd contributed to a large surface area, further enhancing the nanocomposite's photocatalytic potential. Importantly, the formation of a built-in electric field at Pd/MoS₂ interface facilitated the efficient separation of the electron-hole pairs, extending the life time of these photoinduced charge carriers. This study offers valuable insights into development of MoS₂-based photocatalyst, which hold significant promise for addressing water pollution challenges and making substantial contributions to the field of water purification and environmental remediation.</div></div>","PeriodicalId":18265,"journal":{"name":"Materials Research Bulletin","volume":"181 ","pages":"Article 113122"},"PeriodicalIF":5.3,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ratiometric optical temperature sensing properties based on up-conversion luminescence of novel NaLaTi2O6:Yb3+,Er3+/Ho3+ phosphors","authors":"Kai Li ,&nbsp;Daiman Zhu","doi":"10.1016/j.materresbull.2024.113117","DOIUrl":"10.1016/j.materresbull.2024.113117","url":null,"abstract":"<div><div>To satisfy the increasing necessity of contactless optical thermometry, utilizing both thermally coupled (TCLs) or non-thermally-coupled (NTCLs) energy levels of rare earth ions in novel phosphors has significant potential for devising the optical thermometers with high temperature sensitivity. Herein, a sequence of novel Yb³⁺,Er³⁺/Ho³⁺ doped NaLaTi₂O₆ (NLTO) phosphors were sintered using a high-temperature solid-state reaction approach. Structure, phase component and luminescence performance were identified in detail. Upon 980 nm near-infrared (NIR) excitation, the obtained materials presented typical Er³⁺/Ho³⁺ characteristic emission wavelengths in visible region, which include two green emission bands around 522 and 543 nm, as well as a weaker red band around 661 nm for Er³⁺ doped NLTO, a green emission band around 545 nm and a red band around 657 nm for Ho³⁺ doped NLTO. Besides, a unusual emission band around 757 nm of Ho³⁺ in visible edge region was also clearly found. The temperature sensing properties of representative NLTO:Yb³⁺,Er³⁺/Ho³⁺ samples were assessed based on the fluorescence intensity ratio (FIR) technique of TCLs or NTCLs energy levels. The maximal absolute sensitivity (S_a) and relative sensitivity (S_r) were determined to be 0.0374 K^-1 (293 K) and 0.970% K^-1 (293 K) by taking the FIR of NTCLs ²H_11/2→⁴I_15/2 and ⁴F_9/2→⁴I_15/2 transitions in NLTO:Yb³⁺,Er³⁺. Simultaneously, the maximal S_a and S_r were 0.0306 K^-1 (573 K) and 0.776% K^-1 (373 K) using the FIR of NTCLs ⁵F₅→⁵I₈ and ⁵F₄,⁵S₂→⁵I₇ transitions in NLTO:Yb³⁺,Ho³⁺. Consequently, the temperature sensitivities above can be compared to reported results, which indicate that as-prepared materials have a promising application in optical temperature sensors field.</div></div>","PeriodicalId":18265,"journal":{"name":"Materials Research Bulletin","volume":"181 ","pages":"Article 113117"},"PeriodicalIF":5.3,"publicationDate":"2024-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High performance self-powered photodetection and X-ray detection realized by CH3NH3PbI3 single crystal with planar asymmetric Schottky structure","authors":"Ji Yu ,&nbsp;Yinxian Luo ,&nbsp;Ning Tian ,&nbsp;Lin Li ,&nbsp;Wenzhu Tan ,&nbsp;Ruoning Zheng","doi":"10.1016/j.materresbull.2024.113115","DOIUrl":"10.1016/j.materresbull.2024.113115","url":null,"abstract":"<div><div>Organic-inorganic hybrid perovskite CH₃NH₃PbI₃ (MAPbI₃) single crystals (SCs) have been widely investigated in photodetection and X-ray detection. However, external electric-field-driven ion migration seriously affect the stability of MAPbI₃ SCs based optoelectronic devices. Self-powered device can operate without any external power supply, which is suitable for mitigating the ion migration of MAPbI₃ SCs. To realize self-powered MAPbI₃ SC based photodetector and X-ray detector, an asymmetric Au/CH₃NH₃PbI₃ SC/Au planar Schottky structure is employed in this work. At 0 V, the self-powered photodetector can achieve the responsivity of 11.1 mA/W at the wavelength of 795 nm, and the sensitivity of the self-powered X-ray detector can reach 477.1 μC Gy^-1cm^-2 with the detection limit of as low as 140.3 nGy s^-1. Moreover, the self-powered optoelectronic device exhibits good stability in both photodetection and X-ray detection. Most importantly, high-quality near-infrared bioimaging and X-ray imaging are successfully realized by the above self-powered optoelectronic device.</div></div>","PeriodicalId":18265,"journal":{"name":"Materials Research Bulletin","volume":"181 ","pages":"Article 113115"},"PeriodicalIF":5.3,"publicationDate":"2024-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fabrication of sandwich nanostructured substrates with Au@Ag NCs/Graphene/AgMP for ultrasensitive SERS detection","authors":"Jianxia Qi ,&nbsp;Wanting Zhou ,&nbsp;Chengyuan Yang ,&nbsp;Wen Liu ,&nbsp;Chang Guan ,&nbsp;Chengyun Zhang ,&nbsp;Qingyan Han ,&nbsp;Wei Gao ,&nbsp;Lipeng Zhu ,&nbsp;Jun Dong","doi":"10.1016/j.materresbull.2024.113107","DOIUrl":"10.1016/j.materresbull.2024.113107","url":null,"abstract":"<div><div>This paper presents the design of a bottom-up \"sandwich\" configuration substrate via electrostatic self-assembly. A silver microplate (AgMP) serves as the stable structural base, onto which monolayer graphene is wet-transferred. Au@Ag nanocubes (Au@Ag NCs) are then assembled on the upper layer through liquid-liquid three-phase self-assembly, forming a Au@AgNCs/G/AgMP “sandwich” substrate. The combination of electromagnetic enhancement from noble metal nanoparticles and chemical enhancement from graphene synergistically amplifies the signal of detected molecules, leading to significant Surface-Enhanced Raman Scattering (SERS) enhancement. Experimental results demonstrate that this substrate can detect Rhodamine 6 G (R6G) at concentrations as low as 10^–12 M and Crystal Violet (CV) at 10^–9 M. Moreover, the substrate can detect Aspartame (APM) at concentrations as low as 0.0625 g/L, well below the typical daily intake levels for humans. These findings indicate that the substrate exhibits excellent SERS performance and holds significant potential for broad applications.</div></div>","PeriodicalId":18265,"journal":{"name":"Materials Research Bulletin","volume":"181 ","pages":"Article 113107"},"PeriodicalIF":5.3,"publicationDate":"2024-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Flexible PVDF-Ba0.97Ca0.03TiO3 polymer-ceramic composite films for energy storage, biosensor, mechanosensor, and UV–visible light protection","authors":"P. Elorika ,&nbsp;Sharmistha Anwar ,&nbsp;Amritendu Roy ,&nbsp;Shahid Anwar","doi":"10.1016/j.materresbull.2024.113116","DOIUrl":"10.1016/j.materresbull.2024.113116","url":null,"abstract":"<div><div>Multifunctional piezoelectric devices, which can detect pressure, store electrostatic energy, block UV radiation, and generate electricity from body movements, are highly beneficial for enhancing individual well-being. To achieve these capabilities, polyvinylidene fluoride (PVDF) composite films with Ba_0.97Ca_0.03TiO₃ (BCT3) filler were prepared, varying the BCT3 content from 0 to 50 wt.%. The BCT3 ceramic, prepared using a modified solid-state reaction, exhibits a tetragonal phase at room temperature with a d₃₃ value of 105 pC/N. X-ray diffraction confirms composite formation. The beta phase ranges from 75 to 86.9 %. At 40 wt.% BCT3, the dielectric constant, energy density, and piezoelectric properties peak, yielding maximum W_rec and W_tot of 138.1 and 284.7 mJ/cm³ (@ 250 kV/cm), respectively. PVDF-BCT3-40 (40 wt.%) shows maximum voltage, current, and power density of 25 V, 26.8 nA, and 19.8 μW/cm³ under a 50 N load. Increasing BCT3 content enhances UV–visible absorbance, making the composites effective for light shielding.</div></div>","PeriodicalId":18265,"journal":{"name":"Materials Research Bulletin","volume":"181 ","pages":"Article 113116"},"PeriodicalIF":5.3,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extraction of uranium from water: A strategy based on tribocatalysis","authors":"Baoyi Liu ,&nbsp;Shuo Zhang ,&nbsp;Zihao Ye ,&nbsp;Feixue Gao ,&nbsp;Peng Zhao ,&nbsp;Ming Fang ,&nbsp;Bin Ma ,&nbsp;Kangle Shang ,&nbsp;Xiaoli Tan","doi":"10.1016/j.materresbull.2024.113109","DOIUrl":"10.1016/j.materresbull.2024.113109","url":null,"abstract":"<div><div>Due to most of the U(VI) extraction methods suffering the issues of high cost and low efficiency, finding a new method is still urgent. In this work, we report a way to remove U(VI) from water by tribocatalysis, where a natural mineral of attapulgite is used as the tribocatalyst. By a careful investigation, it is confirmed that the ultrasonic-generated microbubbles rub with the attapulgite to form free radicals of h⁺, ·O₂^-, and ·OH, which could then be transformed to H₂O₂ to react with U(VI) to form UO₂O₂. The extraction rate of U(VI) from water is up to 87.88% (50 ppm) in 200 min. This work using the natural mineral attapulgite being tribocatalyst has the advantages of low cost and high efficiency, which also provide new insight into the conversion of U(VI) in natural conditions and will have great potential in the treatment of nuclide wastewater and seawater.</div></div>","PeriodicalId":18265,"journal":{"name":"Materials Research Bulletin","volume":"181 ","pages":"Article 113109"},"PeriodicalIF":5.3,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417901","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}