mesoporous

介孔
  • 文章类型: Journal Article
    开发具有大孔和高比表面积的三维(3D)共价有机骨架(COF)对于实际应用至关重要。然而,协调高孔隙率和高比表面积之间的矛盾仍然是一个巨大的挑战,增加构建块的长度会导致3DCOF中的结构相互渗透。这里,我们报道了一种新的空间位阻工程方法制备介孔三维COF。通过将金刚烷而不是碳中心掺入单体中,我们成功实现了2倍互穿金刚石结构的3DCOFs,具有永久性中孔(高达33µ),特别高的表面积(>3400m2g-1),和低晶体密度(0.123gcm-3)。这些特性远远超过具有类似拓扑的大多数传统3DCOF。这项工作不仅旨在构建低渗透的3DCOF,而且还为3DCOF的系统设计和结构控制奠定了基础。
    The development of three-dimensional (3D) covalent organic frameworks (COFs) with large pores and high specific surface areas is of critical for practical applications. However, it remains a tremendous challenge to reconcile the contradiction between high porosity and high specific surface areas, and increasing the length of building blocks leads to structural interpenetration in 3D COFs. Here, we report the preparation of mesoporous three-dimensional COF by a new steric hindrance engineering method. By incorporating adamantane into the monomers instead of carbon centers, we successfully achieve 2-fold interpenetrated diamondoid-structured 3D COFs, featuring permanent mesopores (up to 33 Å), exceptionally high surface areas (>3400 m2 g-1), and low crystal densities (0.123 g cm-3). These properties far surpass those of most conventional 3D COFs with similar topologies. This work not only aims to construct 3D COFs with low interpenetration but also to establish a foundation for the systematic design and structural control of 3D COFs.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    具有高比表面积的介孔催化剂,可接近的孔隙结构,和适当的带边缘是理想的,以实现跨界面的最佳电荷转移,抑制电子-空穴复合,并促进活性部位的氧化还原反应。本研究证明了介孔ZnFe2O4@g-C3N4磁性纳米复合材料(MNCs)的合理设计,具有不同的孔径和孔体积,并结合了简单的热瘙痒和热浸渍方法。跨国公司保持结构,形态学,和物理属性,同时确保其有效性和卓越的催化能力。形态分析证实了ZnFe2O4纳米颗粒与聚合物g-C3N4纳米片的成功接枝和限制,以形成具有许多界面的异质结。MNCs具有均匀分布的小中孔(孔径<4nm),充足的活跃网站,和62.50m2/g的高比表面积。介孔ZnFe2O4@g-C3N4显著提高了析氢速率和亚甲基蓝染料降解。ZnFe2O4的最佳加载量为20%,在太阳光照射下,MNC显示出最高的氢析出速率为1752µmol-1h-1,光Fenton染料降解速率常数为0.147min-1。此外,光催化剂在五个连续循环中表现出可回收性,确认其稳定性,而容易分离使用一个简单的磁铁强调实用。
    Mesoporous catalysts with a high specific surface area, accessible pore structures, and appropriate band edges are desirable for optimal charge transfer across the interfaces, suppress electron-hole recombination, and promote redox reactions at the active sites. The present study demonstrates the rational design of mesoporous ZnFe2O4@g-C3N4 magnetic nanocomposites (MNCs) with different pore sizes and pore volumes following a combination of facile thermal itching and thermal impregnation methods. The MNCs preserve the structural, morphological, and physical attributes of their counterparts while ensuring their effectiveness and superior catalytic capabilities. The morphological analysis confirms the successful grafting and confinement of ZnFe2O4 nanoparticles with the polymeric g-C3N4 nanosheets to form heterojunctions with numerous interfaces. The MNCs possess uniformly distributed small mesopores (pore size <4 nm), ample active sites, and a high specific surface area of 62.50 m2/g. The mesoporous ZnFe2O4@g-C3N4 notably improve hydrogen evolution rate and methylene blue dye degradation. The optimal loading weight of ZnFe2O4 is 20%, in which the MNCs display the highest hydrogen evolution rate of 1752 µmolg-1h-1 and photo-Fenton dye degradation rate constants of 0.147 min-1, upon solar-light illumination. Furthermore, the photocatalysts demonstrate recyclability over five consecutive cycles, confirming their stability, while easy separation using a simple magnet underscores practical utility.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    Fe单原子(FeSAs)基催化剂因其低成本、高活性等优点,在电催化氧还原反应(ORR)中备受关注。然而,有效和稳定的FeSAs催化剂的容易合成仍然具有挑战性。这里,我们报道了通过喷雾干燥和热解过程锚定在N掺杂的介孔碳微球(NC)催化剂上的FeSAs。高活性FeSAs均匀分布在NC基体上,这阻止了受益于增强的Fe-N键的聚集。此外,介孔碳结构有利于快速的电子和传质。优化的Fe@NC-2-900催化剂在ORR中显示出正半波电位(E1/2=0.86Vvs可逆氢电极(RHE))和起始电位(Eonset=0.98VvsRHE),这与商业Pt/C催化剂相当(E1/2=0.87V,Eonset=1.08V)。具有9小时的电流保持率为92.5%的出色稳定性和良好的甲醇耐受性。组装的锌-空气电池在5mAcm-2的电流密度下显示出高达500小时的良好稳定性。这项工作显示了FeSAs基催化剂在ORR中的实际应用潜力,并为提高其催化性能铺平了新途径。
    Fe single atoms (Fe SAs) based catalysts have received much attention in electrocatalytic oxygen reduction reaction (ORR) due to its low-cost and high activity. Yet, the facile synthesis of efficient and stable Fe SAs catalysts are still challenging. Here, we reported a Fe SAs anchored on N-doped mesoporous carbon microspheres (NC) catalyst via spraying drying and pyrolysis processes. The highly active Fe SAs are uniformly distributed on the NC matrix, which prevented the aggregation benefiting from the enhanced Fe-N bonds. Also, the mesoporous carbon structure is favorable for fast electron and mass transfer. The optimized Fe@NC-2-900 catalyst shows positive half wave potential (E1/2 = 0.86 V vs reversible hydrogen electrodes (RHE)) and starting potential (Eonset = 0.98 V vs RHE) in ORR, which is comparable to the commercial Pt/C catalyst (E1/2= 0.87 V, Eonset = 1.08 V). Outstanding stability with a current retention rate of 92.5% for 9 hours and good methanol tolerance are achieved. The assembled zinc-air batteries showed good stability up to 500 hours at a current density of 5 mA cm-2. This work shows potentials of Fe SAs based catalysts for the practical application in ORR and pave a new avenue for promoting their catalytic performances.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    多材料异质结构导致特性超过单个组件。自然界通过纳米粒子(NPs)的生物矿化控制多种材料的结构和位置;然而,合成异质结构的形成仍然有限,并且通常偏离自组装的优雅。这里,开发了一类嵌段聚合物结构导向剂(SDAs),其中包含能够持续(共价)NP相互作用的重复单元,能够直接制造纳米级多孔异质结构,其中单一材料作为连续层位于孔表面。该SDA结合基序(设计规则1)能够实现序列控制的异质结构,其中组成概况和界面对应于合成添加顺序。使用仅具有持久性SDA-NP相互作用的SDA对5种材料序列进行了概括(\“P-NP1-NP2\”;NPi=TiO2,Nb2O5,ZrO2)。扩展这些聚合物SDA设计指南,表明,持久性和动态(非共价)SDA-NP相互作用(\“PD-NP1-NP2\”)的组合可改善均匀互连孔隙率的产生(设计规则2)。所得的SDA的两个区段之间的竞争性结合(P-vs.D-)需要额外的时间使第一NP类型(NP1)到达并共价连接到SDA(设计规则3)。这三个设计规则的组合使得能够直接自组装异质结构,所述异质结构将单一材料定位在孔表面,同时保持连续的孔隙率。
    Multimaterial heterostructures have led to characteristics surpassing the individual components. Nature controls the architecture and placement of multiple materials through biomineralization of nanoparticles (NPs); however, synthetic heterostructure formation remains limited and generally departs from the elegance of self-assembly. Here, a class of block polymer structure-directing agents (SDAs) are developed containing repeat units capable of persistent (covalent) NP interactions that enable the direct fabrication of nanoscale porous heterostructures, where a single material is localized at the pore surface as a continuous layer. This SDA binding motif (design rule 1) enables sequence-controlled heterostructures, where the composition profile and interfaces correspond to the synthetic addition order. This approach is generalized with 5 material sequences using an SDA with only persistent SDA-NP interactions (\"P-NP1-NP2\"; NPi = TiO2, Nb2O5, ZrO2). Expanding these polymer SDA design guidelines, it is shown that the combination of both persistent and dynamic (noncovalent) SDA-NP interactions (\"PD-NP1-NP2\") improves the production of uniform interconnected porosity (design rule 2). The resulting competitive binding between two segments of the SDA (P- vs D-) requires additional time for the first NP type (NP1) to reach and covalently attach to the SDA (design rule 3). The combination of these three design rules enables the direct self-assembly of heterostructures that localize a single material at the pore surface while preserving continuous porosity.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    在这项研究中,磷酸活化用于从香菇(香菇)残留物中合成氮掺杂的中孔活性炭(称为MR1),同时旨在有效去除对乙酰氨基酚(APAP),卡马西平(CBZ),和甲硝唑(MNZ)来自水溶液。我们使用扫描电子显微镜(SEM)表征了所产生的吸附剂的物理化学性质,氮吸附等温线,和X射线光电子能谱(XPS)。使用1、2和3mL/g的磷酸浸渍比例制备MR1,MR2和MR3,分别。值得注意的是,MR1表现出显著的介孔结构,其体积为0.825cm3/g,季氮含量为2.6%。这赋予了MR1对APAP的高吸附能力,CBZ,和MNZ,将其定位为净水应用的有希望的候选者。污染物的吸附行为遵循Freundlich等温线模型,表明多层吸附过程。值得注意的是,MR1表现出优异的耐久性和可回收性,在五个再生循环后保持其初始吸附效率的95%,并表明其在水处理过程中可持续使用的潜力。
    In this study, phosphoric acid activation was employed to synthesize nitrogen-doped mesoporous activated carbon (designated as MR1) from Lentinus edodes (shiitake mushroom) residue, while aiming to efficiently remove acetaminophen (APAP), carbamazepine (CBZ), and metronidazole (MNZ) from aqueous solutions. We characterized the physicochemical properties of the produced adsorbents using scanning electron microscopy (SEM), nitrogen adsorption isotherms, and X-ray photoelectron spectroscopy (XPS). MR1, MR2, and MR3 were prepared using phosphoric acid impregnation ratios of 1, 2, and 3 mL/g, respectively. Notably, MR1 exhibited a significant mesoporous structure with a volume of 0.825 cm3/g and a quaternary nitrogen content of 2.6%. This endowed MR1 with a high adsorption capacity for APAP, CBZ, and MNZ, positioning it as a promising candidate for water purification applications. The adsorption behavior of the contaminants followed the Freundlich isotherm model, suggesting a multilayer adsorption process. Notably, MR1 showed excellent durability and recyclability, maintaining 95% of its initial adsorption efficiency after five regeneration cycles and indicating its potential for sustainable use in water treatment processes.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    改变形态是改变SBA-15材料的纹理参数的极好选择。这项研究为介孔结构的性质如何根据其形态及其对热稳定性的贡献而表现提供了指导。这项工作的目的是合成不同的形貌(球形,六边形棱镜,像大米一样的谷物,棒,和纤维)的SBA-15材料,并评估现有的质地变化。通过将合成凝胶的温度从25°C改变到55°C来合成材料,在300或500rpm下搅拌。X射线衍射的结果,傅里叶变换红外光谱,N2吸附和解吸,和扫描电子显微镜进行了评价。还在惰性气氛中进行热稳定性测试。材料合成成功,观察到它们都表现出不同的特征,比如他们的订单,面间距离,介孔参数,比表面积,微孔和中孔体积,外部介孔面积,和壁厚。他们还表现出不同的热稳定性。米粒形态具有最高的比表面积(908.8cm2/g)和最好的热稳定性,而棒形态具有最佳的孔径(7.7nm)和微孔体积(0.078cm3/g)。
    Changing the morphology is an excellent option for altering the textural parameters of SBA-15 materials. This study provides a guide on how the properties of mesoporous structures behave according to their morphology and their contribution to thermal stability. The objective of this work was to synthesize different morphologies (spherical, hexagonal prisms, rice-like grains, rods, and fibers) of SBA-15 materials and evaluate the existing textural changes. The materials were synthesized by varying the temperature of the synthesis gel from 25 °C to 55 °C, with stirring at 300 or 500 rpm. The results of X-ray diffraction, Fourier transform infrared spectroscopy, N2 adsorption and desorption, and scanning electron microscopy were evaluated. Thermal stability tests were also conducted in an inert atmosphere. The materials were successfully synthesized, and it was observed that they all exhibited different characteristics, such as their ordering, interplanar distance, mesoporous parameter, specific surface area, micropore and mesopore volumes, external mesoporous area, and wall thickness. They also presented different thermal stabilities. The rice grain morphology had the highest specific surface area (908.8 cm2/g) and the best thermal stability, while the rod morphology had the best pore diameter (7.7 nm) and microporous volume (0.078 cm3/g).
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    有机染料在各种工业应用中的广泛使用,在快速工业化的推动下,已经成为一个重大的环境问题。因此,高效和可重复使用的吸附剂去除污染染料在水处理中越来越受到重视。在这项研究中,我们介绍了通过丙酮沉淀法从蜡质玉米淀粉中获得的短链葡聚糖(SCG)合成了具有分层玫瑰状结构的TiO2纳米颗粒嵌入介孔淀粉基微粒(TiO2@MSMP)。所得的TiO2@MSMP表现出A型结晶多晶型物,平均粒径约为2μm,显示IV型吸附等温线,平均孔径为19nm,平均表面积为12.34m2/g。TiO2@MSMP对MO和CV的吸附能力分别为85.8mg/g和103.8mg/g,分别。TiO2@MSMP的可重用性通过紫外线照射实现,导致吸附染料的光降解超过80%,同时在回收过程中保持良好的吸收能力和结构稳定性。鉴于其成本效益,高吸附能力,和出色的可重用性,TiO2@MSMP有望成为一种有效且环保的吸附剂,具有从水溶液中去除染料和净化水的巨大潜力。
    The widespread use of organic dyes in various industrial applications, driven by rapid industrialization, has become a significant environmental concern. Thus, highly efficient and reusable adsorbent for removal of pollutant dyes have gained increasing attention in water treatment. In this study, we present TiO2 nanoparticle-embedded mesoporous starch-based microparticle (TiO2@MSMP) with hierarchical rose-like structure were synthesis by using acetone precipitation of short-chain glucan (SCG) obtained from waxy maize starch. The resulting TiO2@MSMP exhibits an A-type crystalline polymorph and mean particle size of approximately 2 μm, displaying a type IV adsorption isotherm with a mean pore diameter of 19 nm and an average surface area of 12.34 m2/g. The adsorption ability of TiO2@MSMP towards methyl orange (MO) and crystal violet (CV) were 85.8 mg/g and 103.8 mg/g, respectively. The reusability of TiO2@MSMP was achieved by UV irradiation, which resulted in photodegradation of the adsorbed dye over 80 % while maintaining good absorption ability and structural stability during the recycling process. Given its cost-effectiveness, high adsorption capacity, and excellent reusability, TiO2@MSMP holds promise as an effective and environmentally friendly adsorbent with significant potential for removing dyes from aqueous solutions and purifying water.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    背景:已经合成并开发了负载在MCM-41上的Ni(II)和VO(IV)金属配合物的高效高级催化剂,用于将硫化物化学选择性氧化为亚砜,并将硫醇氧化偶联为其相应的二硫化物使用H2O2作为绿色有效的程序。所有亚砜和二硫化物均在短反应时间内以优异的产率获得。未观察到硫化物或硫醇的过度氧化,并且所有产物均以高纯度合成。这些催化剂可以回收并重复使用几次,而其催化活性没有任何明显损失。与文献中的旧催化剂相比,这些催化剂对亚砜和二硫化物衍生物的合成显示出更好的活性和选择性,这显示了这项工作的新颖性。
    方法:首先,合成了介孔MCM-41,进一步,其表面被(3-氯丙基)-三乙氧基硅烷(CPTES)改性。然后,修饰的MCM-41(nPrCl-MCM-41)被腺嘌呤官能化。下一步,官能化的MCM-41(6AP-MCM-41)用作载体,用于固定镍和氧代钒作为最终催化剂(Ni-6AP-MCM-41或VO-6AP-MCM-41)。通过XRD对这些催化剂的结构和性能进行了鉴定,SEM,TGA,FT-IR,和AAS光谱分析。这些催化剂用于硫化物的化学选择性氧化和硫醇的氧化偶联。
    结果:这些配合物在室温下很好地催化了所有反应。根据获得的结果,一些衍生物的羟基,包括2-(甲硫基)乙醇或2,2-(苯硫基)乙醇,在反应过程中保持不变。
    结论:已发现该方法具有成本低的优点,效率高,高产量,recovery,和可重复使用的几个运行没有显著损失的催化活性。
    BACKGROUND: A highly efficient superior catalyst of Ni (II) and VO (IV) metal complexes supported on MCM-41 has been synthesized and developed for chemoselective oxidation of sulfides to sulfoxides and oxidative coupling of thiols to their corresponding disulfides using H2O2 as a green and efficient procedure. All sulfoxides and disulfides were obtained in short reaction times with excellent yields. The over-oxidation of sulfides or thiols was not observed and all products were synthesized in high purity. These catalysts could be recovered and reused several times without any significant loss in their catalytic activity. Compared to the old catalysts in the literature, these catalysts showed better activity and selectivity for the synthesis of sulfoxide and disulfide derivatives, which shows the novelty of this work.
    METHODS: At first, the mesoporous MCM-41 was synthesized, and further, its surface was modified by (3-chloropropyl)-triethoxysilane (CPTES). Then, the modified MCM-41 (nPrCl-MCM- 41) was functionalized by adenine. In the next step, the functionalized MCM-41 (6AP-MCM- 41) was used as support for the immobilization of nickel and oxo-vanadium as final catalysts (Ni-6AP-MCM-41 or VO-6AP-MCM-41). The structure and properties of these catalysts have been identified by XRD, SEM, TGA, FT-IR, and AAS spectral analyses. These catalysts were used in the chemoselective oxidation of sulfides and oxidative coupling of thiols.
    RESULTS: These complexes catalyzed all reactions well at room temperature. According to the results obtained, the hydroxyl groups of some derivatives, including 2-(methylthio) ethanol or 2,2-(phenylthio) ethanol, remained unchanged during the reaction.
    CONCLUSIONS: The method has been found to possess the advantages of low cost, high efficiency, high yields, recovery, and reusability for several runs without significant loss in the catalytic activity.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    含有顺式二醇的分子,生物体中一种必不可少的化合物,吸引了来自各个领域的密集研究兴趣。含顺式二醇分子的分析仍存在一些弊端,包括低丰度和丰富的干扰。金属有机骨架(MOF)已被证明是用于样品制备的理想吸附剂。然而,大多数报道的MOFs主要限于微孔体系(孔径<2nm),这极大地限制了应用。在这里,通过后合成配体交换过程建立了一个简单的策略来构建硼酸酯亲和力MOF。由于配体交换过程得到了原始金属-有机骨架的结构完整性和点击化学的巨大兼容性的帮助,所获得的EPBA-PCN-333(Fe)能够实现最大限度地保持母材的孔隙率和结晶度。EPBA-PCN-333(Fe)的几个有趣的特征(例如,优异的选择性,有效扩散,良好的可达性,和尺寸排阻效应)通过一系列具有不同分子尺寸的含顺式二醇的分子(小分子,糖肽,和糖蛋白)。EPBA-PCN-333(Fe)的结合性能通过使用邻苯二酚作为测试分子(结合能力:0.25mmol/g,LOD:200ng/mL)。最后,EPBA-PCN-333(Fe)的实际应用通过检测人尿液样品中的核苷证明。
    cis-Diol-containing molecules, an essential type of compounds in living organisms, have attracted intensive research interest from various fields. The analysis of cis-diol-containing molecules is still suffering from some drawbacks, including low abundance and abundant interference. Metal-organic frameworks (MOFs) have proven to be an ideal sorbent for sample preparation. However, most of the reported MOFs are mainly restricted to a microporous regime (pore size <2 nm), which greatly limits the application. Herein, a facile strategy is established to construction of boronate affinity MOFs via the postsynthetic ligand-exchange process. Owing to the fact that the ligand-exchange process was assisted by the structural integrity of the primitive metal-organic framework and the great compatibility of click chemistry, the obtained EPBA-PCN-333(Fe) is able to realize the maximum maintaining the porosity and crystallinity of the parent material. Several intriguing features of EPBA-PCN-333(Fe) (e.g., excellent selectivity, efficient diffusion, good accessibility, and size exclusion effect) are experimentally demonstrated via a series of cis-diol-containing molecules with different molecular sizes (small molecules, glycopeptides, and glycoproteins). The binding performance of EPBA-PCN-333(Fe) is evaluated by employing catechol as the test molecule (binding capacity: 0.25 mmol/g, LOD: 200 ng/mL). Finally, the real-world applications of EPBA-PCN-333(Fe) were demonstrated by the detection of nucleosides of human urine samples.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    目的:开发了具有铜掺杂的介孔生物活性纳米球(Cu-MBGN)的复合材料,以通过赋予抗菌和离子释放/再矿化特性来防止继发性龋齿。
    方法:含有1、5或10wt%Cu-MBGN的七种实验复合材料,制备相应的惰性对照(二氧化硅)和生物活性对照(生物活性玻璃45S5)。光固化过程中的温度上升,通过乙醇软化试验的交联密度,研究了单体洗脱及其对斑马鱼Daniorerio早期发育的潜在不利影响。
    结果:将Cu-MBGN和二氧化硅结合的材料显示出最高的耐乙醇软化性,生物活性对照也是如此。Cu-MBGN复合材料表现出明显的温升,并在最短的时间内达到最高温度。未检测到双酚A,而bis-GMA仅在对照材料中发现,TEGDMA在所有材料的洗脱液中发现。在暴露于任何材料的洗脱液期间,斑马鱼死亡率和异常率没有增加。
    结论:具有5wt%Cu-MBGN与纳米二氧化硅填料结合的复合材料显示出最低的乙醇软化,表明聚合物的最高耐久性和交联密度。尽管所有测试材料都发布了TEGDMA,未观察到胚胎毒性作用。
    OBJECTIVE: Composites with copper-doped mesoporous bioactive nanospheres (Cu-MBGN) were developed to prevent secondary caries by imparting antimicrobial and ion-releasing/remineralizing properties.
    METHODS: Seven experimental composites containing 1, 5 or 10 wt% Cu-MBGN, the corresponding inert controls (silica) and bioactive controls (bioactive glass 45S5) were prepared. The temperature rise during light curing, cross-linking density by ethanol softening test, monomer elution and their potential adverse effects on the early development of zebrafish Danio rerio was investigated.
    RESULTS: Materials combining Cu-MBGN and silica showed the highest resistance to ethanol softening, as did the bioactive controls. Cu-MBGN composites showed significant temperature rise and reached maximum temperature in the shortest time. Bisphenol A was not detected, while bis-GMA was found only in the control materials and TEGDMA in the eluates of all materials. There was no increase in zebrafish mortality and abnormality rates during exposure to the eluates of any of the materials.
    CONCLUSIONS: The composite with 5 wt% Cu-MBGN combined with nanosilica fillers showed the lowest ethanol softening, indicating the polymer\'s highest durability and cross-linking density. Despite the TEGDMA released from all tested materials, no embryotoxic effect was observed.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

公众号