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Experimental Study of the Reinforcement Mechanism for the Tunnel Support Structure in Weak Rock Masses

INTERNATIONAL JOURNAL OF GEOMECHANICS 2023年第10期23卷 04023173-04023173页

作者： Chen, Yulong zhang, xuwen Qiao, Xuanru China Univ Min & Technol Sch Energy & Min Engn Beijing 100083 Peoples R China

This study aims to comprehensively investigate the reinforcement mechanism of the tunnel support structure and its supporting characteristics in layered and weak rock tunnels. Uniaxial compressive tests were carried out to study the mechanical and deformation characteristics of anchored rock with the system anchor bolt and the steel floral pipe. Besides, a three-point bending test of the steel-concrete composite beam was conducted to investigate the bending capacity of the grilles and I-beams. The experiment showed the following results: (1) The anchor bolt achieved the anchoring effect by improving the stress state and the strength of the surrounding rock. The improvement of the anchorage strength to the surrounding rock was reflected by the effect of the compression zone of preload, the healing effect of the anchorage agent on the surrounding rock, and the reinforcement effect of the anchor bolt on the density and strength of the anchor bolt. (2) By the CT scanning of the anchored samples after the experiment, it was found that the crack was blunted and arrested within the anchorage zone, and the crack-arresting effect was related to the range of the anchorage zone. The larger the anchorage zones, the better the crack-arresting effect. (3) The steel arch could effectively improve the ability of concrete antideformation. Compared with the lattice girder, the coordination ability of steel arch and concrete deformation was relatively weak. Its coordinate deformation stage was shorter than that of the lattice girder and earlier into the debonding stage. However, the stiffness of the steel arch and concrete was greater than that of the lattice girder after debonding and showed a strong bearing capacity.

关键词： Tunnel Support structure Uniaxial test Three-point bend test Anchorage mechanism

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Collaborative Morphological and Electrical Regulation of High-Mobility Conjugated Polymers via a Multifunctional Polymeric Additive

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MACROMOLECULES 2024年第22期57卷 10792-10801页

作者： Xu, Chenhui An, Chuanbin Gao, Mengyuan zhang, xuwen He, Chunyong Dong, Weijia Wang, Tianzuo Liu, Yuqian Deng, Yunfeng Ye, Long Han, Yang Geng, Yanhou Tianjin Univ Sch Mat Sci & Engn Tianjin Key Lab Mol Optoelect Sci Key Lab Organ Integrated CircuitsMinist Educ Tianjin 300072 Peoples R China Trina Solar State Key Lab Photovolta Sci & Technol Changzhou 213031 Peoples R China Joint Sch Natl Univ Singapore & Tianjin Univ Fuzhou 350207 Peoples R China China Spallat Neutron Source CSNS Spallat Neutron Source Sci Ctr Dongguan 523803 Peoples R China

Morphological and electrical control over conjugated polymers has a great potential for the fabrication of high-performance organic thin-film transistors (OTFTs). Herein, we employed a multifunctional polymeric additive, namely, PBTTT-b-HTPB, to optimize the molecular packing order of an isoindigo-based model polymer (IIDSiC8) and simultaneously regulate the minority carriers for boosted transport properties in OTFTs via facile solution processing. By detailed comparative study, we demonstrated that PBTTT-b-HTPB remarkably improved the crystallinity of IIDSiC8 by forming elongated fibers with higher molecular order in a thin film, which originated from the larger size ordered solution aggregates due to the presence of the insulating block. On the other hand, the p-type conjugated block of PBTTT worked as a hole trapping center, resulting in significantly increased electron density, reduced off-current, and optimal n-type performance. Benefiting from the collaborative morphological and electrical regulation, IIDSiC8/PBTTT-b-HTPB films displayed well-aligned ordered morphology and a high electron mobility up close to 7 cm2 V-1 s-1 together with an on/off ratio of 106 in bar-coated OTFTs. The high electron mobility is among the top performance values reported for isoindigo-based polymers. Our work has achieved simultaneous optimization of film microstructures and carrier transport characteristics of polymer semiconductors, providing opportunities for the production of OTFT devices with a superior performance.

关键词： Conjugated polymers

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A BOUNDARY MAXIMUM PRINCIPLE FOR STATIONARY PAIRS OF VARIFOLDS WITH FIXED CONTACT ANGLE

arXiv

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arXiv 2022年

作者： zhang, xuwen School of Mathematical Sciences Xiamen University Xiamen361005 China Institut für Mathematik Goethe-Universität Frankfurt60325 Germany

In this note, we establish a boundary maximum principle for a class of stationary pairs of varifolds satisfying a fixed contact angle condition in any compact Riemannian manifold with smooth *** Codes 53C42, 49Q15 Cop... 详细信息

关键词： Maximum principle

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Case study on the combined use of surface seawater injection and depressurization for sustainable natural gas hydrate extraction

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JOURNAL OF CLEANER PRODUCTION 2025年 494卷

作者： zhang, Zhaobin Li, Yuxuan Li, Shouding He, Jianming Li, Xiao Lu, Cheng Qin, xuwen Chinese Acad Sci Inst Geol & Geophys Key Lab Deep Petr Intelligent Explorat & Dev Beijing 100029 Peoples R China Univ Chinese Acad Sci Coll Earth & Planetary Sci Beijing 100049 Peoples R China China Geol Survey Minist Nat Resources Beijing 100037 Peoples R China

In response to the issue of inefficient extraction of natural gas hydrates due to a lack of heat supplementation during long-term production, a combined extraction method integrating surface seawater injection and depressurization has been proposed. Under the premise that the surface seawater injection pipeline possesses certain thermal insulation properties, this method can sustainably harness solar energy to replenish the thermal energy of gas hydrate reservoirs. Numerical simulations based on a validated three-dimensional heterogeneous model from the 2013 Nankai Trough pilot production in Japan demonstrate that this method significantly enhances hydrate extraction efficiency compared to depressurization alone. The results show that, over a 500-day production scenario, methane recovery efficiency can be enhanced by up to 150%. The study reveals that only an appropriate injection temperature can effectively improve the efficiency of hydrate exploitation. Compared to the depressurization-only method, this extraction approach increases the temperature driving force (TDF) near the injection well improved by up to 12 K. However, higher injection rates suppress depressurization effects, requiring a balance between injection temperature and rate. The proposed approach also facilitates more uniform reservoir deformation, reducing localized subsidence risks. These findings suggest that the combined surface seawater injection and depressurization method provides an effective and environmentally friendly solution for sustainable hydrate exploitation.

关键词： Natural gas hydrate Surface seawater injection Injection temperature and rate Temperature driving force Reservoir deformation

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A Two-level Learning Approach for Achieving the Sustainable Development of Service Ecosystem

A Two-level Learning Approach for Achieving the Sustainable ...

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IEEE International Conference on Web Services (IEEE ICWS)

作者： Peng, Chao Xue, Xiao zhang, xuwen Ji, Peilin Shen, Yifan Fang, Li Feng, Zhiyong Tianjin Univ Coll Intelligence & Comp Tianjin Peoples R China Tianjin Key Lab Healthy Habitat & Mart Technol Tianjin Peoples R China Xian Univ Finance & Econ Sch Informat Xian Peoples R China

ISBN: (纸本)9798350368567;9798350368550

The governance of service ecosystem needs to balance efficiency and fairness to promote the sustainable development of the system, making it an important topic. However, service entities in the service ecosystem have autonomy and engage in dynamic game with governance strategies, leading to governance challenges. To address this issue, we model the governance process as a repeated sequential game between the governance algorithm and service entities, and propose a novel two-level learning algorithm. This algorithm considers the learning evolution of service entities and the co-evolutionary of the governance algorithm, using reinforcement learning to learn effective governance strategies while also considering the response function of service entities to balance efficiency and fairness. Combining the ideas of bilevel optimization and online learning, this algorithm effectively balances exploration (understanding the service entities' responses function) and exploitation (choosing efficient actions). We apply the algorithm to a classic service ecosystem, the ride-hailing service system, and empirically demonstrate its effectiveness in the governance task of order dispatching.

关键词： Service Ecosystem Governance Reinforcement Learning Balancing Efficiency and Fairness

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Manganese-based virus-mimicking nanomedicine with triple immunomodulatory functions inhibits breast cancer brain metastasis

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BIOMATERIALS 2025年 320卷 123262-123262页

作者： Zhao, Zhenhao Zhou, Jingyi Li, xuwen zhang, Tongyu Tian, Zonghua Sun, Tao Jiang, Chen Fudan Univ Sch Pharm Dept Pharmaceut Minist EducKey Lab Smart Drug DeliveryState Key Shanghai 201203 Peoples R China MOE Frontiers Ctr Brain Sci Shanghai 201203 Peoples R China Fujian Med Univ Affiliated Hosp 1 Natl Reg Med Ctr Dept Digest Dis Binhai Campus Fuzhou 350212 Peoples R China

Hindered by the challenges of blood-brain barrier (BBB) hindrance, tumor heterogeneity and immunosuppressive microenvironment, patients with breast cancer brain metastasis have yet to benefit from current clinical treatments, experiencing instead a decline in quality of life due to radiochemotherapy. While virus-mimicking nanosystems (VMN) mimicking viral infection processes show promise in treating peripheral tumors, the inability to modulate the immunosuppressive microenvironment limits the efficacy against brain metastasis. Accordingly, a VMN-based triple immunomodulatory strategy is initially proposed, aiming to activate innate and adaptive immune responses and reverse the immunosuppressive microenvironment. Here, manganese-based virus-mimicking nanomedicine (Vir-HD@HM) with intratumoral drug enrichment is engineered. Vir-HD@HM can induce the immune response through the activation of cGAS-STING by mimicking the in vivo infection process of herpesviruses. Meanwhile, DNAzyme mimicking the genome can rescue the epigenetic silencing of PTEN with the assistance of Mn2+, thus ameliorating the immunosuppressive metastatic microenvironment and achieving synergistic sensitizing therapeutic efficacy. In vivo experiments substantiate the efficacy of VirHD@HM in recruiting NK cells and CD8+ T cells to metastatic foci, inhibiting Treg cells infiltration, and prolonging murine survival without adjunctive radiochemotherapy. This study demonstrates that Vir-HD@HM with triple immunomodulation offers an encouraging therapeutic option for patients with brain metastasis.

关键词： Breast cancer brain metastasis Virus-mimicking nanosystem Immune activation Immunosuppressive microenvironment regulation PTEN cGAS-STING

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Multisite synergistic interaction induced selective adsorption of CB5-Ti3C2T2 complex for strontium ion: A combined theoretical and experimental study

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JOURNAL OF HAZARDOUS MATERIALS 2025年 487卷 137288页

作者： Li, Sifan zhang, Pengcheng zhang, Yujuan Qiu, Kaikai Wang, Lin Lan, Jianhui zhang, Yu Zhao, xuwen Miao, Chengzhen Shi, Weiqun Univ Sci & Technol Beijing Sch Mat Sci & Engn Beijing 100083 Peoples R China Chinese Acad Sci Inst High Energy Phys Lab Nucl Energy Chem Beijing 100049 Peoples R China Shanghai Jiao Tong Univ Sch Nucl Sci & Engn Minist Educ Shanghai 200240 Peoples R China Shanghai Jiao Tong Univ Key Lab Nucl Power Syst & Equipment Minist Educ Shanghai 200240 Peoples R China

In this work, we use a well-defined water-soluble macrocyclic molecule cucurbit[5]uril (CB5) to modify 2D Ti3C2T2 MXene and assemble a novel high-performance adsorbent CB5-Ti3C2T2 for Sr ion by density functional theory and experimental methods. The structural stabilities of two distinct types of CB5-Ti3C2T2 (T = F, O and OH) complexes, i.e., CB5-Ti3C2T2(V) and CB5-Ti3C2T2(P) configurations are proved by binding energy and ab initio molecular dynamics (AIMD) simulations. Calculations of adsorption properties reveal that all the considered CB5-Ti3C2T2 complexes can act as efficient adsorbents for Sr ion, among which CB5-Ti3C2O2 complex possesses the best performance. The high affinity (the calculated adsorption energies < -7.6 eV) and selectivity of CB5-Ti3C2T2 complex for Sr ion are attributed to the synergistic effect between CB5 molecule and Ti3C2T2 MXene in the adsorption process, which arises from the multisite interactions of portal carbonyl groups of CB5 and surface functional groups of Ti3C2T2 towards Sr. Finally, CB5-Ti3C2T2 complex was successfully synthesized, and experimental results confirm its synergistic effect, good selectivity and high removal efficiency for Sr ions. In the treatment of strontium-containing wastewater with low concentrations, the distribution coefficient and decontamination factor of CB5-Ti3C2T2 for Sr were determined to be as high as 2.88 x 10(5) mL/g and 144.9, respectively, and the separation factor (SFSr/Ca) achieved a notable value of 67. 5. This work is expected to present a new strategy for the construction of high-performance MXene-based adsorbent for radionuclide elimination.

关键词： MXene Cucurbit[5]uril Adsorption Strontium First-principles simulation

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Design of Wide-Range High-Precision Cesium Oven Temperature Control System for Time-Keeping Cesium Beam Frequency Standards

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APPLIED SCIENCES-BASEL 2025年第3期15卷 1128-1128页

作者： Liu, Jie Li, Xiaofeng Li, Chao Hu, xuwen Li, Qingyue Sun, Fuyu zhang, Shougang Chinese Acad Sci Natl Time Serv Ctr 3 East Shuyuan Rd Xian 710600 Peoples R China Nanchang Univ Sch Phys & Mat Sci Nanchang 330031 Peoples R China Chinese Acad Sci Key Lab Time Reference & Applicat 3 East Shuyuan Rd Xian 710600 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China

The temperature fluctuation of a cesium oven has a significant impact on the performance of time-keeping cesium beam frequency standards. We have designed a circuit system for the precise temperature control of the cesium oven used in it. The use of a 24-bit analog-to-digital converter ensures a temperature measurement resolution more than 0.5 mK within the working range. The digital PID algorithm guarantees the accuracy of error signal computation, and a 16-bit digital-to-analog converter improves the resolution of the control current adjustment. Ultimately, we achieved the goal of keeping the temperature fluctuation of the cesium oven to less than 4 mK within a working range of 120 degrees C. The results indicate that the circuit system effectively ensures the performance of the cesium beam frequency standard.

关键词： time-keeping cesium beam frequency standards cesium oven temperature control digital PID

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Downregulation of Skp2 inhibits the growth and metastasis of gastric cancer cells in vitro and in vivo

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TUMOR BIOLOGY 2013年第1期34卷 181-192页

作者： Wei, Zheng Jiang, Xian Liu, Fengjun Qiao, Haiquan Zhou, Baoguo Zhai, Bo zhang, Lianfeng zhang, xuwen Han, Likun Jiang, Hongchi Krissansen, Geoffrey W. Sun, Xueying Harbin Med Univ Affiliated Hosp 1 Dept Gen Surg Hepatosplen Surg Ctr Harbin 150001 Peoples R China Shandong Univ Qilu Hosp Dept Gen Surg Jinan 250100 Peoples R China Univ Auckland Fac Med & Hlth Sci Dept Mol Med & Pathol Auckland 1005 New Zealand

S-phase kinase-associated protein-2 (Skp2) is overexpressed in human cancers and associated with poor prognosis. Skp2 acts as an oncogenic protein by enhancing cancer cell growth and tumor metastasis. The present study has demonstrated that small hairpin RNA (shRNA)-mediated downregulation of Skp2 markedly inhibits the viability, proliferation, colony formation, migration, invasion, and apoptosis of human gastric cancer MGC803 cells, which express a high level of Skp2. In contrast, Skp2 shRNA had only a slight effect on the above properties of BGC823 cells, which express a low level of Skp2. In accord, knockdown of Skp2 suppressed the ability of MGC803 cells to form tumors and to metastasize to the lungs of mice, and the growth of established tumors, by inhibiting cell proliferation and enhancing cell apoptosis. In contrast, overexpression of Skp2 promoted tumorigenesis of BGC823 cells in mice. Skp2 depletion induced cell cycle arrest in the G(1)/S phase by upregulating p27, p21, and p57 and downregulating cyclin E and cyclin-dependent kinase 2. Skp2 depletion also increased caspase-3 activity, impeded the ability of cells to form filopoidia and locomote, upregulated RECK (reversion-inducing cysteine-rich protein with kazal motifs), and downregulated matrix metalloproteinase (MMP)-2 and MMP-9 activity and expression. The results suggest that downregulating Skp2 warrants investigation as a promising strategy to treat gastric cancers that express high levels of Skp2.

关键词： S-phase kinase-associated protein-2 Gastric cancer Proliferation Cell cycle Metastasis p27

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特高压直流换流站设备的降噪措施

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高电压技术 2006年第9期32卷 149-152页

作者：杨一鸣章旭雯北京网联直流工程技术有限公司北京100005

为了有效抑制换流站可听噪声水平,在总结现有直流输电工程换流站设备噪声源的基础上,采用SOUNDPLAN软件模拟换流站噪声源,计算分析声场,提出了针对换流站从设备本体设计、抑制噪声传播等方面降噪的方法。同时针对特高压换流站噪声水平... 详细信息

为了有效抑制换流站可听噪声水平,在总结现有直流输电工程换流站设备噪声源的基础上,采用SOUNDPLAN软件模拟换流站噪声源,计算分析声场,提出了针对换流站从设备本体设计、抑制噪声传播等方面降噪的方法。同时针对特高压换流站噪声水平进行计算预测,比较特高压换流站采用不同降噪措施后的降噪水平,提出了特高压换流站的换流变压器等设备应采用屏蔽或box-in等措施以抑制噪声水平抑制在国家标准允许的范围内。

关键词：直流输电换流站噪声水平屏蔽降噪

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