检索结果-内蒙古大学图书馆

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

引用

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

来源：评论

学校读者我要写书评

暂无评论

Highly Robust,Compressible,Anisotropic,and Fire-Retardant Polyimide/Hydroxyapatite Nanowires/Reduced Graphene Oxide Aerogel for Rapid Adsorption of Viscous Oil Assisted by sunlight

引用

Research 2024年第4期7卷 58-70页

作者： Pan Huang Yongxiang sun Lin Yang Haoyu Yang Ying Hu Jifang Liu xuwen Peng Hongbo Zeng Department of Chemical and Materials Engineering University of AlbertaEdmontonAlberta T6G 1H9Canada Heavy Machinery Engineering Research Center of Education Ministry Taiyuan University of Science and TechnologyTaiyuan 030024China Cancer Center The Fifth Affiliated HospitalGuangzhou Medical UniversityGuangzhou 510700China Department of Chemical Engineering Tsinghua UniversityBeijing 10084China

Improving the adsorption efficiency of porous adsorbent materials for organic liquids with high viscosity is crucial for addressing oil spill *** this study,a high-performance aerogel adsorbent composed of polyimide(PI),hydroxyapatite nanowires(HAPnws),and reduced graphene oxide(rGO)has been fabricated,which leverages reduced flow tortuosity through anisotropic structures and solar-assisted viscosity reduction via photothermal *** prepared anisotropic PI/HAP/rGO aerogel,with directional channels,shows unique mechanical properties with high stiffness along the axial direction and compressibility along the radial direction.

关键词： nanowires viscosity adsorbent

来源：评论

学校读者我要写书评

暂无评论

Artificial Bee Colony Algorithm Based on Quantum Bloch Spherical Optimization 12th

Artificial Bee Colony Algorithm Based on Quantum Bloch Spher...

引用

12th International Conference on AI and Mobile Services, AIMS 2023

作者： sun, Na Ren, Zeyu Liao, xuwen Minzu University of China Beijing10081 China

ISBN: (纸本)9783031451393

The swarm intelligence optimization algorithm has strong adaptability to optimization problems, fast computational speed, and the ability to quickly find the optimal solution, demonstrating a momentum of rapid development. As a type of swarm intelligence optimization algorithm, artificial bee colony algorithm obtains the optimal solution through the cyclic foraging and iteration of hired bees, observation bees, and reconnaissance bees, and has now been widely applied in various fields, But the artificial bee colony algorithm has the shortcomings of slow Rate of convergence and easy to fall into the local optimal solution. To overcome these shortcomings, this paper proposes an artificial bee colony algorithm based on the quantum Bloch spherical optimization mechanism. The effectiveness of the algorithm is proved through six benchmark test functions. The experimental results of the convergence curve graph can show that the Rate of convergence is greatly accelerated, and the global optimal solution can be obtained quickly. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

关键词： Spheres

来源：评论

学校读者我要写书评

暂无评论

Combined Separated Oscillatory Fields Technique 37

Combined Separated Oscillatory Fields Technique

引用

37th European Frequency and Time Forum, EFTF 2024

作者： sun, Fuyu Li, Chao Hu, xuwen Zhang, Shougang National Time Service Center Chinese Academy of Sciences Xi'an China Chinese Academy of Sciences Key Laboratory of Time Reference and Applications Xi'an China

ISBN: (纸本)9798350354270

Ramsey's method of separated oscillatory fields (SOFs) has been originally used in beam magnetic resonance apparatuses, which leads to the establishment of atomic definition of time interval and frequency. Since then, various versions of the SOFs technique have been widely used for precise measurement of different physical quantities. Here, we present an alternative method to generate atomic beam magnetic resonance signals by combining two Ramsey cavities with phase differences of 0 and 1t. It is found that the strength of the resonance signals generated using this combined SOFs technique is approximately twice that of the resonance signals produced by the conventional SOFs techniques. In addition to generating stronger resonance, the combined Ramsey method eliminates the Rabi background superimposed on the Ramsey interference pattern without increasing the Ramsey signal linewidth. Thus, this technique serves a promising tool for high-precision measurements. © 2024 IEEE.

关键词： Velocity measurement

来源：评论

学校读者我要写书评

暂无评论

A low-temperature process for lithium extraction from lithium-bearing mineral: Conversion behavior and mechanisms

引用

SEPARATION AND PURIFICATION TECHNOLOGY 2025年 357卷

作者： Luo, Shaojun Zheng, Xiaohong Liu, Haichao Zhang, Qing He, Mingming Wang, Yuehai He, xuwen sun, Zhi China Univ Min & Technol Beijing Sch Chem & Environm Engn Beijing 100083 Peoples R China Chinese Acad Sci Inst Proc Engn Natl Engn Res Ctr Green Recycling Strateg Met Res Beijing 100190 Peoples R China China Univ Geosci Beijing Sch Mat Sci & Technol Beijing Key Lab Mat Utilizat Nonmet Minerals & Sol Natl Lab Mineral Mat Beijing 100083 Peoples R China Shanghai Polytech Univ 2360 Jinhai Rd Shanghai 201209 Peoples R China

Lithium extraction from lithium-bearing clay mineral (LiBC) has received significant attention due to the increasing demand of lithium for the advanced renewable energy industry. However, the low contents of valuable elements and stable physiochemical properties of LiBC result in high energy consumption and low efficiency in extracting lithium from LiBC. This study demonstrates a low-temperature strategy using (NH4)2SO4 as an additive to effectively extract lithium from LiBC. In details, the thermodynamic analysis verifies that Li, Al, and Fe can be converted to sulfates at 250-450 degrees C during thermal treatment, indicating the possibility for extraction of Li under low-temperature conditions. Subsequently, the leaching behavior of lithium under different roasting temperatures and water leaching conditions was investigated. The results show that 83.43 % of Li can be extracted under optimized conditions. The mechanism study was carried out through a number of characterization techniques including 3D microscope, TG-DSC, XRD, FTIR, and SEM. It reveals that formation of liquidus phase of molten salt is the key to achieve low-temperature roasting and transfer and reactions at the interface of molten salt and LiBC can be significantly enhanced that can easily breakdown the interlayer structures. Consequently, it offers distinct advantages, since the roasting temperature can be significantly decreased with minor impurity ions being leached into the solutions. This research therefore provides an efficient and environmentally friendly method for lithium extraction from minerals.

关键词： Lithium-bearing mineral Molten salt roasting Solid-liquid reaction Lithium Extraction Ammonium sulfate

来源：评论

学校读者我要写书评

暂无评论

Pioneering Insights into the Reaction Kinetics of Metastable Intermolecular Composites Based on Metal Fluorides: Virtually non-existent condensed Phase Combustion Products and Ultra-Efficient Reactivity

引用

ADVANCED SCIENCE 2025年第14期12卷 e2415073页

作者： Liu, xuwen Li, Jingwei Feng, Shenghua Jia, Yongsheng Hu, Maocong Yao, Yingkang sun, Jinshan Xie, Quanmin Sang, Hongqian Jianghan Univ State Key Lab Precis Blasting Wuhan 430113 Peoples R China Jianghan Univ Hubei Key Lab Blasting Engn Wuhan 430056 Peoples R China Anhui Univ Sci & Technol Sch Chem & Blasting Engn Huainan 232001 Peoples R China Jianghan Univ Sch Optoelect Mat & Technol Wuhan 430056 Peoples R China

As a typical representative of Metastable intermolecular composites (MICs), the energy release of nano-thermites relying on aluminum-oxygen reaction is limited by the formation of high boiling point condensed phase products. Low pressure output performance constitutes another pivotal factor influencing their efficacy. In this work, metal fluorides BiF3 at different scales were incorporated into nano-thermites as oxidants, thereby facilitating the tunability of the released energy. The boiling points of all resultant reaction products fall below the combustion temperature, theoretically abolishing the agglomeration of condensed-phase products, thus preventing the entrapment of active metals. Additionally, it facilitates the smooth conduction of heat flux, thereby averting losses in biphasic flow dynamics. The n-Al/n-BiF3 system exhibits a significant amplification in reactive kinetic properties in stark contrast to the n-Al/n-Bi2O3 system. The reduction in ignition threshold is ascribed to a novel reaction kinetics mechanism within the n-Al/BiF3 system. The highly electronegative fluorine within BiF3 corrodes the Al2O3 shell, inducing a "pre-ignition" reaction. The application of Density Functional Theory (DFT) evaluations has further corroborated the n-Al/n-BiF3 system's preeminence in electron transfer capacity between the oxidizing agent and fuel, thereby furnishing an molecular-electronic basis for its potent reactive kinetic properties.

关键词： combustion mechanism metal fluorides metastable intermolecular composites nanostructured energetic materials pre-ignition reactions

来源：评论

学校读者我要写书评

暂无评论

Intelligent Delivery Systems in Tumor Metabolism Regulation: Exploring the Path Ahead

引用

ADVANCED MATERIALS 2024年第11期36卷 2309582-2309582页

作者： Li, xuwen sun, Tao Jiang, Chen Fudan Univ Sch Pharm Dept Pharmaceut Minist EducKey Lab Smart Drug Delivery Shanghai 201203 Peoples R China MOE Frontiers Ctr Brain Sci Shanghai 201203 Peoples R China

Cancer metabolism plays multifaceted roles in the initiation and progression of tumors, and interventions in metabolism are considered fundamental approaches for cancer control. Within the vast metabolic networks of tumors, there exist numerous potential therapeutic targets, intricately interconnected with each other and with signaling networks related to immunity, metastasis, drug resistance, and more. Based on the characteristics of the tumor microenvironment, constructing drug delivery systems for multi-level modulation of the tumor microenvironment is proven as an effective strategy for achieving multidimensional control of cancer. Consequently, this article summarizes several features of tumor metabolism to provide insights into recent advancements in intelligent drug delivery systems for achieving multi-level regulation of the metabolic microenvironment in cancer, with the aim of offering a novel paradigm for cancer treatment. Latest advancements in intelligent drug delivery systems (DDS) exhibit distinctive advantages, including precise sensing, programmability, feedback control, and intrinsic activity. These attributes render them conducive to facilitating multi-dimensional therapeutic approaches grounded in metabolic ***

关键词： intelligent delivery systems metabolism regulation nanomedicine tumor metabolism

来源：评论

学校读者我要写书评

暂无评论

Discovery of potent thiazolidin-4-one sulfone derivatives for inhibition of proliferation of osteosarcoma in vitro and in vivo

引用

EUROPEAN JOURNAL OF MEDICINAL CHEMISTRY 2024年 266卷 116082页

作者： Chen, xuwen Luo, Zhengli Hu, Zongjing sun, Donghui He, Yingying Lu, Jiani Chen, Lili Liu, Shunying East China Normal Univ Shanghai Engn Res Ctr Mol Therapeut & New Drug Dev Sch Chem & Mol Engn Shanghai 200062 Peoples R China Shanghai Univ Tradit Chinese Med Inst Interdisciplinary Integrat Med Res Shanghai Frontiers Sci Ctr TCM Chem Biol Shanghai 201203 Peoples R China

Chemotherapy combining with surgical treatment has been the main strategy for osteosarcoma treatment in clinical. Due to unclear pathogenesis and unidentified drug targets, significant progress has not been made in the development of targeted drugs for osteosarcoma during the past 50 years. Our previous discovery reported compound R-8i with a high potency for the treatment of osteosarcoma by phenotypic screening. However, both the metabolic stability and bioavailability of R-8i are poor (T1/2 = 5.36 min, mouse liver microsome;and bioavailability in vivo F = 52.1 %, intraperitoneal administration) which limits it use for further drug development. Here, we described an extensive structure-activity relationship study of thiazolidine-4-one sulfone inhibitors from R-8i, which led to the discovery of compound 68. Compound 68 had a potent cellular activity with an IC50 value of 0.217 mu M, much higher half-life (T1/2 = 73.8 min, mouse liver microsome) and an excellent pharmacokinetic profile (in vivo bioavailability F = 115 %, intraperitoneal administration). Compound 68 also showed good antitumor effects and low toxicity in a xenograft model (44.6 % inhibition osteosarcoma growth in BALB/c mice). These results suggest that compound 68 is a potential drug candidate for the treatment of osteosarcoma.

关键词： Osteosarcoma Thiazolidin-4-one sulfone Inhibitors Structure -activity relationship

来源：评论

学校读者我要写书评

暂无评论

Comparative analysis of three heating methods for natural gas hydrate production: Electric heating, steam injection, and hot water injection

引用

APPLIED THERMAL ENGINEERING 2025年 269卷

作者： Zhang, Zhaobin Xu, Tao Li, Shouding Guo, Peng Li, Xiao Lu, Cheng sun, Yiming Wang, Pingkang 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 China Aero Geophys Survey & Remote Sensing Ctr Nat Beijing 100083 Peoples R China Minist Nat Resources China Geol Survey Oil & Gas Resources Survey Beijing 100083 Peoples R China Natl Engn Res Ctr Gas Hydrate Explorat & Dev Guangzhou 510075 Guangdong Peoples R China

Natural gas hydrates are a promising and environmentally sustainable energy resource, but their commercial production remains challenging. External heating is crucial for improving production efficiency. In this study, we employed a self-developed simulator (IGG-hydrate) to compare the thermal performance of three key heating methods: electric heating (EH), steam injection (SI), and hot water injection (WI). Quantitative indicators, including heating and depressurization thresholds, were introduced to assess the effectiveness of each method. The results demonstrate that external heating significantly facilitates hydrate dissociation, with electric heating and steam injection showing comparable gas production rates and early-stage efficiency. However, both electric heating and steam injection methods can cause localized overheating near injection wells, leading to energy inefficiency. In contrast, hot water injection achieves a more uniform temperature distribution and a broader heating range, while avoiding excessive temperature rise. However, it also reduces depressurization efficiency and increases subsidence near the wells. To optimize performance, we propose a steam-water alternating injection strategy: steam is injected initially for rapid dissociation near the wells, followed by hot water injection to extend the heating range and maintain thermal efficiency with the same equipment.

关键词： Heating method Electric heating Steam injection Hot water injection Hydrate

来源：评论

学校读者我要写书评

暂无评论

Boosting catalytic performance of N doped porous carbon derived from coal tar pitch: The role of N species and the contribution of 1O2

引用

JOURNAL OF WATER PROCESS ENGINEERING 2025年 72卷

作者： Huang, Linlin Zhang, xuwen Wang, Lin Liu, Tingting Li, Da Sheng, Tao sun, Caiyu Li, Lixin Heilongjiang Univ Sci & Technol Coll Environm & Chem Engn Harbin 150022 Peoples R China Harbin Inst Technol State Key Lab Urban Water Resource & Environm Harbin 150090 Peoples R China

In this study, nitrogen-doped carbon material (N-PC-d) derived from coal tar pitch using dicyandiamide as N source was successfully synthesized, exhibiting outstanding catalytic performance in the activation of peroxymonosulfate (PMS) for the degradation of Orange G (OG). By optimizing key parameters such as PMS dosage, NPC dosage, nitrogen source, pH, anions, and PS source, the optimal N-PC-d/PMS system achieved a degradation rate 1.45 times higher than that of the PC/PMS system within a broad pH range (2.0-10.0). Through electron paramagnetic resonance (EPR) and quenching experiments, it was found that singlet oxygen (1O2) was the predominant species accountable for OG degradation, while reactive oxygen species (ROS), including superoxide (O2 & sdot;-), hydroxyl radicals (& sdot;OH), and sulfate radicals (SO4 & sdot;-), played auxiliary roles. Moreover, the structure-activity relationship analysis revealed that functional groups such as C--C, C--O, and pyridine N were mainly involved in PMS activation. The degradation mechanism of OG was further elucidated by high-performance liquid chromatography-mass spectrometry (HPLC-MS). This research presented a cost-efficient N-doped porous carbon material for environmental remediation and provides more profound insights into the mechanisms of PMS activation by N doped carbon-based materials.

关键词： N-doped porous carbon Coal tar pitch PMS Singlet oxygen Orange G

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：