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Crack buckling in soft gels under compression

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Acta Mechanica Sinica 2012年第4期28卷 1098-1105页

作者： rong long Chung-Yuen Hui Department of Biological and Environmental Engineering Cornell University Ithaca 14853 New York USA Field of Theoretical and Applied Mechanics Cornell University Ithaca 14850 New York USA

Recent interest in designing soft gels with high fracture toughness has called for simple and robust methods to test fracture behavior. The conventional method of applying tension to a gel sample suffers from a difficulty of sample gripping. In this paper, we study a possible fracture mechanism of soft gels under uni-axial compression. We show that the surfaces of a pre-existing crack, oriented parallel to the loading axis, can buckle at a critical compressive stress. This buckling instability can open the crack surfaces and cre- ate highly concentrated stress fields near the crack tip, which can lead to crack growth. We show that the onset of crack buckling can be deduced by a dimensional argument com- bined with an analysis to determine the critical compression needed to induce surface instabilities of an elastic half space. The critical compression for buckling was verified for a neo- Hookean material model using finite element simulations.

关键词： Fracture mechanics. Soft gels. Buckling. Crack Compression

Aqueous synthesis of CdSe and CdSe/CdS quantum dots with controllable introduction of Se and S sources

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Chinese Chemical Letters 2012年第8期23卷 961-964页

作者： Xiao long rong Qin Zhao Guan Hong Tao College of Chemistry Chemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123China

A new and convenient route is developed to synthesize CdSe and core-shell CdSe/CdS quantum dots（QDs） in aqueous *** gaseous precursors,H2Se and H2S,generated on-line by reducing SeO 3 2à with NaBH 4 and the reaction between Na 2 S and diluted H2SO 4,are used to form high-quality CdSe and CdSe/CdS QDs,*** synthesized water-soluble CdSe and CdSe/CdS QDs possess high quantum yield（3% and 20%） and narrow full-width-at-half-maximum（43 nm and 38 nm）.The synthesis process is easily reproducible with simple apparatus and low-toxic chemicals,and can be readily extended to the large-scale aqueous synthesis of QDs.

关键词： CdSe CdSe/CdS Quantum dots Aqueous synthesis Gaseous precursors

Modeling of air quality with a modified two-dimensional Eulerian model: A case study in the Pearl River Delta (PRD) region of China

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Journal of Environmental Sciences 2007年第5期19卷 572-577页

作者： CHENG Yan-li BAI Yu-hua LI Jin-long LIU Zhao-rong College of Environmental Sciences Peking University Beijing 100871 China

A modified two-dimensional Eulerian air quality model was used to simulate both the gaseous and particulate pollutant concentrations during October 21-24, 2004 in the Pearl River Delta （PRD） region, China. The most significant improvement to the model is the added capability to predict the secondary organic aerosols （SOA） concentrations because of the inclusion of the SOA formation chemistry. The meteorological input data were prepared using the CALMET meteorological model. The concentrations of aerosol-bound species such as NO3^-, NH4^＋, SO4^2-, and SOA were calculated in the fine particle size range （〈2.5 μm）. The results of the two-dimensional model were compared to the measurements at the ground level during the PRD Intensive Monitoring Campaign （IMC）. Overall, there were good agreements between the measured and modeled concentrations of inorganic aerosol components and O3. Both the measured and the modeled results indicated that the maximum hourly O3 concentrations exceeded the China National Air Quality Standard. The predicted 24-h average SOA concentrations were in reasonable agreement with those predicted by the method of minimum OC/EC ratio.

关键词： air quality model numerical simulation secondary organic aerosol inorganic aerosol

Gradually activated lithium uptake in sodium citrate toward high-capacity organic anode for lithium-ion batteries

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Rare Metals 2021年第6期40卷 1366-1372页

作者： rong long Gu-Lian Wang Zhong-Li Hu Peng-Fei Sun Li Zhang College of Chemistry Chongqing Normal UniversityChongqing 401331China College of Energy Soochow Institute for Energy and Materials Innovations and Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu ProvinceSoochow UniversitySuzhou 215006China

Lithium-ion batteries(LIBs)have been used to power various electric devices and store energy,but their toxic components by using inorganic materials generally cause serious environmental issues when ***,environmentally friendly and naturally abundant organic compounds have been adopted as promising electrode materials for next-generation ***,a new organic anode electrode based on sodium citrate is proposed,which shows gradually activated electrochemical behavior and delivers a high reversible capacity of 776.8 mAh·g^(-1)after 1770 cycles at a current density of 2 A·g^(-1).With the aid of the electrochemical characterization,Fourier-transform infrared(FTIR)and X-ray photoelectron spectroscopy(XPS)analysis,the lithium uptake mechanism of sodium citrate-based anodes is identified to be a combination of three-electron lithiation/delithiation and fast Li+intercalation/deintercalation processes,in which Faradaic reactions could offer a theoretical contribution of312 mAh·g^(-1)and intercalation pseudocapacitance would provide extra *** work demonstrates the great potential for developing high-capacity organic electrodes for LIBs in future.

关键词： Faradaic lithiation Lithium-ion battery Li+intercalation pseudocapacitance Multiple lithium-ion storage mechanism Sodium citrate-based anode

Entrapment of the temporal horn secondary to postoperative gamma-knife radiosurgery in intraventricular meningioma: A case report

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World Journal of Clinical Cases 2019年第18期7卷 2894-2898页

作者： Jia Liu Sheng-rong long Guang-Yu Li Department of Neurosurgery the First Hospital of China Medical University

BACKGROUND Entrapment of the temporal horn (ETH) is a rare pathologic condition. It is a kind of focal hydrocephalus caused by obstruction of flow pathway of cerebrospinal fluid. It is caused by various conditions, but ETH secondary to postoperative gamma-knife radiosurgery (GKS) is extremely rare. CASE SUMMARY A 52-year old previously healthy woman underwent resection of a large intraventricular meningioma. A small fragment of residual tumor with no obvious enlargement of the temporal horn was observed 3 mo after surgery, and she was referred for GKS. Two months after GKS, she complained of headache and progressive paralysis of the left limb. Magnetic resonance imaging revealed enlargement of the temporal horn. There was a second procedure to resect the residual tumor 8 mo after GKS. After the second procedure, she recovered smoothly. As of the date of this writing, she has remained in good condition. CONCLUSION This case reminds us that ETH should be considered in the treatment of intraventricular meningiomas, especially before GKS.

关键词： Entrapment of the temporal horn Gamma-knife radiosurgery Intraventricular meningioma Case report

Calculating the Relativistic Wave Functions of 11S0 and 13S1 Positronium

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Communications in Theoretical Physics 2001年第7期36卷 85-90页

作者： QIN Gan WAN Shao-long HAN rong-Dian WANG Ke-Lin CCAST (World Laboratory) P.O. Box 8730 Beijing 100080 China Department of Astronomy and Applied Physics University of Science and Technology of China Hefei 230026 Chinat Department of Astronomy and Applied Physics University of Science and Technology of China Hefei 230026 Chinat Department of Modern Physics University of Science and Technology of China Hefei 230026 China Department of Astronomy and Applied Physics University of Science and Technology of China Hefei 230026 Chinat

Based cn the relativistic Bethe-Salpeter (BS) equation, the positronium wavefunctions in Euclidean momentum space are obtained. Meanwhile the energy levels of positronium ground states 11S0 and 13S1 are fitted to be 6.7934 eV and 6.7929 eV respectively, which qualitatively agree with the previous theoretical values. It is shown that the BS theory is valid and reliable to treat positronium.

关键词： positronium, Bethe-Salpeter equation

Synchronized early gastric cancer occurred in a patient with serrated polyposis syndrome:A case report

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World Journal of Clinical Cases 2022年第8期10卷 2644-2649页

作者： Ying-Ze Ning Guan-Yi Liu Xiao-long Rao Yong-Chen Ma long rong Department of Endoscopy Center Peking University First HospitalBeijing 100032China

BACKGROUND Serrated polyposis syndrome(SPS)is a relatively rare disease that is characterized by multiple serrated lesions/*** little is known regarding the extracolonic cancers associated with *** genetic basis of the process remains *** SUMMARY A 67-year-old male patient initially presented with belching and abdominal distension for a year as well as diarrhea for over 2 *** patient underwent colonoscopy and was diagnosed with serrated polyposis *** a year later,a gastroscopy was performed during the postoperative re-examination to screen for other lesions of the upper gastrointestinal *** elevated lesion was detected in the anterior wall of the gastric *** en bloc resection of the lesion was achieved via endoscopic submucosal *** pathological result was high-grade dysplasia with focal intramucosal *** sequencing was performed for the patient and five gastric cancer-associated variants(methylenetetrahydrofolate reductase,metaxin 1,coiled-coil domain containing 6,glutamate ionotropic receptor delta type subunit 1,and aldehyde dehydrogenase 1)were *** This paper reports a case that presented with both SPS and early gastric *** mutations that were potentially responsible for this condition were sought by exome sequencing.

关键词： Serrated polyposis syndrome Early gastric cancer Gene mutation Endoscopy Exome sequencing Case report

Comprehensive recovery of lead, zinc, and iron from hazardous jarosite residues using direct reduction followed by magnetic separation

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International Journal of Minerals,Metallurgy and Materials 2018年第2期25卷 123-130页

作者： Ya-yun Wang Hui-fen Yang Bo Jiang rong-long Song Wei-hao Zhang Key Laboratory for High-Efficient Mining and Safety of Metal Mines of Ministry of Education University of Science and Technology Beijing School of Civil and Resource Engineering University of Science and Technology Beijing

Lead, zinc, and iron were recovered from jarosite residues using direct reduction followed by magnetic separation. The influence of the coal dosage, reduction temperature, and reduction time on the volatilization rates of lead and zinc and the metallization rate of iron were investigated. The results show that the volatilization rates of lead and zinc were 96.97% and 99.89%, respectively, and the iron metallization rate was 91.97% under the optimal reduction roasting conditions of a coal dosage of 25.0 wt% and reduction roasting at 1250°C for 60 min. The magnetic concentrate with an iron content of 90.59 wt% and an iron recovery rate of 50.87% was obtained under the optimum conditions in which 96.56% of the reduction product particles were smaller than 37 μm and the magnetic field strength was 24 k A/m. Therefore, the results of this study demonstrate that recovering valuable metals such as lead, zinc, and iron from jarosite residues is feasible using the developed approach.

关键词： jarosite residues recovery direct reduction magnetic separation valuable metals

Influences of Electrolytes on the Soap-free Emulsion Copolymerization of St-MMA-AA

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Chinese Chemical Letters 2006年第11期17卷 1503-1506页

作者： rong long LI Cheng You KAN Yi DU Ze Ping LI Department of Chemical Engineering and Key Laboratory of Advanced Materials of Ministry of Education Tsinghua University Beijing 100084

Monodisperse functional polymer microspheres with different particle size and with clean surface were prepared by batch soap-free emulsion polymerization of styrene, methyl methacrylate and acrylic acid in the presence of salts, and the influences of type and amount of electrolytes on polymerization process and particle morphology were investigated. Results showed that there was a critical concentration for different electrolyte to make polymerization process and the resultant emulsion stable, and the particle size increased with the increase of electrolyte concentration. The effect of metal ions was Ca^2＋〉〉K^＋〉Na^＋〉Li^＋, and the effect of haloids was Br〉Cl〉F. Keywords： Electrolyte, soap-free emulsion polymerization, polystyrene, latex particle morphology.

关键词： Electrolyte soap-free emulsion polymerization polystyrene latex particle morphology.