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Nickel nanopore arrays as promising current collectors for constructing solid-state supercapacitors with ultrahigh rate performance

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Frontiers of Chemical Science and Engineering 2018年第3期12卷 339-345页

作者： Huaping Zhao Long Liu Yaoguo Fang ranjith Vellacheri Yong Lei Institute of Physics and IMN MacroNano Ilmenau University of Technology Ilmenau 98693 Germany

In this work, nickel nanopore arrays with a highly-oriented nanoporous structure inherited from por- ous alumina membranes were used as nanostructured current collectors for constructing ultrahigh rate solid-state supercapacitors. A thin layer of poly（3,4-ethylenediox- ythiophene）（PEDOT） as electroactive materials was conformally coated onto nickel nanopores to form heterostructured electrodes. The as-prepared electrodes have a large specific surface area to ensure a high capacity, and the highly-oriented nanoporous structure of nickel nanopores reduces the ion transport resistance, allowing the ions in the solid-state electrolytes to quickly access the PEDOT surface during the fast charge-discharge process. As a result, the assembled solid-state supercapacitor in a symmetric configuration exhibits an ideal capacitive behavior and a superior rate capability even at an ultrahigh scan rate of 50 V· s^-1.

关键词： supercapacitor ultrahigh rate metallic nanopore arrays current collectors PEDOT

Medical therapy for spermatogenic failure

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Asian Journal of Andrology 2012年第1期14卷 57-60,176页

作者： ranjith Ramasamy Peter J Stahl Peter N Schlegel Department of Urology Weill Cornell Medical College New York NY 10065 USA

Medical treatment of men with primary spermatogenic failure remains largely ineffective in contrast to those with secondary testicular failure. Treatment has been attempted with a multitude of agents ranging from hormones to nutritional supplements （antioxidants）. While some studies have demonstrated benefit to some treatments, no treatments have consistently demonstrated efficacy nor has it been possible to reliably identify patients likely to benefit. Idiopathic spermatogenic failure likely results from multiple discrete defects in sperm production that are as yet unidentified. A better understanding of these defects will yield more effective treatment options and appropriate triage of patients to specific therapeutic regimens. This review focuses on the rationale and current evidence for hormonal and antioxidant therapy in medical treatment of male infertility, spermatogenic failure in particular. Although empiric medical therapy for spermatogenic failure has been largely replaced by assisted reproductive techniques, both treatment modalities could play a role, oerhaos as combination therapy.

关键词： antioxidant hormones male infertility sperm spermatogenesis spermatogenic failure testicular failure

Experimental study on the influence of hydrostatic stress on the Lode angle effect of porous rock

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International Journal of Mining Science and Technology 2022年第4期32卷 727-735页

作者： Zhenlong Song Zhenguo Zhang P.G.ranjith Wanchun Zhao Chao Liu Department of Earth and Space Sciences Southern University of Science and TechnologyShenzhenGuangdong 518055China State Key Laboratory of Coalmine Disaster Dynamics and Control Chongqing UniversityChongqing 400030China Deep Earth Energy Research Laboratory Department of Civil EngineeringMonash UniversityMelbourneVictoria 3800Australia School of Earth and Space Sciences University of Science and Technology of ChinaHefei 230026China School of Electrical Engineering&Information Northeast Petroleum UniversityDaqing 163318China

To investigate the deformation mechanisms of rock under hydrostatic stress, destructive experiments were conducted on sandstone under different levels of hydrostatic stress and stress Lode angles. The results reveal that the shape of the strength envelope on the π plane gradually changes from the shape of the Lade criterion to the shape of the Drucker-Prage criterion with an increase in hydrostatic ***, there exists a deviation between the strain and stress paths for porous rocks on the π plane,and the deviation decreases with an increase in stress Lode angle and hydrostatic stress. A rock failure hypothesis based on the rock porous structure was proposed to investigate the reasons for the abovementioned phenomena. It was found that the shear expansion in the minimum principal stress direction is the dominant factor affecting the Lode angle effect(LAE);the magnitude of the hydrostatic stress induces the variation of the porous structure and influences the shear expansion. Therefore, the hydrostatic stress state affects the LAE. The failure hypothesis proposed in this paper can clarify the hydrostatic stress effect, LAE, and the variation of the rock strength envelope shape.

关键词： Lode angle effect Hydrostatic stress effect Strength envelope curve Porous structure

Direct Evidence of Coal Swelling and Shrinkage with Injecting CO_(2) and N_(2) Using in-situ Synchrotron X-ray Microtomography

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Engineering 2022年第11期18卷 88-95页

作者： Guanglei Zhang P.G.ranjith Herbert E.Huppert Department of Earth Science and Engineering Imperial College LondonLondon SW72BPUK Deep Earth Energy Laboratory Department of Civil EngineeringMonash UniversityMelbourneVIC3800Australia Institute of Theoretical Geophysics King’s CollegeCambridge CB21STUK

Deep coal seams are one of the world’s most widespread deposits for carbon dioxide(C02)disposal and are generally located near large point sources of CO_(2)*** injection of CO_(2)into coal seams has great potential to sequester CO_(2)while simultaneously enhancing coalbed methane(CO_(2)-ECBM)*** tests of CO_(2)-ECBM have been conducted in coal seams worldwide with favorable early ***,one of the main technical barriers in coal seams needs to be resolved:Injecting CO_(2)reduces coal permeability and well ***,using in situ synchrotron X-ray microtomography,we provide the first observational evidence that injecting nitrogen(N_(2))can reverse much of this lost permeability by reopening fractures that have closed due to coal swelling induced by CO_(2)*** findings support the notion that injecting minimally treated flue gas-a mixture of mainly N_(2) and CO_(2)-is an attractive alternative for ECBM recovery instead of pure CO_(2)injection in deep coal ***,flue gas produced by power plants could be directly injected after particulate removal,thus avoiding high CO_(2)-separation ***,the presence of N_(2)makes it possible to maintain a sufficiently high level of coal *** results suggest that flue-gas ECBM for deep coal seams may provide a promising path toward net-zero emissions from coal mines.

关键词： CCS CO_(2)-ECBM Carbon neutrality X-ray imaging Coal permeability

The varicocele： diagnostic dilemmas, therapeutic challenges and future perspectives

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Asian Journal of Andrology 2016年第2期18卷 276-281,J0007页

作者： Koji Chiba ranjith Ramasamy Dolores J Lamb Larry I Lipshultz Center for Reproductive Medicine Baylor College of Medicine Houston TX USA Scott Department of Urology Baylor College of Medicine Houston TX USA Department of Molecular and Cellular Biology Baylor College of Medicine Houston TX USA.

A varicocele is defined as the abnormal dilation of the internal testicular vein and pampiniform venus plexus within the spermatic cord. If a semen analysis is not obtained from the adolescent male, in the absence of other symptoms, the main clinical indication used by many urologists to recommend repair is testicular atrophy. The varicocele may result in testicular damage in some males causing testicular atrophy with impaired sperm production and decreased Leydig cell function, while in other males the varicocele may seemingly cause no ill effects. In adult men, varicoceles are frequently present and surgically correctable, yet the measurable benefits of surgical repair are slight according to a Cochrane review. While occurring more commonly in infertile men than fertile men, only 20% of men with a documented varicocele will suffer from fertility problems. Most varicoceles found in adolescents are detected during a routine medical examination, and it is difficult to predict which adolescent presenting with a varicocele will ultimately show diminished testicular function in adolescence or adulthood. As in adults, the mainstay of treatment for varicocele in adolescents is surgical correction. However, unlike an adult varicocelectomy （the microsurgical approach is the most common）, treatment for an adolescent varicocele is more often laparoscopic. Nevertheless, the goals of treatment are the same in the adolescent and adult patients. Controversy remains as to which patients to treat, when to initiate the treatment, and what type of treatment is the best. This review will present the current understanding of the etiology, diagnosis and treatment of the adolescent varicocele.

关键词： adolescent adult management varicocele

Recent advances in the genetics of testicular failure

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Asian Journal of Andrology 2016年第3期18卷 350-355页

作者： Seung-Hun Song Koji Chiba ranjith Ramasamy Dolores J Lamb Center for Reproductive Medicine Baylor College of Medicine Houston Texas USA Scott Department of Urology Baylor College of Medicine Houston lexas USA Department of Urology Miller School of Medicine University of Miami FL USA.

Infertility affects approximately 15% of couples, and male factor is responsible for 30%-50% of all infertility. The most severe form of male infertility is testicular failure, and the typical phenotype of testicular failure is severely impaired spermatogenesis resulting in azoospermia or severe oligozoospermia. Although the etiology of testicular failure remains poorly understood, genetic factor typically is an underlying cause. Modern assisted reproductive techniques have revolutionized the treatment of male factor infertility, allowing biological fatherhood to be achieved by many men who would otherwise have been unable to become father to their children through natural conception. Therefore, identifying genetic abnormalities in male is critical because of the potential risk of transmission of genetic abnormalities to the offspring. Recently, along with other intense researches ongoing, whole-genome approaches have been used increasingly in the genetic studies of male infertility. In this review, we focus on the genetics of testicular failure and provide an update on the advances in the study of genetics of male *** affects approximately 15% of couples, and male factor is responsible for 30%-50% of all infertility. The most severe form of male infertility is testicular failure, and the typical phenotype of testicular failure is severely impaired spermatogenesis resulting in azoospermia or severe oligozoospermia. Although the etiology of testicular failure remains poorly understood, genetic factor typically is an underlying cause. Modern assisted reproductive techniques have revolutionized the treatment of male factor infertility, allowing biological fatherhood to be achieved by many men who would otherwise have been unable to become father to their children through natural conception. Therefore, identifying genetic abnormalities in male is critical because of the potential risk of transmission of genetic abnormalities to the offspring. Recentl

关键词： azoospermia genetics male infertility testicular failure

Percutaneous embolization of varicocele： technique, indications, relative contraindications, and complications

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Asian Journal of Andrology 2016年第2期18卷 234-238,J0005页

作者： Joshua Halpern Sameer Mittal Keith Pereira Shivank Bhatia ranjith Ramasamy Department of Urology New York-Presbyterian Hospital Weill Cornell Medical College New York 10065 USA Department of Radiology University of Miami- Miller School of Medicine Miami 33136 USA Department of Urology University of Miami - Miller School of Medicine Miami 33136 USA.

There are several options for the treatment of varicocele, including surgical repair either by open or microsurgical approach, laparoscopy, or through percutaneous embolization of the internal spermatic vein. The ultimate goal of varicocele treatment relies on the occlusion of the dilated veins that drain the testis. Percutaneous embolization offers a rapid recovery and can be successfully accomplished in approximately 90% of attempts. However, the technique demands interventional radiologic expertise and has potential serious complications, including vascular perforation, coil migration, and thrombosis of pampiniform plexus. This review discusses the common indications, relative contraindications, technical details, and risks associated with percutaneous embolization of varicocele.

关键词： interventional radiology male infertility therapeutic embolization varicocele

CO_2 permeability of fractured coal subject to confining pressures and elevated temperature: Experiments and modeling

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Science China(Technological Sciences) 2016年第12期59卷 1931-1942页

作者： JU Yang WANG JianGuo WANG HuiJie ZHENG JiangTao ranjith Pathegama G GAO Feng State Key Laboratory for Geomechanics & Deep Underground Engineering China University of Mining & Technology State Key Laboratory of Coal Resources & Safe Mining China University of Mining & Technology College of Engineering Peking University Department of Engineering Mechanics School of AerospaceTsinghua University Department of Civil Engineering Monash University

The CO_2 permeability of fractured coal is of great significance to both coalbed gas extraction and CO_2 storage in coal seams, but the effects of high confining pressure, high injection pressure and elevated temperature on the CO_2 permeability of fractured coal with different fracture extents have not been investigated thoroughly. In this paper, the CO_2 permeability of fractured coals sampled from a Pingdingshan coal mine in China and artificially fractured to a certain extent is investigated through undrained triaxial tests. The CO_2 permeability is measured under the confining pressure with a range of 10–25 MPa, injection pressure with a range of 6–12 MPa and elevated temperature with a range of 25–70°C. A mechanistic model is then proposed to characterize the CO_2 permeability of the fractured coals. The effects of thermal expansion, temperature-induced reduction of adsorption capacity, and thermal micro-cracking on the CO_2 permeability are explored. The test results show that the CO_2 permeability of naturally fractured coal saliently increases with increasing injection pressure. The increase of confining pressure reduces the permeability of both naturally fractured coal and secondarily fractured coal. It is also observed that initial fracturing by external loads can enhance the permeability, but further fracturing reduces the permeability. The CO_2 permeability decreases with the elevation of temperature if the temperature is lower than 44°C, but the permeability increases with temperature once the temperature is beyond 44°C. The mechanistic model well describes these compaction mechanisms induced by confining pressure, injection pressure and the complex effects induced by elevated temperature.

关键词： CO2 permeability fractured coal confining pressure elevated temperature thermal effects mechanistic models

Experimental investigations on effects of gas pressure on mechanical behaviors and failure characteristic of coals

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第2期15卷 412-428页

作者： Yi Xue P.G.ranjith Feng Gao Zhizhen Zhang Songhe Wang State Key Laboratory of Eco-hydraulics in Northwest Arid Region Xi’an University of TechnologyXi’an710048China Deep Earth Energy Laboratory Department of Civil EngineeringMonash UniversityBuilding 60MelbourneVictoria3800Australia State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou221006China

The mechanical behavior of coal is the key factor affecting underground coal mining and coalbed methane *** this study,triaxial compression and seepage tests were carried out on coal at different gas *** mechanical properties and failure process of coal were studied,as well as the acoustic emission(AE)and strain *** influence of gas pressure on the mechanical parameters of this coal was *** on the conventional energy calculation formula,the pore pressure was introduced through the effective stress formula,and each energy component of coal containing gas was refined *** contribution of gas pressure to the total energy input and dissipation during loading was quantitatively ***,the influence of gas pressure on coal strength was theo-retically analyzed from the perspectives of MohreCoulomb criterion and fracture *** results show that the total absorbed energy comprises the absorbed energy in the axial pressure direction(positive)and in the confining pressure direction(negative),as well as that induced by the pore pressure(initially negative and then positive).The absorbed energy in the axial pressure direction accounts for the main proportion of the total energy absorbed by *** quiet period of AE in the initial stage shortens,and AE activity increases during the pre-peak stage under high gas *** fractal characteristics of AE in three stages are studied using the correlation *** AE process has different forms of self-similarity in various deformation stages.

关键词： Coal Gas pressure Acoustic emission(AE) Strain energy Fractal characteristics