检索结果-南通市图书馆

Improving the performance of LOX/kerosene upper stage rocket engines

Propulsion and Power Research 2017年第3期6卷 157-176页

作者： Igor n.nikischenko Raymond D.Wright Roman A.Marchan Firefly Europe B.V. Blaricum 1261 GAThe Netherlands Spacefleet Ltd DevizesWiltshireSN103APUnited Kingdom

Improved liquid rocket engine cycles were proposed and analyzed via comparison with existing staged combustion and gas-generator *** key features of the proposed cycles are regenerative cooling of thrust chamber by oxygen and subsequent use of this oxygen for driving one or two oxygen *** fuel pump(s)are driven in a conventional manner,for example,using a fuel-rich gas-generator *** with staged combustion cycle based on oxygen-rich pre-burner showed that one of the proposed semi-expander cycles has a specific impulse only on 0.4%lower while providing much lower oxygen temperature,more efficient tank pressurizing system and built-in roll *** semi-expander cycle can be considered as a more reliable and cost-effective alternative of staged combustion *** semi-expander cycle can be considered as an improvement of gas-generator *** proposed semi-expander cycles were developed as a derivative of thrust chamber regenerative cooling performed by *** of existing oxygen/kerosene engines showed that replacing of kerosene regenerative cooling with oxygen allows a significant increase of achievable specific impulse,via optimization of mixture *** is especially the case for upper stage *** increasing of propellants average density can be considered as an additional benefit of mixture ratio *** was demonstrated that oxygen regenerative cooling of thrust chamber is a feasible and the most promising option for oxygen/kerosene *** of oxygen regenerative cooling and semi-expander cycles potentially allows creating the oxygen/kerosene propulsion systems with minimum specific impulse *** is important that such propulsion systems can be fully based on inherited and well-proven technical solutions.A hypothetic upper stage engine with thrust 19.6 kn was chosen as a prospective candidate for theoretical analysis of the proposed semi-expander *** newly-developed software RECS

关键词： Oxygen Kerosene Liquid rocket engine Upper stage

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Mobile power generation system based on biomass gasifcation

引用

International Journal of Coal Science & Technology 2022年第3期9卷 171-184页

作者： Lu Ding Mingming Yang Kai Dong Dai‑Viet n.Vo Douglas Hungwe Jiahan Ye Alexander Ryzhkov Kunio Yoshikawa Institute of Clean Coal Technology East China University of Science and TechnologyShanghai 200237China Department of Environmental Science and Technology Tokyo Institute of Technology4259 Nagatsuta-choMidori-kuYokohama 226-8503Japan College of Chemistry Chemical Engineering and Material ScienceZaozhuang UniversityZaozhuang 277160China Institute of Environmental Technology and Sustainable Development Nguyen Tat Thanh UniversityHo Chi Minh City 755414Vietnam ZHE JIAnG ECO EnVIROnMEnTAL TECHnOLOGY CO. LTD.1188The Headquarters of the Free Port H Building 20FWuxing DistrictHuzhou CityZhejiang ProvinceChina Ural Federal University EkaterinburgRussia

Disaster-hit and/or un-electrifed remote areas usually have electricity accessibility issues and an abundance of plant-derived debris and wood from destroyed wooden structures;this can be potentially addressed by employing a decentralized ultrasmall biomass-fed gasifcation power generating *** paper presents an assessment of the technical viability of an ultra-small gasifcation system that utilizes densifed carbonized wood pellets/*** setup was run continuously for 100 h.A variety of biomass was densifed and carbonized by harnessing fugitive heat sources before charging into the *** briquettes and furnished blends exhibited inferior gasifcation performance compared to the carbonized *** the absence of tar blockage problems,steady-state conditions were achieved when pre-treated feedstock was *** steady-state conditions for carbonized pellets gasifcation operated at an equivalence ratio of 0.32,cold gas efciency and carbon conversion achieved 49.2%and 70.5%,*** efciency and maximum power output of 20.3%and 21 kW were realised,*** was found that the system could keep stable while the low heating valve of syngas was over 4 MJ/m^(3)on condition that avoiding tar blocking *** results indicate that the proposed compact ultra-small power generation system is a technically feasible approach to remedy power shortage *** addition,process simulation considering carbonized wood gasifcation combined power generation was formulated to produce syngas and *** pellets with the fow rate of 20 kg/h could generate a 15.18 kW power at the air fow rate of 40 nm^(3)/h,which is in a good agreement with 15 kW in the 100 h *** is indicated that the gasifcation combined power generation cycle simulated by Aspen simulator could achieve reliable data to assist the complicated experiment operation.

关键词： Small-scale power generation Densifcation Carbonized pellet Carbonized briquette Gasifcation

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

3D-Printed electrochemical sensor-integrated transwell systems

引用

Microsystems & nanoengineering 2020年第1期6卷 357-368页

作者： Pradeep Ramiah Rajasekaran Ashley Augustiny Chapin David n.Quan Jens Herberholz William E.Bentley Reza Ghodssi Institute for Systems Research University of MarylandCollege ParkMDUSA Fischell Department of Bioengineering University of MarylandCollege ParkMDUSA Department of Psychology and neuroscience and Cognitive Science Program University of MarylandCollege ParkMDUSA Institute for Bioscience and Biotechnology Research University of MarylandCollege ParkMDUSA Robert E.Fischell Institute for Biomedical Devices University of MarylandCollege ParkMDUSA Department of Electrical and Computer Engineering University of MarylandCollege ParkMDUSA

This work presents a 3D-printed,modular,electrochemical sensor-integrated transwell system for monitoring cellular and molecular events in situ without sample extraction or microfluidics-assisted downstream *** additive manufacturing techniques such as 3D printing,shadow masking,and molding are used to fabricate this modular system,which is autoclavable,biocompatible,and designed to operate following standard operating protocols(SOPs)of cellular *** to the platform is a flexible porous membrane,which is used as a cell culture substrate similarly to a commercial transwell *** electrochemical sensors fabricated on the membrane allow direct access to cells and their products.A pair of gold electrodes on the top side of the membrane measures impedance over the course of cell attachment and growth,characterized by an exponential decrease(~160%at 10Hz)due to an increase in the double layer capacitance from secreted extracellular matrix(ECM)*** voltammetry(CV)sensor electrodes,fabricated on the bottom side of the membrane,enable sensing of molecular release at the site of cell culture without the need for downstream ***-time detection of ferrocene dimethanol injection across the membrane showed a three order-of-magnitude higher signal at the membrane than in the bulk media after reaching *** modular sensor-integrated transwell system allows unprecedented direct,real-time,and noninvasive access to physical and biochemical information,which cannot be obtained in a conventional transwell system.

关键词： transwell electrochemical culture

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Long-Term Cropping System, Tillage, and Poultry Litter Application Affect the Chemical Properties of an Alabama Ultisol

引用

Pedosphere 2019年第2期29卷 180-194页

作者： Zhongqi HE Irenus A.TAZISOnG Xinhua YIn Dexter B.WATTS Zachary n.SEnWO Henry Allen TORBERT United States Department of Agriculture-Agricultural Research Service(USDA-ARS) Southern Regional Research Center Department of Biological and Environmental Sciences Alabama A&M University Department of Plant Sciences University of Tennessee United States Department of Agriculture-Agricultural Research Service(USDA-ARS) National Soil Dynamics Laboratory

Sustainable agricultural practices have been steadily increasing in the last couple of decades. These management practices frequently involve cover crops, less or no-tillage, and organic fertilization. In this study, we evaluated the effects of cropping systems,tillage and no-tillage, and the application of poultry litter(PL) on selected soil physicochemical properties and soil test nutrients. Soil samples were collected from the topmost surface(0–5 cm) and subsurface(5–10 cm) layers. The general effect trend was PL application > no-tillage > cover crop > cropping type. There were more statistically significant(P ≤ 0.05) correlations between the 18 soil attributes at the topmost surface than at the subsurface. This could be due to the accumulation of external C inputs and nutrients by crop residues and PL application as well as the retaining effects of no-tillage on less mobile nutrient components. Because of their high mobility and volatile nature, total nitrogen(n), ammonia-n(nH_4^+-n), and nitrate-n(nO_3^--n) levels varied greatly(high standard deviations), showing no consistent patterns among the treatments. Compared to the soybean cropping system, corn, especially with the wheat cover crop, contributed more to the total carbon(C) and sulfur(S) in the topmost surface soils(0–5 cm). Poultry litter application greatly increased pH, cation exchange capacity(CEC), base saturation, magnesium(Mg), phosphorus(P), calcium(Ca),sodium(na), potassium(K), manganese(Mn), copper(Cu), and zinc(Zn) in both soil layers. Contrast comparisons revealed that PL application had more of an effect on these soil chemical properties than no-tillage and cropping systems. These results will shed light on developing better nutrient management practices while reducing their runoff potentials.

关键词： conventional tillage cover crop Mehlich-3 extraction no-tillage nutrient management practice organic fertilization soil attributes soil test nutrients

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Out of Africa: Miocene Dispersal, Vicariance, and Extinction within Hyacinthaceae Subfamily Urgineoideae

引用

Journal of Integrative Plant Biology 2013年第10期55卷 950-964页

作者： Syed Shujait Ali Martin Pfosser Wolfgang Wetschnig Mario Martínez Azorín Manuel B.Crespo Yan Yu Institute of Plant Sciences Karl Franzens University Graz Biocenter Linz Institute of Biotechnology and Microbiology University of Swat CIBIO (Instituto Universitario de la Biodiversidad) Universidad de Alicante Key Laboratory of Bio Resources and Eco Environment of Ministry of Education College of Life Sciences Sichuan University

Disjunct distribution patterns in plant lineages are usually explained according to three hypotheses： vicariance, geodispersal, and long-distance dispersal. The role of these hypotheses is tested in Urgineoideae （Hyacinthaceae）, a subfamily disjunctly distributed in Africa, Madagascar, India, and the Mediterranean region. The potential ancestral range, dispersal routes, and factors responsible for the current distribution in Urgineoideae are investigated using divergence time estimations. Urgineoideae originated in Southern Africa approximately 48.9 Mya. Two independent dispersal events in the Western Mediterranean region possibly occurred during Early Oligocene and Miocene （29.9-8.5 Mya） via Eastern and northwestern Africa. A dispersal from northwestern Africa to India could have occurred between 16.3 and 7.6 Mya. Vicariance and extinction events occurred approximately 21.6 Mya. Colonization of Madagascar occurred between 30.6 and 16.6 Mya, after a single transoceanic dispersal event from Southern Africa. The current disjunct distributions of Urgineoideae are not satisfactorily explained by Gondwana fragmentation or dispersal via boreotropical forests, due to the younger divergence time estimates. The flattened winged seeds of Urgineoideae could have played an important role in long- distance dispersal by strong winds and big storms, whereas geodispersal could have also occurred from Southern Africa to Asia and the Mediterranean region via the so-called arid and high-altitude corridors.

关键词： Bayesian binary method Bayesian divergence estimates biogeography disjunct distribution time-event curve Urgineoideae.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A Statistical Analysis of Point-like Sources in the Chandra Galactic Center Survey

引用

Chinese Journal of Astronomy and Astrophysics 2007年第1期7卷 81-90页

作者： J. E Wu S. n. Zhang F.J. Lu Y. K. Jin Department of Physics and Center for Astrophysics Tsinghua University Beijing 100084 Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy ofSciences Beijing 100049 Department of Engineering Physics and Center for Astrophysics Tsinghua University Beijing 100084

The Chandra Galactic Center Survey detected -800 X-ray point-like sources in the 2°× 0.8° sky region around the Galactic Center. We study the spatial and luminosity distributions of these sources according to their spectral properties. Fourteen bright sources detected are used to fit jointly an absorbed power-law model, from which the power-law photon index is determined to be -2.5. Assuming that all other sources have the same power-law form, the relation between hardness ratio and HI column density nH is used to estimate the nH values for all sources. Monte Carlo simulations show that these sources are more likely concentrated in the Galactic center region, rather than distributed throughout the Galactic disk. We also find that the luminosities of the sources are positively correlated with their HI column densities, i.e., a more luminous source has a higher HI column density. From this relation, we suggest that the X-ray luminosity comes from the interaction between an isolated old neutron star and interstellar medium （mainly dense molecular clouds）. Using the standard Bondi accretion theory and the statistical information of molecular clouds in the Galactic center, we confirm this positive correlation and calculate the luminosity range in this scenario, which is consistent with the observation （10^32 - 10^35 erg s^-1）.

关键词： methods data analysis-Galaxy center-X-ray stars

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Amino Compounds in Poultry Litter,Litter-Amended Pasture Soils and Grass Shoots

引用

Pedosphere 2014年第2期24卷 178-185页

作者： Z.Q.HE Z.n.SEnWO H.X.ZOU I.A.TAZISOnG D.A.MARTEnS USDA-ARS Southern Regional Research Center Department of Biological and Environmental Sciences Alabama A&M University Department of Chemical and Biological Engineering the University of Maine USDA-ARS Southwest Watershed Research Center

Amino compounds （ACs）, i.e., amino acids and amino sugars, are the major forms of organic nitrogen （n） in animal manure and soil. To increase our understanding on the effect of long-term poultry litter （PL） application on soil AC pools and turnover, in this study, we determined the contents of 21 ACs in 23 PL samples, i5 soil samples collected from 0-20, 20-40, and 40-60 cm layers of five pasture plots with 0, 5, 10, 15 and 20 years of PL applications, and 5 grass shoot samples grown on these pasture fields. The contents of 21 ACs were simultaneously determined by methanesulfonic acid hydrolysis/extraction and anion chromatography-pulsed amperometry. PL application increased soil total and individual AC contents with a distribution pattern similar to that of AC in PL. The highest AC-n concentrations were observed in the soils with 10- or 15-year PL applications, inconsistent with the order of annual application rates or eunmlative applied PL amounts. Application of PL increased the AC contents in grass shoots whereby the highest increase of most ACs was with the shoots from the fields that received PL for 5 years. These observations suggested that both freshly applied and residual PL had contributions to the soil AC-n, and that PL application also accelerated AC-n transformation in soil.

关键词： amino acids amino sugars broiler feed soil nitrogen

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Expression of Insulin-like Growth Factor-I in Uterusis Ovarian Steroid Dependent:An in situ Immunohistochemical Study in Rat

引用

Journal of Reproduction and Contraception 2012年第4期23卷 222-236页

作者： Daniel Mize Purba Jyoti Saikia Hirendra n Sarma Department of Zoology (Center with potential for excellence in Biodiversity) Rajiv Gandhi University

Objective To study the immunohistochemical localization of insulin-like growth factor- I （IGF-I） in rats＇ uteri to determine if expression of the growth factor is ovarian steroid dependent. The study was carried out in presence and absence of ovary in situ of non pregnant females and during early gestation （day 1 to day 5.5）. Cyclic females were tested to observe the effect of native steroids on IGF-I expression. Adult females were ovariectomized （OVX） and injected （s.c） with estradiol-1713 in a dose of O.1 I^g/ml per day for three consecutive days at interval of 24 h prior to the collection of uterine horns. During the early pregnancy, studies were carried out on day 3.5 and day 5. 5 of geatation respectively to determine the Steroids＇ effects during pre- and post-implantation period Tamoxifen was administered （s.c） in a dose of 250 Ug/ml per day from day 1 to day 3 of gestation while, the prostaglandin F2a （PGF2a） was administered （s.c） from day 3 of gestation onward for three consecutive days at interval of 24 h in a dose of 150 μg/ml per day. Expression of lGF-I was immunohistochemically localised using IGF-1 antibody in paraffin embedded sections. Results IGF-I was expressed in rat uterus during estrus phase as well as during pre and post-implantation period The ovariectomized females＇ uteri lost the expression of IGF-1. Exogenous administration of tamoxifen and PGF2a reduce the expression of the growth factor. Conclusion Expression of lGF-1 in rat uterus during cyclic stage and early gestation depends upon the availability of circulating estrogen and progesterone. Uterine expression of lGF-I can be modulated by manipulating circulating ovarian steroid either during cyclic stage or during gestation.

关键词： IGF-I tamoxifen, PGF2a uterus implantation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Lenvatinib as first-line therapy for recurrent hepatocellular carcinoma after liver transplantation:Is the current evidence applicable to these patients?

引用

World Journal of Transplantation 2020年第11期10卷 297-306页

作者： Federico Piñero Marcos Thompson Juan Ignacio Marín Marcelo Silva Hepatology and Liver Transplant Unit Hospital Universitario AustralBuenos Aires B1629HJArgentina Hospital Universitario Austral Facultad de Ciencias BiomédicasUniversidad AustralBuenos Aires B1629HJArgentina Latin American Liver Research Educational and Awareness network(LALREAn) Buenos Aires B1629HJArgentina Hepatology and Liver Transplantation Unit Hospital Pablo Tobón UribeMedellín 240Colombia

Liver transplantation(LT)is one of the leading curative therapies for hepatocellular carcinoma(HCC).Despite recent optimization of transplant selection criteria,including alpha-feto protein,HCC recurrence after LT is still the leading cause of death in these *** the last decades,effective systemic treatments for HCC,including tyrosine kinase inhibitors and immunotherapy,have been *** describe the clinical scenario of a patient with recurrence of HCC five years after LT,who received lenvatinib as first-line systemic therapy to introduce systemic treatment options in this clinical *** this opinion review,we detail first and second-line systemic treatment options,focusing on those feasible for patients with recurrent HCC after *** trials have evaluated new drugs to treat HCC patients in first and secondline therapy,but patients with recurrent HCC after LT have been excluded from these ***,most of the evidence comes from observational retrospective *** tyrosine kinase inhibitors will remain the primary therapeutic approach in these patients,due to a relative contraindication for immunotherapy,may be clarified in the near future.

关键词： Liver transplantation Recurrence Systemic therapies Hepatocellular carcinoma

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Adsorption and Uptake of Cadmium by Azolla pinnata:Kinetics of Inhibition by Cations

引用

Biomedical and Environmental Sciences 1995年第2期8卷 149-157页

作者： J.P.GAUR n.nORAHO LaboratoryofAlgalBiology CentreofAdvancedStudyinBotanyBanarasHinduUniversityVaranasi221005India Bo

A. pinnata showed a remarkable ability of taking up Cd from the external medium. Of the total Cd taken up by the test plant, surface adsorption was about 90%. Cd adsorption did not occur at a constant rate, however, an equilibrium was reached in 2 h. The uptake of Cd occurred at a constant rate. Test cations, including heavy metals (Ca, Mg, K, na,ni, Fe, Cu and Zn), inhibited adsorption as well as uptake of Cd. Cd adsorption was competitively inhibited by Cu, Fe and Zn, whereas Ca, Mg, K, na and ni caused non-competitive inhibition. Similarly, Cd uptake was competitively (Ca, Mg, Fe) or non-competitively (na, K, ni, Zn) inhibited by cations. Inhibition of Cd uptake by Cu was not wholly competitive

关键词： Adsorption and Uptake of Cadmium by Azolla pinnata

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

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

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

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

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

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：