检索结果-南通市图书馆

A study of flames with millimeter-wave radiation

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2020年第4期16卷 876-882页

作者： Jing-ran Xu Ru Peng Chen-guang Zhu Xiao xie Chen-guang Yan Department of Applied Chemistry School of Chemical EngineeringNanjing University of Science and TechnologyNanjingJiangsuChina

It is a valuable issue to explore whether a flame can radiate microwaves,in spite of the electric field formed in the *** herein is an experimental study on a series of flames with millimeterwave radiation in the combustion of pyrotechnic *** pyrotechnic films were composed of ultrafine red phosphorus(P),sodium nitrate(NaNO_3),Polyvinyl Alcohol(PVA) and some additives such as chopped carbon fibers(CFs) and aluminized glass fibers(GFs).The combustion temperatures and millimeter-wave radiation signals of the flames were measured,the millimeter-wave emissivity and spectral radiant exitance were calculated to describe the millimeter-wave radiation *** results demonstrate that the flame of the pyrotechnic films based on P/NaNO_3/CFs can radiate millimeter waves,and different materials and their proportion have a great effect on the millimeter-wave radiation intensity.

关键词： Combustion Flame Pyrotechnics Millimeter-wave radiation

The Effects of Climate Change on the Planting Boundary and Potential Yield for Different Rice Cropping Systems in Southern China

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2014年第7期13卷 1546-1554页

作者： YE Qing YANG Xiao-guang LIU Zhi-juan DAI shu-wei LI Yong xie Wen-juan CHEN Fu Forestry Institute Jiangxi Agricultural University College of Resources and Environmental Sciences China Agricultural University School of Natural Resources University of Nebraska-Lincoln Lincoln NE 68583 USA Guizhou Key Laboratory of Mountainous Climate and Resources College of Agriculture and Biotechnology China Agricultural University

Based on climate data from 254 meteorological stations, this study estimated the effects of climate change on rice planting boundaries and potential yields in the southern China during 1951-2010. The results indicated a signiifcant northward shift and westward expansion of northern boundaries for rice planting in the southern China. Compared with the period of 1951-1980, the average temperature during rice growing season in the period of 1981-2010 increased by 0.4＆#176;C, and the northern planting boundaries for single rice cropping system （SRCS）, early triple cropping rice system （ETCRS）, medium triple cropping rice system （MTCRS）, and late triple cropping rice system （LTCRS） moved northward by 10, 30, 52 and 66 km, respectively. In addition, compared with the period of 1951-1980, the suitable planting area for SRCS was reduced by 11%during the period of 1981-2010. However, the suitable planting areas for other rice cropping systems increased, with the increasing amplitude of 3, 8, and 10%for ETCRS, MTCRS and LTCRS, respectively. In general, the light and temperature potential productivity of rice decreased by 2.5%. Without considering the change of rice cultivars, the northern planting boundaries for different rice cropping systems showed a northward shift tendency. Climate change resulted in decrease of per unit area yield for SRCS and the annual average yields of ETCRS and LTCRS. Nevertheless, the overall rice production in the entire research area showed a decreasing trend even with the increasing trend of annual average yield for MTCRS.

关键词： climate change potential yield rice cropping system planting boundary

Role of contrast-enhanced ultrasound in follow-up assessment after ablation for hepatocellular carcinoma

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2013年第6期19卷 855-865页

作者： shu-guang Zheng Hui-Xiong Xu Ming-De Lu Xiao-Yan xie Zuo-Feng Xu guang-Jian Liu Lin-Na Liu Department of Medical Ultrasound Tenth People's Hospital of Tongji University Department of Medical Ultrasonics the First Affiliated HospitalSun Yat-Sen University

AIM:To assess the usefulness of contrast-enhanced ultrasound (CEUS) during follow-up after percutaneous ablation therapy for hepatocellular carcinoma (HCC).METHODS:A total of 141 patients with HCCs who received percutaneous ablation therapy were assessed by paired follow-up CEUS and contrast-enhanced computed tomography (CECT).The follow-up scheme was designed prospectively and the intervals between CEUS and CECT examinations were less than 14 *** im-ages of follow-up CEUS and CECT were reviewed by *** ablated lesions were evaluated and classified as local tumor progression (LTP) and *** was defined as regrowth of tumor inside or adjacent to the successfully treated *** detected new intrahepatic recurrences were also evaluated and defined as presence of intrahepatic new *** CEUS and CECT,LTP and new intrahepatic recurrence both were displayed as typical enhancement pattern of HCC (i.e.,hyper-enhancing during the arterial phase and washout in the late phase).With CECT as the reference standard,the ability of CEUS in detecting LTP or new intrahepatic recurrence during follow-up was ***:During a follow-up period of 1-31 mo (median,4 mo),169 paired CEUS and CECT examinations were carried out for the 141 *** a total of 221 ablated lesions,266 comparisons between CEUS and CECT findings were ***-three LTPs were detected on CEUS whereas 40 LTPs were detected on CECT,there was significant difference (P < 0.001).In comparison with CECT,the numbers of false positive and false negative LTPs detected on CEUS were 6 and 13,respectively;the sensitivity,specificity,positive predictive value (PPV),negative predictive value (NPV) and overall accuracy of CEUS in detecting LTPs were 67.5%,97.4%,81.8%,94.4% and 92.3%,***,131 new intrahepatic recurrent foci were detected on CEUS whereas 183 were detected on CECT,there was also significant difference (P < 0.05).In comparison with CECT,the numbers of

关键词： Contrast-enhanced ultrasound Contrastenhanced computed tomography Hepatocellular carcinoma Radiofrequency ablation Microwave ablation

Field theory of the correlation function of mass density fluctuations for self-gravitating systems

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

Research in Astronomy and Astrophysics 2019年第4期19卷 41-52页

作者： Yang Zhang Qing Chen shu-guang Wu Department of Astronomy Key Laboratory for Researches in Galaxies and Cosmology University of Science and Technology of China

The mass density distribution of Newtonian self-gravitating systems is studied analytically in the field theoretical method. Modeling the system as a fluid in hydrostatic equilibrium, we apply Schwinger's functional derivative on the average of the field equation of mass density, and obtain the field equation of 2-point correlation function ξ(r) of the mass density fluctuation, which includes the next order of nonlinearity beyond the Gaussian approximation. The 3-point correlation occurs hierarchically in the equation,and is cut off by the Groth-Peebles ansatz, making it closed. We perform renormalization and write the equation with three nonlinear coefficients. The equation tells us that ξ depends on the point mass m and the Jeans wavelength scale λ_0, which are different for galaxies and clusters. Applying this to large scale structures, it predicts that the profile of ξcc for clusters is similar to ξgg for galaxies but with a higher amplitude, and that the correlation length increases with the mean separation between clusters, i.e., a scaling behavior r_0■0.4 d. The solution yields the galaxy correlation ξ_(gg)(r)■(r_0/r)^(1.7) valid only in a range1 < r < 10 h^(-1) Mpc. At larger scales the solution ξgg deviates below the power law and goes to zero around ~50 h^(-1) Mpc, just as the observations show. We also derive the field equation of the 3-point correlation function in the Gaussian approximation and its analytical solution, for which the Groth-Peebles ansatz with Q = 1 holds.

关键词： cosmology:theory cosmology:large-scale structure of universe

Online algorithms for scheduling with machine activation cost on two uniform machines

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第1期8卷 127-133页

作者： HAN shu-guang JIANG Yi-wei HU Jue-liang Department of Mathematics Zhejiang University Hangzhou 310027 China Faculty of Science Zhej iang Sci- Tech University Hangzhou 310018 China

In this paper we investigate a variant of the scheduling problem on two uniform machines with speeds 1 and s. For this problem, we are given two potential uniform machines to process a sequence of independent jobs. Machines need to be activated before starting to process, and each machine activated incurs a fixed machine activation cost. No machines are initially activated, and when a job is revealed, the algorithm has the option to activate new machines. The objective is to minimize the sum of the makespan and the machine activation cost. We design optimal online algorithms with competitive ratio of (2s+1)/(s+1) for every s≥1.

关键词： Online algorithm Competitive analysis Uniform machine scheduling Machine activation cost

Glycogen synthase kinase 3 signaling in neural regeneration in vivo

在线全文

学校读者我要写书评

暂无评论

Journal of Molecular Cell Biology 2023年第12期15卷 1-11页

作者： Jing Zhang shu-guang Yang Feng-Quan Zhou Sir Run Run Shaw Hospital Zhejiang University School of MedicineHangzhou 310016China

Glycogen synthase kinase 3(GSK3)signaling plays important and broad roles in regulating neural development in vitro and in ***,we reviewed recent findings of GSK3-regulated axon regeneration in vivo in both the peripheral and central nervous systems and discussed a few controversial findings in the ***,current evidence indicates that GSK3βsignaling serves as an important downstream mediator of the PI3K–AKT pathway to regulate axon regeneration in parallel with the mTORC1 ***,the mTORC1 pathway supports axon regeneration mainly through its role in regulating cap-dependent protein translation,whereas GSK3βsignaling might be involved in regulating N6-methyladenosine mRNA methylation-mediated,cap-independent protein *** addition,GSK3 signaling also plays a key role in reshaping the neuronal transcriptomic landscape during ***,we proposed some research directions to further elucidate the molecular mechanisms underlying the regulatory function of GSK3 signaling and discover novel GSK3 signaling-related therapeutic ***,we hope to provide an updated and insightful overview of how GSK3 signaling regulates neural regeneration in vivo.

关键词： GSK3 neural regeneration protein translation gene transcription

Integrated Entry Guidance for Reusable Launch Vehicle

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

Chinese Journal of Aeronautics 2007年第1期20卷 1-8页

作者： NING Guo-dong ZHANG shu-guang FANG Zhen-ping School of Aeronautical Science and Technology Beijing University of Aeronautics and Astronautics Beijing 100083 China

A method for the implementation of integrated three-degree-of-freedom constrained entry guidance for reusable launch vehicle is presented. Given any feasible entry conditions, terminal area energy management interface conditions, and the reference trajectory generated onboard then, the method can generate a longitudinal guidance profile rapidly, featuring linear quadratic regular method and a proportional-integral-derivative tracking law with time-varying gains, which satisfies all the entry corridor constraints and meets the requirements with high precision. Afterwards, by utilizing special features of crossrange parameter, establishing bank-reversal corridor, and determining bank-reversals according to dynamically adjusted method, the algorithm enables the lateral entry guidance system to fly a wide range of missions and provides reliable and good performance in the presence of significant aerodynamic modeling uncertainty. Fast trajectory guidance profiles and simulations with a reusable launch vehicle model for various missions and aerodynamic uncertainties are presented to demonstrate the capacity and reliability of this method.

关键词： guidance trajectory generation entry onboard constraint robustness

Θ-type Calderón-Zygmund Operators with Non-doubling Measures

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2013年第2期29卷 263-280页

作者： Ru-long xie Li-sheng shu School of Mathematical Sciences University of Science and Technology of China Department of Mathematics Chaohu University Department of Mathematics Anhui Normal University

Let μ be a Radon measure on Rd which may be non-doubling. The only condition that μ must satisfy is μ（B（x,r）） ≤ Urn for all x∈Rd, r 〉 0 and for some fixed 0 〈 n 〈 d. In this paper, under this assumption, we prove that 0-type Calder6n-Zygmund operator which is bounded on L2 （μ） is also bounded from L^∞（μ） into RBMO （μ） and from Hb （μ） into L1（μ）. According to the interpolation theorem introduced by Tolsa, the LP（μ）-boundedness （1 〈 p 〈 ∞） is established for θ-type Calder6n-Zygmund operators. Via a sharp maximal operator, it is shown that commutators and multilinear commutators of θ-type CMderθn-Zygmundoperator with RBMO （μ） function are bounded on LP（μ）（1 〈 p 〈 ∞）.

关键词： non-doubling measure θ-type Calderón-Zygmund operator, commutators multilinear commuta-tors RBMO ( μ ) space H1,∞atb ( μ ) space

Analysis of Effect of Gas Temperature on Cooling Stave of Blast Furnace

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2010年第1期17卷 1-6页

作者： xie Ning-qiang CHENG shu-sen School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China

In order to study the effect of gas temperature variation on cooling stave, temperature, stress and displacement distributions of cooling stave were analyzed respectively when gas temperature inside- blast furnace increases from 1000 to 1 600 ℃. The results show that the temperature field on cold side is under control of cooling pipes and hardly changes when gas temperature increases. The temperature gradient and change rate with time near hot sides are greater than those in other regions and the later can reach 100 ℃/s. The stress intensity near middle area of hot surface is up to 400 MPa and that＇s why there are lots of cracks at this place. The edge of stave is bent to cold side and middle regions between fixed bolts and pin moves to hot side. The displacement around fixed pin is smaller but larger on the edge and the maximum is located on hot side of top surface. The maximum displacement in z direction is about 4 mm and 3 mm in y direction. If the expansion coefficient of packing layer is 1/4, the thickness of packing layer between the cooling staves is 32 mm and 24 mm between sides up and down.

关键词： temperature variation displacement temperature change rate stress intensity packing layer