484 research outputs found
Comparative Analysis of Clinical Epidemiology and Pathological Characteristics of 908 Patients with Primary Lung Cancer of Hunan Province in 1997 and 2007
Background and objective Epidemiology of lung cancer will be changed along with time and region. The aim of this study is to acknowledge the tendency of primary lung cancer in hunan province in recent years by comparing and analyzing the distribution of gender, age, area, smoking and pathology of patients who were initial diagnosed lung cancer and ancestral or permanent residence of hunan province in 1997 and 2007. Methods Clinical data of 908 patients with primary lung cancer hospitalized in Xiangya hospital were collected and evaluated. Results Compared patients in 2007 with those in 1997, ratio between male and female dropped from 3.8:1 to 2.98:1, while the proportion of young patients who were under 40 years old raised from 4.4% to 8.6% (χ2=4.465, P=0.035), patients living in the county raised from 19.9% to 40.1% (χ2=30.670, P < 0.001), smoking rate of patients from county raised from 16.9% to 39.9% (χ2= 24.939, P < 0.01). In addition, the proportion of rare histological types of lung cancer were also increased from 1.3% to 4.5% (χ2= 5.142, P=0.023). Conclusion Female patients, young patients, rural patients and rare histological types of lung cancer may have a tendency of increase in hunan province in recent years, whereas smoking cessation education should be strengthened
The fermi arc and fermi pocket in cuprates in a short-range diagonal stripe phase
In this paper we studied the fermi arc and the fermi pocket in cuprates in a
short-range diagonal stripe phase with wave vectors , which
reproduce with a high accuracy the positions and sizes of the fermi arc and
fermi pocket and the superstructure in cuprates observed by Meng et
al\cite{Meng}. The low-energy spectral function indicates that the fermi pocket
results from the main band and the shadow band at the fermi energy. Above the
fermi energy the shadow band gradually departs away from the main band, leaving
a fermi arc. Thus we conclude that the fermi arc and fermi pocket can be fully
attributed to the stripe phase but has nothing to do with pairing.
Incorporating a d-wave pairing potential in the stripe phase the spectral
weight in the antinodal region is removed, leaving a clean fermi pocket in the
nodal region.Comment: 5 pages, 6 figure
Unprecedented High Irreversibility Line in Nontoxic Cuprate Superconductor (Cu,C)Ba2Ca3Cu4O11+delta
One of the key factors limiting the high power applications for a type-II
superconductor is the irreversibility line Hirr(T) which reflects the very
boundary of resistive dissipation in the phase diagram of magnetic field versus
temperature. In cuprate family, the Y-, Bi-, Hg- and Tl-based systems have
superconducting transition temperatures exceeding the liquid nitrogen boiling
temperature (~77K). However, the toxic elements Hg and Tl in the latter two
systems strongly constrain the possible applications. The Bi-based (2223)
system is nontoxic, but the irreversibility magnetic field is strongly
suppressed in the liquid nitrogen temperature region. For this purpose, the
best perspective so far is relying on the YBa2Cu3O7 (Tc~90 K) system which is
nontoxic and has a relatively high irreversibility magnetic field. Here we
report the study of a nontoxic superconductor (Cu,C)Ba2Ca3Cu4O11+{\delta} with
Tc = 116K. It is found that the irreversibility magnetic field is
unprecedentedly high among all superconductors and it thus provides a great
potential of applications in the liquid nitrogen temperature region.Comment: 15 pages, 7 figures, including Supplementary Material
Multi-Area Interconnected Integrated Energy System Planning Considering Cloud Energy Storage
ObjectivesIn order to promote the efficient utilization of energy storage and user-side resources and improve the level of clean energy consumption, a multi-area interconnected integrated energy system planning model considering cloud energy storage was proposed.MethodsOn the basis of establishing the energy router model of the regional integrated energy system, a virtual energy router model considering electricity/heat/gas cloud energy storage was proposed. Aiming at the problem that cloud energy storage and integrated energy system belong to different investment entities, considering the limitation of the investment return period of cloud energy storage, a dual-subject two-stage planning model was proposed. In the first stage, the grid, equipment capacity and cloud energy storage price were planned. In the second stage, the operation strategy of the integrated energy system was optimized. Aiming at the high complexity of multi-energy flow grid planning, a pre-screening algorithm based on minimum spanning tree was proposed.ResultsThe example analysis results of a three-park integrated energy system planning show that the proposed model is helpful to improve energy efficiency, reduce carbon emissions, and improve the economic benefits of interconnected integrated energy systems.ConclusionsThe research reveals the potential of collaborative planning between cloud energy storage and multi-area integrated energy systems, and provides reference for the in-depth application and commercial promotion of multi-type energy storage in the energy field
Absence of near-ambient superconductivity in LuHN
Recently near-ambient superconductivity was claimed in N-doped lutetium
hydride (ref. 1). This induces a worldwide fanaticism about the dream of room
temperature superconductivity under low pressures. By using a high pressure and
high temperature synthesis technique, we have successfully obtained the
nitrogen doped lutetium hydride (LuHN) with a dark-bluish
color and a structure with the space group of evidenced by x-ray
diffraction. This structure is the same as that reported in ref. 1. The energy
dispersive X-ray spectroscopy (EDS) confirmed the existence of nitrogen in some
areas of the samples. At ambient pressure, we witness a kink of resistivity and
magnetization at about 300 K, which may correspond to a rearrangement of
hydrogen/nitrogen atoms, namely a structural transition. However, by applying a
pressure from 1 GPa to 6 GPa, we have seen a progressively optimized metallic
behavior without showing superconductivity down to 10 K. Temperature dependence
of magnetization shows a roughly flat feature between 100 and 320 K, and the
magnetization increases with magnetic field at 100 K, all these are not
expected for superconductivity at 100 K. Thus, we conclude the absence of
near-ambient superconductivity in this nitrogen-doped lutetium hydride under
pressures below 6 GPa.Comment: An updated version with more data was published in Nature online on
11th May 2023 as an Accelerated Article Preview for
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