检索结果-南通市图书馆

One Hair Postulate for Hawking Radiation as Tunneling Process

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2014年第3期61卷 289-292页

作者： dong Hui CAI qing-yu LIU Xu-feng SUN Chang-Pu Institute of Theoretical Physics Chinese Academy of Science Beijing 100190 China State Key Laboratory of Magnetic Resonances and Atomic and Molecular Physics Wuhan Institute of Physics andMathematics Chinese Academy of Sciences Wuhan 430071 China Department of Mathematics Peking University Beijing 100871 China

For Hawking radiation, treated as a tunneling process, the no-hair theorem of black hole together with the law of energy conservation is utilized to postulate that the tunneling rate only depends on the external qualities(e.g., the mass for the Schwarzschild black hole) and the energy of the radiated particle. This postulate is justified by the WKB approximation for calculating the tunneling probability. Based on this postulate, a general formula for the tunneling probability is derived without referring to the concrete form of black hole metric. This formula implies an intrinsic correlation between the successive processes of the black hole radiation of two or more particles. It also suggests a kind of entropy conservation and thus resolves the puzzle of black hole information loss in some sense.

关键词： tunneling formulism modified probability correlation entropy conservation black hole

Medical comorbidities at admission is predictive for 30-day in-hospital mortality in patients with acute myocardial infarction： analysis of 5161 cases

在线全文

学校读者我要写书评

暂无评论

Journal of Geriatric Cardiology 2011年第1期8卷 31-34页

作者： Xue-dong Yang yu-Sheng Zhao yu-feng Li Xin-Hong guo Institute of Geriatric Cardiology Chinese PLA General Hospital Beijing 100853 China

Background The present study investigated the prognostic value of medical comorbidities at admission for 30-day in-hospital mortality in patients with acute myocardial infarction （AMI）. Methods A total of 5161 patients with AMI were admitted in Chinese PLA General Hospital between January 1, 1993 and December 31, 2007. Medical comorbidities including hypertension, diabetes mellitus, previous myocardial infarction, valvular heart disease, chronic obstructive pulmonary disease （COPD）, renal insufficiency, previous stroke, atrial fibrillation and anemia, were identified at admission. The patients were divided into 4 groups based on the number of medical comorbidities at admission （0, 1, 2, and ≥3）. Cox regression analysis was used to calculate relative risk （RR） and 95% confidence intervals （CI）, with adjustment for age, sex, heart failure and percutaneous coronary intervention （PCI）. Results The mean age of the studied population was 63.9 ± 13.6 years, and 80.1% of the patients were male. In 74.6% of the patients at least one comorbidity were identified. Hypertension （50.7%）, diabetes mellitus （24.0%） and previous myocardial infarction （12%） were the leading common comorbidities at admission. The 30-day in-hospital mortality in patients with 0, 1, 2, and ≥3 comorbidities at admission （7.2%） was 4.9%, 7.2%, 11.1%, and 20.3%, respectively. The presence of 2 or more comorbidities was associated with higher 30-day in-hospital mortality compared with patients without comorbidity （RR： 1.41, 95% CI： 1.13-1.77, P = 0.003, and RR： 1.95, 95% CI： 1.59-2.39, P = 0.000, respectively）. Conclusions Medical comorbidities were frequently found in patients with AMI. AMI patients with more comorbidities had a higher 30-day in-hospital mortality might be predictive of early poor outcome in patients with AMI.

关键词： acute myocardial infarction comorbidity mortality

Wear properties of nonhydrogenated,hydrogenated,and dehydrogenated Ti6A14V alloy

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

Rare Metals 2018年第7期37卷 574-578页

作者： Bao-guo yuan Hai-Ping yu Chun-feng Li dong-Li Sun School of Materials Science and Engineering Hefei University of Technology Hefei 230009 China School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China

Wear properties of the nonhydrogenated, hydrogenated 0.5 wt%, and dehydrogenated Ti6Al4V alloys were studied through dry sliding wear tests using an M-200 type pin-on-disk wear testing machine in ambient air at room temperature to reveal the effects of hydrogen on wear properties of Ti6Al4V alloy. Morphology and chemical element of worn surface were investigated by means of scanning electron microscope （SEM） and energy dispersive spectroscopy （EDS）. Results show that hydrogen decreases the wear resistance of Ti6Al4V alloy. Wear rate of the Ti6Al4V alloy increases after hydrogenation. Wear rate increases by 244.3 % when 0.5 wt% hydrogen is introduced into a Ti6Al4V alloy. Wear rate of the dehydrogenated Ti6Al4V alloy recovers. Wear mechanisms of the nonhydrogenated, hydrogenated, and dehydrogenated Ti6Al4V alloys are determined. The nonhydrogenated Ti6Al4V alloy is controlled by oxidative wear. The hydrogenated Ti6Al4V alloy is dominated by abrasive wear. Wear mechanism of the dehydrogenated Ti6Al4V alloys is a mixture of oxidative wear and abrasive wear.

关键词： Titanium alloy Hydrogen Wear Mechanism

Enhanced resistance to Botrytis cinerea and Rhizoctonia solani in transgenic broccoli with a Trichoderma viride endochitinase gene

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2015年第3期14卷 430-437页

作者： yu Ya ZHANG Lei LIAN Wei-ran XU feng-feng LI Shuang-tao XIANG Juan ZHANG guo-zhen HU Zan-min ZHAO bing REN Shu-xin guo Yang-dong College of Agriculture & Biotechnology China Agricultural University Department of Biology Science & Technology Wuhan Institute of Bioengineering Institute of Genetics & Developmental Biology Chinese Academy of Sciences School of Agriculture Virginia State University

A endochitinase gene（Tch） from the fungus Trichoderma viride was introduced into broccoli（Brassica oleracea var. italica） by Agrobacterium-mediated transformation. Sixty-eight putative transformants were obtained and the presence of the Tch gene was confirmed by both PCR and Southern blot analysis. RT-PCR analysis showed an accumulation of the transcript encoding the endochitinase protein in the transgenic plants. Using real-time quantitative PCR, the expression profiling of endochitinase gene was analyzed. Primary transformants and selfed progeny were examined for expression of the endochitinase using a fluorometric assay and for their resistance to the pathogenic fungi Botrytis cinerea and Rhizoctonia solani. The endochitinase activities in T0 in vitro plants, T0 mature plants and T1 mature plants were correlated with leaf lesions, and the transgenic line T618 had high endochitinse activities of 102.68, 114.53 and 120.27 nmol L–1 MU min–1 mg–1 protein in the three kinds of plants, respectively. The endochitinase activity showed a positive correlation with the resistance to the pathogens. Most transgenic T0 broccoli had increased resistance to the pathogens of B. cinerea and R. solani in leaf assays and this resistance was confirmed to be inheritable. These findings suggested that expression of the Tch gene from T. viride could enhance resistance to pathogenic fungi in Brassica species.

关键词： Botrytis cinerea broccoli endochitinase gene genetic transformation Rhizoctonia solani

Electrochemical potassium ion sensor based on DNA G-quadruplex conformation and gold nanoparticle amplification

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2013年第4期32卷 369-374页

作者： Li-dong Li Xiao-qing Huang Lin guo School of Chemistry and Environment Beijing University of Aeronautics and Astronautics

A simple, rapid, highly sensitive electrochem-ical sensor for potassium ion （K^＋） based on the confor-mationai change of DNA sequence containing guanine-rich segments is presented. In the presence of K^＋, guanine-rich DNA sequence folds to G-quadruplex structure, allowing a ferrocene tag to transfer electrons to the electrode. Gold nanoparticles （AuNPs）, which are self-assembled on the surface of a bare gold electrode by using 4-aminothio-phenol as a medium, offer a big surface area to immobilize a large number of aptamers and improve the sensitivity of the sensor. The square-wave voltammetry peak current increases with K^＋ concentration. The plots of peak current against K^＋ concentration and the logarithm of K^＋ con- centration are linear over the range from 0.1 to 1.0 mmol·L^-1 and from 1 to 30 mmol·L^-1, respectively. A lower detection limit of 0.1 mmol·L^-1 K^＋ is obtained for AuNPs-modified sensor, which greatly surpasses that （100 mmol·L^-1） of the sensor without AuNPs modification by three orders of magnitude. Thus, the sensor with AuNPs amplification is expected to open new opportunities for highly sensitive detection of other biomolecules in the future.

关键词： Electrochemistry G-quadruplex Gold nanoparticles Potassium Sensor

Optimized nitrogen application methods to improve nitrogen use efficiency and nodule nitrogen fixation in a maize-soybean relay intercropping system

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2018年第3期17卷 664-676页

作者： YONG Tai-wen CHEN Ping dong Qian DU qing YANG feng WANG Xiao-chun LIU Wei-guo YANG Wen-yu College of Agronomy Sichuan Agricultural University/Key Laboratory of Crop Eco-physiology and Farming System in Southwest Ministry of Agriculture Chengdu 611130 P.R. China Shehong Farm Bureau Suining 629200 PR.China

In China, the abuse of chemical nitrogen （N） fertilizer results in decreasing N use efficiency （NUE）, wasting resources and causing serious environmental problems. Cereal-legume intercropping is widely used to enhance crop yield and improve resource use efficiency, especially in Southwest China. To optimize N utilization and increase grain yield, we conducted a two-year field experiment with single-factor randomized block designs of a maize-soybean intercropping system （IMS）. Three N rates, NN （no nitrogen application）, LN （lower N application： 270 kg N ha-1）, and CN （conventional N application： 330 kg N ha-1）, and three topdressing distances of LN （LND）, e.g., 15 cm （LND1）, 30 cm （LND2） and 45 cm （LND3） from maize rows were evaluated. At the beginning seed stage （R5）, the leghemoglobin content and nitrogenase activity of LND3 were 1.86 mg plant-1 and 0.14 mL h-1 plant-1, and those of LND1 and LND2 were increased by 31.4 and 24.5%, 6.4 and 32.9% compared with LND3, respectively. The ureide content and N accumulation of soybean organs in LND1 and LND2 were higher than those of LND3. The N uptake, NUE and N agronomy efficiency （NAE） of IMS under CN were 308.3 kg ha-1, 28.5%, and 5.7 kg grain kg-1 N, respectively; however, those of LN were significantly increased by 12.4, 72.5, and 51.6% compared with CN, respectively. The total yield in LND1 and LND2 was increased by 12.3 and 8.3% compared with CN, respectively. Those results suggested that LN with distances of 15-30 cm from the topdressing strip to the maize row was optimal in maize-soybean intercropping. Lower N input with an optimized fertilization location for IMS increased N fixation and N use efficiency without decreasing grain yield.

关键词： relay intercropping lower nitrogen nitrogen use efficiency nitrogen fixation nitrogen uptake

Development of a clinical nomogram for prediction of response to neoadjuvant chemotherapy in patients with advanced gastric cancer

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastrointestinal Surgery 2024年第2期16卷 396-408页

作者： bing Liu yu-Jie Xu feng-Ran Chu Guang Sun guo-dong Zhao Sheng-Zhong Wang Department of Gastrointestinal Surgery Central South University Xiangya School of Medicine Affiliated Haikou HospitalHaikou 570208Hainan ProvinceChina Clinical College Hainan Medical UniversityHaikou 571199Hainan ProvinceChina

BACKGROUND The efficacy of neoadjuvant chemotherapy(NAC)in advanced gastric cancer(GC)is still a controversial *** To find factors associated with chemosensitivity to NAC treatment and to provide the optimal therapeutic strategies for GC patients receiving *** The clinical information was collected from 230 GC patients who received NAC treatment at the Central South University Xiangya School of Medicine Affiliated Haikou Hospital from January 2016 to December *** absolute shrinkage and selection operator logistic regression analysis was used to find the possible predictors.A nomogram model was employed to predict the response to *** In total 230 patients were finally included in this study,including 154 males(67.0%)and 76 females(33.0%).The mean age was(59.37±10.60)years,ranging from 24 years to 80 *** to the tumor regression grade standard,there were 95 cases in the obvious response group(grade 0 or grade 1)and 135 cases in the poor response group(grade 2 or grade 3).The obvious response rate was 41.3%.Least absolute shrinkage and selection operator analysis showed that four risk factors significantly related to the efficacy of NAC were tumor location(P<0.001),histological differentiation(P=0.001),clinical T stage(P=0.008),and carbohydrate antigen 724(P=0.008).The C-index for the prediction nomogram was *** calibration curve revealed that the predicted value exhibited good agreement with the actual *** curve analysis showed that the nomogram had a good value in clinical *** A nomogram combining tumor location,histological differentiation,clinical T stage,and carbohydrate antigen 724 showed satisfactory predictive power to the response of NAC and can be used by gastrointestinal surgeons to determine the optimal treatment strategies for advanced GC patients.

关键词： Advanced gastric cancer Predictor Neoadjuvant chemotherapy Nomogram Tumor regression grade

Preparation of β-SiC by combustion synthesis in a large-scale reactor

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

International Journal of Minerals,Metallurgy and Materials 2009年第3期16卷 322-326页

作者： yu-qiong Liu Li-feng Zhang qing-zhi Yan Xiao-dong Mao Qiao feng Chang-chun Ge Laboratory of Special Ceramics and Powder Metallurgy University of Science and Technology Beijing Beijing 100083 China Beijing Chunshu Rectifier Co. Ltd. Beijing 100040 China

The feasibility of 5 kg β-SiC synthesized in one batch was demonstrated through igniting the mixture of Si, C-black and polytetrafluoroethylene （PTFE） under different nitrogen pressures. The effect of experimental parameters, including the contents of PTFE, nitrogen pressure, preheating, and raw materials distribution forms were investigated. The results show that the products are β-SiC with equiaxed grains. The average grain size is less than 200 nm. The powders loaded loosely promote reaction heat dispersing, resulting in small grains. High purity β-SiC powders are obtained when the PTFE content is as low as 5wt%, which simplifies the process and decreases the cost effectively. The ceramic sintered from the obtained β-SiC powders presents the hardness of 22.20 GPa, the bending strength as high as 715.15 MPa and the fracture toughness of 8.179 MPa·m^1/2, which are higher than those of ceramics fabricated with α-SiC produced by combustion synthesis.

关键词： silicon carbide combustion synthesis β-SiC reaction parameter large-scale reactor self-propagating high-temperature synthesis

Removal of Methylene Blue with Hemicellulose/Clay Hybrid Hydrogels

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2016年第6期34卷 709-719页

作者： He-li Cheng qing-hua feng Chuan-an Liao yu Liu dong-bei Wu 王启刚 Department of Chemistry Tongji University Institute of Pulp and Papermaking Hubei University of Technology Pharmaceutical College Guangxi Medical University Key Laboratory of Pulp and Paper Science & Technology of Ministry of Education of China Qilu University of Technology

In this study, we chose corn stover hemicellulose for the preparation of hydrogels with admirable adsorption properties under mild alkaline conditions. Clay nanosheets were introduced to this system and hemicellulose/clay hybrid hydrogels were prepared. Morphological, mechanical properties and the methylene blue adsorption behaviors of the prepared hydrogels were studied. Results suggested that the addition of clay not only improved the mechanical strength of hemicellulose-based hydrogels, but also increased the adsorption capacity on methylene blue. Moreover, the adsorptions were confirmed to follow pseudo-second order equation for both gels with and without clay. The maximum adsorption capacities on methylene blue for hemicellulose-based hydrogels with or without clay reached 148.8 and 95.6 mg/g, respectively. These results implied that hemicellulose-based hydrogels could be used as promising adsorbents for the removal of methylene blue from waste water.

关键词： Hemicellulose Hybrid hydrogel Clay Adsorption.