bluuebunny/crossref_metadata_2025 huggingface dataset:
Pathology of early hepatocellular carcinoma
Authors: Sakamoto Michiie
Published: September 2007

As is observed in many types of human cancers, hepatocellular carcinoma (HCC) is characterized by an obvious multistage process of tumor progression. Histopathological and molecular biological studies have revealed that HCC associated with chronic liver disease evolves from precancerous lesions called adenomatous hyperplasia (also called dysplastic nodules) and early HCC to a progressed form. Early HCC corresponds to in situ or microinvasive carcinoma, and develops to progressed HCC through the stage of “nodule‐in‐nodule” type HCC (progressed HCC within early HCC), which indicates a transition from early to progressed HCC. It is consideredthat early HCC is a key step in the process of HCC development and progression. However, the molecular mechanisms of early hepatocarcinogenesis are far from clear. Specific mutations of classical oncogenes or tumor suppressor genes have not been identified in early HCC so far. Recent progress in comprehensive analysis of gene expression is shedding some light on this issue.
Screening of hepatocellular cancer: Japanese strategy
Authors: Okita Kiwamu , Kurokawa Fumie , Yamasaki Takahiro , Sakaida Isao
Published: September 2007

In Japan, hepatocellular carcinoma ranks as the fourth most common cancer and is responsible for about 40,000 deaths annually. Accordingly, the development of a screening system for its early detection will be linked to early treatment with a view to increasing survival. Algorithms for surveillance of hepatocellular carcinoma established in Japan will be useful for its early detection.
Role of tumor markers in assessment of tumor progression and prediction of outcomes in patients with hepatocellular carcinoma
Authors: Toyoda Hidenori , Kumada Takashi , Osaki Yukio , Oka Hiroko , Kudo Masatoshi
Published: September 2007

The efficacies of tumor markers, alfa‐fetoprotein (AFP), Lens culinaris agglutinin A‐reactive fraction of alfa‐fetoprotein (AFP‐L3), and des‐gamma‐carboxy prothrombin (DCP) were evaluated for assessment of progression of hepatocellular carcinoma (HCC) and patient prognosis. The prevalence of elevated levels of each tumor marker increased with progression of tumor stage for all three markers among patients with HCC. Survival was poorer among patients with elevated levels of tumor markers than among those without elevated levels.Evaluation of tumor progression with tumor markers was based only on the results of laboratory tests. The tests are objective, simple to perform, and easy to repeat, and therefore, may be useful to supplement conventional tumor staging for the evaluation of tumor progression and prediction of patient outcome.
Recent advances in the diagnosis of hepatocellular carcinoma
Authors: Piscaglia Fabio , Bolondi Luigi
Published: September 2007

In the last decade, new imaging techniques have become available, offering the possibility of investigating contrast perfusion of liver nodules in cirrhosis. It is now accepted that a non‐invasive diagnosis of hepatocellular carcinoma (HCC) can be established based on the vascular pattern, obtained with pure blood pool contrast agents. The diagnostic pattern includes: hypervascularity in the arterial phase (15–35 s after contrast injection), consisting in a contrast signal in the nodule greater than in the surrounding parenchyma, followed by contrast wash out, which leads the nodule to show the same, or, more specifically, a lower contrast signal, than the surrounding parenchyma in the portal and late phases (>40 s after injection). Such a pattern can be obtained not only by computed tomography or magnetic resonance imaging, but also by contrast‐enhanced ultrasonography, most simply with real‐time low mechanical index harmonic imaging ultrasound equipment with second‐generation ultrasound contrast agents. The risk of false‐positive diagnosis of malignancy isnearly abolished when the functional vascular pattern is not the only feature, but is superimposed on a nodule visible also without contrast. One single contrast imaging technique may suffice to make a diagnosis of HCC if the nodule is >1 cm in diameter and has developed during a surveillance program. Other types of contrast agents, such as those taken up by the reticular‐endothelial system cells, may offer additional diagnostic clues, but definitive evidence of their efficacy is still to be produced. In conclusion, contrast‐enhanced imaging techniques now offer the possibility of a non‐invasive diagnosis of HCC in a large number of cases, reducing the need of invasive investigations, such as ultrasound‐guided biopsy or angiography.
Review of current staging systems for hepatocellular carcinoma
Authors: Chung Hobyung , Kudo Masatoshi , Takahashi Shunsuke , Hagiwara Satoru , Sakaguchi Yasuhiro , Inoue Tatsuo , Minami Yasunori , Ueshima Kazuomi , Fukunaga Toyokazu
Published: September 2007

Several staging systems have been developed to classify patients with hepatocellular carcinoma (HCC), however, there is no consensus on which of these is the most useful and reliable. In this review article, currently available integrated staging systems taking into account both liver function and tumor progression are presented, and their characteristics and applicability for current HCC patients, many of whom are diagnosed in the early stage of the disease and treated by curative therapy, are discussed. Based on the original andsubsequent validation studies of these staging systems, we recommend that further validation studies of staging systems for HCC should focus on the revised Barcelona Clinic Liver Cancer (BCLC) staging classification, Japan Integrated Staging (JIS) score and Tokyo score.
Japanese experience in ablation therapies for hepatocellular carcinoma
Authors: Shiina Shuichiro
Published: September 2007

In the treatment of hepatocellular carcinoma, only 20–30% of patients are candidates for surgery. Still worse, even after curative surgical resection, 80% of patients develop recurrence within 5 years. Thus, various non‐surgical therapies have developed. Among them, image‐guided local ablation therapies, such as percutaneous ethanol injection, microwave coagulation and radiofrequency ablation, have been widely used for small hepatocellular carcinoma, because they are potentially curative, minimally invasive and easily repeatable. Percutaneous ethanol injection was a standard therapy. However, there has been a drastic shift from ethanol injection to radiofrequency ablation in recent years. In Japan, 1500 institutes have already introduced radiofrequency ablation in the treatment of liver tumors and the cool‐tip electrode system has an 80% share of the market. Radiofrequency ablation can achieve complete tumor necrosis in most cases.Long‐term survival seems considerably good, and complications are not frequent in radiofrequency ablation. Randomized controlled trials have proved that radiofrequency ablation is superior to ethanol injection in the treatment of small hepatocellular carcinoma from the viewpoint of, not only treatment response, but also long‐term survival. Radiofrequency ablation seems feasible, efficacious and considerably safe. Radiofrequency ablation will be more widely performed in the treatment of primary and metastatic liver tumors in Japan.
Transarterial chemoembolization for patients with hepatocellular carcinoma
Authors: Forner Alejandro , Real M Isabel , Varela Maria , Bruix Jordi
Published: September 2007

Hepatocellular carcinoma (HCC) has gained interest among the scientific community due to its increasing incidence in developed countries and the improvement of its diagnostic algorithm and therapeutic approach. Despite the universal implementation of screening programs in cirrhotics through biannual abdominal ultrasound, only 30% of HCC are diagnosed at an early stage, when radical treatments, surgical resection, liver transplantation and percutaneous ablation, are possible. Several therapies have been proposed for patients who cannot benefit from a radical approach, but only transarterial chemoembolization has demonstrated survival benefits. However, it can only be performed in patients withpreserved liver function, absence of extrahepatic spread/vascular invasion, and no significant cancer‐related symptoms. Therefore, no more than 20% of the patients affected by HCC can be benefited by this therapeutic modality. The objective responses after procedure vary between 20% and 50%, with a significant rate of adverse‐effects, particularly post‐embolization syndrome. Further randomized controlled trials are needed to assess the best chemotherapeutic agent and the ideal re‐treatment schedule.
Liver transplantation for hepatocellular carcinoma
Authors: Sarpel Umut , Schwartz Myron
Published: September 2007

Hepatocellular carcinoma can only be cured by physical removal or destruction of the tumor before it has spread. This can be accomplished by the ablation of the tumor, surgical resection of the tumor‐bearing liver, or by liver transplantation. Ablation and resection can only be performed in patients who will be left with sufficient liver volume to sustain normal hepatic function. Unfortunately, the same disease that caused the HCC also limits the amount of parenchymal loss that can be tolerated by the patient. Liver transplantation is an appealing treatment option because it has the potential to cure patient of both the cancer and the predisposinig liver disease. Excellent survival rates are possible in patients with early HCC who receive a transplant, but dismal results are seen when patients with advanced tumors are transplanted.Wide criteria for transplant allow for more patients to be cured of HCC, but this comes at the expense of a greater overall recurrence rate. The acceptable recurrence rate is not a concrete number, but this is a function of donor organ availability. A 50% cure rate is viewed as an excellent outcome for many accepted cancer operations; however, in the case of transplant for HCC, this would represent a poor use of the scarce donor resource when the same liver offers a 70% 5‐year survival rate to a non‐HCC patient. These issues and methods retarding tumor progression while on the transplant waiting list are reviewed herein.
Glycyrrhizin injection therapy prevents hepatocellular carcinogenesis in patients with interferon‐resistant active chronic hepatitis C
Authors: Ikeda Kenji
Published: September 2007

Aim:  There is no useful and effective treatment for patients with non‐sustained response to interferon, from the viewpoint of cancer prevention. Our aim was to elucidate the influence of a glycyrrhizin therapy on hepatocarcinogenesis rate in interferon‐resistant hepatitis C

Methods:  We retrospectively analyzed 1249 patients with chronic hepatitis with or without cirrhosis. Among 346 patients with high alanine transaminase values of twice or more of the upper limit of normal, 244 patients received i.v. glycyrrhizin injection and 102 patients did not, after judgment of interferon resistance.

Results:  Crude carcinogenesis rates in the treated and untreated group were 13.3%, 26.0% at the fifth year, and 21.5% and 35.5% at the 10th year, respectively (P = 0.021). Proportional hazard analysis using time‐dependent covariates disclosed that fibrotic stage, gender and glycyrrhizin treatmentwere significantly associated with future carcinogenesis. A long‐term glycyrrhizin injection therapy decreased the hepatocarcinogenesis rate (hazard ratio, 0.49; 95% confidence interval, 0.27–0.86, P = 0.014) after adjusting the background features with significant covariates. Cancer preventive activity was also found in a subgroup of older patients of 60 years or more.

Conclusions:  Glycyrrhizin injection therapy significantly decreased the incidence of hepatocellular carcinoma in patients with interferon‐resistant active chronic hepatitis C, whose average aminotransferase value was twice or more of the upper limit of normal after interferon.
Antiviral therapy and primary and secondary prevention of hepatocellular carcinoma
Authors: Wright Teresa L.
Published: September 2007

Viral hepatitis due to chronic hepatitis B and C virus (HBV/HCV) infects more than 500 000 000 individuals worldwide. These chronic viral diseases are highly linked to the development of hepatocellular carcinoma (HCC), the fifth most common cause of cancer death worldwide. HCC is much more common in Asia and Africa than in the USA and Europe, although HCC is one of the few cancers with a rising incidence in the USA. There are 530 000 cases of HCC worldwide of which 82% are related to viral hepatitis. 316 000 cases of HCC are HBV‐associated, 118 000 are HCV‐associated. The most effective way to prevent HCC is to prevent viral infection through immunization. Currently there are effective vaccinesagainst hepatitis B and A, but not against HCV, the virus that accounts for most HCC in the USA. The published work supporting the use of antiviral therapy in preventing liver cancer is limited. Data supporting the use of antiviral therapy in preventing recurrence of HCC after initial anticancer approaches is even less available. Nevertheless, the weight of evidence suggests that treatment of HBV/HCV‐related fibrosis will reduce the risk of developing HCC.
Chemoprevention of liver carcinogenesis with retinoids: Basic and clinical aspects
Authors: Moriwaki Hisataka , Shimizu Masahito , Okuno Masataka , Nishiwaki‐Matsushima Rie
Published: September 2007

The strategy to prevent liver carcinogenesis consists of: (i) antiviral modalities such as vaccination, lamivudin, and interferon; (ii) anti‐inflammatory modality; and (iii) chemoprevention using such compounds as retinoid analog and vitamin K. Cancer chemoprevention is defined as an approach where natural or synthetic chemical compound works to arrest or reverse premalignant cells by using physiological pathways. As a consequence, such a clone of premalignant cells is eradicated (clonal deletion) by differentiation induction or apoptosis, and thus the process toward the development of clinically detectable cancer is disrupted. A particularly effective candidate target of chemoprevention in liver diseases is an advanced stage of chronic hepatitis, that is supposed to contain transformed hepatocyte clone(s); that is, primary prevention from liver cirrhosis and prevention of recurrent and second primary hepatocellular carcinoma following the treatment of the initial cancer. Retinoid is a collective term of vitamin A analog that binds to nuclear retinoid receptors;retinoic acid receptors (RAR) and retinoid X receptors (RXR). After ligand coupling, these receptors form homo‐ or heterodimers, bind to the response element (RARE or RXRE) upstream of the target gene, and regulate the gene expression as a transcriptional factor. Biological phenotypes of such transcriptional regulation by retinoid include cellular differentiation, tissue morphogenesis, and programmed cell death (apoptosis). Due to these functions, retinoid analogs are clinically tried to prevent/treat carcinoma in a wide variety of organs including head and neck cancer, uterine cervical cancer, certain leukemia and liver cancer. In this article, clinical trials of retinoid analog to inhibit second primary hepatoma, supposed molecular mechanism of the action of the compound, and aberrant metabolism of RXR and its role in liver carcinogenesis are briefly reviewed.
Potential role of vitamin K2 as a chemopreventive agent against hepatocellular carcinoma
Authors: Tamori Akihiro , Habu Daiki , Shiomi Susumu , Kubo Shoji , Nishiguchi Shuhei
Published: September 2007

Vitamin K, a cofactor necessary for the production of several antihemorrhagic factors, can inhibit the growth of various types of cells derived from neoplasms. In hepatoma cells, vitamin K2 causes cell‐cycle arrest and apoptosis. Vitamin K2 is widely used in Japan to treat osteoporosis. The safety, relatively low cost and ease of use of vitamin K2 have led to good compliance with treatment. The result of preliminary clinical trials in patients with chronic liver diseases are intriguing and suggest that vitamin K2 might reduce the risk of hepatocellular carcinoma (HCC) in patients with liver cirrhosis as well as prevent disease recurrence after curative therapy in patients with HCC. This article reviews the potential role of vitamin K2 as a chemopreventive agent against HCC and discusses future directions for clinical trials.
Mortality among shipyard Coast Guard workers: a retrospective cohort study
Authors: Krstev S , Stewart P , Rusiecki J , Blair A
Published: September 2007

Background:

The mortality experience of 4702 (4413 men and 289 women) civilian workers in a US Coast Guard shipyard was evaluated.

Methods:

All workers employed at the shipyard between 1 January 1950 and 31 December 1964 were included in the study and were followed through 31 December 2001 for vital status. Detailed shipyard and lifetime work histories found in the shipyard personnel records and job descriptions were evaluated. Workers were classified as likely exposed to any potential hazardous substances. In addition, 20 job groups were created on likely similar exposures. Standardised mortality ratios (SMRs) were calculated based on the general population of the state and adjusted for age, calendar period, sex and race.

Results:

The follow-up was successful for 93.3% of the workers. Among all men employed in the shipyard, there was an excess of mortality from all causes of death (SMR 1.08; 95% CI 1.04 to 1.12), respiratory cancers (SMR 1.29; 95% CI 1.15 to 1.43), lung cancer (SMR 1.26; 95% CI 1.12 to 1.41), mesothelioma (SMR 5.07; 95% CI 1.85 to 11.03) and emphysema (SMR 1.44; 95% CI 1.01 to 1.99) and a decrease for cardiovascular diseases (OR 0.95; 95% CI 0.90 to 1.00), vascular lesions of the central nervous system (SMR 0.80; 95% CI 0.67 to 0.96), cirrhosis of the liver (SMR 0.38; 95% CI 0.25 to 0.57) and external causes of death (SMR 0.55; 95% CI 0.44 to 0.68). A similar pattern was observed for the men classified as exposed. No increasing trend of mortality was found with duration of employment in the shipyard, with the exception of mesothelioma (SMRs of 4.23 and 6.27 for <10 years and ⩾10 years, respectively). In occupations with at least three cases and with an SMR of ⩾1.3, the authors observed a significantly elevated mortality for lung cancer among machinists (SMR 1.60; 95% CI 1.08 to 2.29) and shipfitters, welders and cutters (SMR 1.34; 95% CI 1.07 to 1.65) and for oral and nasopharyngeal cancers among wood workers (SMR 6.20; 95% CI 2.27 to 13.50).

Conclusion:

Employment in this Coast Guard shipyard revealed a small but significant excess mortality from all causes, lung cancer and mesothelioma, most of which is probably related to asbestos exposure.
MULTIPLE PAIRING IN THE BCS MODEL
Authors: FAN J. D. , MALOZOVSKY Y. M.
Published: September 2007

We study Cooper's paring for more than two particles in terms of the BCS model. We consider multiple pairing in terms of the BCS Hamiltonian in a quiescent Fermi sea model and in the BCS ground state. Although there is no interaction between Cooper's pairs in terms of the BCS Hamiltonian, yet we show that four particles are paired and form a bound state in the singlet state with just twice the bound state energy of a single Cooper's pair. Four-particle bound state - quartet only exists as a result of the Pauli principle and the sharp Fermi edge. We have also shown that the smearing of the Fermi edge due to Δ(k) as it is in the BCS ground state weakens the pairing of either two or four particles. We show that in the particle-hole channel there exists the multiple particle-hole resonance for four particles and four holes in a quiescent Fermi sea model similar to the resonance of two particles and two holes. There is no the particle-hole resonance in the BCS ground state as shown, which means that the particle-hole resonance is removed by Δ(k) due to smearing of the Fermi distribution. The wave function for the multiple pairing model is discussed as well.
QUASIPARTICLE SPECTRAL WEIGHT OF KINETIC ENERGY DRIVEN D-WAVE SUPERCONDUCTORS
Authors: GUO HUAIMING , FENG SHIPING
Published: September 2007

Within the kinetic energy driven superconducting mechanism, we study the superconducting quasiparticle spectral weight of cuprate superconductors. It is shown that although the spectral weight is continuous along the high symmetry directions, the overall spectral weight is reduced by the strong electron correlation in cuprate superconductors.
THE RESONATING VALENCE BOND STATE IN HIGH Tc SUPERCONDUCTORS
Authors: GUO WEI , YIN XIAOGANG , HAN RUSHAN
Published: September 2007

As indicated by NMR experimental results, there are two types of electrons in a doped cuprate: the localized Cu3d electrons, which are responsible for magnetism, and the itinerant p-band electrons carrying the charge transports. We show that the uncompensated spins at oxygen sites created by holes can pair into a resonating valence bond (RVB) state via local exchange interactions where the quasi-free local Cu spins play a role of the mediation for spin pairing. The two-component model gives a proper interpretation of the magnetic origin of high Tc superconductivity, especially, in explanation of the cross over from the anti-ferromagnetic to the RVB state.
SUPERCONDUCTIVITY WITH SHORT COHERENCE LENGTH
Authors: TAKADA YASUTAMI
Published: September 2007

Exploiting the shortness of the coherence length in many of the recently discovered superconductors, we propose a new formulation to evaluate the superconducting transition temperature Tc. Its tentative application to the Hubbard-Holstein model suggests the appearance of very high Tc in a reasonable range of parameters involved in the model.
EVOLUTION OF SPIN OF A QUANTUM DOT EMBEDDED IN A SUPERCONDUCTING RING
Authors: FENG J. F. , REN S. L. , JIAO C. H. , QIAN B. , HU A. , WU X. S.
Published: September 2007

We study the spin oscillations of a quantum dot (QD) embedded in a superconducting ring. The dot is characterized by the Coulomb interaction and the gate voltage. The pairing potential is considered in the superconducting ring. We found that the amplitude and frequency of the oscillations depend sensitively on the pairing potential of superconducting lead, the coupling strength between the dot and superconducting lead. We also show that the magnetic moment on the dot can be controlled by changing the pairing potential of superconducting lead.
PROPERTIES OF Y1-XSRXBA2-XLAXCU3OY CARRIER COMPENSATION SYSTEM
Authors: YU J. , SUN X. F. , XU Y. Y. , ZHANG H.
Published: September 2007

The samples of Y 1-x Sr x Ba 2-x La x Cu 3 O y (YSBLCO) were synthesized and characterized by DC magnetization measurements and X-ray diffraction. The structures of the samples were refined by Rietveld method. Although the carrier concentration in the samples is constant at different dopant levels, the superconductivity evidently changes. We attribute decrease in Tc to a charge redistribution in the crystalline lattice. Comparing the change of the T c value caused by structural influence and carrier concentration, it is suggested that the influence of structural changes on the superconductivity is independent of that induced by carrier concentration.
PRELIMINARY COMMISSIONING OF SUPERCONDUCTING MAGNETS AND CRYOGENIC SYSTEM OF BEPC II
Authors: ZONG Z. G. , LIU L. Q. , XU Q. J. , XIONG L. Y. , ZHANG L. , LI S. P. , HE K.
Published: September 2007

A helium cryogenic system with cooling capacity of 1 kW at 4.5 K was set up at Institute of High Energy Physics, Chinese Academy of Sciences, Beijing. This helium refrigerating system is dedicated for the cooling of two superconducting radio frequency (SRF) cavities, two interaction region superconducting collision quadrupole (SCQ) magnets, a detector superconducting solenoid magnet (SSM), which are the key items of the upgrade project of Beijing Electron-Positron Collider (BEPC II). Commissioning with the detector and SCQ magnets was carried out, which will be introduced in this paper. The cryogenic system shows very robust as SSM quench. This paper presents the overall status and some test results of superconducting and cryogenic system.
THEORETICAL EXPLANATIONS OF THE SPIN HAMILTONIAN PARAMETERS FORCu2+ION INLaSrAl1-xCuxO4SOLID SOLUTION
Authors: DONG HUI-NING , KEEBLE DAVID J. , WU SHAO-YI
Published: September 2007

It is of interest for layered oxides containing copper because they are related to high temperature superconductivity. Among them, LaSrAl1-xCuxO4solid solution has received much attention due to its elastic and elasto-optic properties and application as promising substrate for high- Tcsuperconducting thin films. So many theoretical and experimental works have been done to understand the several characteristics of the LaSrAl1-xCuxO4materials. In this paper, the electron paramagnetic resonance g factors g//, g⊥and hyperfine structure constants A//, A⊥for the tetragonal Cu2+center in LaSrAl1-xCuxO4solid solution are theoretically explained by the method of diagonalizing the full Hamiltonian matrix. The related crystal field parameters are calculated from the superposition model and the local structural parameters of the impurity Cu2+occupying the host Al3+site. The superposition model parameters used in this work are comparable with those for similar tetragonal ( CuO6)10-clusters in the previous works. The calculated results are in reasonable agreement with the observed values. The results are discussed.
PREPARATION AND CHARACTERIZATION OF TlBa2Ca2Cu3Oy WITH A DIFFERENT MAXIMUM Tc
Authors: MIKUSU S. , TAKAMI S. , TOKIWA K. , TAKEUCHI K. , IYO A. , TANAKA Y. , WATANABE T.
Published: September 2007

We have succeeded to prepare Tl -1223 samples with a maximum Tc above 130K at ambient pressure using a conventional sealed quartz tube method. We found that, by adequately controlling the starting composition, it is possible to control the maximum Tc from ~120K to 130K. In order to seek the key factors for a drastic increase in the Tc, we carried out the measurements of the thermoelectric power, powder X-ray diffraction and neutron diffraction for these samples. As a result, it is found that the characteristics in the Tl -1223 samples with high Tc show essentially similar to those in the Hg -1223 with the highest Tc and are different from those in the Tl -1223 samples with low Tc. The details of the synthesis conditions, the transport properties and the refinements of the crystal structure will be presented.
TUNNELING STUDY ON Ba2Ca3Cu4O8(O1-xFx)2
Authors: MIYAKAWA N. , HOYA H. , IYO A. , TANAKA Y. , TOKIWA K. , WATANABE T. , KANEKO T.
Published: September 2007

We report the tunneling conductance on a quadruple-layered cuprate, Ba 2 Ca 3 Cu 4 O 8( O 1-x F x)2 (2x~1.4, Tc~100 K ) that includes inequivalent outer (OP) and inner (IP) CuO 2 planes in a unit cell. Typical tunneling conductance displays the spectral dip structures as well as the superconducting gap (SCG) with clear coherence peaks. However we sometimes observe a pseudogap (PG) like structure without coherence peak at 4.2K. The magnitude of PG at 4.2K is larger than that of SCG at 4.2K and its conductance curve displays a faint structure at low energy. Therefore its origin would be different from that of small-PG observed at above Tc. In addition, we find that there are two kinds of SCGs that originate from IP and OP, and this result suggests that the superconducting property at IP is different from that at OP because of the imbalance of doped carrier between IP and OP. The observation of large PG at low temperature suggests the existence of some form of hidden ordered state at T<Tc and it would coexist with superconductivity.
TRANSPORT PROPERTIES OF ELECTRON-DOPED La2−xCexCuO4 THIN FILM IN THE UNDER-DOPED REGION
Authors: YUAN J. , WU H. , ZHAO L. , JIN K. , XU B. , ZHU B. Y. , CAO L. X. , QIU X. G. , ZHAO B. R.
Published: September 2007

Underdoped electron-doped La 2-x Ce x CuO 4 ( x =0.06-0.09) thin films were successfully grown and investigated for the transport properties in ab-plane. It was found that the in-plane resistivity ρab shows a semiconductor behavior when x =0.06, with increasing the Ce concentration to the optimal doping level, it changes to the two dimensional Fermi-liquid behavior. In the films with x≥0.08, a Kondo effect like scattering is observed in the low temperature range.
DEVELOPMENT OF HTS MICROWAVE FILTERS FOR APPLICATIONS IN MOBILE COMMUNICATION, SATELLITE RECEIVER AND METEOROLOGICAL RADAR
Authors: LI HONG , HE AISHENG , LI SHUNZHOU , ZHANG XUEQIANG , LI CHUNGUANG , SUN LIANG , ZHANG QIANG , LI FEI , LUO QIANG , GU CHANGZHI , HE YUSHENG
Published: September 2007

Recent development in the applications of high temperature superconductor (HTS) filters is introduced. Breakthrough had been made in ultra selective band-pass filter with extremely small fractional bandwidth for 3G mobile base stations. Satisfactory results were achieved in the space qualification mechanical tests of the HTS filters. Field trail of the meteorological radar showed that with HTS subsystem the sensitivity and anti-interference ability of the radar were greatly improved.
CRITICAL CURRENT DEPENDENCE OF STACKED JOSEPHSON JUNCTIONS DC SQUID IN Bi2Sr2CaCu2O8+Δ
Authors: KIM SANG-JAE
Published: September 2007

We investigate critical current (Ic) modulation of stacked Josephson junctions (SJJs) dc superconducting quantum interference device ( dc SQUID) on a Bi 2 Sr 2 CaCu 2 O 8+δ ( Bi -2212) whisker. A coupled SJJs with a completely perforated hole of 0.1 μ m × 0.2 μ m were fabricated by using a 3-D focused-ion-beam (FIB) etching method. Those dc SQUIDs exhibited uniform multi-branch structures and clearly oscillated critical current under external magnetic fields (He). With applying He, the clear periodic modulation patterns of Ic are obtained and well fitted to the calculated value from the loop area of 0.02 μm2.
DETECTION OF HIGH-FREQUENCY GRAVITATIONAL WAVES BY SUPERCONDUCTORS
Authors: LI FANGYU , BAKER ROBERT M. L.
Published: September 2007

We present a detecting scheme of high-frequency gravitational waves (HFGWs) which is based upon coupling between superconducting open cavity and electromagnetic fields stored in the cavity. Utilizing zero resistance and perfect diamagnetism of the superconductors, one can obtain very large quality factor and high sensitivity for the cavity to detect the HFGWs in GHz band. In addition, we review other possible superconducting systems for detection of the HFGWs, such as superconducting resonant-mass detector, toroidal waveguide, coupled superconducting spherical cavities and superconducting quantum antennas.
HIGH PRESSURE STUDY OF NOVEL ELECTRONIC PROPERTIES IN Sr2Fe(W1-xMox)O6 NEAR METAL-INSULATOR TRANSITION
Authors: OOMI G. , KAJI S. , TOMIOKA Y. , TOKURA Y.
Published: September 2007

Electrical resistivities of double perovskite oxides Sr 2 Fe ( W 1-x Mo x) O 6 have been measured at high pressure and high magnetic field to elucidate the transport properties of these materials. It is found that the main mechanism of the transport in the semiconducting phase is variable range hopping conduction and the insulating properties are suppressed by high pressure to show a crossover to metallic state. The magnetoresistances of these oxides are revealed to decrease at high pressure above 1 GPa. Extremely large Grüneisen parameters are found near x = 0.2, where the metal-insulator transition occurs. The origin for these properties will be briefly discussed in connection with the phase diagram.
ANISOTROPY OF MULTILAYERED (CU,C)BA2CA3CU4OY SUPERCONDUCTORS STUDIED BY TORQUE MAGNETOMETRY
Authors: TOKIWA K. , KOGANEZAWA T. , MIKUSU S. , WATANABE T. , IYO A. , TANAKA Y.
Published: September 2007

The magnetic torque of ( Cu , C ) Ba 2 Ca 3 Cu 4 O y ( ( Cu , C )-1234) aligned samples with various carrier concentrations has been measured under a magnetic field of 9 T at 80 K and 90 K. The carrier concentration was determined by Hall effect measurements. From angular dependent torque measurements, the anisotropy ratio γ was estimated using the 3D anisotropic London model. The γvalues decreased from 23 to 10 with an increase in the average Hall number per CuO 2 plane ( n H); however, these samples showed a nearly constant Tc of about 117 K. These results indicate that the anisotropy of ( Cu , C )-1234 strongly reflects the doping levels of the outer planes.
A PROPOSED NEW MEASUREMENT OF THE SUPERCONDUCTING GAP IN YBa2Cu3O7
Authors: ZHAO G. L. , BAGAYOKO D.
Published: September 2007

The superconducting energy gap of YBa 2 Cu 3 O 7 (YBCO) varies strongly with [Formula: see text] and from a sheet of the Fermi surface to another. The strong anisotropic superconducting gap in high Tc materials such as YBCO has led to conflicting d-wave and s-wave interpretations. We have utilized electronic wave functions from the ab-initio density functional calculation and the related electron-phonon interaction matrix elements for the calculation of the superconducting gap values of YBCO. We have found that the superconducting gap on one sheet of the Fermi surface around S-point only shows a minor variation from about 18 meV to 25 meV. Especially, there is no node on this sheet of the Fermi surface around the S-point. We propose a new test measurement of the superconducting gap of YBCO on this sheet of the Fermi surface around the S-point in the Brillouin zone. This measurement is expected to shed light on the gap symmetry properties of high Tc superconductors.
DEPENDENCE OF THE CRITICAL TEMPERATURE OF YBCO THIN FILMS ON SPINPOLARIZED QUASIPARTICLE INJECTION
Authors: HABERMEIER HANNS-ULRICH , SOLTAN S. , ALBRECHT J.
Published: September 2007

Heterostructures consisting of ferromagnetic La 2/3 Ca 1/3 MnO 3 and superconducting YBa 2 Cu 3 O 7- x layers were fabricated by conventional pulsed laser deposition in conjunction with shadow mask techniques to define appropriate sample geometries. Using standard dc- four probe measurements we observe a 2% decrease of T c for injection current densities of 5.10-2 A/cm2 in the case of unpolarized quasiparticles whereas highly spin polarized quasiparticles show a much stronger decrease of 14%. This result clearly demonstrates that the spin plays a crucial role in the T c reduction. The results are discussed within the frame of a theoretical model based on the Owen-Scalapino approach for nonequilibrium effects in superconductors.
EXPLORATION AND SEARCH ON NEW HIGH TC SUPERCONDUCTIVE MATERIALS
Authors: LIN DE-HUA , CUI DA-JIAN , LI BO
Published: September 2007

On the basis of Fan and Malozovsky theory, which had discussed the non-phonon mechanism of the layered Fermi liquid superconductivity, and of the experimental studies and theoretical analyses obtained by Zhang et al. as well as other scientists, we have analyzed and discussed the extrinsic and intrinsic factors of affecting the transition temperature Tc of cuprate superconductors. We also will present some possible approaches to explore new high Tc superconductive materials, and pay more attention to the non-traditional phonon mechanism, low dimensional or quasi two-dimensional system, and hexagonal structure materials, etc.
STUDY ON THE SUPERCONDUCTIVITY OF AMORPHOUS COMPOSITE METAL
Authors: WANG YINFENG , LIU ANPING , LI FANGYU , HE GUANGHONG
Published: September 2007

The amorphous composite metal studied in this paper is a kind of bulk metallic glass (BMG), which has special physical properties at low temperature. Zr -based bulk metallic glass chose as a sample, we report the results of microstructure, superconductivity and its corresponding crystallized sample. According to the results, the superconducting transition temperatures present before and after annealing, Zr -based bulk metallic glass has a negative coefficient of resistivity - temperature before annealing, and the superconducting critical temperature Tc was improved after annealing, for the amorphous Tc = 1.85K and for annealed sample Tc = 3.87K. Amorphous composite structure can help understand the physical properties at low temperature.
QUASI-ONE-DIMENSIONAL SUPERCONDUCTIVITY IN Sc5Ir4Si10 AND Lu5Ir4Si10 SINGLE CRYSTALS
Authors: TAMEGAI T. , LI G. J.
Published: September 2007

Anisotropic superconducting properties in Sc 5 Ir 4 Si 10 and Lu 5 Ir 4 Si 10 single crystals are investigated. Both of these compounds are found to show quasi-one-dimensional superconductivity with better conduction along the c-axis and anisotropy parameter of about 2. Reflecting the partial destruction of the Fermi surface due to charge-density-wave formation, Lu 5 Ir 4 Si 10 shows higher residual resistivity, lower superconducting transition temperature, and longer magnetic penetration depths compared with those of Sc 5 Ir 4 Si 10. Similarity of superconducting properties including the anisotropy in Sc 5 Ir 4 Si 10 and Lu 5 Ir 4 Si 10 indicates that the absence of the charge-density wave in Sc 5 Ir 4 Si 10 is controlled by a subtle difference in the Fermi surface topologies in these two compounds.
A REVIEW OF HIGH TEMPERATURE SUPERCONDUCTING PROPERTY OF PDH SYSTEM
Authors: TRIPODI PAOLO , DI GIOACCHINO DANIELE , VINKO JENNY DARJA
Published: September 2007

The discovery of superconductivity in palladium-hydrogen ( PdH ) and its isotopes ( D , T ) at low temperature, brought about extensive study of this system. These studies have shown that the critical transition temperature is a function of the H concentration x in the PdHxsystem with Tc=9 K for x =1. In the last decade we defined a room temperature and room pressure technique to load H and maintain stable the stoichiometry in Pd lattice at levels higher than unit. Several magnetic and electric transport measurements have been performed showing transition temperature in the range of [18 K < Tc< 273 K ]. Moreover in a typical critical current measurement configuration, current density greater than 6*104Acm-2⊐ has been measured at liquid nitrogen temperature. The 263.5K superconducting transition after a week of sample storage at room pressure and temperature, decreased down to 261.5K and after 2 years it became 160.5K, demonstrating a fairly good stability of the sample. Evidences of the flux exclusion (ZFC measurements) and the flux expulsion (FC measurements) have been found at very high transition temperature ( Tc =235 K ) for the PdH system.
SURFACE MORPHOLOGY AND MICROSTRUCTURE OF DIRECT CURRENT SPUTTERING GROWTH OF BUFFER LAYERS FOR YBCO COATED CONDUCTOR
Authors: YANG J. , LIU H. Z. , ZHANG H. , QU F. , ZHOU Q. , GU H. W.
Published: September 2007

A composite buffer of CeO 2/ YSZ / Y 2 O 3 was investigated on the biaxially textured NiW long tape for YBCO coated conductor with magnetron sputtering technique. Every layer's surface morphology was observed by scanning electron microscopy. The seed layer Y 2 O 3 film was full coverage of the NiW substrate. The cap layer CeO 2 showed a smooth and crack-free surface and good crystallinity. The roughness of CeO 2 surface was measured by atom force microscopy. The transmission electron microscopy was used to analyze the cross-section of buffer layers and YBCO layer.
VORTEX STATES AND PEAK EFFECT AT LOW TEMPERATURE IN THICK AMORPHOUS FILMS WITH WEAK PINNING
Authors: OKUMA S. , KASHIRO K. , KOKUBO N.
Published: September 2007

We report on the dynamic as well as static properties of vortices in the low-temperature (T) solid phase of a thick amorphous Mo x Ge 1-x film with weak pinning. The vortex-solid state is considered to be a weakly disordered vortex lattice, which is inferred from the mode-locking resonance over the broad field region. The peak effect of the critical current Ic with magnetic field is clearly visible down to the lowest T measured (0.2 K), which corresponds to 3.3% of the superconducting transition temperature. We find that largest voltage noise originating from current-driven vortices appears in the field region just prior to the peak field at which Ic takes a peak. This is in accord with the result reported in NbSe 2 single crystals.
ELECTRIC AND MAGNETIC PROPERTIES OF NEW APPROXIMATE HALF-METAL Fe3F4
Authors: LIU J. , WANG X. Q. , HU B. Q. , LIU A. P. , DONG H. N. , LIU Y. , LI D. F.
Published: September 2007

Fe 3 F 4 with the spinel structure was designed, and its electric and magnetic properties were calculated in system based on density function theories. And then they were compared with those of Fe 3 O 4. From our calculation, Fe 3 F 4 is a kind of new stable approximate half-metal material because its spin-polarization at fermi level is about 95%, which is near to 100%. The steady constant of crystal lattice is 0.643 nm. The energy distance between the top of the up-spin valence band and the fermi level is about 2.05 eV, which is much larger than 0.6 eV of Fe 3 O 4. In the other hand, the resistivity of Fe 3 F 4 is lower than that of Fe 3 O 4. The molecular magnetic moments 10.68μB of Fe 3 F 4 are evidently higher than 4.0μB of Fe 3 O 4. This shows that there is stronger spin-correlation scattering on transmitted carriers in Fe 3 F 4 than in Fe 3 O 4 so that Fe 3 F 4 may have higher magnetoresistance than Fe 3 O 4. Extremely localization of 3d-electrons caused by hybrid orbits of F2p and Fe3d orbits is the mechanism of the distribution of electronic charges and magnetic moments of Fe 3 F 4.
PHENOMENOLOGICAL MAGNETORESISTANCE THEORY OF FE3F4 FILMS DOPED BY TRANSITION METAL
Authors: LIU J. , WANG X. Q. , LIU A. P. , DONG H. N. , LIU Y. , LI D. F.
Published: September 2007

Microstructures of the Fe 3 F 4 granular films doped by transition metal (TM) were analyzed and the phenomenological magnetoresistance theory was proposed in this paper. Influences of technological parameters including the temperature (T), the applied field (H) and the content (x) on the magnetoresistance (MR) are analyzed in detail. Through theoretical analysis, there are the following conclusions. Firstly, variations of MR with x are non-linear and MR may arrive at the maximum at a certain x. Secondly, MR decreases strongly with the increase of T, but the decreases may be reduced by doped TM. Then doped TM can help to improve electric and magnetic properties of half metals. Thirdly, MR increases with the increase of H when the magnetization of grains is unsaturated.
MEASUREMENT OF DIELECTRIC DISPERSION IN MULTI-FERROIC TbMnO3
Authors: SAKATA H. , HOSOKAWA K. , KATO T.
Published: September 2007

We measured the dielectric dispersion in multi-ferroic TbMnO 3. We observed two kinds of the dielectric dispersions. One dispersion showed the monotonous temperature dependence of the relaxation frequency across the ferroelectric transition temperature, Tc. This dispersion is thought to be originated from the localized charge. The other dispersion existed only near the Tc, attributed to the ferroelectric transition. We found the former dispersion enhanced its strength near Tc. This indicates that the localized charge couples with the electric moment which orders in the ferroelectric phase.
X-RAY RADIATION EFFECTS ON THE DIELECTRIC PROPERTIES OF PZT CERAMICS
Authors: WANG J. T. , ZHANG C. , FITZGERALD A. , FU Y. , HALL S.
Published: September 2007

We have systematically studied the X-ray radiation effects on PZT thin ceramic disk provided by CTS Communications Components, Inc using the X-ray beam line in the Center for Advanced Micro-Structure and Devices (CAMD) in Baton Rouge, Louisiana. The photo energies of the X-ray range from 2000 eV to 8000 eV. The beam size is 10.0 cm ×1.0 cm .We measure the dielectric constant in situ with different dose of the radiation in one sample and in different samples. The dielectric constants as a function of radiation dose are presented in the paper. It demonstrates the effects on the dielectric constant. Unexpectedly, we also found that X-ray radiation on the PZT disk generates charges on the surface of the samples. We measured the surface voltage due to the X-ray radiation with different radiation dose at the same temperature for these samples. This founding may have application potential for photoelectric devices. This is just a preliminary study. More thorough investigations are needed.
INFLUENCE OF GRAIN SIZE OF ZnO NANOCRYSTALLINE FILMS FOR APPLICATION IN DYE-SENSITIZED SOLAR CELLS
Authors: KAO M. C. , YOUNG S. L. , CHEN H. Z. , CHEN Y. C. , HSIEH P. T. , WEI S. Y.
Published: September 2007

The preferred (002) orientation Zinc oxide ( ZnO ) nanocrystalline thin films have been deposited on ITO-coated glass substrates by means of sol-gel spin-coating technology and rapid thermal annealing for use in dye-sensitized solar cells (DSSC). The effects of annealing temperature (400 ~ 700 ° C ) on the microstructure and morphology of ZnO thin films were studied. With the increase of heating temperature from 400 °C to 700 °C, the grain size of ZnO thin films decreases from 80 to 10 nm. The decreases in grain size of ZnO thin films contributed to the improvement on the absorption of dye onto the films. The ITO/ZnO/RuL 2 (NCS) 2 electrodes with high absorption in the wide range containing visible light reveal that the nanoporous structure can adsorb easily the dye and can be expected in the application of DSSC.
ORIENTATION DEPENDENCE OF DIELECTRIC AND PYROELECTRIC PROPERTIES OF 0.65Pb(Mg1/3Nb2/3)O3- 0.35PbTiO3 SINGLE CRYSTAL
Authors: WANG J. T. , ZHANG C. , HALL S. , FITZGERALD A. , YE Z.
Published: September 2007

Samples of 0.65 Pb ( Mg 1/3 Nb 2/3) O 3-0.35 PbTiO 3 single crystal cut in three orientations <001>, <110>, <111> were supplied by H. C. Materials Corporation, Urbana, Illinois, U.S.A. The dielectric constant was first measured for these three samples with different orientations. It shows the samples are of high quality. Then we observed the hysteresis loops at different temperatures for these samples. From hysteresis loops we obtained the remnant polarization as a function of temperature. It is found that the remnant polarization changes with temperature rapidly in the temperature region from 80°C to 130°C. The displacement current without sustained applied electric field on it that is supposed to be proportional to the pyroelectric coefficient in different orientation was measured by a Picoammeter under no applied electric field and the comparison of the displacement current density with the pyroelectric coefficient was presented.
STRUCTURE AND MAGNETIC PROPERTIES IN Mn-DOPED Si
Authors: ZHAI Z. Y. , WU X. S. , ZHANG W. , QIAN B. , ZHANG Y. M. , ZHANG F. M. , YAN W. S. , WANG F. , GAO C.
Published: September 2007

The composition of Mn 0.05 Si 0.95 polycrystalline films on (001) Si substrate are prepared by vacuum deposition and post-crystallization processes. X-ray diffraction studies indicate that there are two phases coexist in the film: tetragonal, Mn 4 Si 7 and diamond-like Si (Mn) . The content of Si(Mn) phase increases with increasing the post-annealing temperature. Temperature dependence of the magnetization shows that there are two ferromagnetic phases with Curie temperature of around 50 K and near room temperature, which is confirmed by x-ray magnetic circular dichroism (XMCD).
SYNCHRO DESIGN METHOD FOR LOW-TEMPERATURE PIPELINE AND ITS INSULATION
Authors: TANG JING-WEN , LI YOU-RONG , PENG LAN , WU SHUANG-YING , LAN BO
Published: September 2007

Based on the principle of exergy-economy, the equation for the annual total cost of the low-temperature pipeline is derived by analyzing the process of the transport, which can be used to discuss the effects of the pipe diameter and insulation thickness on the annual total cost. An approach of the synchro-design method for the low-temperature pipeline and its insulation is proposed. From the point of reducing the annual total cost, the calculating formulas of the low-temperature pipeline and insulation thickness are obtained.
THE ANALYSIS OF EXERGY EFFICIENCY IN THE LOW TEMPERATURE HEAT EXCHANGER
Authors: PENG LAN , LI YOU-RONG , WU SHUANG-YING , LAN BO
Published: September 2007

Based on the analyzing of the thermodynamic performance of the heat transfer process in the low temperature heat exchangers, the exergy efficiency of the heat transfer process is defined and a general expression for the exergy efficiency is derived, which can be used to discuss the effect of heat transfer units number and heat capacity ratio of fluids on the exergy efficiency of the low temperature heat exchanger. The variation of the exergy efficiency for several kinds of flow patterns in the low heat exchangers is compared and the calculating method of the optimal values of heat capacity ratio for the maximum exergy efficiency is given.