Z Wang

Publications (189)390.94 Total impact

• Source

  Available from: arxiv.org

  Article: Quantum-disordered slave-boson theory of underdoped cuprates

  Y. B. Kim, Z. Wang
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  ABSTRACT: We study the stability of the spin gap phase in the U(1) slave-boson theory of the t-J model in connection with the underdoped cuprates. We approach the spin gap phase from the superconducting state and consider the quantum phase transition of the slave bosons at zero temperature by introducing vortices in the boson superfluid. At finite temperatures, the properties of the bosons are different from those in the strange-metal phase and lead to modified gauge field fluctuations. As a result, the spin gap phase can be stabilized in the quantum-critical (QC) and quantum-disordered (QD) regime of the boson system. We also show that the regime of QD bosons with the paired fermions can be regarded as a strong-coupling version of the recently proposed nodal liquid theory.
  EPL (Europhysics Letters) 01/2007; 50(5):656. · 2.17 Impact Factor
• Article: Angular Distribution of Elastically Scattered Electrons from Ar7+

  J Matsumoto, Z Wang, H Tanuma, A Danjo, M Yoshino, N Kobayashi
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  ABSTRACT: Using a crossed beam method elastically scattered electrons from Ar7+ were observed at an electron energy of 100 eV. The scattered electrons are analyzed simultaneously both in energy and angular dispersion by using a toroidal electron analyzer with a two-dimensional position sensitive electron detector.
  Physica Scripta 11/2006; 1999(T80B):274. · 1.20 Impact Factor
• Article: Nodular fasciitis in the orofacial region.

  W Han, Q Hu, X Yang, Z Wang, X Huang
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  ABSTRACT: Nodular fasciitis (NF) is a benign, reactive proliferation of fibroblasts in subcutaneous tissues which commonly occurs in the deep fascia. It can only be diagnosed by histopathological examination of a biopsy. A total of 23 orofacial NF patients was analysed, including those reported in the English language literature and six new patients from the files of this hospital. All patients were treated between 1994 and 2005. The reported lesions were located in cheek masseter muscle, parotid gland, upper neck, upper gingiva and body of mandibular. The clinical and histological features and differential diagnoses are discussed. All lesions were removed under general or local anaesthesia and no recurrence of the lesions was found.
  International Journal of Oral and Maxillofacial Surgery 11/2006; 35(10):924-7. · 1.51 Impact Factor
• Article: Differential Cross Section Measurements in Electron-Ion Collisions using a Toroidal Analyzer

  J Matsumoto, Z Wang, A Danjo, M Yoshino, H Tanuma, N Kobayashi
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  ABSTRACT: Angular distributions of elastic scattering electrons from Ar7+ and Ar8+ have been measured at a collision energy of 100 eV and in the angular range between 34°–85° simultaneously by using a toroidal analyzer. Relative differential cross sections for the e + Ar7+ system have been obtained after calibration for the detection efficiency by using the results of the e + Ar8+ system, where the differential cross sections are assumed to be the Rutherford cross sections. The measured cross sections for the e + Ar7+ system are compared with both Rutherford cross sections and R-matrix calculations.
  Physica Scripta 08/2006; 2001(T92):367. · 1.20 Impact Factor
• Source

  Available from: Dapeng Yu

  Article: Fabrication and characterization of single-crystalline nanostructured Zn1−xMnxS

  Y Q Chang, D P Yu, H Z Zhang, Z Wang, Y Long, W J Qiang
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  ABSTRACT: Single-crystalline nanostructured Zn1−xMnxS, a diluted magnetic semiconductor, was achieved via a simple vapour phase deposition on silicon substrates. Morphology, structure, and composition of the nanostructured Zn1−xMnxS were studied by using x-ray diffraction, transmission electron microscopy, and energy-dispersive spectroscopy. The nanostructured Zn1−xMnxS is composed of nanowires and nanobelts, which are quite flexible and free of defects. Both of them have smooth and straight surfaces with lengths over 10 µm. They possess cubic structure with a principal axis along their axes. The nanostructured Zn1−xMnxS exhibits paramagnetic behaviour. Photoluminescence study shows a blue band and a yellow band, which are due to the surface states and the transitions of Mn2+ (4T1(G)–6A1(S)), respectively. The growth of the nanostructured Zn1−xMnxS could be explained by a self-catalyst growth mechanism.
  Nanotechnology 03/2006; 17(8):1999. · 3.98 Impact Factor
• Article: Measurement of the axial displacement with information entropy

  J H Bao, Y M Li, L R Lou, Z Wang
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  ABSTRACT: For completely describing the movement of a bead in an optical tweezer system, the measurement of the axial movement of the bead is necessary as well as its lateral movement. In order to find a convenient method to measure the axial displacement of the trapped bead, a new method based on Shannon's information entropy is developed. When the bead is in a different axial position, the value of the information entropy of its image is different. The key of the method is calibrating the relation between the information entropy and the axial displacement. In the paper the experimental methods for axial position measurement of a static bead and a suspended bead are introduced in turn. The results with a 3 µm diameter polystyrene sphere indicate that when the bead moves in a certain axial range the relation between the information entropy and the axial displacement is linear and the range of the axial displacement corresponding to the linear region is larger than 2 µm with a sensitivity of 5 nm.
  Journal of Optics A Pure and Applied Optics 12/2004; 7(1):76. · 1.92 Impact Factor
• Article: Structural and analytical characterization of as-grown MgB2 film sputtered on differently oriented α-Al2O3 substrate

  W-J Moon, K Kaneko, S Toh, M Saunders, A Saito, Z Wang, H Abe, M Naito
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  ABSTRACT: Superconducting MgB2 films were prepared on differently oriented α-Al2O3 substrates, C- and R-planes, which yielded superconducting transition temperatures of about 28 K. The electric resistivity of the MgB2 film deposited on an R-plane substrate is 300 µΩ cm, six times larger than that on a C-plane substrate, 50 µΩ cm. To understand these differences in the electrical properties, various transmission electron microscopes were used to carry out a structural and the compositional analysis. It was shown from selected-area electron diffraction patterns that the microstructure consists of a mixture of columnar MgB2 grains and amorphous phases in the case of the R-plane specimen, while no amorphous phase was present in the case of the C-plane specimen.
  Superconductor Science and Technology 11/2004; 18(1):92. · 2.66 Impact Factor
• Article: Effects of high intensity focused ultrasound on vascular endothelial growth factor in melanoma bearing mice.

  X Yang, J Bai, T Yu, Z Wang, Q Li
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  ABSTRACT: This study was to investigate the effects of high intensity focused ultrasound on vascular endothelial growth factor. A B16 melanoma model was adopted in our study. Melanoma bearing mice were randomly divided into two groups: HIFU group and surgery group. While the control group was only injected with isovolumetric normal saline solution and treated as the surgery group. We detected VEGF both in tissues and sera through immunohistochemical method and ELISA respectively. Tissues were sampled pre- and at the 3rd day post-operation in HIFU group and blood samples were taken pre- and at the 1st, 3rd, and 7th day post-operation in all the groups. As a result, in the tissues, VEGF was expressed in 80% melanomas, but none was detected in the targeted area after HIFU treatment. In the sera, there was a decreasing tendency of serum-VEGF concentrations in group HIFU and surgery after operation, while that in the control group increased after operation. The levels in the HIFU group on day 1, 3, and 7 postoperatively were all lower than that in the surgery group respectively (79.16 pg/ml vs 91.59 pg/ml; 33.64 pg/ml vs 49.39 pg/ml; 30.37 pg/ml vs 46.68 pg/ml), but there wasn't any significant difference (P > 0.05). So HIFU can destroy VEGF in the targeted area and maybe have less of an effect on serum-VEGF than surgery.
  Technology in cancer research & treatment 10/2004; 3(5):499-503. · 2.02 Impact Factor
• Article: Interface structures of AlN∕MgB2 thin films sputtered on sapphire c- and r-plane

  H. Abe, M. Naito, W.-J. Moon, K. Kaneko, A. Saito, Z. Wang
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  ABSTRACT: Structures of interfaces between AlN and MgB2 thin films were investigated by cross-sectional transmission electron microscopy. These layers were deposited on sapphire substrate with different orientations by a conventional method. A thick amorphous layer was present between films in the case of r-plane substrate, whereas many AlN crystals were grown epitaxially in the case of c-plane substrate. Then NbN∕AlN∕MgB2 trilayers were intentionally fabricated on sapphire c-plane and showed Josephson and quasiparticle tunneling property with small subgap leakage current.
  Journal of Applied Physics 08/2004; 96(4):2343-2346. · 2.17 Impact Factor
• Conference Proceeding: A novel multi-level matrix converter

  X. Yang, Y. Shi, Q. He, Z. Wang
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  ABSTRACT: A new multi-level matrix converter is presented. The operation, control strategy are discussed. Simulations are intensively carried out, and comparisons are made between the multi-level matrix converter and the normal matrix converter. Experiments were carried out.
  Applied Power Electronics Conference and Exposition, 2004. APEC '04. Nineteenth Annual IEEE; 02/2004
• Article: A statistical model for functional mapping of quantitative trait loci regulating drug response.

  Y Gong, Z Wang, T Liu, W Zhao, Y Zhu, J A Johnson, R Wu
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  ABSTRACT: Differential drug response, that is, pharmacodynamics, is most often likely to be a complex trait, controlled by the combined influences of multiple genes and environmental influences. Genetic mapping has proven to be a powerful tool for detecting and identifying specific genes affecting complex traits, that is, quantitative trait loci (QTL), based on polymorphic markers. In this article, we present a novel statistical model for genetic mapping of QTL governing pharmacodynamic processes. In principle, this model is a combination of functional mapping proposed to map function-valued traits and linkage disequilibrium mapping designed to provide high-resolution mapping of QTL by making use of recombination events created at a historic time. We implement a closed-form solution for the Expectation-Maximization algorithm to estimate the population genetic parameters of QTL and the simplex algorithm to estimate the curve parameters describing the pharmacodynamic changes of different QTL genotypes in response to drug dose or concentrations. Extensive simulations are performed to investigate the statistical properties of our model. The implications of our model in pharmacogenetic and pharmacogenomic research are discussed.
  The Pharmacogenomics Journal 02/2004; 4(5):315-21. · 4.54 Impact Factor
• Article: A submillimetre-wave SIS mixer using NbN/MgO/NbN trilayers grown epitaxially on an MgO substrate

  Y Uzawa, A Kawakami, A Saito, M Takeda, Z Wang
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  ABSTRACT: We have designed, fabricated and tested a quasi-optical superconductor–insulator–superconductor (SIS) mixer employing distributed NbN/MgO/NbN tunnel junctions and NbN/MgO/NbN microstriplines at submillimetre-wave frequencies. These trilayers were fabricated by dc- and rf-magnetron sputtering on an MgO substrate at ambient temperature so that the NbN and MgO films were grown epitaxially. Our SIS mixer consists of an MgO hyperhemispherical lens with an antireflection cap and a self-complementary log-periodic antenna made of a single-crystal NbN film, on which the distributed SIS junctions and the two-section impedance transformers were mirror-symmetrically placed at the feed point of the antenna. As designed, the junctions are 0.6 μm wide and 15.5 μm long, which is sufficient to absorb the incoming signal along this lossy transmission line, assuming a current density of 10 kA cm−2. The mixer showed good I–V characteristics, with subgap-to-normal resistance ratios of about 13, although weak-link breaks were observed above the gap voltage. The minimum double side band receiver noise temperature was 334 K at 678 GHz, including the input noise of about 200 K as estimated by the standard technique. The noise temperature gradually rose to 672 K at 820 GHz. This behaviour may be caused by RF losses from the weak-link parts, due to the steps between the distributed junctions and the microstriplines being less than 1 μm wide.
  Superconductor Science and Technology 11/2002; 15(12):1760. · 2.66 Impact Factor
• Article: Crystal Structure of (Et2Me2N)3Cu4Cl11: An Antiferromagnetic Chain of Ferromagnetically Coupled Tetramers

  Y. Fujii, Z. Wang, R. D. Willett, W. Zhang, C. P. Landee
  04/2002;
• Article: Structures and Magnetic Susceptibility Studies of Four New High-Nuclearity Copper(II) Halide Oligomers

  M. R. Bond, H. Place, Z. Wang, R. D. Willett, Ying Liu, Todd E. Grigereit, John E. Drumheller, George F. Tuthill
  04/2002;
• Article: Performance of a quasi-optical NbN hot-electron bolometric mixer at terahertz frequencies

  Y Uzawa, S Miki, Z Wang, A Kawakami, M Kroug, P Yagoubov, E Kollberg
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  ABSTRACT: The performance of a hot-electron bolometric (HEB) mixer based on NbN from 0.9 to 2.5 THz was investigated using a quasi-optical receiver configuration. An HEB mixer is an ultra-thin superconducting NbN strip located at the feed point of a thick normal conducting Au spiral antenna on a high-resistivity Si substrate. The active area of the mixer was 3 nm thick, 0.4 μm long and 4 μm wide. The quasi-optics consisted of an MgO hyperhemisphere with anti-reflection caps made of Kapton-JP polyimide film and an offset parabola to reduce input losses. The frequency dependence of the double-sideband receiver noise temperature was investigated at several frequencies by using a backward wave oscillator or an optically pumped far-infrared laser as the local oscillator. Results demonstrated low-noise and wide-band characteristics, below 1 K GHz−1 over the measured frequency range. At 917 GHz, the measured receiver noise temperature was 550 K across a 500 MHz intermediate-frequency bandwidth centred at 1.5 GHz, which is slightly better than that of other HEB mixers at around this frequency. This paper was presented at the 8th International Superconductive Electronics Conference, Osaka, Japan, 19–22 June 2001.
  Superconductor Science and Technology 12/2001; 15(1):141. · 2.66 Impact Factor
• Article: [The biological effect of verapamil on hypertrophic scar fibroblast].

  Z Wang, S Guo, K Lu
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  ABSTRACT: To study the mechanism of calcium channel antagonist Verapamil on the treatment of hypertrophic scar and explore the possibility of further clinical application. After six strains of HSFB were cultured in vitro, we investigated HSFB proliferation by MTT method, investigated HSFB collagen synthesis by 3H-proline uptaken and Hydroxyproline colorimetric analysis, and investigated collagen gene expression by Northern Blot. Verapamil can inhibit HSFB proliferation, collagen synthesis and gene expression by a dose-depended manner, especially treated with 100 mumol/L Verapamil. By inhibiting I, III procollagen gene expression, Verapamil can inhibit the formation of hypertrophic scar.
  Zhonghua zheng xing wai ke za zhi = Zhonghua zhengxing waike zazhi = Chinese journal of plastic surgery 12/2001; 17(6):328-31.
• Article: [A study for the relationship between serum calcitonin gene-related peptide and coronary arteriopathy].

  Z Wang, J Guo, X Wang
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  ABSTRACT: To investigate the relationship between serum calcitonin gene-related peptide (CGRP) and coronary angiopathy. In a cross-sectional study, serum CGRP levels of 119 patients with coronary heart disease (CHD), 78 with non CHD and 39 healthy subjects were measured with radioassay method. The information on conventional risk factors were collected by interviews. The development of coronary angiopathy was correlated with smoking, diabetes and aging. The mean serum CGRP level was significantly lower in CHD than in NCHD patients [(35.5 +/- 48.8) mumol/L vs (63.8 +/- 47.3) mumol/L, P < 0.01). There was no difference between the mean serum CGRP level in NCHD patients and healthy controls. By multivariate logistic regression, the odds ratios (OR) of aging, smoking and diabetes were all > or = 1 (P < 0.01), that means they are independent risk factors for the development of coronary angiopathy. The OR of CGRP was < or = 1, indicating that it was an independent protective factor. It is shown that aging, smoking and diabetes are all independent risk factors for the development of angiopathy, while CGRP is an independent protective factor for the development of coronary angiopathy.
  Zhonghua nei ke za zhi [Chinese journal of internal medicine] 11/2001; 40(11):750-2.
• Article: Experiences from a collaborative project on the prevention of disability in leprosy patients in Shandong Province, the People's Republic of China.

  S Chen, L Zhang, Z Wang, J Zhou, Y Liu, C Mao
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  ABSTRACT: Shandong Province (present population 89 million) in the People's Republic of China established a leprosy control programme in 1955. Between that year and the end of 1999, allowing for death and migration, the cumulative number of cases registered was 53,618, including 120 cases on multiple drug therapy (MDT) and 18,248 who had completed satisfactory courses of dapsone monotherapy and/or MDT. Of this latter group, 9500 cases (52%) suffered from visible disabilities (grade 2 of the WHO classification). Prevalence and incidence rates of leprosy have decreased dramatically since 1955 and, on average, only 50-70 new cases are now being detected annually in the entire province. Leprosy is thus no longer a public health problem, but the existence of such a large number of patients with grade 2 disabilities is clearly a matter of serious concern. This paper describes a pilot project to investigate the potential of health personnel in the leprosy programme and the dermatology and sexually transmitted diseases services to (a) prevent deterioration of existing disabilities in ex-patients through self-care and (b) prevent new neuritis in patients on MDT through early detection and the use of steroids.
  Leprosy review 10/2001; 72(3):330-6. · 1.04 Impact Factor
• Article: Treatment of hordeolum by bloodletting at ear apex.

  Z Wang, X Wan, Q Zhang
  Journal of Traditional Chinese Medicine 10/2001; 21(3):213-4. · 0.30 Impact Factor
• Article: Effect of fetal spinal cord graft with different methods on axonal pathology after spinal cord contusion.

  Q Zhang, W Liao, Z Wang, Y Wu
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  ABSTRACT: To investigate the effect of fetal spinal cord (FSC) graft with different methods on axonal pathology and neurological function recovery after spinal cord injury (SCI). Forty Wistar rats were divided into 4 groups. In Group A, the spinal cord was injured and hemisected. In Group B, fetal spinal cord (FSC) was transferred into the injured site. In Group C, after having done as Group B, the upper and lower spinal nerve roots were anastomosed. And in Group D, after having done as Group B, the pedicled omentum was transferred into the hemisection cavity. At 6 weeks after operation, light and electronic microscopes were used to examine the axonal pathology. The neurological function was assessed with inclined plane tests in the open field. The number of axons was quantitated by a computer image analysis system. A greater loss of axons was observed in Group A than that of other groups at 6 weeks. The sequence of the reduced rate of the axons was as following, Group A>Group B>Group C>Group D (P<0.05). The remaining axons were paralleled with the significant improvement in neurological function recovery of the rats. It indicates that FSC and pedicled omentum grafts after SCI can protect the axons and promote the neurological function recovery of the rats.
  Chinese Journal of Traumatology (English Edition) 09/2001; 4(3):147-51.