Showing papers by "Qian Zhang published in 2007"
TL;DR: In this article, a three-parameter data-fitting equation has been developed to predict the rate-dependent compressive stress at relatively low strains for the syntactic foams.
94 citations
TL;DR: A SnCl4.5H2O-mediated facile and efficient one-step synthesis of the tricyclic core of martinellic acid from readily available 2-(cyanomethyl)-3-oxo-N-arylbutanamides was developed and a mechanism involving consecutive hydrolysis of a cyano group and a double annulation process is proposed.
Abstract: A SnCl4·5H2O-mediated facile and efficient one-step synthesis of the tricyclic core of martinellic acid from readily available 2-(cyanomethyl)-3-oxo-N-arylbutanamides was developed and a mechanism involving consecutive hydrolysis of a cyano group and a double annulation process is proposed.
44 citations
TL;DR: In this article, the magnetic phase transition and magnetocaloric effect on e-(Mn0.83Fe0.17)3.25Ge compound was investigated and a large positive magnetic entropy change ΔSM was observed, which was accompanied with a field-induced metamagnetic transition from a collinear to a triangular antiferromagnetic configuration in this compound.
Abstract: The magnetic phase transition and magnetocaloric effect are investigated on e-(Mn0.83Fe0.17)3.25Ge compound. A large positive magnetic entropy change ΔSM is observed, which is accompanied with a field-induced metamagnetic transition from a collinear to a triangular antiferromagnetic configuration in this antiferromagnetic compound. The maximum value of ΔSM is 11.6J∕kgK at 93K for a magnetic field change of 7T. The study on systems with antiferromagnetic phases may open an important field in searching new materials for magnetic refrigeration.
43 citations
TL;DR: In this paper, the magnetic and magnetocaloric effects of (Mn1-xFex)(5)Ge-3 compounds are studied systematically and the maximum of magnetic entropy changes of 8.01 J/kg K under an external field change of 5 T is obtained for (mn0.9Fe0.1) and Mn5Ge3-based solid solutions.
Abstract: Magnetic and magnetocaloric effects of (Mn1-xFex)(5)Ge-3 compounds are studied systematically. The maximum of magnetic entropy changes of 8.01 J/kg K under an external field change of 5 T is obtained for (Mn0.9Fe0.1)(5)Ge-3, which is the largest value in Mn5Ge3-based solid solutions. Moreover, the Fe substitution increases the refrigeration capacity (RC) value greatly. The largest RC value of 237 J/kg in (Mn0.8Fe0.2)(5)Ge-3 even compares favorably to that of many well-known magnetic refrigeration materials. Thus the Fe-containing (Mn1-xFex)(5)Ge-3 compounds are much-improved magnetic refrigerants for the application of room-temperature magnetic refrigeration. The increase of the RC value is probably resulted from the formation of magnetic nanostructure. (c) 2007 American Institute of Physics.
36 citations
TL;DR: In this article, the electrical conductivity and Seebeck coefficient measurements of Mg2Si1−xSnx (x = 0.4, 0.6 and 0.8) thermoelectric materials have been measured.
Abstract: Mg2Si1−xSnx (x = 0.2, 0.4, 0.6 and 0.8) thermoelectric materials have been prepared by vacuum melting and melting/hot-pressing methods. The phase structures and electrical transport properties were measured. The relationships between electronic structures and electronic properties are discussed. X-ray diffraction (XRD) showed that the hot-pressed compounds were better formed. The electrical conductivity and Seebeck coefficient measurements showed that the properties of the compounds were dramatically affected by solid solubility. When x= 0.2, the highest electrical conductivity resulted in the highest power factor of 1.32×10−3 W m−1 K−2 at about 500 K, while the highest value of Seebeck coefficient of −459 μV K−1 was obtained at about 450 K for x= 0.6.
26 citations
TL;DR: An extreme thermostable and acidic tolerable beta-glucanase was isolated and characterized from aerobic fungi Trichoderma koningii ZJU-T and showed increased stability at higher temperatures and lower pH values when compared to other beta- glucanases.
Abstract: An extreme thermostable and acidic tolerable beta-glucanase was isolated and characterized from aerobic fungi Trichoderma koningii ZJU-T. The optimal reaction temperature and pH for the beta-glucanase were 100 degrees C and pH 2.0, respectively. The beta-glucanase showed increased stability at higher temperatures and lower pH values when compared to other beta-glucanases. The optimum conditions for the beta-glucanase stability were found to be pH 4.0 and 80 degrees C. Even subjected to 100 degrees C for 3 h, beta-glucanase activity did not show significant reduction. Moreover, K(+) significantly enhanced beta-glucanase activity at the concentration of 1 mM, while EDTA and other metal ions such as Mg(2+), Mn(2+), Zn(2+), Ca(2+), Fe(2+), Pb(2+), and Fe(3+) inhibited beta-glucanase activity. Denaturants, including sodium dodecyl sulfate (SDS) and mercaptoethanol, also inhibited beta-glucanase activity at a concentration of 5%. However, in the presence of 7 M urea, residual activity of the beta-glucanase still remained 14.5%.
22 citations
Journal Article•
TL;DR: The results showed that Chinese subjects who are 65 years old have an average of 20 teeth, and that few prosthodontic data could be extracted from the selected studies, and these data were often unspecific or inconclusive.
Abstract: PURPOSE: To assess oral health and prosthodontic conditions of Chinese adults and the changes in these conditions over time. MATERIALS AND METHODS: PubMed was searched by combining the keyword China with dental health survey, oral health, tooth loss, DMFT (decayed/missing/filled teeth), dental prosthesis, or dentures. After selection, 12 studies remained. Data were obtained from these studies on DMFT, DMFT components, and teeth present and were tested against the following independent variables using analysis of variance: age, residence, and year of data collection. RESULTS: DMFT increased with age (P = .0001). Rural subjects presented higher DMFT based on the higher "decayed" component (P = .003), which increased markedly for subjects over 45 years of age. The number of teeth present decreased with increasing age (P = .0002). The results showed that Chinese subjects who are 65 years old have an average of 20 teeth. Urban subjects had more teeth present (P= .05), although no difference was seen for the "missing" component of DMFT. In general, few prosthodontic data could be extracted from the selected studies, and these data were often unspecific or inconclusive. CONCLUSIONS: The "filled" component of DMFT remained consistently low for all ages, indicating limited care. All outcomes were independent from year of data collection, indicating unchanged care. Outcome aggregation on the number of functional teeth and prosthetic care was impossible. For future reports, it is recommended to include additional information about location and function (in terms of occluding pairs) of teeth present when describing oral health status.
19 citations
TL;DR: It can be concluded that the ASA-GSH cycle plays an important role in enhancement of freezing resistance of P. suaveolens cuttings during freezing acclimation, and indicated that a higher capacity of the ascorbate-glutathione cycle is required for H2O2 detoxification, and growth and development of Cuttings.
Abstract: We investigated the changes in the contents of H2O2, malonaldehyde (MDA) and endogenous antioxidants, the activities of protective enzymes and some critical enzymes involved in the ascorbate-glutathione (ASA-GSH) cycle as well as freezing resistance (expressed as LT50) and correlations mentioned above, in detail using Populus suaveolens cuttings. The purpose was to explore the physiological mechanism of the enhancement of freezing resistance induced by freezing acclimation at −20°C, and to elucidate the physiological mechanisms by which trees adapt to freezing. The results showed that freezing acclimation enhanced the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), monodehydroascorbate reductase (MDAR), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR) and glutathione reductase (GR). And it increased the contents of reduced ascorbate (ASA), reduced glutathione (GSH), dehydroascorbate (DHA) and oxidized glutathione (GSSG). However, H2O2 and MDA contents and LT50 of cuttings were decreased. LT50 in cuttings was found to be closely correlated to the levels of SOD, POD, CAT, APX, DHAR, MDAR, GR, H2O2, MDA, ASA, GSH, DHA and GSSG during freezing acclimation. This suggested that the enhancement of freezing resistance of cuttings induced by freezing acclimation may relate to the distinct increase for the levels of SOD, POD, CAT, APX, DHAR, MDAR, GR, ASA, GSH, DHA, and GSSG. In addition, the observed levels of APX, DHAR, MDAR, GR, ASA, DHA, GSH and GSSG were higher than those of SOD, POD and CAT during freezing acclimation. It indicated that a higher capacity of the ASA-GSH cycle is required for H2O2 detoxification, and growth and development of cuttings. Based on the obtained results, it can be concluded that the ASA-GSH cycle plays an important role in enhancement of freezing resistance of P. suaveolens cuttings during freezing acclimation.
16 citations
29 Oct 2007
TL;DR: A new framework to cope with the uncertain time delay of networked control system with event-clock-driven controller nodes, together with clock-driven sensor nodes and actuator nodes are required.
Abstract: A new framework is proposed to cope with the uncertain time delay of networked control system. Event-clock-driven controller nodes, together with clock-driven sensor nodes and actuator nodes are required in this framework. Queuing Strategy is introduced both in controller nodes and actuator nodes while the time delay between controller node and actuator node is compensated by multi-step control increment given by the algorithm of General Predictive Control. An output error prediction model is built using BP neural network to deal with the time delay between sensor node and controller node. The principle of this model is to revise the predictive output of general predictive control model using predictive error signal; if the value of time delay exceeds the upper limit, controller nodes will immediately produce the control strategies adopting the revised predictive output, and thus the compensation for time delay between sensor nodes and controller nodes would be accomplished. Simulation experiments are practiced over Ethernet network which embraces both kinds of time delay. It is proved that the scheme of complete compensation remains a good control performance.
11 citations
TL;DR: It can be suggested that TIR-specific promoter might be a pathogen-inducible promoter and be necessary for the inducible expression of defense-related genes in plants.
Abstract: A 5′ flanking region of the well-conserved Toll/interleukin-1 receptor domain (TIR)-encoding sequence was isolated from the genomic DNA of Melampsora magnusiana Wagner resistant clones of hybrid triploid poplars [(Populus tomentosa × P. bolleana) × P. tomentosa]. Sequencing results and alignment analysis show that the obtained TIR-specific promoter (named as PtTIRp01) was 1,732 bp in length; moreover 3′ region of the PtTIRp01 contains a 398 bp complete TIR-encoding sequence, which significantly corresponds to the 5′ composition of TIR-NBS type gene PtDRG02, indicating that the obtained TIR-specific promoter region consists of 747 bp long 5′ region of TIR-NBS type gene PtDRG02 and its upstream region of promoter (985 bp). It was found that the 5′ region of TIR-NBS type gene PtDRG02 was characterized in the downstream region of the transcriptional start, named as 5′-untranslated region (5′ UTR), consisting of one 93 bp 5′-untranslation exon, one 213 bp intron and one 441 bp TIR-encoding open reading frame (ORF). In addition, several putative cis-acting motifs were present in the obtained TIR-specific promoter of PtDRG02, including one TATA box, one GC-rich, one AT-rich, one P-box, one 3-AF1 binding site, two CAAT boxes, two GT-1 motifs, three typical W-boxes, four I-boxes, and one multi-cis-acting fragment (MCF). The latter contains five types of regulatory elements (E4, G-box, ABRE motif, box1 and HVA1s), most of which were homologous to the cis-acting regulatory elements involved in the activation of defense genes in plants. Thus, it can be suggested that TIR-specific promoter might be a pathogen-inducible promoter and be necessary for the inducible expression of defense-related genes.
6 citations
TL;DR: In the presence of titanium(IV) chloride, the C-C bond-forming reaction of the α-cyanoketene cyclic dithioacetal 1,3-dithiolan-2-ylideneacetonitrile with various aldehydes and ketones afforded multifunctional pentanedinitriles, 3-substituted- or 3,3 -disubstitized 2,4-di-1,3dithioxinitrile, respectively, in good yield under very mild conditions as mentioned in this paper.
Abstract: In the presence of titanium(IV) chloride, the C-C bond-forming reaction of the α-cyanoketene cyclic dithioacetal 1,3-dithiolan-2-ylideneacetonitrile with various aldehydes and ketones afforded multifunctional pentanedinitriles, 3-substituted- or 3,3-disubstituted 2,4-di-1,3-dithiolan-2-ylidenepentanedinitriles, respectively, in good to excellent yields under very mild conditions. A possible mechanism involving consecutive C-C bond formation was proposed.