A Novel 6500 V SiC Trench MOSFET with Integrated Unipolar Diode for Improved Third Quadrant and Switching Characteristics.

A 6500 V SiC trench MOSFET with integrated unipolar diode (UD-MOS) is proposed to improve reverse conduction characteristics, suppress bipolar degradation, and reduce switching loss. An N type base region under the trench dummy gate provides a low barrier path to suppress hole injection during the reverse conduction operation. The reverse conduction voltage VON is reduced to 1.11 V, and the reverse recovery charge (QRR) is reduced to 1.22 µC/cm2. The gate-to-drain capacitance (CGD) and gate-to-source capacitance (CGS) of the UD-MOS are also reduced to improve switching loss due to the thick oxide layer between the trench gate and dummy gate. The proposed device exhibits an excellent loss-related figure of merit (FOM). It provides a high-voltage SiC MOSFET prototype with potential performance advantages for voltage source converter-based high voltage direct current applications.

SiC Fin-Shaped Gate Trench MOSFET with Integrated Schottky Diode.

A silicon carbide (SiC) trench MOSFET featuring fin-shaped gate and integrated Schottky barrier diode under split P type shield (SPS) protection (FS-TMOS) is proposed by finite element modeling. The physical mechanism of FS-TMOS is studied comprehensively in terms of fundamental (blocking, conduction, and dynamic) performance and transient extreme stress reliability. The fin-shaped gate on the sidewall of the trench and integrated Schottky diode at the bottom of trench aim to the reduction of gate charge and improvement on the third quadrant performance, respectively. The SPS region is fully utilized to suppress excessive electric field both at trench oxide and Schottky contact when OFF-state. Compared with conventional trench MOSFET (C-TMOS), the gate charge, Miller charge, Von at third quadrant, Ron,sp·Qgd, and Ron,sp·Qg of FS-TMOS are significantly reduced by 34%, 20%, 65%, 0.1%, and 14%, respectively. Furthermore, short-circuit and avalanche capabilities are discussed, verifying the FS-TMOS is more robust than C-TMOS. It suggests that the proposed FS-TMOS is a promising candidate for next-generation high efficiency and high-power density applications.

Characterization and Fabrication of the CFM-JTE for 4H-SiC Power Device with High-Efficiency Protection and Increased JTE Dose Tolerance Window.

A 13.5 kV 4H-SiC PiN rectifier with a considerable active area of 0.1 cm2 is fabricated in this paper. Charge-field-modulated junction termination extension (CFM-JTE) has been proposed for satisfying the requirement of ultra-high reverse voltage, which enlarges the JTE dose tolerance window, making it approximately 2.8 times that of the conventional two-zone JTE. Besides, the CFM-JTE can be implemented through the conventional two-zone JTE process. The measured forward current is up to 100 A @ VF = 5.2 V in the absence of carrier lifetime enhancement technology. The CFM-JTE structure accomplishes 96% of the theoretical breakdown voltage of the parallel plane junction with a relatively small terminal area of 400 µm, which contributes to achieving the Baliga's figure of merit of 58.8 GW/cm2.

Theoretical and Experimental Study of 13.4 kV/55 A SiC PiN Diodes with an Improved Trade-Off between Blocking Voltage and Differential On-Resistance.

In this paper, a 13.4 kV/55 A 4H-silicon carbide (SiC) PiN diode with a better trade-off between blocking voltage, differential on-resistance, and technological process complexity has been successfully developed. A multiple zone gradient modulation field limiting ring (MGM-FLR) for extremely high-power handling applications was applied and investigated. The reverse blocking voltage of 13.4 kV, close to 95% of the theoretical value of parallel plane breakdown voltage, was obtained at a leakage current of 10 µA for a 100 µm thick, lightly doped, 5 × 1014 cm-3 n-type SiC epitaxial layer. Meanwhile, a fairly low differential on-resistance of 2.5 mΩ·cm2 at 55 A forward current (4.1 mΩ·cm2 at a current density of 100 A/cm2) was calculated for the fabricated SiC PiN with 0.1 cm2 active area. The highest Baliga's figure-of-merit (BFOM) of 72 GW/cm2 was obtained for the fabricated SiC PiN diode. Additionally, the dependence of the breakdown voltage on transition region width, number of rings in each zone, as well as the junction-to-ring spacing of SiC PiN diodes is also discussed. Our findings indicate that this proposed device structure is one potential candidate for an ultra-high voltage power system, and it represents an option to maximize power density and reduce system complexity.

Effect of Divalent Metals on the UV-Shielding Properties of MII/MgAl Layered Double Hydroxides.

Both the particle size and compositions have a strong influence on the UV-shielding performance of layered double hydroxides (LDHs), and they will interact with each other. To investigate the effects of divalent metal ions on the UV-shielding properties of layered double hydroxides (LDHs), MII/MgAl-CO3 LDHs (M = Mg, Co, Ni, Cu, or Zn) with the same primary and secondary particle size have been prepared and their UV-shielding performance have been studied in this work. The UV-vis spectra show that the ZnMgAl-LDHs exhibit the highest absorbance under the ultraviolet B and ultraviolet A rays among these LDH samples, but in the ultraviolet C region, the CuMgAl-LDHs show the highest absorbance and this result is in good accordance with the UV-shielding performance, which was examined by protecting the photocatalytic degradation of rhodamine B aqueous solution. Moreover, under UV rays, PP/ZnMgAl-LDH films show excellent resistance to UV aging, which can be attributed to the strong inhibition of ZnMgAl-LDHs during the production of free radicals in polypropene, as has been confirmed by electron spin resonance results.

The H2 sensing properties of facets-dependent Pd nanoparticles-supported ZnO nanorods.

The loading of noble-metal nanoparticles (NPs) is an effective approach for the enhancement of H2 sensing performances, although there have been rare reports focused on the effect of the facets of noble-metal nanoparticles in the H2 sensing performance. The catalytic and adsorption performance of noble-metal nanocrystals is mainly determined by their exposed facets, while the gas sensing performance of sensors is strongly correlated to the adsorption and reaction between the gases and sensor materials. Hence, it is very important to study the gas sensing performance of the different facets-exposed noble-metal nanoparticles. In this study, a set of shape-controlled Pd NPs have been prepared and loaded onto the ZnO nanorods, and the gas sensing performance of the Pd nanoparticle-loaded ZnO to 250 ppm of H2 has been detected. The results indicate that the cubic Pd NPs-loaded ZnO shows higher and faster sensing response to H2 than the octahedral and spherical Pd-loaded ZnO owing to the stronger adsorption of the H2 by cubic Pd NPs enclosed by (100) facets than the octahedral NPs enclosed by (111) facets. The cubic Pd NPs-loaded ZnO also exhibits better sensing selectivity and repeatability towards H2.

Gonadal transcriptome sequencing of the critically endangered Acipenser dabryanus to discover candidate sex-related genes.

BACKGROUND: Acipenser dabryanus, an endemic Chinese species, has been listed as a first-class protected animal in China. Sturgeons are among the oldest and most primitive group of existing fish in the world and occupy a special place in the evolutionary history of fish. Thus, a study of the reproduction and sex differentiation of sturgeon will be of great value for fish as well as the whole vertebrate group. METHODS: In this study, we conducted comparative analysis of the testes and ovaries transcriptomes of A. dabryanus to screen for sex-differentiation and sexual development-related genes. RESULTS: The transcriptome sequencing of six cDNA libraries generated 265 million clean reads, encompassing 79 Gb of sequences. The N50 and mean length of the identified 91,375 unigenes were 1,718 and 989 bp, respectively. A total of 6,306, 9,961, 13,170, 15,484, and 23,588 unigenes were annotated in the clusters of orthologous groups, gene ontology categories, Kyoto Encyclopedia of Genes and Genomes Pathway, euKaryotic orthologous groups, and NCBI non-redundant protein databases, respectively. A total of 5,396 differentially expressed genes were found between the two sexes, with 1,938 predicted to be up-regulated in ovaries and 3,458 in testes. A total of 73 candidate genes known to be involved in sex differentiation and sexual development were searched in the transcriptome of A. dabryanus of which 52 showed significant similarity. We highlighted six genes that are differentially expressed between the two sexes and may play important roles in sex differentiation and gonad maintenance. In addition, 24,271 simple sequence repeats (SSRs) and 550,519 single-nucleotide polymorphisms (SNPs) were detected. DISCUSSION: This work represents the first transcriptome study comparing the ovary and testis in A. dabryanus. The putative differentially expressed genes between the gonads provide an important source of information for further study of the sex-differentiation related genes and the sex-differentiation mechanism in sturgeons. The SSRs or SNPs identified in this study will be helpful in the discovery of sex-related markers in A. dabryanus.

Paternity assignment in the polyploid Acipenser dabryanus based on a novel microsatellite marker system.

Acipenser dabryanus is listed as a Critical Endangered species in the IUCN Red List and the first class protected animals in China. Fortunately, A. dabryanus specimens are being successfully bred in captivity for conservation. However, for effective ex situ conservation, we should be aware of the genetic diversity and the degree of relatedness of the individuals selected for breeding. In this study, we aimed at the development of novel and reliable microsatellites used for the genetic study of A. dabryanus. A total of 14,321 simple sequence repeats (SSRs) were detected by transcriptome sequencing and screening. We selected 20 novel and polymorphic microsatellites (non-dinucleotide) with good repeatability from the 100 tested loci for a subsequent genetic and paternity study. A set of captive broodstock (F1 stock, n = 43) and their offspring (F2 stock, n = 96) were used to examine the efficiency of the 20 SSRs for assigning parentage to offspring, with an allocation success of 91.7%. We also found that only a few families predominantly contributed to the progeny produced by the 43 breeders. In addition, mitochondrial DNA data showed that the captive broodstock (F1 individuals) had an excellent probability of the same lineage, implying that a high level of inbreeding may have occurred in these individuals. Our research provides useful information on genetic diversity and reproductive pattern of A. dabryanus, and the 20 SSRs developed in this study can be applied to the future breeding program to avoid inbreeding for this stock or other related species of Acipenseriformes.

The complete mitochondrial genome of Hemiculterella sauvagei (Teleostei, Cyprinidae, Hemiculterella).

Hemiculterella sauvagei, a Chinese minnow endemic to the upper Yangtze River, is an important part of the aquatic ecosystem and plays a vital ecological role in maintaining aquatic biodiversity. In this study, we provide the first mitochondrial genome of H. sauvagei. The complete mitochondrial genome of H. sauvagei is 16618 bp in length, containing 13 protein-coding genes, two rRNA genes (12 S and 16 S rRNA), 22 tRNA genes and a non-coding control region (D-loop). The gene nucleotide composition of H. sauvagei is A = 29.9%, T = 27.0%, C = 17.4% and G = 25.6%, with a slight AT bias of 56.9%. The complete mitochondrial genome of H. sauvagei would be useful for further studies on genetic diversity and molecular phylogenetic relationship of the subfamily Cultrinae.

Relationship between the degree of severe acute pancreatitis and patient immunity.

PURPOSE: To investigate the relationship between the APACHE II score and the immunity of patients with severe acute pancreatitis. METHODS: Clinical data were collected from 88 patients with acute pancreatitis, divided into four groups according to the severity of the disease. C-reactive protein (CRP), tumor necrosis factor-α, interleukin-6, interleukin-10, interleukin-4 and endotoxin (ET) in serum were measured on admission and then on days 3, 5, and 7. RESULTS: The incidence of local complications and multiple organ dysfunction syndrome increased with a higher APACHE II score. The CRP levels were increased significantly on day 3 in all four groups, but remained high only in the extremely severe group. In the mild and moderate groups, the pro-/anti-inflammatory cytokines peaked on day 3 and then decreased slowly. In the severe and extremely severe groups, the proinflammatory cytokines levels peaked on days 3 and 5, and then decreased rapidly. The antiinflammatory cytokines increased progressively on days 3, 5 and 7. The ET levels peaked significantly and then decreased slowly in the mild, moderate and severe groups, but remained high in the extremely severe group. CONCLUSIONS: An APACHE II score of 16 or higher is predictive of more local and systemic complications, excessive immune response, and premature immunosuppression.

Effect of pharmaconutrition-supplemented parenteral nutrition for severe acute pancreatitis: a meta-analysis of randomized controlled trials.

OBJECTIVE: To evaluate the effectiveness of pharmaconutrition-supplemented parenteral nutrition (PN) for severe acute pancreatitis (SAP). METHODS: A comprehensive search of abstracts was performed in the MEDLINE, OVID, Springer, and Cochrane Library database. Published data of randomized clinical trials (RCTs) comparing the clinically relevant outcomes of pharmaconutrition-supplemented PN versus PN for patients with SAP were analyzed. The analyzed outcome variables included infection, mortality, intensive care unit (ICU) stay, hospital stay, and leukocytes change. Statistical analyses were performed using the Cochrane Collaboration's RevMan 5.1 software. RESULTS: Four RCTs published in 1998 or later were included in this meta-analysis, in which 76 patients with pharmaconutrition-supplemented PN and 77 patients with PN. Pharmaconutrition-supplemented PN showed significantly better results in terms of infection (OR, 0.42; 95% CI, 0.20-0.91; P =0.03) and leukocytes change (before treated: mean different, 0.93; 95% CI, 0.21-1.65; P =0.01; after treated: mean different, -0.77; 95% CI, -1.47- -0.08; P =0.03). No significant difference could be found in mortality (OR, 0.30; 95% CI, 0.07-1.19; P =0.09), ICU stay (mean different, -3.65; 95% CI, -9.39-2.10; P =0.21), and hospital stay (mean different, -1.20; 95% CI, -9.89-7.48; P =0.79). CONCLUSIONS: The current meta-analysis indicates that pharmaconutrition-supplemented PN only show advantages in infection and leukocytes change.

[Panlongqi tablet (Chinese characters) combined with lumbar facet joint release for the treatment of lumbar spinal stenosis of Fengshi Bizu (Chinese characters)].

OBJECTIVE: To investigate the clinical efficacy of Panlongqi tablet (Chinese characters) combined with lumbar facet joint release for lumbar spinal stenosis of type Fengshi Bizu (Chinese characters). METHODS: Since February 2012 to February 2013, 120 patients with lumbar spinal stenosis of Fengshi Bizu (Chinese characters) syndrome were retrospectively studied. According to different treatment methods, 120 patients with lumbar spinal stenosis were divided into Panlongqi tablet (Chinese characters)group and control groups, respectively. In Panlongqi tablet (Chinese characters)group, 60 patients were treated by Panlongqi tablet (Chinese characters) combined with lumbar facet joints release solution including 26 males and 34 females with an average age of (60.40±3.36) years old ranging from 46 to 65 ; the course of the disease was 2 to 15 years (averaged 7.6 years). In control group the other 60 patients were treated with lumbar facet joint release including 24 males and 36 females with an average age of (61.20±2.47) years old ranging from 48 to 63; the course was 3 to 14 years (averaged 6.9 years). The clinical effect of patients were evaluated by JOA and ODI score before treatment, at 4 weeks and 3 months after treatment. RESULTS: All patients were followed up for 4 to 7 months (means 5.6 months). After 3 months,7 cases in control group recurrenced symptoms,only 1 case in Panlongqi tablet (Chinese characters) group recurrenced. At 4 weeks and 3 months of follow-up, ODI score and JOA score of Panlongqi tablet group were much better than those of the control group. CONCLUSION: For lumbar spinal stenosis of type Fengshi Bizu (Chinese characters),which were treated with lumbar facet joint release with Panlongqi tablet(Chinese characters), supplemented by back muscle exercise, in relieving waist and low back pain symptoms and improving functional status of lower lumbar spine, can obtain satisfactory clinical outcome, is a good method of conservative treatment for such diseases.

Removal of boron from refined brine by using selective ion exchange resins.

Boron removal by ion exchange resin from refined brine which was used to produce low-boron lithium salts was studied. A new boron-specific resin, XSC-800 was used in the experiments for the separation of boron. The column-mode and batch-mode sorption studies were both performed so as to obtain the optimum conditions for boron removal from refined brine. Parameters such as flow rate of brine, boron concentration, temperature, pH, height/diameter (H/D) ratio of the column, anion concentration, stirring speed and diameter of the resin were investigated. The results showed that the removal effect of boron by XSC-800 improved with increasing temperature, pH, H/D ratio, and with decreasing the flow rate of brine, boron concentration, chloride anion concentration and diameter of the resin. While the stirring speed and the recycles of the resin had no significant effects on boron removal. As a result, boron can be removed from refined brine much completely by the resin at the optimum conditions. On the other hand, kinetics of the exchange process was studied by using the moving boundary model. In order to describe the kinetics more accurately, the model was modified by introducing a time correction factor. The results showed that the rate-determining step of this process under the conditions studied was controlled by particle diffusion. In addition, the apparent activation energy Ea of the process was found to be 20.38 kJ/mol.

[Spectral studies of novel Na specific adsorbent Li(1+x)Al(x)Ti(2-x)(PO4)3].

A novel Na specific adsorbent Li(1+x)Al(x)Ti(2-x)(PO4)3 was synthesized by high temperature solid state reaction method. The samples were characterized by X-ray diffraction(XRD) and scanning electron microscope(SEM). Raman and FTIR spectroscopic studies of these materials were carried out, and the vibrational bands were assigned. Their adsorption performances were investigated. The results indicate that the low concentration (x < 0.6) Al dopant does not affect the structure of the material but makes it able to selectively adsorb sodium. The adsorbing test results show that its exchange capacity is high with the maximum value of adsorption capacity of 11.76 mg x g(-1) at x = 0.4 and pH = 10.0-11.0. So it can be used to remove the microamounts impurity-sodium in the production of high purity lithium salt.