含14H-LPSO结构的Mg-7Gd-3Y-1Nd-1Zn-0.5Zr合金在240℃时效过程中析出相的演化

通过TEM与HAADF-STEM技术分析含14H-LPSO结构的Mg-7Gd-3Y-1Nd-1Zn-0.5Zr (质量分数,%)合金在240℃时效过程中析出相的形貌和晶体学特征。薄片状14H-LPSO结构在500℃、2 h热处理过程中析出,而β型析出相在240℃时效过程中析出。14H-LPSO结构沿[0001]α方向的原子堆垛顺序为ABABCACACACBABA。240℃时效2 h时,β型析出相为有序固溶团簇、之字形GP区和少量的β′相。240℃时效18 h达到峰值,相应的布氏硬度值为112,β型析出相为β′相和局部富RE结构。240℃时效100 h时,β型析出相为β′、β1和β’F。β′相不经过β″相直接从之字形GP区形核,然后通过β′→β’F→β1转变成β1相。Zn的添加不仅可以形成LPSO结构,而且参与β1相的形成。LPSO结构阻碍β’和β1相沿<0001>α的生长。

Mg-7Gd-3Y-1Nd-1Zn-0.5Zr合金在240℃等温时效过程中析出相的演化（英文）

采用TEM和HAADF-STEM技术,研究Mg-7Gd-3Y-1Nd-1Zn-0.5Zr合金在240℃等温时效过程中析出相的形态与晶体学特征。经2h欠时效,析出相为稀土原子柱呈六角环状结构的有序溶质团簇、之字形GP区和早期形成的β'相。经18h峰时效,析出相主要为β'相和与其伴生的一种新型棒状相β'p。经100h过时效,析出相为β'相、β1相、长程堆垛有序(LPSO)构建块γ′相和14H-LPSO。β'相三维形貌呈凸透镜状,沿<0001>α方向观察,其长宽比小于EW75合金中β'相的长宽比。该合金优异的热稳定性归功于γ′和14H-LPSO阻碍β'和β1的生长、稀土原子低的扩散速率以及β'和β1相的物理特性。

Perineural dexamethasone does not enhance the analgesic efficacy of ultrasound-guided subcostal transversus abdominis plane block during laparoscopic cholecystectomy

BACKGROUND: Ultrasound-guided transversus abdominis plane (TAP) block is an adjunct therapy to provide effective postoperative analgesia in abdominal surgical procedures. Dexamethasone is a supplement agent that can improve the efifcacy of local anesthesia. However, information about its additive effect is limited. This study aimed to compare the an-algesic efifciency using ultrasound-guided TAP block with and without perineural dexamethasone for patients who under-went laparoscopic cholecystectomy. METHODS: Sixty patients who underwent laparoscopic cho-lecystectomy were randomly divided into three groups: group I, controls; group II, TAP; and group III, TAP+perineural dexamethasone supplement. The requirement of additional analgesia and the ifrst-time request of rescue-analgesia were recorded after operation and the numerical rating scale was evaluated at speciifc intervals. RESULTS: Compared to group I, the ifrst-time requirement of rescue-analgesia in groups II and III was signiifcantly delayed (403.0±230.9, 436.0±225.3 vs 152.3±124.7,P<0.01). Compared with those in group I, patients in groups II and III were associ-ated with lower numerical rating scale pain scores (P<0.01) and less postoperative analgesic consumption (P<0.01). There&nbsp;was no signiifcant difference in the variables mentioned above between groups II and III (P>0.05). CONCLUSION: Perineural dexamethasone has no additive/synergistic effect with subcostal TAP block on analgesic efif-cacy for the patients undergoing laparoscopic cholecystectomy.

Pancreatic cancer with synchronous liver and colon metastases: A case report

BACKGROUND Metastasis of pancreatic cancer to the colon is rare and the features need to be further elucidated.Herein,we report a rare case of pancreatic cancer with simultaneous liver and colon metastases.CASE SUMMARY A 48-year-old man with intrahepatic space-occupying lesions based on a computed tomography scan was admitted to our hospital for further treatment.Abdominal magnetic resonance imaging revealed a 6.4 cm×4.2 cm mass in the tail of the pancreas and multiple low-density masses in the liver parenchyma.In addition,a mass of 2.2 cm×1.6 cm with surface congestive erosions in the sigmoid colon was detected by colonoscopy.Histopathological examination of biopsies from both the liver and colon lesions revealed a moderately to poorly differentiated adenocarcinoma.Immunohistochemical staining of the colon tumor was positive for cytokeratin(CK)7 and CK,but negative for colorectal adenocarcinoma-related markers CK 20,CDX2,and SATB2,thus indicating that the metastasis originated from the pancreas.Next-generation sequencing for genomic profiling of the liver and colon metastases both found mutations in KRAS(p.G12D)and TP53(c.376-1delG),with microsatellite stable and low tumor mutational burden without actionable or cancer-predisposing gene mutations detected.The patient was subsequently treated with 12 cycles of FOLFIRINOX which led to a sustainable response,followed by ongoing maintenance treatment with irinotecan plus fluorouracil.CONCLUSION For this rare case,careful evaluation of histopathological and immunohistochemical staining results are required.The genomic profiling of colon lesions was revealed for the first time,and FOLFIRINOX showed good treatment efficacy in this patient.

Hierarchical control for parallel bidirectional power converters of a grid-connected DC mlcrogrnd

直流微电网通过多个双向变流器并联连接到交流电网,其控制方法直接影响到直流电网的性能。目前的研究工作主要集中在交流、直流及混合微电网的分层控制,而较少关注直流微电网互联的双向变流器的分层控制。本文提出一种直流微电网联网双向变流器的分层控制方法。为抑制交流测零序环流并实现电压控制的反馈线性化,采用d-q-0控制策略来控制内环电流并采用直流电压平方实现外环电压控制。在一次控制阶段采用直流电压下垂控制来实现直流电流的分担,直流电压下垂控制会产生直流电压偏差。接着分析了直流电压偏差和电流分担误差之间的关系。为同时消除直流电压偏差和电流分担误差,在二次控制中采用了下垂斜率调节和电压平移。三次控制中通过多双向变流器的精确有功和无功控制实现直流微网的经济运行。本文提出的直流微网多并联双向变流器分层控制方法可以实现微网内可控/不可控分布式电源的协调。通过Matlab/Simulink仿真验证了算法的有效性,结果表明该算法能满足实际应用需求。

Comparative Transcriptional Profiling and Preliminary Study on Heterosis Mechanism of Super-Hybrid Rice

Heterosis is a biological phenomenon whereby the offspring from two parents show improved and superior performance than either inbred parental lines. Hybrid rice is one of the most successful apotheoses in crops utilizing heterosis. Transcriptional profiling of F1 super-hybrid rice Liangyou-2186 and its parents by serial analysis of gene expression （SAGE） revealed 1183 differentially expressed genes （DGs）, among which DGs were found significantly enriched in pathways such as photosynthesis and carbon-fixation, and most of the key genes involved in the carbon-fixation pathway exhibited up-regulated expression in F1 hybrid rice. Moreover, increased catabolic activity of corresponding enzymes and photosynthetic efficiency were also detected, which combined to indicate that carbon fixation is enhanced in F1 hybrid, and might probably be associated with the yield vigor and heterosis in super-hybrid rice. By correlating DGs with yield-related quantitative trait loci （QTL）, a potential relationship between differential gene expression and phenotypic changes was also found. In addition, a regulatory network involving circadian-rhythms and light signaling pathways was also found, as previously reported in Arabidopsis, which suggest that such a network might also be related with heterosis in hybrid rice. Altogether, the present study provides another view for understanding the molecular mechanism underlying heterosis in rice.

Cell-wall Invertases from Rice are Differentially Expressed in Caryopsis during the Grain Filling Stage

Cell-wall invertase plays an important role in sucrose partitioning between source and sink organs in higher plants. To investigate the role of cell-wall invertases for seed development in rice （Oryza sativa L.）, cDNAs of three putative cell- wall invertase genes OsCIN1, OsCIN2 and OsCIN3 were isolated. Semi-quantitative reverse transcription-polymerase chain reaction analysis revealed different expression patterns of the three genes in various rice tissues/organs. In developing caryopses, they exhibited similar temporal expression patterns, expressed highly at the early and middle grain filling stages and gradually declined to low levels afterward. However, the spatial expression patterns of them were very different, with OsCIN1 primarily expressed in the caryopsis coat, OsCIN2 in embryo and endosperm, and OsCIN3 in embryo. Further RNA in situ hybridization analysis revealed that a strong signal of OsCIN2 mRNA was detected in the vascular parenchyma surrounding the xylem of the chalazal vein and the aleurone layer, whereas OsCIN3 transcript was strongly detected in the vascular parenchyma surrounding the phloem of the chalazal vein, cross-cells, the aleurone layer and the nuceUar tissue. These data indicate that the three cell-wall invertase genes play complementary/synergetic roles in assimilate unloading during the grain filling stage. In addition, the cell type-specific expression patterns of OsCIN3 in source leaf blades and anthers were also investigated, and its corresponding physiological roles were discussed.

Model predictive control of servo motor driven constant pump hydraulic system in injection molding process based on neurodynamic optimization

In view of the high energy consumption and low response speed of the traditional hydraulic system for an injection molding machine,a servo motor driven constant pump hydraulic system is designed for a precision injection molding process,which uses a servo motor,a constant pump,and a pressure sensor,instead of a common motor,a constant pump,a pressure proportion valve,and a flow proportion valve.A model predictive control strategy based on neurodynamic optimization is proposed to control this new hydraulic system in the injection molding process.Simulation results showed that this control method has good control precision and quick response.

Linear dipole behavior of single quantum dots encased in metal oxide semiconductor nanoparticles films

Understanding of charge/energy exchange processes and interfacial interactions that occur between quantum dots (QDs) and the metal oxides is of critical importance to these QD-based optoelectronic devices. This work reports on linear dipole behavior of single near-infrared emitting CdSeTe/ZnS core/shell QDs which are encased in indium tin oxide (ITO) semiconductor lianoparticles films. A strong polarization anisotropy in photohiminescence emission is observed by defocused wide-field imaging and polarization measuremen11echniques, and the average polarization degree is up to 0.45. A possible mechanism for the observation is presented in which the electrons, locating at single QD surface from ITO by electron transfer due to the equilibration of the Fermi levels, result in a significant Stark distortion of the QD electron/hole wavefunctions. The Stark distortion results in the linear polarization property of the single QDs. The investigation of linear dipole behavior for single QDs encased in ITO films would be helpful for further improving QD-based device performance.

Influence of surface charges on the emission polarization properties of single CdSe/CdS dot-in-rods

We report an experimental investigation of the influence of surface charges on the emission polarization properties of single CdSe/CdS dot-in-rods(DRs),which is important for their polarization-based practical applications.By covering the single DRs with N-type semiconductor indium tin oxide(ITO)nanoparticles,the surface of single DRs is charged by ITO through interracial electron transfer.This is confirmed by the experimental observations of the reduced photoluminescence intensities and lifetimes as well as the suppressing blinking.It is found that the full width at half maximum of histogram of polarization degrees of the single DRs is broadened from 0.24(on glass)to 0.41(in ITO).In order to explain the exprimental results,the band-edge exciton fine structure of single DRs is calculated by taking into account the sample parameters,the emission polarization,and the surface charges.The calculation results show that the level ordering of the emitting states determines the polarization degrees tending to increase or decrease under the influence of surface electrons.The surface electrons can induce an increase in the spacing between the emitting levels to change the populations and thus change the polarization degrees.In addition,different numbers of surface electrons may randomly distribute on the long CdSe/CdS rods,leading to the heterogeneous influences on the single DRs causing the broadening of polarization degrees also.