基于制作离散性对策的高性能CMOS DAC

基于CMOS器件的离散性机理及误差消除对策，研究了高速、高精度嵌入式CMOS数/模转换器（DAC）IP核的设计与实现。采用行、列独立译码的二次中心对称电流源矩阵结构，优化了电流源开关电路结构与开关次序；利用Cadence的Skill语言独立开发电流源矩阵的版图排序和布线方法。在0.6μm N阱CMOS工艺平台下，12-bitDAC的微分线性误差和积分线性误差分别为1LSB和1.5LSB，在采样率为150MHz、工作电源为3.3V时的平均耗为140mW。流片一次成功，主要性能指标满足设计要求

Communication chip architecture based on IEC 61158 standard field bus

本发明涉及一种基于IEC61158标准现场总线的通信芯片架构，具有：内部数据总线控制单元，在组态单元的控制下通过内部RAM存储区的缓存完成CPU数据总线到DMA现场总线数据传输单元的数据传输；DMA现场总线数据传输单元，在组态单元的控制下完成内部数据总线控制单元内部RAM存储区的发送数据到现场总线的数据传输；在组态单元的控制下完成现场总线的接收数据及识别信息到内部总线控制单元内部RAM存储区的数据传输；组态单元，在外部CPU的控制下，完成现场总线数据传输的配置信息到内部数据总线控制单元和DMA现场总线数据传输单元的数据传输。本发明符合IEC61158规范，便于开发调试，提高了微控器工作效率

超临界碳氢燃料供给系统的动态频域特性研究

主动再生冷却是对超燃冲压发动机进行冷却的一种十分有效的冷却方式,吸热型碳氢燃料由于具有较高的物理和化学热沉而被认为是最优潜力的燃料。本文针对发动机燃料供给系统的动态变化特性,建立了高温燃油供给管道零维模型,采用频域特性方法研究了供油系统在超临界条件的动态特性,并分析了不同结构参数时动态特性参数的变化过程。最后,基于高温燃油加热实验台进行了对比实验,实验结果验证了频域分析结果的准确性,获得了不同结构参数下碳氢燃料供给系统动态过程的变化规律

Study on the differences of root spatial distribution characteristics of Phragmites australis in two different water-salt habitats in the Yellow River Delta

In order to study the growth differences of Phragmites australis, especially the differences of root ecological characteristics, between the tidal and fresh water habitats of the Yellow River Delta, two typical habitats of P. australis in tidal and fresh water habitats were chosen, and the electrical conductivity (EC) and pH of different soil layers were measured; the height, density, biomass of stem, leaf, main and fibrous root and ion content in different soil layers of P. australis were also analyzed. The results showed that the EC of surface soil (0-10 cm) was higher than that of the lower soil in both habitats and the minimum EC was tested in 20-30 cm soil layer. However, with the increase of soil depth deeper than 20-30 cm, the EC value increased and the pH decreased. The mean density and height of P. australis were (20.805.93) stem·m~(-2) and (35.7016.01) cm in tidal area, (309.60 39.15) stem·m~(-2) and (91.48 13.09) cm in fresh water habitat, separately. In terms of biomass allocation, the proportion of the main root, fibrous root, stem and leaf of P. australis in tidal and fresh water habitats were 79.70%, 11.88%, 6.79%, 1.64% and 66.77%, 8.76%, 18.54%, 5.92%, respectively. The main and fibrous root biomass of P. australis in fresh water habitat was mainly concentrated in 0-30 cm and 0-10 cm(68.1838.99) g·m~(-2) soil layer, respectively. And the main root biomass of P. australis in tidal water area was mainly concentrated in 20-3 0cm (146.57109.94) g·m~(-2) soil layer. After analyzing the ion content of roots in two habitats, we found the average content of Na~+ and K~+ in the main root of P. australis from tidal water habitat were (6.381.56) mg·g~(-1) and (1.080.17) mg·g~(-1) respectively, and the distribution of Na~+ and Cl- had a significantly positive correction (P<0.01). The average contents of these two ions in the main root of P. australis in fresh water habitat were (2.820.56) mg·g~(-1) and (3.931.10) mg·g~(-1) respectively. The results show that P. australis can adjust the height, density and biomass allocation of different organs and the distribution of ions to adapt to the different salt-water environment, which is the typical adaptation mechanism of P. australis in high-salt areas

Effects of different restoration ages on plant diversity and community stability of wetlands in the Yellow River Delta

Ecological restoration is an efficient method to reduce the degradation of natural coastal wetlands.Restoration age has important effects on soil chemical properties and plant community characteristics.However,long-term monitoring on the effects of wetland restoration projects and their underlying mechanism is still limited.Here,we examined the effects of different restoration ages (0,3,7,10,and 19 years) of wetlands on soil properties,plant species diversity,and community stability in the Yellow River Delta.The results showed that soil electric conductivity,available phosphorus concentration,and available potassium concentration decreased with increasing restoration age.However,soil available nitrogen concentration increased during the restoration process.Shannon index,Pielou evenness index,and species richness index of plant communities increased continuously with increasing restoration age,while plant diversity indices were mainly driven by the changes in soil electrical conductivity.In addition,restoration age also promoted plant community stability,which was significantly and negatively related to soil electric conductivity,available phosphorus and available potassium,and positively related to available nitrogen concentration.With the proceeding of restoration,soil environment and plant community structure improved continuously.Therefore,restoration projects can stimulate positive succession of community and improve the stability of coastal wetland ecosystems

驼绒藜属牧草种子生物学特性、种子生产技术及基地建设

该项研究针对具有广泛开发利用前景的驼绒藜属牧草种子存在的寿命短，易于劣变等问题进行了种子生物学特性的系统研究，包括种子的发育、萌发、贮藏、活力、营养代谢和激素调节、抗逆性以及遗传差异等；探索了驼绒藜属植物“短命种子”的发育规律和劣变机理，提出的种子超干燥贮藏技术具有创新性；首次系统研究并提出的驼绒藜属种子生产和贮藏技术体系，可提高种子产量3～5倍，延长种子寿命1～2年，秋季种苗移栽定植技术成活率达80%以上，比传统技术提高50%以上；建立了华北驼绒藜人工种子生产基地1000亩、天然种群原种基地2000亩，年产种子15吨，对恢复和保护利用驼绒藜属植物资源具有重要意义

Aripiprazole versus other atypical antipsychotics for schizophrenia

BACKGROUND: In most western industrialised countries, second generation (atypical) antipsychotics are recommended as first line drug treatments for people with schizophrenia. In this review we specifically examine how the efficacy and tolerability of one such agent - aripiprazole - differs from that of other comparable second generation antipsychotics. OBJECTIVES: To evaluate the effects of aripiprazole compared with other atypical antipsychotics for people with schizophrenia and schizophrenia-like psychoses. SEARCH METHODS: We searched the Cochrane Schizophrenia Group Trials Register (November 2011), inspected references of all identified studies for further trials, and contacted relevant pharmaceutical companies, drug approval agencies and authors of trials for additional information. SELECTION CRITERIA: We included all randomised clinical trials (RCTs) comparing aripiprazole (oral) with oral and parenteral forms of amisulpride, clozapine, olanzapine, quetiapine, risperidone, sertindole, ziprasidone or zotepine for people with schizophrenia or schizophrenia-like psychoses. DATA COLLECTION AND ANALYSIS: We extracted data independently. For dichotomous data we calculated risk ratios (RR) and their 95% confidence intervals (CI) on an intention-to-treat basis based on a random-effects model. Where possible, we calculated illustrative comparative risks for primary outcomes. For continuous data, we calculated mean differences (MD), again based on a random-effects model. We assessed risk of bias for each included study. MAIN RESULTS: We included 12 trials involving 6389 patients. Aripiprazole was compared to olanzapine, risperidone and ziprasidone. All trials were sponsored by an interested drug manufacturer. The overall number of participants leaving studies early was 30% to 40%, limiting validity (no differences between groups).When compared with olanzapine no differences were apparent for global state (no clinically important change: n = 703, 1 RCT, RR short-term 1.00 95% CI 0.81 to 1.22; n = 317, 1 RCT, RR medium-term 1.08 95% CI 0.95 to 1.22) but mental state tended to favour olanzapine (n = 1360, 3 RCTs, MD total Positive and Negative Syndrome Scale (PANSS) 4.68 95% CI 2.21 to 7.16). There was no significant difference in extrapyramidal symptoms (n = 529, 2 RCTs, RR 0.99 95% CI 0.62 to 1.59) but fewer in the aripiprazole group had increased cholesterol levels (n = 223, 1 RCT, RR 0.32 95% CI 0.19 to 0.54) or weight gain of 7% or more of total body weight (n = 1095, 3 RCTs, RR 0.39 95% CI 0.28 to 0.54).When compared with risperidone, aripiprazole showed no advantage in terms of global state (n = 384, 2 RCTs, RR no important improvement 1.14 95% CI 0.81 to 1.60) or mental state (n = 372, 2 RCTs, MD total PANSS 1.50 95% CI -2.96 to 5.96).One study compared aripiprazole with ziprasidone (n = 247) and both the groups reported similar change in the global state (n = 247, 1 RCT, MD average change in Clinical Global Impression-Severity (CGI-S) score -0.03 95% CI -0.28 to 0.22) and mental state (n = 247, 1 RCT, MD change PANSS -3.00 95% CI -7.29 to 1.29).When compared with any one of several new generation antipsychotic drugs the aripiprazole group showed improvement in global state in energy (n = 523, 1 RCT, RR 0.69 95% CI 0.56 to 0.84), mood (n = 523, 1 RCT, RR 0.77 95% CI 0.65 to 0.92), negative symptoms (n = 523, 1 RCT, RR 0.82 95% CI 0.68 to 0.99), somnolence (n = 523, 1 RCT, RR 0.80 95% CI 0.69 to 0.93) and weight gain (n = 523, 1 RCT, RR 0.84 95% CI 0.76 to 0.94). Significantly more people given aripiprazole reported symptoms of nausea (n = 2881, 3 RCTs, RR 3.13 95% CI 2.12 to 4.61) but weight gain (7% or more of total body weight) was less common in people allocated aripiprazole (n = 330, 1 RCT, RR 0.35 95% CI 0.19 to 0.64). Aripiprazole may have value in aggression but data are limited. This will be the focus of another review. AUTHORS' CONCLUSIONS: Information on all comparisons are of limited quality, are incomplete and problematic to apply clinically. Aripiprazole is an antipsychotic drug with a variant but not absent adverse effect profile. Long-term data are sparse and there is considerable scope for another update of this review as new data emerges from the many Chinese studies as well as from ongoing larger, independent pragmatic trials