The Causes of Conversion from Laparoscopy to Laparotomy in Patients with Laparoscopic Repair of Perforated Peptic Ulcer

Purpose: Perforated peptic ulcer is an emergency condition. Laparoscopic ulcer repair is a feasible and safe procedure. The aim of this study was to research the efficacy of laparoscopic repair of peptic ulcer and to discuss the causes of conversion from laparoscopy to laparotomy. Methods: We collected 34 patients with perforated peptic ulcer underwent laparoscopic surgery from October 2003 to October 2008. Thirty four patients with perforated peptic ulcer underwent laparoscopic intervention and 6 cases were converted to laparotomy. The demographics, laboratory data, perioperative data, morbidity and mortality were compared. Results: In demographics of two groups, there were no significant differences in sex, age, location, and mean duration of symptoms of acute abdominal pain. However, there were significant differences in median size of perforation, mean duration of history of peptic ulcer related pain, and the experiences of surgeon. There were no significant differences in the laboratory data and perioperative data of two groups. In morbidity?and mortality of two groups, there were no significant differences in leakage, wound infection, intra-abdominal abscess, ileus, urinary tract infection, pneumonia, and mortality, but there was significant difference in overall morbidity in two groups. Conclusions: Laparoscopic repair of perforated peptic ulcer is safe and could be used in routine clinical practice. However, patients with larger perforations (>10 mm), longer duration of history peptic ulcer related pain (>2 years), and learning curve of surgeon could be associated with conversion rate. It is associated with higher morbidity in patients with conversion from laparoscopy to laparotomy.

72 MHz/54 MHz SAMPLING RATE CONVERSION SYSTEM OF HDTV STUDIO SIGNAL

７２ＭＨｚ／５４ＭＨｚＳＡＭＰＬＩＮＧＲＡＴＥＣＯＮＶＥＲＳＩＯＮＳＹＳＴＥＭＯＦＨＤＴＶＳＴＵＤＩＯＳＩＧＮＡＬＺｈｏｕＧｏｎｇｙｕ（周功禹）ＹｕＺｈｅｎｇｈｕａ＊（虞正华）ＺｈｅｎｇＺｈｉｈａｎｇ（郑志航）（Ｄｅｐｔ．ｏｆＥｌｅｃｔｒｏｎｉｃＥｎ...

An estimate of the conversion rates of SO_2 to SO_4^(2-)- and NO_2 to HNO_(3+) NO_3^- for the evaluation air pollution in Beijing

The conversion rates of SO2 to SO42- and NO2 to HNO3+NO3- are estimated from the field-data obtained in Beijing in summer, 1988. The results show that the conversion rate of NO2 is about four times as much as that of SO2; The conversion rates have a diurnal variation in a day. On the average, the rate of SO2 is estimated to be 4.7% h-1 during the daytime and 3.4% h-1 during the nighttime. Similarly, the rate of NO2 is estimated to be 17.2% h-1 and 12% h-1 respectively.

Thermal Degradation of Polyethylene Bags and Millet Stalks: Influence of the Temperature and the Local Concentration of Oxygen on the Conversion Rate of Carbon

This paper concerns the influence of temperature and local concentration of oxygen on the conversion efficiency of carbon into CO, CO2, CH4, C3H8, C2H4, C2H2, C2H6, C6H6, during the thermal degradation of plastic bags and millet stalks. The experimental device used is the tubular kiln, coupled to an analyzer Fourier Transform Infrared (FTIR) and a Non Dispersive Infrared analyzer (NDIR). Temperatures are considered between 800 and 1000°C. Local concentrations of oxygen during thermal degradation are 0%, 10% and 21%. On the one hand results obtained on the influence of temperature show that for each type of thermal degradation and whatever the temperature of the combustion, the rate of conversion of carbon remains substantially the same. In the case of plastic bags, the rate of carbon converted during pyrolysis is about 90% of carbon converted during reductive combustion. On the other hand, with millet stalks, the carbon converted represents only 60% of the rate of carbon converted during combustion to 10% oxygen. 1 to 2% of carbon not analyzed is in the form of aromatic compounds that are found most often in the soot and/or tar from this combustion system. Moreover, whatever the temperature, the overall efficiency of carbon conversion increases linearly with the local concentration of oxygen. During the thermal degradation of plastic bags, we see that the reducer environment has fostered the conversion of 7% of carbon more while the presence of oxygen in double proportion promotes the conversion of 27% carbon. Regarding the influence of the local content of oxygen, it is clear that for plastic bags, the reactions of oxidation of CO into CO2 tend to be favored for the benefit of those of hydrocarbons into CO. The formation of CO and CO2 by oxidation of light hydrocarbons is primarily from gaseous compounds CH4 and C2H4. At 950°C, we have also acetylene (C2H2) which is involved in the production of carbon oxides. At 1000°C, benzene (C6H6) heavily involved in the formation of CO and CO2. However, with millet stalks, more the local content of oxygen increases, more combustion is better, that is to say that the oxidation reactions producing CO2 are faster than the oxidation reactions of hydrocarbons into CO. The rate of carbon converted into CO and CO2 is higher for millet stalks than for plastic bags, due to this oxygen levels higher in millet stalks than in plastic bags. Similarly, for the millet stalks, from pyrolysis to combustion (at 10 and 21% oxygen), there is practically no hydrocarbon emitted.

Study on the Relationships between Utilization Ratios and Conversion Rates of Nitrogen,Phosphorus and Potassium for Wheat

This paper studied the relationships between utilization ratios and conversion rates of nitrogen,phosphorus and potassium for wheat by data mining method based on data of"3414 fertilizer field trials"of wheat by published papers from national soil testing and recommendation since 2005.The results and conclusions were as follows:①the conceptual model of fertilizer utilization ratio of wheat for plot was that,Y N≈a+b×optimum nitrogen application amount+c×optimum fertilizer amount of K+d×rainfall in growth season,Y P≈a+b×optimum fertilizer amount of K+c×rainfall in growth season,Y K≈a+b×temperature in growth season+c×rainfall in growth season-d×optimum yield-e×optimum nitrogen application amount,respectively.②Fertilizer utilization ratio and nutrient conversion rate had 4 kinds of relationships.No significant relationships:13,of which 8 were soil nutrients,the results showed that soil nutrients had little effect on nutrient conversion rate and fertilizer utilization ratio;consistent significant relationships:4,they were all nitrogen and phosphorus,explaining the importance of nitrogen and phosphorus;contrary significant relationships:6,they were all nitrogen and phosphorus,illustrating that phosphorus and nitrogen had inhibitory effect;complementary significant relationships:31,the cause of the complementary phenomenon was that the fertilizer utilization ratio was the measuring index of fertilizer efficiency in one season,while the nutrient conversion rate was the measuring index of fertilizer efficiency in more seasons.It showed that the fertilizer utilization rate was significantly correlated,or the nutrient conversion rate was significantly correlated.

Study on the Relationship between Utilization Ratios and Conversion Rates of Nitrogen,Phosphorus and Potassium for Rice

This paper studied the relationships between utilization ratios and conversion rates of nitrogen,phosphorus and potassium for rice by data mining method based on data of"3414 fertilizer field trials"of rice by published papers from national soil testing and recommendation since 2005.The results and conclusions were as follows:①the conceptual model of fertilizer utilization ratio of rice for plot was that,Y N≈a+b×optimum yield+c×optimum fertilizer amount of K,Y P≈a+b×optimum yield,Y K≈a respectively.②Fertilizer utilization ratio and nutrient conversion rate had 4 kinds of relationships:①no significant relationships:25,of which 14 were soil nutrients and 9 were environmental factors,the results showed that soil nutrients and environmental factors had little effect on nutrient yield ratio and fertilizer utilization ratio;②consistent significant relationships:2,one was that yield ratio and utilization ratio of N were positively correlated with the optimum production,explaining the importance of N for production,the other was that yield ratio and utilization ratio of P had a significantly positive correlation with conversion rate and utilization ratio of N,illustrating that nitrogen and phosphorus had mutual promotion;③contrary significant relationships:5,these showed as negative correlations of fertilizer utilization ratio and positive correlation of nutrient conversion ratio;④complementary significant relationships:22,the cause of the complementary phenomenon was that the fertilizer utilization ratio was the index of fertilizer efficiency in one season,while the nutrient conversion rate was the index of fertilizer efficiency in more seasons,which showed that the fertilizer utilization rate was significantly correlated,or the nutrient conversion rate was significantly correlated.

Study on the Relationships between Utilization Ratios and Conversion Rates of Nitrogen,Phosphorus and Potassium for Maize

This paper studied the relationships between utilization ratios and conversion rates of nitrogen,phosphorus and potassium for maize by data mining method based on data of"3414 fertilizer field trials"of maize by published papers from national soil testing and recommendation since 2005.The results and conclusions were as follows:①the conceptual model of fertilizer utilization ratio of maize for plot was that,Y N≈a+b×optimum yield,Y P≈a+b×optimum yield-c×optimum nitrogen application amount-d×optimum potassium application amount,Y K≈a-b×optimum nitrogen application amount-c×temperature in growth season-d×rainfall in growth season,respectively.②Fertilizer utilization ratio and nutrient conversion rate had 4 kinds of relationships.No significant relationships:22,of which 16 were soil nutrients and 5 were environmental factors,the results showed that soil nutrients and environmental factors had little effect on nutrient conversion rate and fertilizer utilization ratio;consistent significant relationships:14,illustrating that conversion rate and utilization ratio of maize were consistent in most cases,and it was because that maize was planted for a long term,and its fertilizer absorption law was basically stable;contrary significant relationships:0,illustrating that there was no reverse relationship between conversion rate and utilization ratio of maize;complementary significant relationships:18,the cause of the complementary phenomenon was that the fertilizer utilization ratio was the measuring index of fertilizer efficiency in one season,while the nutrient conversion rate was the measuring index of fertilizer efficiency in more seasons.It showed that the fertilizer utilization ratio was significantly correlated,or the nutrient conversion rate was significantly correlated.

Frame rate up-conversion using multiresolution critical point filters with occlusion refinement

In this paper, multiresolution critical-point filters (CPFs) are employed to image matching for frame rate up-conversion (FRUC). By CPF matching, the dense motion field can be obtained for representing object motions accurately. However, the elastic motion model does not hold in the areas of occlusion, thus resulting in blur artifacts in the interpolated frame. To tackle this problem, we propose a new FRUC scheme using an occlusion refined CPF matching interpolation (ORCMI). In the proposed approach, the occlusion refinement is based on a bidirectional CPF mapping. And the intermediate frames are generated by the bidirectional interpolation for non-occlusion pixels combined with unidirectional projection for the occlusion pixels. Experimental results show that ORCMI improves the visual quality of the interpolated frames, especially at the occlusion regions. Compared to the block matching based FRUC algorithm, ORCMI can achieve 1～2 dB PSNR gain for standard video sequences.

CONVERSION RATES OF SURFACE HOX RADICALS IN BEIJING CITY

Surface OH radical concentration in Beijing City was measured by impregnated filter trapping technique-high performance liquid chromatography (IFT-HPLC). The observed concentration of OH radical showed obvious diurnal and seasonal variations, with maximum readings at noon or afternoon, ～80×106OH/cm3 in summer and ～20×106-40×106OH/cm3 in fall. On the basis of measured data, the reaction rates related to the photochemical process of Hox (OH+HO2) were derived and characteristics of atmospheric chemical processes in the city were analyzed. The results showed that conversion rates of atmospheric OH and HO2 in the summer of Beijing City were air of the city mainly originated from the photolysis of the gaseous HNO2, and the main sink of OH were the photochemical reactions with VOCs, NO2, HCHO and CO. It was different from the clean area.

Conversion regular patterns of acetic acid,propionic acid and butyric acid in UASB reactor

On the basis of continuous tests and batch tests, conversion regular patterns of acetate, propionate and butyrate in activated sludge at different heights of the UASB reactor were conducted. Results indicated that the conversion capacity of the microbe is decided by the substrate characteristic when sole VFA is used as the only substrate. But when mixed substrates are used,the conversion regulations would have changed accordingly. Relationships of different substrates vary according to their locations. In the whole reactor, propionate's conversion is restrained by acetate and butyrate of high concentration. On the top and at the bottom of the reactor, conversion of acetate, but butyrate, is restrained by propionate. And in the midst, acetate's conversion is accelerated by propionate while that of butyrate is restrained. It is proved, based on the analysis of specific conversion rate, that the space distribution of the microbe is the main factor that affects substrates' conversion. The ethanol type fermentation of the acidogenic phase is the optimal acid type fermentation for the two phase anaerobic process.

Interannual variations in energy conversion and interaction between the mesoscale eddy field and mean flow in the Kuroshio south of Japan

Using 19-year satellite altimetric data, variations in the eddy kinetic energy, energy exchanges and interaction between the eddy fi eld and mean fl ow are discussed for the Kuroshio south of Japan. In the seasonal cycle, the eddy kinetic energy level is a minimum in December/January and a maximum in April/May. In addition to seasonal variations, the eddy kinetic energy undergoes interannual changes. The energy transfers mainly from the mean fl ow to the eddy fi eld in the Kuroshio south of Japan, and dominant energy exchanges mainly occur along the Kuroshio path south of Japan in each year from 1993 to 2011. In addition, there is often barotropic instability south of Honshu. Regarding interactions between the eddy fi eld and mean fl ow, cyclonic and anticyclonic accelerations are also found along the Kuroshio path and they fl ank each other. There is cyclonic acceleration always imposed on southeast of Kyushu, and anticyclonic acceleration dominates south of Honshu from 2001 to mid-2005. Reynolds stress is used to explain the dynamic process of energy exchange. Furthermore, lag-correlation and linear regression analysis show that variability of the energy conversion rate and Reynolds stress involve responses to eddy acceleration at two time scales. The enhanced eddy acceleration induces large Reynolds stress, and enhanced Reynolds stress or barotropic instability further enforces energy transfer from the mean fl ow to the eddy fi eld.

Rate-distortion optimized frame dropping and scheduling for multi-user conversational and streaming video

We propose a Rate-Distortion (RD) optimized strategy for frame-dropping and scheduling of multi-user conversa- tional and streaming videos. We consider a scenario where conversational and streaming videos share the forwarding resources at a network node. Two buffers are setup on the node to temporarily store the packets for these two types of video applications. For streaming video, a big buffer is used as the associated delay constraint of the application is moderate and a very small buffer is used for conversational video to ensure that the forwarding delay of every packet is limited. A scheduler is located behind these two buffers that dynamically assigns transmission slots on the outgoing link to the two buffers. Rate-distortion side information is used to perform RD-optimized frame dropping in case of node overload. Sharing the data rate on the outgoing link between the con- versational and the streaming videos is done either based on the fullness of the two associated buffers or on the mean incoming rates of the respective videos. Simulation results showed that our proposed RD-optimized frame dropping and scheduling ap- proach provides significant improvements in performance over the popular priority-based random dropping (PRD) technique.

Modeling the kinetics of methane conversion in steam reforming process of coke-oven gas based on experimental data

Steam-reforming is an effective approach for upgrading methane and hydrocarbon of coke-oven gas into CO and H2, but the kinetic behavior needs more study. We investigated the conversion of methane in coke-oven gas by steam reforming process in an electric tubular flow at 14 kPa with temperature varying from 500 °C to 950 °C, and developed a kenetic model for , ignoring the effects of adsorption and diffusion. The optimal dynamic conditions for methane conversion 14 kPa are as follows:the ratio of the amount of water to the amount of methane is from 1.1 to 1.3;the reaction temperature is from 1 223 K to 1 273 K. The methane conversion rate is larger than 95% when the ratio of the amount of water to the amount of methane is 1.2 at a temperature above 1 223 K with the residence time up to 0.75 s.

Laser-assisted Simulation of Dose Rate Effects of Wide Band Gap Semiconductor Devices

Laser-assisted simulation technique has played a crucial role in the investigation of dose rate effects of silicon-based devices and integrated circuits,due to its exceptional advantages in terms of flexibility,safety,convenience,and precision.In recent years,wide band gap materials,known for their strong bonding and high ionization energy,have gained increasing attention from researchers and hold significant promise for extensive applications in specialized environments.Consequently,there is a growing need for comprehensive research on the dose rate effects of wide band gap materials.In response to this need,the use of laser-assisted simulation technology has emerged as a promising approach,offering an effective means to assess the efficacy of investigating these materials and devices.This paper focused on investigating the feasibility of laser-assisted simulation to study the dose rate effects of wide band gap semiconductor devices.Theoretical conversion factors for laser-assisted simulation of dose rate effects of GaN-based and SiC-based devices were been provided.Moreover,to validate the accuracy of the conversion factors,pulsed laser and dose rate experiments were conducted on GaN-based and SiC-based PIN diodes.The results demonstrate that pulsed laser radiation andγ-ray radiation can produce highly similar photocurrent responses in GaN-based and SiC-based PIN diodes,with correlation coefficients of 0.98 and 0.974,respectively.This finding reaffirms the effectiveness of laser-assisted simulation technology,making it a valuable complement in studying the dose rate effects of wide band gap semiconductor devices.

基于AMESim的柴油机SCR系统NO_(X)转化率仿真与验证

为研究车用柴油机SCR系统催化转化效率的影响因素,利用AMESim软件建立SCR系统仿真模型,结合台架试验,分析了排气温度、NO_(2)/NO_(X)值以及排气流量对系统NO_(X)转化率的影响。将不同温度下SCR系统仿真输出的NO_(X)转化率数据进行了实验验证,结果表明模型预测误差小于5%。仿真结果显示:SCR系统的NO_(X)转化率会随排气温度升高而明显增大,370~450℃为系统性能的最佳温度区间,NO_(X)转化率最大值均在88%以上。NO_(X)转化率随着NO_(2)/NO_(X)值的提高而增加,且当NO_(2)/NO_(X)值为55%~60%时达到峰值。当排气温度处于400~450℃之间时,NO_(X)转化率受排气流量影响较小,转化率稳定在90%左右。确定了SCR系统在发动机不同工况条件下的工作性能,为后续的尿素喷射控制研究提供指导依据。

人工饲料饲育家蚕5龄期的饲料效率研究

【目的】探明人工饲料饲育家蚕5龄期饲料效率与全龄桑叶育间的差异,为家蚕人工饲料的改进和饲育技术的优化提供技术支撑。【方法】以全龄桑叶育为对照(CK),研究家蚕5龄期不同饲育方式[1~5龄饲料育(5龄饲料育)、1~4龄饲料育5龄桑叶育(5龄桑叶育)]饲料效率间的差异。【结果】5龄饲料育家蚕第3天、第4天、第5天蚕体质量增量高于CK,第2天、第3天、第4天、第6天消化量低于CK,第2天、第3天、第4天、第5天体质转化率高于CK。5龄饲料育和5龄桑叶育的全茧转化效率、全茧生产效率、茧层转化效率和茧层生产效率均低于CK,5龄饲料育较CK分别低0.53百分点、0.10百分点、0.25百分点和0.08百分点,5龄桑叶育较CK分别低0.38百分点、0.14百分点、0.14百分点和0.06百分点;与5龄桑叶育相比,5龄饲料育除全茧生产效率高0.04百分点外,全茧转化效率、茧层转化效率、茧层生产效率分别低0.15百分点、0.11百分点和0.02百分点。【结论】全龄人工饲料育家蚕5龄期饲料效率低于全龄桑叶育,人工饲料饲育家蚕在饲料效率方面与全龄桑叶育有一定差距。

SO_(2)平衡转化的公式分析和相关工艺探讨

主要介绍了对SO_(2)平衡转化率公式的推导变化,使其适用于含有初始SO_(3)的烟气条件,并对温升估算公式进行了数据计算。利用推导公式和估算结果对分气预转化和循环转化工艺进行过程分析,得到了应用条件的上限和关键控制点,并且讨论了工艺适应性。

太赫兹各向异性超材料极化调控器设计与实现

电磁波极化特性会影响无线通信系统的性能,随着电磁场与微波技术的广泛应用,为满足信息传输和信息获取需求,电磁波极化特性的自由调控变得非常重要,在无线通信和雷达目标识别技术领域,都是通过改变极化状态来实现极化自由调控,随着波长的变短,相比微波通信,太赫兹通信具备频谱资源更丰富、传输速率更高的优势,但传统结构的极化调控器因存在各种缺陷,在太赫兹频段中的应用具有一定的局限性。针对这个问题,利用各向异性超材料设计了一款可用于太赫兹频段的双功能极化调控器,首先采用坐标分解法分析了器件的双功能极化调控特性,分析结果表明所设计的调控器既可以实现线极化波调控,又可以实现圆极化波调控,具备双功能调控特点;然后采用表面电流法分析了调控器的极化转换机理,仿真结果表明调控器具有4个谐振点,超材料单元结构中发生的四阶电磁谐振叠加,使得调控器工作频带宽,且极化转化效率高,在0.45~1.152 THz的频带内效率可高达90%以上;最后还分析了器件的不同参数对器件性能的影响,提出了调控器性能的优化思路和调控器的实际使用条件。通过对结构参数的分析,发现结构参数的变化会影响调控器工作时的频带宽度和谐振点的分布位置,调控器性能与自身工作频带宽度存在互斥关系,工作频带变宽,调控器性能变差,工作频带变窄,调控器性能变好,在调控器的实际应用过程中,为获取满意的调控特性,要根据具体的调控要求对结构参数进行优化调整;通过对入射角和方位角的分析,发现调控器性能对入射角的变化非常敏感,并指出在使用调控器时,它的摆放位置方向要满足入射波在调控器中的投影与调控器边沿保持平行。与现有工作相比,所设计的调控器性能更高效,结构更简单,并且双功能特性使器件的使用更加便捷和多样化,该工作为太赫兹极化转化器的发展和应用提供了理论参考。

高质量保护与转化导向下高校专利申请前评估框架体系探索

立足专利申请之初以推动成果高质量保护与转化为出发点,重点围绕技术价值高度、市场需求前景、文件撰写质量、专利布局水平4个方向探索高校专利申请前评估框架体系。提出较完善的专利申请前评估框架、评估流程及方案及基于评估结果的分级管理模式,为高校专利申请前评估提供内容全面、切实可行的评估框架体系,为推动高校专利高质量申请与高效率转化提供助力。