下腔静脉吸气扩张率在预测腹腔镜结直肠手术老年患者液体反应性的应用

目的运用多普勒超声(doppler ultrasound)测定计算下腔静脉吸气扩张率(distensibility index of inferior vena cava,dIVC)评估患者液体反应性(fluid responsiveness)。方法选取2021年8月至2023年8月期间本院择期行腹腔镜结直肠手术的老年患者100例,使用数字表法随机分组,FloTrac组50例为对照组。多普勒超声组50例为观察组。对照组运用FloTrac/Vigileo系统监测每搏量变异度(stroke volume variation,SVV),监测诱导前(T_(1))、诱导后(T_(2))、切皮时(T_(3))、手术20 min后(T_(4))、手术40 min后(T_(5))等时点的SVV值,并根据SVV值指导术中补液。观察组运用多普勒超声组测定计算dIVC(dIVC=(IVC max-IVC min)/IVC min),测定计算相应时间点的dIVC值,并根据dIVC值指导术中补液。同时记录各时点平均动脉压(mean arterial pressure,MAP)、心率(heart rate,HR)和动脉血乳酸值、记录麻醉苏醒时间、住院时间及住院费用。结果两组MAP、HR和血乳酸值差异无统计学意义(P>0.05)。两组麻醉苏醒时间和住院时间无统计学意义(P>0.05)。观察组住院费用低于对照组,差异有统计学意义(P<0.05)。结论运用多普勒超声测定计算下腔静脉吸气扩张率来评估患者液体反应性是一种无创、即时和价廉的方法,不仅与FloTrac/Vigileo评估效能类似,而且降低了患者的住院费用,值得在临床实践中推广使用。

开敞式进水池喇叭口悬空高度对吸气涡的影响

开敞式进水池是中小型泵站中重要的水工建筑,其在结构尺寸设计不合理时易出现空气吸入涡(air-en-trained vortex,简称吸气涡),严重时会发生空蚀,从而严重影响泵站安全稳定运行。在开敞式进水池中,喇叭口悬空高度C对进水池流动影响较大。本文根据泵站设计规范中给定的悬空高取值范围,采用简化的耦合水平集与流体体积方法(simple coupled level-set and volume-of-fluid method,S-CLSVOF)捕捉水气交界面,并基于分叉模型(bifurcation model,BM)进行数值模拟,分析了吸气涡随喇叭口悬空高度的变化规律,并从喇叭口处涡量及涡拟能的角度,分析了产生该规律的机理。结果表明:吸气涡的大小和进水管内相对吸气率β呈正相关,且平均相对吸气率在3×10^(-4)~7×10^(-4)之间;平均相对吸气率基本随悬空高度的增加呈下降趋势,但在C=0.35D(D为喇叭口直径)处出现突降的情况;每个方案涡量随时间的变化规律表明涡量可定量体现吸气涡的强度;通过对涡拟能输运方程中的分析,发现漩涡受到的拉伸作用决定了平均相对吸气率的变化规律,且与吸气率的变化规律一致,揭示了吸气率突降的机理。同时,分析研究结果发现,在设计进水池时,考虑到吸气涡程度与泵的安装,C=0.35D的悬空高度为最优选择。本文结论对进水池的设计具有指导意义。

阻塞性睡眠呼吸暂停综合征患者吸气肺功能及口腔阻断压的变化

目的经吸气肺功能判断阻塞性睡眠呼吸暂停综合征(OSAS)患者上气道阻塞程度,推测吸气肌群功能状态,进而探讨OSAS发病机制。方法通过对51例门诊可疑的OSAS患者进行睡眠监测及睡前和醒后的肺功能监测,观察15例鼾症和36例OSAS患者的最大吸气压(MIP)、最大呼气压(MEP)、用力吸气1 s率(FIV1/VC%)、用力呼气1 s率(FEV1/FVC%)及口腔阻断压(P0.1)变化,并进行分析。结果①鼾症组醒后MIP和P0.1有增高趋势,MEP、FIV1/VC%和FEV1/FVC%均有所降低;②OSAS组醒后数值变化趋势与鼾症组相同,但MIP、FIV1/VC%和FEV1/FVC%有显著性差异(P均<0.05);③OSAS组和鼾症组相比,睡前及醒后除FEV1/FVC%变化不明显外,MIP、MEP和P0.1均有增高趋势,FIV1/VC%有所降低,但2组间数据均无显著性差异。结论OSAS组和鼾症组醒后吸气肺功能下降,而且OSAS组醒后较睡前明显下降,提示OSAS患者可能存在吸气肌疲劳。在除外慢性心脑肺疾病情况下,上气道扩张肌功能状态在吸气肺功能改变中起主要作用。所以通过监测MIP和FIV1/VC%可以判断OSAS患者上气道阻塞程度,初步推测上气道扩张肌功能下降可能与OSAS发生有关。

Modified Malkmus band model for clear-sky atmospheric transmittance calculation

The Malkmus band model has been widely used in remote sensing and climate studies. However, its accuracy is not high. To solve this problem, a modified Malkmus band model was proposed by introducing a correction item. The HITRAN (High-resolution TRANsmission) 2008 database and the atmospheric models provided by the Air Force Geophysics Laboratory (AFGL) were used to calculate the molecular transmittances. By fitting the calculated transmittances to those by MODTRAN (MODerate resolution atmospheric TRANsmission) package with the least-squares method, the fitting coefficients of the correction item were obtained under different atmosphere models. The experimental results show that the root mean square errors (RMSE) of the modified model are significantly less than that of the traditional Malkmus band model by 1-2 orders of magnitude. In addition, the modified method is suitable for different atmospheric models and molecules.

OPTIMUM OF PRESSURE RATIOS OF MULTI-STAGE RECIPROCATING COMPRESSOR WITH PRACTICAL INTER-COOLING

The optimum pressure ratio distribution of a multistage reciprocating compressor is presented based on the assumption, i.e. the inter stage cooling is perfect and there are no pressure losses. The optimization of the two or three stage pressure ratio is analyzed in two cases of constant heat transfer rate for the inter cooler or constant inter stage inlet temperature, based on the minimum of the sum of theoretical compression power at each stage about a multi stage reciprocating compressor. Furthermore, with an example of two stage compressor the influence on the sum of the power of each stage is analyzed when practical pressure ratio deviates from the optimum value. It is obtained that under different cooling conditions the optimum pressure ratio distribution of the multi stage compression is various, and the change of the optimum pressure ratio within a small range has little influence on the sum of the power each stage. For the two stage compression, this range can be represented as ε 1=(0 96～1 06)ε 1j .

Effect of water stress on N_2O emission rate of 5 tree species

The N2O emission rates, photosynthesis, respiration and stomatal conductance of the dominant tree species from broadleaf/Korean pine forest in Changbai Mountain were measured by simulated water stress with the closed bag-gas chromatography. A total of five species seedlings were involved in this study, i.e.,Pinus koraiensis Sieb. et Zucc,Fraxinus mandshurica Rupr,Juglans mandshurica Maxim,Tilia amurensis Rupr, andQuercus mongolica Fisch. ex Turcz.. The results showed that the stomatal conductance, net photosynthetic rate and N2O emission of leaves were significantly reduced under the water stress. The stoma in the leaves of trees is the main pathway of N2O emission. N2O emission in the trees mainly occurred during daytime. N2O emission rates were different in various tree specie seedlings at the same water status. In the same tree species, N2O emission rates decreased as the reduction of soil water contents. At different soil water contents (MW, LW) the N2O emission rates ofPinus koraiensis decreased by 34.43% and 100.6% of those in normal water condition, respectively. In broadleaf arbor decreased by 31.93% and 86.35%, respectively. Under different water stresses N2O emission rates in five tree species such asPinus koraiensis, Fraxinus mandshurica, Juglans mandshurica, Tilia amurensis, andQuercus mongolica were 38.22, 14.44, 33.02, 16.48 and 32.33 ngN2O·g?1DW·h?1, respectively. Keywords Trees - N2O emission rate - Soil water stress - broadleaf/Korean pine forest - Changbai Mountain CLC number S718.55 Document code A Foundation item: This project was supported by the National Natural Science Foundation of China (No. 30271068), the grant of the Knowledge Innovation Program of Chinese Academy of Sciences (KZ-CX-SW-01-01B-10), and the Special Funds for Major State Basic Research Program of China (No. G1999043407)Biography: Wang Miao (1964-), male, associate professor in Institute of Applied Ecology, Chinese Academy of Science, Shenyang 110016, P. R. China.Responsible editor: Song Funan

Model of gas exchange dynamics for modified-atmosphere packages containing fresh produce

A model for modified-atmosphere packaging （MAP） systems containing fruits and vegetables was developed.The computer simulation was performed to predict the gas mass concentrations inside the packages and was successfully verified by experiments with yellow peaches at 5,15 and 25 ℃ using two types of packaging films.A Michaelis-Menten type respiration model with noncompetitive inhibition mechanism due to CO2 was adopted while the respiration rates were measured with an improved permeable system method suitable for either steady or unsteady state.The applicability of the model in the design of MAP systems was demonstrated with a calculation to evaluate film specification and equilibrium concentrations of O2 and CO2 in the package containing yellow peaches.

Path Analysis on the Meteorological Factors Impacting Soil Respiration Rate of Wheat Field

[Objective]The experiment aimed to study the effects of meteorological factors under different weather conditions on soil respiration. [ Method] The path analysis was used to analyze meteorological factors which influenced soil respiration of wheat field under different weather condition and at jointing stage. [ Result] In sunny day, the correlations between ground temperature at 5 cm, solar radiation, air relative humidity, air temperature and soil respiration were all at significant level while solar radiation and ground temperature at 5 cm were the major factors which influenced soil respiration. In cloudy day, solar radiation was a major factor which influenced soil respiration.[ Conclusion] The soil respiration and surplus path coefficient in sunny day were all higher than these in cloudy day, which demonstrated that except influenced by ground temperature, air temperature, solar radiation and air relative humidity, the soil respiration was also influenced by other factors especially biological factor.

Modeling of mass transfer characteristics of bubble column reactor with surfactant present

Danckwert’s method was used to determine the specific interfacial area, a, and the individual mass transfer coefficient, kL, during absorption of CO2 in a bubble column with an anionic surfactant in the carbonate-bicarbonate buffer solution and NaAsO2 as catalyst, the presence of which decreases the specific interfacial area and the individual mass transfer coefficient. The specific interfacial area and the individual mass transfer coefficient increase with increasing su- perficial gas velocity. The specific interfacial area decreases whereas the individual mass transfer coefficient increases with increasing temperature. The results of experiments were used to determine the dependence of a, kL, and kLa on the surface tension, the temperature of the absorption phase, and the superficial velocity of the gas. The calculated results from the correlation were found to be within 10% deviation from the actual experimental results.

Research on the sensitivity for the coal mine gas concentration detection by laser spectrum absorption

Because of the former gas chemistry examination method defects, tunable diode laser absorption spectrum technology （TDLAS） was used. It used an isolated absorption spectrum of the gas molecule to measure the gas absorption spectrum in order to distinguish the gas conveniently. The second harmonic （20 was measured in this system. Due to the fact which the harmonious signal is proportional to the concentration of the absorption gas, the gas concentration may be obtained through examining harmonious signal. The theoretical analysis and the experimental result indicate that under the same level of pressure, survey with the signal-to-noise ratio（SNR） of 2fsignal increases the accuracy by one order of magnitude and may reach 10 ^-3 and the sensitivity may reach the 10^-6 level compared to that of direct absorption. 5% methane density and a 30 cm absorption cell were used in the experiment. It has several advantages including high sensitivity, best resolution, and faster response and so on. The gas concentration monitoring of coal mine may be accomplished.

Study on law of raw coal seepage during loading process at different gas pressures

In order to reveal the law of raw coal seepage at different gas pressures, the gravity constant load seepage experimental system was developed and used. The law of raw coal seepage at different gas pressures with He, N2 and CO2 was investigated. The results show that, in a given state of stress during the experiment, with the increase of gas pressure, the permeability of raw coal sample prone to outburst exhibits a significantly decrease, and then exhibits an increasing trend when reaching the extreme point. The law of Klingberg coefficient related to the stress state and the gas adsorption properties was also obtained. Under the same experimental conditions, the Klingberg coefficient of He is greater than that of N2; and the Klingberg coefficient of CO2 has minimum value; so the stronger the gas adsorption is, the smaller the Klingberg coefficient of gas goes. Klinkenberg coefficient decreases with the increase of effective stress. Under the same conditions, the permeability of He is greater than that of N2; the permeability of CO2 has minimum value; so the stronger the gas adsorption is, the lower the permeability of the coal sample goes. The results have important significance in revealing the mechanism of gas seenage. Dredicting coal mine gas disaster, and gas drainage and safety nroduction.

Experimental study on effects of CBM temperature-rising desorption

To study the effects of CBM （coal bed methane） temperature-rising desorption, isothermal adsorption/desorption experiments on three ranks （anthracite, coking coal and lignite） of coal at different temperatures were designed based on the traditional CBM decompression desorption. The experimental results indicate that temperature-rising desorption is more effec- tive in high-rank coal, and ever-increasing temperature of high-rank coal reservoir can reduce the negative effects of coal ma- trix shrinkage in the process of production and improve the permeability of the coal reservoir as well. It is also revealed that the technique of temperature-rising desorption applied in higher-rank coal reservoir can enhance CBM recovery ratio. This study provided theoretical support for the application of temperature-rising desorption technique in practical discharging and mining projects, which can effectively tackle the gas production bottleneck problem.

Prediction on adsorption ratio of carbon dioxide to methane on coals with multiple linear regression

The multiple linear regression equations for adsorption ratio of CO2/CH4 and its coal quality indexes were built with SPSS software on basis of existing coal quality data and its adsorption amount of CO2 and OH4. The regression equations built were tested with data collected from some s, and the influences of coal quality indexes on adsorption ratio of CO2/CH4 were studied with investigation of regression equations. The study results show that the regression equation for adsorption ratio of CO2/CH4 and volatile matter, ash and moisture in coal can be obtained with multiple linear regression analysis, that the influence of same coal quality index with the degree of metamorphosis or influence of coal quality indexes for same coal rank on adsorption ratio is not consistent.

Study on the Relationship of Spray Rate to Air Pressure and Gravity Drop of Siphonic Nozzle

In order to further clarify the spraying performance of siphonic nozzle, the spray rate of siponic cone nozzle with aperture of 1.0 mm was determined at 15 different air pressure levels and 12 gravity drop levels, and DPS and SPSS were used to make the difference analysis and modeling, which clarified the relationship between the spray rate of the siphonic cone nozzle with aperture of 1.0 mm and air pressure and gravity drop, getting the regression equation of Y=406.854P＋ 1.904G＋77.524. The study could provide a theoretical basis for the optimization and improvement of plant protection spraying equipment.

Assessment of natural radioactivity levels in Yemen rocks

Studies on radiation level and radionuclide distribution in Yemen were studied. The samples were collected from eight locations： Ma＇rib, A1 Jawf, Sana＇a, Dhamar, Amran, Ibb, Al Bayda and Al Dalea. The purpose of this study is to provide a baseline map of radioactivity background levels in the investigated area and this study will be used as reference information to assess any change in the radioactive background level due to geological processes. The highest values of 22~ and 2~l＇h concentrations （8797.2 and 24984.1 Bq.kg＂l, respectively） were observed at A1 Jawf, region, whereas the highest average value of 40K concentration was 1561.9 Bq.kg-1. The investigation of the geological maps of the area under study showed that the surface rock outcrops consist mainly of granites, diorite, granodiorite, gneisses, and schists. All these rock types arc known to be rich in radioactive materials, which are considered natural sources for gamma radiation. The low mdiological background characterizing some Yemeni rocks could be attributed to nature of these rocks which consist of lime stone （sands and gravels）. The absorbed dose rate in air was found to be in the range between 5.40 and 45.11 nGy.h-1 depending on the geological features, and radium equivalent activity concentration was found in the range between 29.57 and 71.85 Bq.kg-1. Also the representative extcmal hazard index values for the corresponding samples were also estinlated and given.

Comparative Study of the Impact of Climate Variability on Prevalence of Urinary Schistosomiasis： Cases at Sunyani Regional Hospital and among School Children in Atronie, Sunyani

A study has been conducted to determine the impact of climate variability on Schistosoma haematobium infection among patients and school children in Sunyani between 2006 and 2009. Urine samples from the subjects were collected and examined in the laboratory using the Filteration technique for the detection and quantification ofSchistosoma haematobium eggs. The prevalence rate of urinary schistosomiasis at the Sunyani Regional Hospital for 2006, 2007, 2008 and 2009 were found to be 0.24%, 0.55%, 0.55% and 0.75% respectively while that for Methodist Junior High School in 2008 and 2009 were 60.1% and 60.3% respectively. A decrease in the relative humidity and average annual rainfall were identified as factors contributory to the increase in urinary schistosomiasis prevalence rate. The temperature values obtained throughout the study period did not have any significant effect on the prevalence rate. The temperature values, however, were those that enhanced cercarial incubation （15-35 ℃） with a resultant increase in shedding of cercariae leading to more infections among water contacts. The infection rate due to the stream Amama was 20.1%, while that due to river Tano was 36.6%. The highest risk group was children aged 15-19 years. Praziquantel was administered to treat the infection, producing a cure rate of 93%. Recognition of urinary schistosomiasis as a public health problem in Ghana is the main challenge to prevention and control of the disease.

Effect of pyrolysis temperature on properties of ACF/CNT composites

Activated carbon fiber/carbon nanotube(ACF/CNT) composites were fabricated by chemical vapor deposition(CVD) process.The effects of pyrolysis temperature on properties of ACF/CNT composites,including BET specific surface area,mass increment rate and adsorption efficiency for rhodamine B in solution,were investigated by scanning electron microscopy.The results show that the pyrolysis temperature is a key factor affecting the qualities of ACF/CNT composites.The mass increment rate and BET specific surface area sharply decrease with the increase of pyrolysis temperatures from 550 ℃ to 850 ℃ and the minimum diameter of CNTs appears at 750 ℃.The maximum adsorption efficiency of ACF/CNT composites for rhodamine B is obtained at 650 ℃.ACF/CNT composites are expected to be useful in adsorption field.

Experimental study of water effects on gas desorption during highpressure water injection

For the question of applying high-pressure water injection to increase gas extraction efficiency by increasing the permeability of water to drive gas action, an independently designed gas desorption experimental measuring device was used under the condition of external solution invasion. The law of water effect on gas desorption was obtained after water invasion through experiment for the first time. The results show that water＇s later invasion not only can make the quantity of gas dcsorp- tion greatly reduced, but also can make gas desorption end early. Therefore, when evaluating the applications of high-pressure water injection to increase gas extraction efficiency, we should take water damaging effects on gas desorption into account.

Experimental Study of the Adsorption of Mercury Vapor by Rice Husk Ash

Biomass has a tendency to adsorb mercury from the flue gas emissions from fossil fuel combustion. In this paper, we have established an experimental table of the adsorption of mercury vapor by rice husk ash according to the method described in the Chinese national standard GB/T 5009.17-1996. The experimental stud）＇ was made using rice husk ash samples of different types and at different temperatures. The results show that the carbon content of the rice husk ash was 3.81% after treatment for 1 h at 600℃, the mercury removal rate was above 95%, but the adsorption efficiency was below 20% after incineration for 4 h. The adsorption efficiency of rice husk ash treated by H202 or HCI was very low, while the adsorption efficiency was very high when rice husk ash was pyrolytically carbonized or basified by NaOH; the adsorption efficiency ofbasified rice husk ash sample was up to 98.5%. The carbon content of rice husk ash could affect the adsorption of mercury to some degree, but the internal structure of the rice husk ash samples was a more important factor for adsorption.

A Technical Feasibility Study on Odorous Eliminator

An odorous eliminator consists of the three systems： Firstly, an oxidation system by ozone gas obtained from an ozone generator, type corona discharge was used as an oxidizing agent. This gas has got enough concentration to eliminate malodor and poisonous gas especially H2S. Alternatively, the excess concentration of ozone gas could be used for disinfection into an oxidized bag; Secondly, the odorous was trap and disinfection system by acid or base and water for disinfection air pollution from incomplete oxidation before transfer to an adsorption system; Finally, the adsorption system which is contained high efficiency activated carbon was used as an adsorbent. This research was undertaken to study the method of improving the adsorption capacity of coconut shell-based activated carbon for H2S by surface oxidation and metal addition techniques. The carbon sample treated with 6.0 M HNOs and Zn impregnation gave the highest adsorption capacity for H2S, with increased adsorption efficiency of 230% over that of the untreated sample at 45 ℃. The maximum increase of 180% adsorption efficiency over that of untreated sample was observed for the O3 oxidized sample impregnated with Zn.