Low-pressure pneumoperitoneum with abdominal wall lift in laparoscopic total mesorectal excision for rectal cancer:initial experience

AIM To evaluate the safety and feasibility of a new technology combining low-pressure pneumoperitoneum(LPP) and abdominal wall lift(AWL) in laparoscopic total mesorectal excision(TME) for rectal cancer.METHODS From November 2015 to July 2017,26 patients underwent laparoscopic TME for rectal cancer using LPP(6-8 mm Hg) with subcutaneous AWL in Qilu Hospital of Shandong University,Jinan,China.Clinical data regarding patients' demographics,intraoperative monitoring indices,operation-related indices andpathological outcomes were prospectively collected.RESULTS Laparoscopic TME was performed in 26 cases(14 anterior resection and 12 abdominoperineal resection) successfully,without conversion to open or laparoscopic surgery with standard-pressure pneumoperitoneum.Intraoperative monitoring showed stable heart rate,blood pressure and paw airway pressure.The mean operative time was 194.29 ± 41.27 min(range:125-270 min) and 200.41 ± 20.56 min(range:170-230 min) for anterior resection and abdominoperineal resection,respectively.The mean number of lymph nodes harvested was 16.71 ± 5.06(range:7-27).There was no positive circumferential or distal resection margin.No local recurrence was observed during a median follow-up period of 11.96 ± 5.55 mo(range:5-23 mo).CONCLUSION LPP combined with AWL is safe and feasible for laparoscopic TME.The technique can provide satisfactory exposure of the operative field and stable operative monitoring indices.

Process Optimization for AZ91 Mg-alloy Low-pressure EPC Process

The influence of a key process variable on the mold filling characteristics of AZ91 Mg-alloy was studied in the low pressure EPC process.The applied flow quantity of insert gas from 1 to 5 m~3/h associated with the pressurizing rate in the low pressure EPC casting process was considered for rectangle and L-shape plate casting. The experimental results show that there is an optimal flow quantity of insert gas for good mold filling characteristics in AZ91 Mg-alloy low-pressure EPC process. The optimal flow quantity of insert gas for the specimens is 3 to 4 m~3/h. Either less or higher than the optimal flow quantity of insert gas would lead to misrun defects or folds, blisters and porosity defects. The practice of hub casting confirmed that the low-pressure EPC process with an optimal processing variable exemplified as 4 m~3/h gas flow quantity was capable of producing complicated magnesium castings without misrun defects.

Numerical simulation and analysis of lithium plasma during low-pressure DC arc discharge

Alkali metal DC arc discharge has the characteristics of easy ionization,low power consumption,high plasma temperature and ionization degree,etc,which can be applied in aerospace vehicles in various ways.In this paper,we calculate the physical property parameters of lithium vapor,one of the major alkali metals,and analyze the discharge characteristics of lithium plasma with the magnetohydrodynamic(MHD)model.The discharge effects between constant current and voltage sources are also compared.It is shown that the lithium plasma of DC arc discharge has relatively high temperature and current density.The peak temperature can reach tens of thousands of K,and the current density reaches 6 x 107 A m 2.Under the same rated power,the plasma parameters of the constant voltage source discharge are much higher than those of the constant current source discharge,which can be used as the preferred discharge mode for aerospace applications.

An Experimental and Numerical Study on the Cleaning of Pleated Bag Filters Using Low-Pressure Pulsed-Jets

Pulsed-jet cleaning is recognized as the most efficient method to regenerate bag dust collectors traditionally used in industrial processes to control the emission of particulates.In this study,non-woven needle felt filter bags with and without a film coating material have been analyzed considering different geometries(different number N of pairs of pleated filter bag sides)in the frame of dedicated low-pressure pulsed-jet cleaning experiments.The flow structure inside the bag and the response characteristics of its wall have also been analyzed numerically through a computational fluid-dynamics/structural-dynamics(CFD-CSD)unidirectional fluid-solid coupling method.As shown by the experiments,the peak pressure(P_(0))on the wall of the filter bag with N=8 and 12 is higher,which indicates dust can be removed more effectively in these cases.The peak pressure on the wall increases first and then decreases along the direction of the bag length,while the peak pressure of the pleated filter bag with nonwoven needled felt film coating is greater than that without film coating.A comprehensive analysis of the time variation of acceleration,deformation,strain,stress and other factors,has led to the conclusion that the pleated filter bag with N=12 would be the optimal choice.

Neutrons in a nanosecond low-pressure discharge in deuterium

Stable neutron generation with a yield of ~1.2×10^(4) neutrons per pulse was obtained during d(d,n)^(3)He reaction initiated by the high-voltage nanosecond discharge in a gap with a potential tungsten cylinder(anode)and a grounded deuterated zirconium plate(cathode)filled with deuterium at a pressure of ~10^(2) Pa.Estimated duration of the neutron pulse was ~1.5 ns.Less intensive neutron emission was registered without deuterated plate.Splashing of material of the tungsten electrode was observed during the high-voltage nanosecond discharge in the deuterium,hydrogen,helium and argon at pressures of 10^(2)-10^(4) Pa.

A LOW-PRESSURE AND ONE-STEP METHOD FOR THE SYNTHESIS OF ALKYLIDYNETRICOBALT NONACARBONYL CLUSTERS:RCCo_8(CO)_9

Metal clusters RCCo_3(CO)_9(R-H,C1,Br,CH_3,Ph) were prepared in 18.8-57.3% yields from the reaction of cobalt(Ⅱ)salt and RCX_a under mild PTC conditions(latm CO,25℃).The cobalt salt was reduced to Co(CO)_4 in the presence of Na_3S_2O_4.

The mechanism study of low-pressure air plasma cleaning on large-aperture optical surface unraveled by experiment and reactive molecular dynamics simulation

Low-pressure air plasma cleaning is an effective method for removing organic contaminants on large-aperture optical components in situ in the inertial confinement fusion facility.Chemical reactions play a significant role in plasma cleaning,which is a complex process involving abundant bond cleavage and species generation.In this work,experiments and reactive molecular dynamics simulations were carried out to unravel the reaction mechanism between the benchmark organic contaminants of dibutyl phthalate and air plasma.The optical emission spectroscopy was used to study the overall evolution behaviors of excited molecular species and radical signals from air plasma as a reference to simulations.Detailed reaction pathways were revealed and characterized,and specific intermediate radicals and products were analyzed during experiments and simulation.The reactive species in the air plasma,such as O,HO_(2)and O_(3)radicals,played a crucial role in cleaving organic molecular structures.Together,our findings provide an atomic-level understanding of complex reaction processes of low-pressure air plasma cleaning mechanisms and are essential for its application in industrial plasma cleaning.

Simulation of propagation of the HPM in the low-pressure argon plasma

The propagation of the high-power microwave（HPM） with a frequency of 6 GHz in the lowpressure argon plasma was studied by the method of fluid approximation.The two-dimensional transmission model was built based on the wave equation,the electron drift-diffusion equations and the heavy species transport equations,which were solved by means of COMSOL Multiphysics software.The simulation results showed that the propagation characteristic of the HPM was closely related to the average electron density of the plasma.The attenuation of the transmitted wave increased nonlinearly with the electron density.Specifically,the growth of the attenuation slowed down as the electron density increased uniformly.In addition,the concrete transmission process of the HPM wave in the low-pressure argon plasma was given.

Microstructure and Properties of Low-pressure Cold Sprayed Al-based Composite Coatings on Magnesium Alloy Surface

Pure Al and Al-30%Al_(2)O_(3)composite coatings are prepared on the surface of AZ31B magnesium alloy by low-pressure cold spraying.The morphology and structure of the coatings are analyzed by scanning electron microscope (SEM),energy dispersive spectroscopy (EDS),and X-ray diffraction (XRD),and the effects of the addition of Al_(2)O_(3)on the microstructure of the Al-based coatings are discussed.The mechanical properties and corrosion resistance of the coatings are fully evaluated by the micro-hardness tester,electronic tensile machine,and electrochemical workstation.The results show that the coating structure is more uniform and denser,and the porosity is significantly reduced after the addition of Al_(2)O_(3).The interfaces between the coatings and the magnesium alloy substrate are distinct,and the coatings and the substrate are mechanically combined.Compared with the pure Al coating,the microhardness of the Al-Al_(2)O_(3)composite coating is increased to 61.1 HV_(0.2),and the bonding strength reaches above 53.1 MPa.The self-corrosion potential of the two coatings is higher than that of the magnesium alloy,and the self-corrosion current density is significantly lower than that of the magnesium alloy substrate.The Al-based coatings prepared by low-pressure cold spraying have high hardness,good bonding strength,and good corrosion resistance,which can be used for the repair and protection of magnesium alloy structural parts.

常见化学烧伤的救治方法

随着新化工产品的不断涌现,化学烧伤在工作中发生率明显升高,化学烧伤的损伤一般发生在工作环境中,严重程度和化学品的性质、剂量、浓度、接触时间和接触面积、急救措施等有着密切的关系。目前较多医疗机构内缺乏化学烧伤救治的标准操作流程,本文通过介绍常见局部化学烧伤的处理的基本原则,为临床治疗提供参考。

硅钢推拉式酸洗机组酸洗能力提升与效果

随着市场对硅钢需求的增加,原工序中的酸洗产能已不能满足生产需要,因此对漂洗段及循环系统、酸洗槽进行了改进。改进后产线的酸洗能力提高,酸槽酸液浓度梯度优化后,酸洗能力进一步改善,同时,设备和工艺的改进也降低了能耗、减少了机组的废液排放。

海带漂烫-盐渍加工过程中碘形态含量变化规律

通过测定漂烫水、漂洗水、盐渍水以及剩余海带中碘离子(I^(-))、碘酸根(IO_(3)^(-))、一碘酪氨酸(mono-iodotyrosine,MIT)和二碘酪氨酸(diiodotyrosine,DIT)4种碘形态的含量,研究海带漂烫-漂洗-盐渍过程中碘形态的溶出规律。鲜海带、漂烫海带、一次漂洗海带和二次漂洗海带I^(-)含量在1689.41~8753.24 mg/kg,IO_(3)^(-)含量在42.67~442.00mg/kg之间,MIT和DIT含量分别在698.22~861.90mg/kg和123.97~158.67mg/kg之间。其中漂烫过程I^(-)、MIT和DIT溶出率最高,分别为(64.38±2.99)%、(19.35±0.97)%和(6.55±0.53)%。随着海带加入量的增大,除漂烫水的DTT外,所有水体中I^(-)、MIT和DIT含量整体上呈先增大后趋于平稳的趋势,所有水体中IO_(3)^(-)含量均呈上升趋势。随海带漂烫颗数增加,I^(-)溶出率先降低后基本保持不变,与鲜海带相比,第1颗盐渍海带的I^(-)含量降低(80.72±2.66)%,碘主要以I^(-)的形式释放到水体中,并且在漂烫过程中释放量最大。

内镜终末漂洗水的晨间排放时间及其管路消毒频率研究

目的根据微生物培养结果,探究内镜中心终末漂洗水的最佳晨间排放时间及其管路消毒频率。方法监测江苏省某院内镜中心内镜终末漂洗水不同晨间排放时间及其管路细菌菌落数。对内镜室2个终末漂洗水采样端口排放0、1、3、5、7 min后分别取水样(各100 mL,连续监测35 d,每时间组各70份标本)进行微生物检测,探究最佳排放时间。根据确定的最佳晨间排放时间,探究纯化水管路消毒的最佳频率。管路消毒后每日从2个采样口采样2份,连续监测5周,共70份标本。结果终末漂洗水不同晨间排放时间点采样监测,0、1、3、5、7 min组的菌落中位数分别为745.00(373.00,1452.50)、150.00(96.75,235.75)、44.00(38.00,48.00)、12.00(5.00,18.00)、6.00(4.00,9.00)CFU/100 mL。除5 min组与7 min组间差异无统计学意义(P>0.05)外,其他各组之间差异均有统计学意义(均P<0.05)。0、1、3、5 min组的中位数>10 CFU/100 mL,而7 min组的中位数<10 CFU/100 mL,达到合格范围,确定排放时间为7 min。管路消毒后不同时间点(消毒后1、2、3、4、5周)采样,终末漂洗水细菌菌落数平均值分别为(4.21±0.86)、(4.43±0.71)、(6.00±0.56)、(6.43±0.45)、(13.57±1.03)CFU/100 mL,细菌菌落数合格率分别为100%、100%、100%、100%、28.57%。纯化水管路消毒后不同时间点采样,终末漂洗水细菌菌落数比较,差异存在统计学意义(P<0.001),纯化水管路消毒后1、2、3、4周与5周之间差异均有统计学意义(均P<0.05),其余各组差异均无统计学意义(均P>0.05),纯化水管路最佳消毒频率为每4周一次。结论残留在末端管路内的终末漂洗水存在一定程度的污染,建议晨间排放7 min后再开始用水工作,每隔4周对纯化水管路进行消毒。

RINs简介及对炼油商的影响

2013年后RINs交易价格突然大幅上扬,成为业内关注的焦点问题。本文描述了可再生燃料标识码RINs的概念、形成和交易过程,RFS法规对生物燃料调合目标量的要求,并分析了RINs价格大幅上涨的原因及对炼油商的影响。

4种鱼糜加工漂洗液回收蛋白对罗非鱼鱼糜凝胶特性与质构的影响

目的探究4种回收水溶性蛋白对罗非鱼鱼糜凝胶特性及质构的影响。方法分别将等电点沉降法回收蛋白、海藻酸钠单一絮凝剂回收蛋白、壳聚糖单一絮凝剂回收蛋白和海藻酸钠-壳聚糖复合絮凝剂沉降回收蛋白以0%、5%、10%、15%、20%掺入罗非鱼鱼糜制备鱼肠,比较各样品在凝胶强度与全质构分析(texture profile analysis,TPA)参数上的差异,包括硬度、胶着性、咀嚼性、内聚性与弹性。结果4种回收蛋白替代会对凝胶强度产生不利影响,通过等电点沉降法回收的蛋白对凝胶强度的影响最大,凝胶强度持续下降,最低达1708g·mm;以复合絮凝剂回收蛋白的掺入对原凝胶强度的影响最小,通过替代5%鱼糜,凝胶强度降为3833 g·mm。当用壳聚糖单一絮凝剂回收蛋白掺入5%时,与原鱼糜制品的TPA参数最接近,表现为硬度2505 g,胶着性1788 g,咀嚼性192.3 mJ,且内聚性和弹性也没有表现出明显差异。结论这4种回收蛋白均以5%的添加量替代罗非鱼鱼糜时,制品凝胶强度在企业的可接受线性范围内,综合凝胶强度与TPA参数,以壳聚糖单一絮凝剂回收的蛋白替代产生的影响最小,可为回收鱼糜蛋白这一资源的研究与再利用技术开发提供参考依据。

乙炔发生器排渣过程的自动化控制

针对乙炔发生器排渣操作频繁、操作强度高、人为误操作多的问题,进行了排渣过程自动化改造,增加了自动排渣程序,实现了一键排渣;同时优化了排渣工艺,增加了排渣前反冲洗步骤,减少了排渣时VOCs外排大气造成的环境污染和可燃气体探头报警问题。

Controlling secondary flow in high-lift low-pressure turbine using boundary-layer slot suction

The design of high-lift Low-Pressure Turbines(LPTs)causes the separation of the boundary layer on the suction side of the blade and leads to a strong secondary flow.This present study aims to minimize secondary losses through endwall slot suction and incoming wakes in a front-loaded high-lift LPT cascade with Zweifel of 1.58 under low Reynolds number of 25000.Two slotted schemes for the boundary layer of the endwall were designed(Plan A and Plan B),and the effects of suction mass flow on secondary flow were studied.The underlying physics of the endwall boundary layer of the suction and secondary flow under unsteady wakes was discussed.The results show that slot suction at the endwall boundary layer can significantly suppress the secondary flow by removing low-momentum fluids.Plans A and B significantly reduced the secondary kinetic energy by 44.2%and 36.9%,respectively,compared with the baseline cascade at the suction mass flow ratios of 1%.With an increase in the mass flow ratio of suction,the secondary flow was gradually reduced in both Plans A and B.It is more beneficial to control the secondary flow to destroy the intersection of the pressure side and suction side of the horseshoe vortex before it develops into a passage vortex.Under unsteady wakes,the combined effects of incoming wakes and endwall boundary layer suction can further suppress the secondary flow at the suction mass flow ratios of 2%for Plan A,because the positive and negative vorticity inside upstream wakes accelerated the mixing of the main flow and secondary flow and thus increased the energy of secondary vortices.

LPCS Ni-Zn-Al_(2)O_(3) Intermediate Layer Enhanced SPS NiCr-Cr_(3)C_(2) Coating with Higher Corrosion and Wear Resistances

The double-layer NiCr-Cr_(3)C_(2)/Ni-Zn-Al_(2)O_(3) coatings with sufficient corrosion and wear resistance were prepared on low carbon steel substrates.The intermediate layers Ni-Zn-Al_(2)O_(3) were fabricated by using low-pressure cold spray (LPCS) method to improve the salt fog corrosion resistance properties of the supersonic plasma spray (SPS) NiCr-Cr_(3)C_(2) coatings.The friction and wear performance for the double-layer and single-layer NiCr-Cr_(3)C_(2) coatings were carried out by line-contact reciprocating sliding,respectively.Combined with the coating surface analysis techniques,the effect of the salt fog corrosion on the tribological properties of the double-layer coatings was studied.The results showed that the double-layer coatings exhibited better wear resistance than that of the single-layer coatings,due to the better corrosion resistance of the intermediate layer;the wear mass losses of the double-layer coatings was reduced by 70%than that of the single layer coatings and the wear mechanism of coatings after salt fog corrosion conditions is mainly corrosion wear.

羧甲基壳聚糖与复合盐单次漂洗对白鲢鱼糜品质的影响

为减少鱼糜漂洗用水并保持鱼糜品质,利用氯化钾(KCl)、柠檬酸钠与羧甲基壳聚糖(CMC)对鱼糜进行单次漂洗。在单因素实验中,当漂洗液中KCl质量分数为1.0%时,凝胶强度为312.28 g·cm,白度为75.28,达到最大值,显著改善其质构特性与持水性(80.98%)。当漂洗液中柠檬酸钠质量分数为0.15%时,凝胶强度为300.78 g·cm,白度为75.34,达到最大值,显著改善其质构特性与持水性(85.55%)。当漂洗液中CMC质量分数为1.2%时,凝胶强度为348.39 g·cm,白度为73.89,达到最大值,显著改善质构特性与持水性(85.48%),且持水性随CMC含量增大而递增。在此基础上进行组合漂洗1次,结果发现采用1.0%KCl+0.15%柠檬酸钠+1.2%CMC的漂洗方法改善效果最佳,漂洗后的鱼糜凝胶强度为365.62 g·cm,白度为75.31,持水性为87.12%,鱼糜得率为75.41%。与工业中的3次漂洗法相比,除了鱼糜凝胶强度下降10.55%,其它指标都显著提升。该单次漂洗方法可有效改善鱼糜品质,减少漂洗次数,且漂洗耗水量约为工业漂洗的1/3。

Analysis of the Heavy Rainfall Process in Mangshi City on August 8, 2023

On August 7,2023,Mangshi City,Dehong Prefecture experienced a local heavy rainstorm,and the geological disaster caused by the heavy rainfall caused casualties and property losses.Based on the real-time observation data of automatic stations,Doppler weather radar detection and meteorological risk warning products,the disaster situation,social impact,forecast and early warning service,causes of heavy precipitation and forecast and early warning inspection were summarized and analyzed.The results show that the heavy rainfall was prominent locally,lasted for a long time and accumulated a large amount of rainfall.There were biases in model products,and it was difficult for forecasters to make subjective corrections in complex terrain.The analysis ideas and focus points of heavy rainfall forecast,the improvement ideas and technical schemes of forecast deviation,and the improvement ideas and suggestions of services were summarized.It provides a reference for the forecast and early warning of severe weather in the future.