One-step green method to prepare progressive burning gun propellant through gradient denitration strategy

Gradiently denitrated gun propellant(GDGP)prepared by a“gradient denitration”strategy is obviously superior in progressive burning performance to the traditional deterred gun propellant.Currently,the preparation of GDGP employed a tedious two-step method involving organic solvents,which hinders the large-scale preparation of GDGP.In this paper,GDGP was successfully prepared via a novelty and environmentally friendly one-step method.The obtained samples were characterized by FT-IR,Raman,SEM and XPS.The results showed that the content of nitrate groups gradiently increased from the surface to the core in the surface layer of GDGP and the surface layer of GDGP exhibited a higher compaction than that of raw gun propellant,with a well-preserved nitrocellulose structure.The denitration process enabled the propellant surface with regressive energy density and good progressive burning performance,as confirmed by oxygen bomb and closed bomb test.At the same time,the effects of different solvents on the component loss of propellant were compared.The result showed that water caused the least component loss.Finally,the stability of GDGP was confirmed by methyl-violet test.This work not only provided environmentally friendly,simple and economic preparation of GDGP,but also confirmed the stability of GDGP prepared by this method.

Solid-phase extraction of trace Au(Ⅲ) with SDG and determination by the catalytic spectrophotometric method

The new catalytic kinetic spectrophotometric method for Au（III） determination was developed and validated. It was based on the catalytic effect of gold on the oxidation of sudan red III by ammonium peroxodisulfate （（NH4）2S2O8） with nitrilo triacetic acid as an activator in microemulsion and H2SO4 medium. Under optimum conditions, there was the linearity of the calibration curve in the concentration range from 0 to 20 μg/L Au（Ⅲ） at 520 nm. The relative standard deviation was 3.0% with a correlation coefficient of 0.9986. The detection limit achieved was 9.75 × 10^-5 μg/mL. A new method using a column packed with sulfhydryl dextrose gel （SDG） as a solid-phase extractant has been developed for the preconcentration and separation of Au（Ⅲ） ions. The method has been applied to the determination of trace gold with satisfactory results.

EFFECT OF BURNING METHOD ON THE FORMING PROCESSES OF PORTLAND CEMENT CLINKER

The forming temperature of Clinker melt underdifferent burning conditions has been studied by appearance examination and thermal shrinker determination, and the viscosity of melt has been discussed by studying the coordination number of Al^(3+) and Fe^(3+) in cement clinker burned by different method with x^- ray fluorescence analysis and Moss- bauer spectroscopy. The results show that the clin- ker melt under rapid burning may come into exis- tence at lower temperature and It's viscosity is lower. So the forming processes of clinker may be different at rapid burning from ordinary burning. They are probably an important factor to promote the formation of clinker burned at lower temperature with rapid burning method.

Neutron excess method for performance assessment of thoriumbased fuel in a breed-and-burn reactor with various coolants

Fertile fuel, such as thorium or depleted uranium, can be bred into fissile fuel and burnt in a breed-andburn(B&B) reactor. Modeling a full core with fertile fuel can assess the performance of a B&B reactor with exact quantitative estimates, but costs too much computation time. For simplicity, performing the recently developed neutron balance method with a zero-dimensional(0-D)model can also provide a reasonable result. Based on the0-D model, the feasibility of the B&B mode for thorium fuel in a fast reactor cooled by sodium was investigated by considering the(n, 2n) and(n, 3n) reaction rates of fuel and coolant in this work, and compared with that of depleted uranium fuel. Afterward, the performance of the same thorium-based fuel core, but cooled by helium, lead-bismuth, and FLi Be, respectively, is discussed. It is found that the(n, 2n) and(n, 3n) reactions should not be neglected for the neutron balance calculation for thorium-based fuel to sustain the B&B mode of operation.

Solid-Phase Preparation and Characterization of Chitosan

Chitosan was prepared with stressing method by blending chitin and solid alkali in a single-screw extruder at given temperature and characterized by potentiometric titration, gel permeation chromatography (GPC), infrared spectrum (IR) and carbon-13 magnetic resonance sperctroscopy ( 13 C NMR) . Chitosan with a deacetylation degree (DD) of 76.1% was obtained at a mass ratio 0.2∶1∶1 for H_ 2 O/chitin/NaOH at 160 ℃ for 12 min. Compared to conventional solution method(usually 1∶10 for chitin/NaOH), the alkali assumption greatly decreased. Molecular weight of chitosan obtained by solid-phase method(S3,M_w1.54×10 5 ) was lower than that obtained by suspension method(Y2,M_w3.34×10 5 ). During deacetylation, molecular weight decreased with high reaction temperature and long reaction time but remained same at different initial ratios of NaOH/chitin. It might be concluded that degradation of chitosan was caused by breakout of the main chain of the oxidized chitosan catalyzed by alkali during the deactylation. IR and 13 C NMR showed that structures of chitosans prepared by solid-phase method were not changed.

基于Burn-in和D8法的岩溶区流域边界提取研究

以中国西南岩溶区典型流域——澄碧河流域为研究对象,采用Burn-in法对流域的DEM进行预处理,进而优化流域边界。在此基础上通过径流模拟检验岩溶区流域划分结果的合理性。结果表明,Burn-in法处理后,提取出流域面积为2035.26 km^2(大于处理前的1558.14 km^2),流域验证期月径流模拟的纳什效率系数达到0.83(优于处理前的0.60)。结合研究区的径流模拟结果与流域水系特征,认为Burn-in法处理后的流域划分成果更为合理。

改性轻烧氧化镁细粉的抗水化性能

为解决MgO的易水化问题,以乙二醇和聚异丁烯顺丁烯酸酐共聚物(ISOBAM-104)为改性剂,经混合、研磨、热处理对轻烧MgO细粉进行了改性处理,研究了ISOBAM-104的加入量(分别加入MgO细粉质量的0、1%、3%、5%、7%、9%)和热处理温度(200、250、300℃保温1 h)对改性后轻烧MgO的物相组成、显微结构及抗水化性的影响。结果表明:当ISOBAM-104的加入量为MgO细粉质量的7%时,经250℃保温1 h热处理后改性轻烧MgO的水化质量增加率最低,为2.2%。ISOBAM-104/乙二醇改性轻烧MgO细粉抗水化性能提高的主要原因是其表面生成了醇镁化合物及疏水性亚酰胺基团。

蜡烛火焰振荡行为的实验探究

燃烧的火焰在一定条件下会呈现出时间上的周期振荡行为,但人们对其背后的动力学机制一直不是很清楚。本文首先利用纹影法对蜡烛的火焰振荡行为进行了实验研究,发现随着火焰尺寸的增加火焰首先从平稳燃烧变为振荡燃烧,之后火焰的振荡频率会逐渐降低。通过简化的燃烧动力学模型,文中进一步对蜡烛火焰的振荡行为进行了数值和理论分析,发现火焰的振荡频率密切依赖于燃料的供应速率和火焰的体积。随着燃料供应速率和火焰体积的增大,火焰首先经历了一次霍普夫分岔进而从平稳燃烧变为振荡燃烧,之后火焰的振荡频率逐渐降低。理论分析结果与实验结论定性吻合。

不同堵塞条件下硬岩隧道直眼掏槽破岩效果数值模拟研究

为研究不同堵塞材料及堵塞长度对硬岩隧道直眼掏槽爆破效果的影响,依托工程实例,采用ANSYS/LS一DYNA仿真模拟软件建立三维数值模型,对5种不同堵塞条件展开研究。根据数值模型计算结果,对掏槽区域爆破裂纹拓展情况进行了定性分析,对典型部位的岩石受力情况进行了定量分析。结果表明:1)自由面岩石主要受拉应力作用产生裂纹,炮孔堵塞使得爆炸荷载整体作用时间延长,致使自由面上裂纹更加密集;2)位于炸药和堵塞材料之间空气段附近的围岩,先受爆炸应力波作用岩石被压碎,后受力在拉压应力之间多次转化,致使裂纹被放大,结合爆生气体发挥的“气楔”作用,使得裂纹几乎贯穿模型截面;3)炮孔堵塞后炸药段周围岩石受到的爆生气体作用应力值显著提升,比不堵塞时的炸药段周围岩石峰值应力高出1.31~2.34倍,炮孔堵塞使得爆生气体持续稳定发挥作用时的压应力值提高3.70~4.70倍;4)以黏土和水作为堵塞材料时,堵塞长度为40cm的直眼掏槽破岩效果优于堵塞长度为60cm的效果。研究成果可为优化硬岩隧道直眼掏槽爆破参数提供理论基础。

两种换药方式对降低经烧伤创面置股静脉管感染率的效果观察

目的 探究不同换药方式对经烧伤创面置股静脉管感染率的效果,进一步探究经烧伤创面置股静脉管的换药规范和标准。方法 选取2022年3月—2023年2月本院收治的烧伤创面置股静脉管患者60例为研究对象,随机将患者分成观察组(30例)和对照组(30例)。其中,观察组使用规范换药方式,对照组使用常规换药方式。对两组的感染率实施对比。结果 观察组总感染率明显小于对照组,两组数据具备统计学意义(P<0.05)。观察组总满意率明显大于对照组,两组数据有统计学意义(P<0.05)。结论 规范换药方式可降低导管感染发生率,有效提高经烧伤创面股静脉置管期间患者护理质量,提升期间的安全性,增强患者对标准用药的满意度,值得临床推广。

油气储运中油气回收技术的应用

在油品装车、装船过程中,大量的挥发性油气会进入大气,导致资源的浪费和周边环境的污染。为了解决这个难题,将对罐区现有设备与其他成熟的技术进行对比分析,阐述各项技术的优缺点及我公司现有设施的使用情况。

葡萄糖仿生纤维定性鉴别方法探讨

为了找出定性鉴别葡萄糖仿生纤维的方法,选取手感目测、燃烧、显微镜观察、化学溶解、熔点法和红外光谱6种纤维定性鉴别方法,根据每种方法的特点选取4种纤维进行对比分析,尝试找出鉴别葡萄糖仿生纤维的简便方法。通过试验分析得出:葡萄糖仿生纤维的鉴别需要结合色泽、纤维特殊燃烧现象、熔点差异和显微镜观察,可以将化学性能相近的聚乳酸纤维排除,选用二氯甲烷试剂或红外光谱法进行辅助确认,几种方法相互验证可以准确定性鉴别葡萄糖仿生纤维。

燃烧法沥青含量测试仪校准方法的研究

沥青含量是影响沥青混凝土路面施工质量的关键指标,其准确、快速的测定可为施工控制提供科学、准确的数据支撑。本文通过对燃烧法沥青含量测试仪校准方法进行研究,提出改进现有的检定过程,以及对主燃烧室和二次燃烧室的温度示值误差、升温时间、称量示值误差、称量重复性主要参数进行校准的方案,并阐述了该测试仪校准各参数时所需的测量标准、校准方法及不确定度评定,为检测和计量校准提供了参考。

多种物探方法在昌吉硫磺沟地区煤田火烧区勘查中的应用研究

煤层自燃不仅影响周边生态环境,也存在较大的安全隐患。以昌吉硫磺沟地区为例,根据煤层自燃所产生的物理化学变化与周围岩石产生的物性差异,运用无人机红外成像、无人机航空磁测和自然电位法开展勘查,通过对三种方法的成果分析与解译,圈定煤田火烧区的范围,为后期治理等工作提供基础资料。

The New Approach to the Diagnostics and Treatment of Endogenous Intoxication in Patients with Burn Injury

Background: The main causes of mortality in patients with burn injury are the development of systemic inflammatory process, multiple organ failure and septic complications. The aim of the research: Improvement of diagnostic and therapeutic approaches to the detection and elimination of endogenous intoxication in patients with burn injury. Materials and methods: The main study group consisted of 19 patients and the comparison group—of 10 patients with burn injury. 92 blood serum (BS) samples of the patients of the main group were tested, using the method of fluorescence spectroscopy (MFS). The advanced therapeutic tactics were proposed for the patients of both groups. The control group consisted of 40 healthy individuals (donors). BS of these patients was also tested using MFS. Results: Patients with burn injury have endogenous intoxication in their blood. The effective concentration of albumin is reduced in patients with burn injury due to the blockage of albumin binding centers by bacterial metabolism products. Fluorescence spectra (FS) of BS in patients with burn trauma and donors were obtained and investigated. Based on MFS results, an improved treatment regimen using infusion of albumin solution was proposed. Conclusions: An improved technique for the management of patients with burn injury is based on the use of MFS for the diagnostic evaluation of endogenous intoxication in them. The idea of pathological changes in albumin molecules in patients with burn injury is pathogenetically substantiated by the successful use of infusion of albumin solution in these patients on the basis of the MFS.

冲量法固体推进剂燃速测试原始数据有效性判定

为了定义并明确冲量法燃速测试的应用边界,通过对“推进剂药柱点火不同步”、“存在侵蚀”、“推进剂药柱同心度不好”3种情况下终了燃面偏离设计值的分析,提出以最大压强尤其是最大推力处的下降速率作为冲量法燃速测试数据有效性的判据,该判据同时解决了“裸露的推进剂药柱表面同步点火”无法评判的问题。根据燃烧室在无加质条件下燃气质量的变化规律,计算获得燃烧室压强随时间的改变趋势,与试验压强-时间曲线进行对比,提出数据有效性因子K,给出了原始数据有效性的数值判定方法。研究表明,当数据有效性因子K=1~1.2时,冲量法燃速测试结果与恒压发动机燃速测试结果一致性较好,数据有效。同时验证了喷管烧蚀会影响冲量燃速测试的压强范围,但不影响燃速测试结果。

时移航空磁法在煤矿火烧区探测中的应用研究

煤层自燃后导致上覆地层中的矿物质形成磁性矿物,呈现高磁异常特征,为磁法探测火烧区提供了物性前提。航空磁法在煤矿火烧区探测取得了良好效果,但无法有效探测煤层火烧区发展趋势。针对上述问题,在航空磁法的基础上,提出了时移航空磁法,即在一定时间间隔内开展2次航空磁法探测,根据2次航磁反演结果之间的差值,判断煤矿火烧区随时间的变化特征,达到有效探测煤矿火烧区分布范围及发展趋势的目的。为兼顾起伏地区的地形拟合效果和反演计算效率,采用规则与非规则复合网格剖分方法,即在地表起伏的地方采用四面体非规则网格剖分,在地表以下的地方采用六面体规则网格剖分。结果表明,规则与非规则复合网格剖分方法不仅满足起伏地形条件下对反演精度的要求,而且反演计算效率较四面体非规则网格剖分方法提升了近6倍。基于实际地质情况建立了数值模型,并利用无人机和航空光泵磁力仪进行实际测试。数值模拟和实测结果表明,时移航空磁法能够准确探测火烧区分布范围及火烧区随时间变化的发展趋势,可为煤矿开展防灭火工作提供依据。

基于增强型燃烧指数的中小型火烧迹地自动提取研究

火烧迹地提取是林火灾后评估和重建的重要内容。中小型森林火灾分布范围广,发生频率高,人工判识耗时耗力。卫星遥感能大范围、高时效地提取火烧迹地,但不同区域地表环境和气候条件差异使得其自动提取难度大。以浙江省2019—2021年7个中小型林火为研究对象,基于Sentinel-2和Landsat-8卫星影像开展火烧迹地自动提取研究。首先,利用实测信息进行火场模糊定位,结合谷歌地球引擎完成火灾定位和卫星数据获取;其次,基于卫星影像多波段反射率,利用云过滤、大津法(Ostu)、指数分割、图像膨胀等预处理识别和剔除云、水体和非林地等干扰信号。最后,通过燃烧面积指数和归一化燃烧指数计算,图像增强和波段合成等,自主构建增强型归一化燃烧指数(ENBR),并结合高斯滤波和Ostu完成中小型火烧迹地的自动提取。结果表明:ENBR能显著凸出火烧迹地和周边环境特征差异;2021年实验样本自动提取经目视判读和实测数据验证,面积偏差分别为3.69±3.09和2.51±3.33 hm^(2),提取精度达(94.20±3.03)%和(90.54±8.21)%,显著优于dNBR和BAI的人工阈值判识结果;2019—2021年12次提取应用整体偏差为5.00±4.70 hm^(2),提取精度达(92.50±5.06)%。研究表明,ENBR和Ostu自动提取方法精度高,且区域自适应能力强。因此,研发的ENBR和火烧迹地自动提取方法对广泛发生中小型林火的中国南方地区具有重要应用价值。

基于蓝光阴影图像法的固体推进剂药条燃速测量方法

针对图像法固体推进剂药条燃速测量方法受火焰辐射影响问题,提出蓝光阴影图像法固体推进剂药条实时燃速测量方法,搭建相应的实验测量系统并进行燃速测试。在常压下利用该方法对药条A进行了5次重复性实验,开展了6种不同配方推进剂药条燃速测试,将蓝光阴影图像法得到的拟合燃速与靶线法测试结果进行对比,并对6种药条的实时燃速进行分析。结果表明,与直接成像法比较,蓝光阴影图像法可有效消除燃面处火焰自发辐射影响,提高燃面识别精度;对药条A进行的重复性实验中,平均值为2.534 mm/s,标准差为0.034 mm/s,扩展不确定度为0.069 mm/s,表明方法具有较高的稳定性;6种药条的拟合燃速与靶线法燃速结果对比,最大相对偏差为3.7%,说明该方法具有较高的测量精度。分析6种药条实时燃速的波动性发现,燃速高的药条往往其波动性较大,燃速接近时药条的波动性主要受药条配方的影响。

Burning products of TA15 titanium alloy by friction oxygen concentration method

The microstructural characteristics, elemental distribution law and microscopic formation mechanism of the burning products of TA15 titanium alloy were investigated by friction oxygen concentration method, associated with in situ observation, X-ray diffraction(XRD),scanning electron microscopy(SEM) and energy-dispersive spectroscopy(EDS) analyses, providing the thoughts to improve fireproof property. The results show that, when the friction contact pressure(p) is 0.20 MPa and oxygen concentration of premixed air flow(c) is 60 vol%, TA15 titanium alloy produces violent sparks and presents dazzling white light during combustion. The generated products after burning are mainly TiOand small amount of AlOoxides. Four distinct zones form from the combustion surface to the alloy matrix, and they are in the sequence of combustion zone, fusion zone, heat-affected zone and transition zone. Further, combustion zone is composed of TiOand A1203 compounds, containing obvious cracks. In the fusion zone, discontinuous oxygenrich Al-based solid solution forms, and the elemental distribution has strong volatility. In the heat-affected zone,there are abundant of Ti-based solid solution and small amount of Al-and Mo-based solid solution. Transition zone is made of lamellar structure. Two technical approaches are given to prevent oxygen diffusion inside the reaction zone and reaction-affected zone. On the one hand,the content of Al is designed as the upper limit of alloy composition; on the other hand, fireproof coatings are deposited on the surface of the alloy.