Enhancing hydrothermal stability of framework Al in ZSM-5:From the view on the transformation between P and Al species by solid-state NMR spectroscopy

HZSM-5,with good surface acidity and shape selectivity,was reported as hydrocarbon cracking catalyst for multiple decades,however the hydrothermal stability,especially dealumination of tetrahedrally coordinated framework aluminum(TFAl),has been proved extensively as one of the major challenges during reactionregeneration process.Phosphorus was proposed to stabilize TFAl and indeed it enhanced the hydrothermal stability.Unfortunately,most of the phosphorus species would remain outside of the zeolite pore,mainly as polyphosphate species,and block the micropore severely,with only a limited portion introduced into the channel being able to interact with TFAl.Enlarging the pore size by alkali treatment(desilication)is one of the most convinced methods,but the details about specific P species during alkali treatment and its transformation upon hydrothermal activation is not acquired,thus the mechanism has not been fully understood.Herein,the P-containing species and its transformation during direct P modification and acid/alkali treatment followed by Pmodification have been studied,and the mechanism on the interaction between P and Al species has been investigated,using several analytical methods,especially Solid-state nuclear magnetic resonance(SSNMR)spectroscopy.It was found that the combination of desilication and subsequent phosphorus modification can enhance the activity of the ZSM-5 for the cracking of ethylcyclohexane,due to the better hydrothermal stabilization of acid sites by the enhanced interaction between phosphorus and TFAl,resulting from the improved accessibility of TFAl because of the successful generation of mesoporosity.Whereas the acid treatment followed by phosphorus modification,with declined retention of crystallinity and P/Al ratio,monoclinic/orthorhombic transition during steam activation,and the failed generation of mesopores,would cause obvious aggregation of the phosphorus species and could not improve the hydrothermal stability of the ZSM-5 effectively,and the direct phosphatation turned out much worse.Finally,a specific index that the intensity of the signal at 39 in 27Al MAS NMR spectra before steam activation was proposed as the indicator for determining the efficiency of phosphorus modification.And the proposed mechanism on the interaction between phosphorus and TFAl during the phosphorus modification could also be applicable in other zeolites.

Distribution of wetlands and salt lakes in the Yadong region of Tibet based on remote sensing, and their geo-climatic environmental changes

Based on the 16 scenes GF-1 satellite multi-spectral remote sensing images,through the adoption of data processing methods including orthorectification,geometric rectification,data fusion and image mosaic,integrated with field surveys,the remote sensing interpretation signs for the inland wetland types have been built,and the remote sensing survey of inland wetlands in Yadong region has been initiated,with six types of inland wetlands recognized in Yadong region,namely permanent rivers,seasonal rivers,lakes,salt lakes,alpine meadows,and inundated land.The spatial distribution characteristics and the spreading rules of these wetlands have also been revealed.Based on full understanding of the overall characteristics of the inland wetlands in the Yadong region,using the three phases of TM images acquired in 1989,2003 and 2008 as well as the PMS2 data gathered by GF-1 in 2014,and the wide-range data(WFV3)gathered by GF-1 in 2020.As to the typical salt lakes,a long-time salt lakes transition study was carried out.The results show that the typical salt lakes in Yadong have been shrinking in the past three decades.The average annual shrinkage of Duoqing Co(Co means lake in Tibetan)was stronger than that of Gala Co,which are respective 87.30 hectares(usually short as ha;1 ha equals to 0.01 km^(2))/a and 24.20 ha/a;the shrinkage degree of Gala Co was higher than that of Duoqing Co,shrank by 59.27% and 35.73% respectively.Based on the remote sensing survey results and an integrated analysis of the predecessors’researchers,the reason for the shrinkage of the salt lakes is more inclined to geological factors.Geological process is manifested by a series of extensional faults at the bottom of the lake basin generated from tectonic activities,providing fluid infiltration channels,and inducing the eventual leakage of lake water to the lower strata.The result provides an important instance for understanding the evolution characteristics of wetlands and salt lakes in specific environment of the Tibetan Plateau.

A dynamic evaluation technique for assessing gas output from coal seams during commingling production within a coalbed methane well: a case study from the Qinshui Basin

Gas drainage is carried out based on output from each coal bed throughout commingling production of coalbed methane(CBM).A reasonable drainage process should therefore initially guarantee main coal bed production and then enhance gas output from other beds.Permanent damage can result if this is not the case,especially with regard to fracture development in the main gas-producing coal bed and can greatly reduce single well output.Current theoretical models and measuring devices are inapplicable to commingled CBM drainage,however,and so large errors in predictive models cannot always be avoided.The most effective currently available method involves directly measuring gas output from each coal bed as well as determining the dominant gas-producing unit.A dynamic evaluation technique for gas output from each coal bed during commingling CBM production is therefore proposed in this study.This technique comprises a downhole measurement system combined with a theoretical calculation model.Gas output parameters(i.e.,gas-phase flow rate,temperature,pressure)are measured in this approach via a downhole measurement system;substituting these parameters into a deduced theoretical calculation model then means that gas output from each seam can be calculated to determine the main gas-producing unit.Trends in gas output from a single well or each seam can therefore be predicted.The laboratory and field test results presented here demonstrate that calculation errors in CBM outputs can be controlled within a margin of 15%and therefore conform with field use requirements.

The Climate Change in Qingdao during 1899-2015 and Its Response to Global Warming

In this work, the average mean (TAvg), maximum (TMax), and minimum temperature (TMin) and precipitation records of Qingdao from 1899 to 2015 are analyzed. The TAvg, TMax and TMin all go through several warm and cold periods, and exhibit statistically significant linear warming trend especially in spring and winter, as a response to global warming. Besides, the TAvg reflects more the TMin evolution for the most part, either as a trend or an abrupt change, and the contribution of TMin to Tavg is far greater than that of TMax. The abrupt change year of climate is also around 1979 in Qingdao, and it is 2 or 3-years later than the TAvg for the TMin, while there is no abrupt change of TMax. In terms of the precipitation in Qingdao, it varies periodically and dramatically with a slow increasing trend. As for the seasonal precipitation, the precipitation varies widely year by year for the four seasons but with no obvious variation trend except for spring.

应用型电子直线加速器用C波段大功率速调管研究与开发

为满足C波段应用型直线加速器功率源要求,研制了一支C波段大功率速调管。通过对电子枪结构模拟计算并利用正反向组合式聚焦线圈调整过渡区磁场,完成了电子光学系统设计,电子注通过率达到100%,电子注波动率为4.8%。综合应用一维至三维计算程序对注-波互作用段开展参数优化及PIC仿真,最终确定了6个谐振腔的速调管方案。腔体加工冷测调配后焊接形成整管,并开展了高功率测试,在电子注电压为115 kV、电流为79.6 A条件下,馈入频率为5712 MHz、功率为100 W的信号时,该速调管可输出的峰值功率为3.52 MW,增益为45.5 dB,效率为38.5%,达到了预期研制目标。

煤矿坚硬顶板灾害水力压裂防治技术监测及评估

水力压裂技术具备安全性好、施工工艺简单的优点,被广泛应用于煤层坚硬顶板灾害治理。但由于岩体的不均质性,压裂孔周围裂隙网络扩展规律复杂,水力压裂裂纹监测精度低,压裂效果评估难度大。针对上述问题,通过对比分析常见水力压裂监测方法及监测方案的差异,揭示微震监测技术的优越性,并对水力压裂效果评估技术进行了讨论。研究表明,微震监测技术具有监测范围广、灵敏度高、连续性好的优点;地面监测、井下监测、联合监测等微震监测方法适用工况不同,监测精度相差较大,应根据现场工程布置与实际岩层条件选取合适的监测方法。坚硬顶板水力压裂效果评估多采用裂缝发育长度、来压步距等间接指标,基于微震参变量直接指标的效果评估相对较少。在此基础上,提出了水力压裂效果评估精细化的发展建议。研究成果对开展坚硬顶板水力压裂现场监测、优化坚硬顶板水力压裂工程设计具有重要指导意义。

Intelligent Recognition Using Ultralight Multifunctional Nano‑Layered Carbon Aerogel Sensors with Human‑Like Tactile Perception

Humans can perceive our complex world through multi-sensory fusion.Under limited visual conditions,people can sense a variety of tactile signals to identify objects accurately and rapidly.However,replicating this unique capability in robots remains a significant challenge.Here,we present a new form of ultralight multifunctional tactile nano-layered carbon aerogel sensor that provides pressure,temperature,material recognition and 3D location capabilities,which is combined with multimodal supervised learning algorithms for object recognition.The sensor exhibits human-like pressure(0.04–100 kPa)and temperature(21.5–66.2℃)detection,millisecond response times(11 ms),a pressure sensitivity of 92.22 kPa^(−1)and triboelectric durability of over 6000 cycles.The devised algorithm has universality and can accommodate a range of application scenarios.The tactile system can identify common foods in a kitchen scene with 94.63%accuracy and explore the topographic and geomorphic features of a Mars scene with 100%accuracy.This sensing approach empowers robots with versatile tactile perception to advance future society toward heightened sensing,recognition and intelligence.

A Deep Learning Approach for Forecasting Thunderstorm Gusts in the Beijing–Tianjin–Hebei Region

Thunderstorm gusts are a common form of severe convective weather in the warm season in North China,and it is of great importance to correctly forecast them.At present,the forecasting of thunderstorm gusts is mainly based on traditional subjective methods,which fails to achieve high-resolution and high-frequency gridded forecasts based on multiple observation sources.In this paper,we propose a deep learning method called Thunderstorm Gusts TransU-net(TGTransUnet)to forecast thunderstorm gusts in North China based on multi-source gridded product data from the Institute of Urban Meteorology(IUM)with a lead time of 1 to 6 h.To determine the specific range of thunderstorm gusts,we combine three meteorological variables:radar reflectivity factor,lightning location,and 1-h maximum instantaneous wind speed from automatic weather stations(AWSs),and obtain a reasonable ground truth of thunderstorm gusts.Then,we transform the forecasting problem into an image-to-image problem in deep learning under the TG-TransUnet architecture,which is based on convolutional neural networks and a transformer.The analysis and forecast data of the enriched multi-source gridded comprehensive forecasting system for the period 2021–23 are then used as training,validation,and testing datasets.Finally,the performance of TG-TransUnet is compared with other methods.The results show that TG-TransUnet has the best prediction results at 1–6 h.The IUM is currently using this model to support the forecasting of thunderstorm gusts in North China.

Megafossils of Betulaceae from the Oligocene of Qaidam Basin and their paleoenvironmental and phytogeographic implications

Understanding the paleoenvironment and phytogeographical history of the Tibetan Plateau,China relies on discovering new plant fossils.The Qaidam Basin has long been regarded as an ideal‘field laboratory’to investigate the paleoclimate and paleobiological evolution of the northern Tibetan Plateau.However,fossil angiosperms from the Qaidam Basin are rare,and our knowledge of its paleovegetation is poor.Here,we report fossil leaves and fruits of Betulaceae found from the Oligocene Shangganchaigou Formation of northwestern Qaidam Basin(Huatugou area).Comparative morphological analysis led us to assign the fruits to the Betula subgenus Betula and the leaves to Carpinus grandis.These findings,together with other reported fossil plants from the same locality,reveal a close floristic linkage between the Qaidam Basin and Europe during the Oligocene.The northern pathway of this floristic exchange may have crossed through the Qaidam Basin during the late Paleogene.This floristic linkage may have been facilitated by the continuous narrowing of the Turgai Strait and stronger westerlies,which transported moisture and provided favorable climatic conditions.Indeed,fossil plants collected from the Qaidam Basin suggest that during the Oligocene this region had warm and humid deciduous broad-leaf forest,which differs from the region’s modern vegetation and indicates that the Qaidam Basin may have been a suitable region for these plants to flourish and spread during the Oligocene.

Effect of sintering temperature and holding time on structure and properties of Li_(1.5)Ga_(0.5)Ti_(1.5)(PO_4)_(3)electrolyte with fast ionic conductivity

Li_(1.5)Ga_(0.5)Ti_(1.5)PO_(4))_(3)(LGTP)is recognized as a promising solid electrolyte material for lithium ions.In this work,LGTP solid electrolyte materials were prepared under different process conditions to explore the effects of sintering temperature and holding time on relative density,phase composition,microstructure,bulk conductivity,and total conductivity.In the impedance test under frequency of 1-10^(6) Hz,the bulk conductivity of the samples increased with increasing sintering temperature,and the total conductivity first increased and then decreased.SEM results showed that the average grain size in the ceramics was controlled by the sintering temperature,which increased from(0.54±0.01)μm to(1.21±0.01)μm when the temperature changed from 750 to 950°C.The relative density of the ceramics increased and then decreased with increasing temperature as the porosity increased.The holding time had little effect on the grain size growth or sample density,but an extended holding time resulted in crack generation that served to reduce the conductivity of the solid electrolyte.

Comparative study on the performance of ConvLSTM and ConvGRU in classification problems-taking early warning of short-duration heavy rainfall as an example

卷积长短期记忆单元ConvLSTM和卷积门控循环单元ConvGRU是两种广泛应用的深度学习单元,通过将循环机制与卷积运算相结合,常常用于时空序列的预测.为了明确上述两种模型的收敛速度和分类能力,需要使用相同的模型架构对相同的分类问题进行预测.本研究将北京短时强降水区级预警问题看作深度学习中的二分类问题,使用京津冀雷达网的组合反射率数据和北京区域内的自动气象站降雨数据进行深度学习模型的训练和评估.结果表明,ConvGRU的收敛速度比ConvLSTM快约25%.ConvLSTM和ConvGRU的预警性能随地区,时间,降雨强度的变化趋势相似,但大部分ConvLSTM的得分较高,少数情况下ConvGRU的得分较高.

我国各地按病种收付费改革进展与启示

按病种收付费改革是国家深化医药卫生体制改革的部署和要求,是推进医疗服务定价方式改革的重要内容。根据国家的要求,2017年底前,城市公立医疗机构综合改革试点地区实行按病种收费的病种应不少于100个。文章检索了2017年1月4日至2018年1月10日省级行政区公开发布的关于按病种收付费的政策文件,对按病种收付费政策实施的核心要素进行了梳理,在此基础上,为进一步推进按病种收付费改革提出政策建议。

色块拼接手法在针织服装设计中的研究与应用

采用案例分析以及设计与实践相结合的研究方法,深入分析色块拼接手法在针织服装设计中的实际应用及应用效果。通过研究色块拼接手法在针织服装设计中的运用,旨在丰富针织服装设计的艺术表现力,提升设计的时尚感和个性化,为针织服装行业的发展提供新的思路和方向。

磁性羧甲基壳聚糖复合微球的制备及其对锰离子去除研究

现有水体除锰工艺中存在反应条件较苛刻、锰离子的回收较复杂等问题,而羧甲基壳聚糖经span-80表面活化后包裹Fe_3O_4@SiO_2颗粒,与戊二醛发生交联后制得磁性羧甲基壳聚糖复合微球(MCMCMs),可在温和的条件下吸附水中重金属Mn(Ⅱ),且易于回收。该复合微球粒径约508.26μm,比饱和磁化强度为13.42emu·g^(-1),具有良好的磁稳定性,在磁场作用下可快速分离。在室温下,pH=7、MCMCMs投加量为2g·L^(-1)时,其对Mn(Ⅱ)吸附效果最好,吸附在48h达到平衡,吸附率达到90%以上,且吸附过程高度符合Langmuir吸附平衡模型及二级动力学模型,在25℃时对Mn(Ⅱ)饱和吸附容量约为75.74mg·g^(-1)。MCMCMs回收重复利用性能较好,经过多次氨水洗脱,吸附性能仍可达到初始状态的75%以上,且回收性能与投加量呈现正相关关系。

某车载武器系统侦测折叠装置设计与分析

车载武器系统模块化设计是实现机动性和轻量化的重要途径。根据侦测设备模块化设计需求和道路运输高度限制,创新设计了一种基于双曲柄折叠机构的侦测折叠装置,以实现侦测安装小转台相对于回转发射转台的自动架设和撤收功能。随后,详细阐述了侦测折叠装置的结构组成和工作原理,并根据其机构原理与力学计算,进行了驱动系统选型设计。最后,采用有限元法对侦测折叠装置进行了力学分析,结果表明:该装置在架撤折叠运动过程中结构可靠,可满足侦测设备使用及运输过程中的安装要求。设计的侦测折叠装置满足了武器系统模块化设计需求,具有一定的推广应用价值。

药学专业表面活性剂化学课程的教学探索

通过对我校药学专业表面活性剂化学课程的教学探索发现,将该课程的教学内容进行单元模块化,利用讨论式(小组现场讨论、课堂PPT相互评价、课后收集材料课堂提问交流三种方式)教学,发挥传统文化的特点,并融入课程思政的元素,可以使该课堂的学习活跃度高涨,大幅提高了以学生为主的课堂效果,同时发挥了高校课程作为思政教育的载体作用,本实践中所用的模式和方法对其他化学课程有一定的借鉴作用。

市场化改革与共同富裕——基于企业间工资差距视角

中国式现代化要求着力促进全体人民共同富裕。我国收入差距问题仍然存在且形式复杂,长此以往可能阻碍经济高质量发展,不利于实现全体人民共同富裕目标。与此同时,我国市场化改革有力提高了经济发展效率,但其对公平的影响还有待验证。为此,本文基于企业间工资差距视角,分析了市场化改革是否有利于促进共同富裕。研究结果显示,市场化改革显著缩小了企业间工资差距。具体来说,市场化指数每增加一个单位,企业工资基尼系数将下降3.37%。该结果在更换收入差距衡量指标、更换研究样本后仍然稳健。机制分析显示,生产率差距缩小和劳动者企业间流转是市场化改革影响企业间工资差距的两个主要机制。此外,本文发现进入企业、中小企业和非国有企业间工资差距更小,且市场化改革缩小企业间工资差距的作用在这些企业组中更显著。本文研究结果显示,市场化改革可以促进收入分配结果公平,有助于推进全体人民共同富裕。

定子无铁心轴向磁通永磁电机的绕组损耗与效率研究

定子无铁心轴向磁通永磁电机没有定子铁心,具有输出转矩平稳、质量轻、装配简单等优势,但同时也存在绕组涡流损耗大的问题。基于利兹线绕组,对定子无铁心轴向磁通电机的绕组涡流损耗进行了分析,给出了绕组涡流损耗计算的解析公式与有限元结合的非均匀分层混合计算模型,并通过简化的全绕组三维有限元模型,验证了混合计算模型的正确性和有效性。研究了以电机效率最大化为目标的利兹线规格选型方法。由于利兹线的实际制造工艺的问题,对电机效率进行了计算和分析,并给出了利兹线选型相关的定性结论。

基于温控器热仿真的特种车辆方舱设计

由于车辆温控器工作时产生的流场变化可能对车载激光设备的作战产生较大影响,因此本文针对该特种车辆设计了一种设备方舱,并对温控器开启和关闭时,车内外流场的温度和速度进行了数值计算,计算结果表明:温控器工作时,温控器上部区域温度基本与初始环境温度一致,不影响激光设备工作,同时舱内中部位置流速低于1m/s,适用于安装较为脆弱的光学设备;温控器风扇关闭后45s内,温控器上部区域温度最高温升仅为3℃;整个流场最大流速在0.2m/s以内,不影响激光设备的工作,方舱设计满足使用要求。

车载自动调平系统的设计与分析

为了满足现代战争高机动性、高作业稳定性的需求,论文简单介绍了一种以角度误差控制法和位置误差控制法相结合的算法。同时,承载结构作为自动调平系统的重要组成部分,其设计的成功与否会直接或间接影响到车载武器的工作性能。论文设计了一种新型的机电式调平支腿,并详细阐述了支腿的组成,根据要求计算了丝杆驱动所需力矩以及转速,由此确定了电机的选型,同时还对梯形丝杆进行了校核计算。最后,论文采用有限元法对调平支腿进行了力学、模态分析,结果表明:即使在极限承载下,支腿伸出后其结构的强度、刚度也是符合结构设计要求的,同时,模态分析的结果也保证了支腿在工作过程中有着很好平稳性。