转化废热锅炉高温端管箱壳体超温的原因分析及措施

分析某100kt/a合成氨装置转化废热锅炉管侧(工艺气侧)多次发生蒸汽冷凝-汽化,导致其高温端的衬里产生裂纹及高温端管箱壳体超温的原因,提出解决措施。

一种单组分酮肟型硅酮密封胶的高温封端工艺

107胶与填料的混合物经高温脱水后,在温度120℃、-0.85 MPa下加入交联剂进行封端,经冷凝器降温至50℃以下,再加入偶联剂和催化剂。以此工艺生产酮肟型硅酮密封胶,相比传统的低温封端工艺可显著降低交联剂用量,减轻渗油现象,提高胶浆稳定性,降低酮肟型硅酮密封胶使用时的VOC。本工艺适用于封闭式的自动化连续生产线。

Implications of the extremely hot summer of 2022 on urban ozone control in China

Frequent occurrences of extreme heat are causing severe ozone pollution over China.This study examined the driving factors of urban ozone pollution in China during the extremely hot summer of 2022 and the impact of emission control strategies using surface measurements and the GEOS-Chem model.The results show that ozone pollution was extremely severe in summer 2022,with a significant rebound by 12-15 ppbv in the North China Plain(NCP),Yangtze River Delta(YRD),and Sichuan basin(SCB),compared to 2021.Especially over the NCP,the MDA8(maximum daily 8-hourly average)ozone exceeded 160 ppbv,and the number of ozone exceedances was over 42 days.Based on an IPR(integrated process rate)analysis,the authors found that the net chemical production was the dominant factor contributing to the strong ozone increase in summer 2022.For example,in June over the NCP,the net chemical production resulted in an increase by 3.08 Gg d^(−1)(∼270%)in ozone mass change.Sensitivity simulations showed that both NO_(x)(nitrogen oxides)and VOC(volatile organic compound)reductions were important over the NCP,and NO_(x)reductions were more important than VOCs over southern China.To keep the ozone of 2022 at the same level as 2021,a joint reduction of NO_(x)and VOCs by at least 50%-60%would have been required.This study highlights the urgency to develop effective ozone management since extreme heat will become more frequent.

新型热电偶温度测量仪的研制

热电偶是一种由2种导体组成并将温度转化为热电动势的传感器设备。介绍了热电偶温差电势实验仪的工作原理、设计思想以及低温端测量原理和高温端测温控温原理的电子线路实现。本仪器具有安全、自动控温、超温保护、对电网的干扰小等优点。

Climate state of the Three Gorges Region in the Yangtze River basin in 2022–2023

Based on daily observation data of the Three Gorges Region(TGR)of the Yangtze River basin and global reanalysis data,the climate characteristics,climate events,and meteorological disasters of the TGR in 2022 and 2023 were analyzed.For the TGR,the average annual temperature for 2022 and 2023 was 0.8℃ and 0.4℃ higher than normal,respectively,making them the two warmest years in the past decade.In 2022,the TGR experienced its warmest summer on record.The average air temperature was 2.4℃ higher than the average,and there were 24.8 days of above-average high temperature days during summer.Rainfall in the TGR varied significantly between 2022 and 2023.Annual rainfall was 18.4%below normal and drier than normal in most parts of the region.In contrast,the precipitation in 2023 was considerably higher than the long-term average,and above normal for almost the entire year.The average wind speed exhibited minimal variation between the two years.However,the number of foggy days and relative humidity increased in 2023 compared to 2022.In 2022–2023,the TGR mainly experienced meteorological disasters such as extreme high temperatures,regional heavy rain and flooding,overcast rain,and inverted spring chill.Analysis indicates that the abnormal western Pacific subtropical high and the abnormal persistence of the eastward-shifted South Asian high were the two important drivers of the durative enhancement of record-breaking high temperature in the summer of 2022.

The Greening Construction and Technology of the Management in the Lop Nur Potash Mine

Lop Nur potash mine greening projects is located in the heart of the Lop Nur, known as the ＂green zone ban＂. The project overcomes the extreme drought, high temperature, gale and dust salt and salt, and many other adverse environmen- tal factors. Adopted the suitable salt improvement measures and management tech- nology, the artificial green has emerged in the sea of death. At the same time the greening project improved the office environment of mining area, and shaped ex- treme environment greening projects successful cases.

Responses of some landscape trees to the drought and high temperature events during 2006 and 2007 in Yamaguchi,Japan

Extreme weather events were analyzed based on the meteorological data from the year of 1967 to 2007 for Yamaguchi, Japan. The responses from landscape trees were also investigated mainly by the analysis of image pixel and spectral reflectance. Results show that after the dry, hot and windy summer in 2007, many landscape trees in Yamaguchi City tended to respond the extreme weather events by reducing their leaf surface area and receiving less radiation energy. Premature leaf discoloration or defoliation appeared on some landscape tree species and leaf necrosis occurred on tip and margin of many Kousa dogwood (Cornus kousa) trees at unfavorable sites. Described by image pixel analysis method, the leaf necrotic area percentage (LNAP) of sampled dogwood trees averaged 41.6% and the sampled Sasanqua camellia (Camelia sasanqua) tree also showed fewer flowers in flower season of 2007 than that in 2006. By differential analysis of partial discolored crown, it presented a logistic differential equation of crown color for sweet gum (Liquidambar styraciflua) trees. It suggested that the persistent higher temperature and lower precipitation could be injurious to the sensitive landscape trees at poor sites, even in relative humid area like Yamaguchi.

A review of recent studies on extreme heat in China

This paper reviews recent studies on extreme high temperatures in China during summer. The focus is on the variation in extreme heat and tropical nights（i.e. high temperature at night）, and the factors of influence. Potential research topics in the future are also discussed.

Trends in extreme high temperature at different altitudes of Southwest China during 1961–2014

This study analyzed the trends in extreme high temperature in Southwest China based on the observed daily maximum temperature and average temperature data from 410 Chinese stations recently released by the China Meteorological Administration.The authors found that the trends in extreme high temperature at different altitudes of Southwest China exhibit staged variations during a recent 50-year period(1961–2014).The trends in mean temperature and maximum temperature also exhibit phase variation.All temperature-related variables increase gently during the period 1975–94,whereas they increase dramatically during the recent period of 1995–2014,with a rate that is approximately two to ten times more than that during 1975–94.In addition,the trends in mean temperature,maximum temperature,and the frequency of extreme high temperature in the low altitudes transit from negative to positive in the two periods,while they increase dramatically in the mid-and high-altitude areas during 1995–2014,the well-known global warming hiatus period.In particular,the maximum temperature increases much faster than that of average temperature.This result implies that the regional temperature trend could be apparently different from the global mean temperature change.

Possible Impact of the Summer North Atlantic Oscillation on Extreme Hot Events in China

This paper reveals that the summer North Atlantic Oscillation (SNAO) is closely related to the extreme hot event (EHE) variability in China during the period of 1979 2009, with a positive-phase (negative-phase) SNAO corresponding to less (more) EHEs in northern China. The summer circulation anomalies associated with the SNAO give further confirmation of the above relationship. In a positive-phase (negative-phase) SNAO year, there is an anomalous cyclone (anticyclone) over central East Asia, which can increase (decrease) the total cloud cover over this region. Such changes of the total cloud cover can then decrease (increase) the solar radiation reaching the surface, which is consequently unfavorable (favorable) to the formation of EHEs over northern China.

Changes of Temperature and Precipitation Extremes in Hengduan Mountains,Qinghai-Tibet Plateau in 1961-2008

Variations and trends in extreme climate events are more sensitive to climate change than the mean values, and so have received much attention. In this study, twelve indices of temperature extremes and 11 indices of precipita- tion extremes at 32 meteorological stations in Hengduan Mountains were examined for the period 1961-2008. The re- suits reveal statistically significant increases in the temperature of the warmest and coldest nights and in the frequen- cies of extreme warm days and nights. Decreases of the diurnal temperature range and the numbers of frost days and ice days are statistically significant. Regional averages of growing season length also display the trends consistent and significant with warming. At a large proportion of the stations, patterns of temperature extremes are consistent with warming since 1961： warming trends in minimum temperature indices are greater than those relating to maximum temperature. As the center of the Shaluli Mountain, the warming magnitudes decrease from inner to outer. Changes in precipitation extremes is low： trends are difficult to detect against the larger inter-annual and decadal-scale variability of precipitation, and only the wet day precipitation and the regional trend in consecutive dry days are significant at the 0.05 level. It can be concluded that the variation of extreme precipitation events is not obvious in the Hengduan Mountains, however, the regional trends generally decrease from the south to the north. Overall, the spatial distribution of temporal changes of all extreme climate indices in the Hengduan Mountains illustrated here reflects the climatic complexity in mountainous regions.

Changes in Daily Climate Extremes of Observed Temperature and Precipitation in China

Daily precipitation for 1960-2011 and maximum/minimum temperature extremes for 1960-2008 recorded at 549 stations in China are utilized to investigate climate extreme variations.A set of indices is derived and analyzed with a main focus on the trends and variabilities of daily extreme occurrences.Results show significant increases in daily extreme warm temperatures and decreases in daily extreme cold temperatures,defined as the number of days in which daily maximum temperature （Tmax） and daily minimum temperature （Tmin） are greater than the 90th percentile and less than thel0th percentile,respectively.Generally,the trend magnitudes are larger in indices derived from Tmin than those from Tmax.Trends of percentile-based precipitation indices show distinct spatial patterns with increases in heavy precipitation events,defined as the top 95th percentile of daily precipitation,in westem and northeastern China and in the low reaches of the Yangtze River basin region,and slight decreases in other areas.Light precipitation,defined as the tail of the 5th percentile of daily precipitation,however,decreases in most areas.The annual maximum consecutive dry days （CDD） show an increasing trend in southem China and the middle-low reach of the Yellow River basin,while the annual maximum consecutive wet days （CWD） displays a downtrend over most regions except western China.These indices vary significantly with regions and seasons.Overall,occurrences of extreme events in China are more frequent,particularly the night time extreme temperature,and landmasses in China become warmer and wetter.

Effects of temperature and salinity on the development of the amphipod crustacean Eogammarus sinensis

The amphipod crustacean Eogammarus sinensis has useful features that make it suitable for use in the aquaculture of fish and large decapod crustaceans.In this study,we investigated the effects of temperature and salinity on the development,fecundity,survival,and growth rate of E.sinensis.The results show that temperature significantly affected E.sinensis development,but salinity.As temperature increased,the duration of E.sinensis embryonic development decreased.Fecundity was affected significantly by temperature and the combination of temperature and salinity,but by salinity alone.In addition,high temperatures accelerated E.sinensis juvenile growth rates,whereas high salinity reduced it.Therefore,our data suggest that E.sinensis tolerates a wide range of salinities and that temperature has more significant effects than salinity on the embryonic development,fecundity,and growth of E.sinensis.Our results shall be useful for mass production of this species for use in aquaculture.

Inhomogeneous trends in the onset date of extreme hot days in China over the last five decades

Using a homogenized daily maximum temperature(T_(max))dataset across China,this study characterized the spatiotemporal variation of the onset date of extreme hot days in a year(i.e.,FirstEHD)during 1960-2018.Inhomogeneous trends of FirstEHD over China during 1960-2018 can be found,with the advanced trend of FirstEHD over most parts in China,while a number of stations in North-Central China(NC)show the delayed trend of FirstEHD.Moreover,there exist interdecadal changes of FirstEHD trend,with a remarkable difference in the trend magnitude before and after the 1990s over South China(SC),and the sign of trend can even reverse from negative to positive after the 1990s in Xinjiang(XJ)and Yangtze River Basin(YR),and from positive to negative in NC.The overall trends of FirstEHD over NC,YR,and XJ during 1960-2018 are dominated by the trends before the 1990s,while they are dominated by the sharp advance after the 1990s over SC.It is further found that the trend of FirstEHD can generally be explained by the long-term trend in T_(max) over most parts of China,but the contribution from T_(max) variabilities is also non-negligible and can even account for more than 75% of the overall trend over NC.The possible factors responsible for the decadal changes in FirstEHD trends are also discussed.

An interdecadal decrease in extreme heat days in August over Northeast China around the early 1990s

Northeast China(NEC)witnessed an interdecadal increase in summer extreme heat days(EHDs)around the mid-1990s.The current study reveals that this interdecadal increase only occurs in June and July,while August features a unique interdecadal decrease in EHDs around the early 1990s.Plausible reasons for the interdecadal decrease in EHDs in August are further investigated.Results show that the interdecadal decrease in EHDs in August is due to the deceased variability of daily maximum temperature(Tmax).Overall,the variation of the Tmax over NEC in August is modulated by the Eurasian teleconnection pattern,Silk Road pattern,and East AsiaPacific pattern.However,the influence of the Silk Road pattern dramatically weakens after the early 1990s because the meridional wind variability along the westerly jet significantly decreases.The weakened influence of the Silk Road pattern contributes to the decreased Tmax variability over NEC.Meanwhile,the convection over the western North Pacific,which accompanies the East Asia-Pacific pattern,presents a significant decrease in variance after the early 1990s,further decreasing the Tmax variability over NEC.

Uncertainty in hottest years ranking: analysis of Tibetan Plateau surface air temperature

Changes in surface air temperature can directly affect hydrology, agriculture, and ecosystems through extreme climate events such as heat waves. For this reason, and to improve climate change adaptation strategies, it is important to investigate the ranking of hottest years. In this study, the Wilcoxon signed-ranktest and Monte Carlo simulation are used to estimate the ranking of the hottest years for theTibetan Plateau （TP） in recent decades, and the uncertainty in the ranking.The Wilcoxon signed-rank test shows that the top 10 hottest years on record over the TP mainly occur after 1998. The top three hottest years are ranked as 2006, 2009, and 2010, but there is almost no significant difference between them. When both sampling and observational errors are considered, only five years have a non-zero probability of being the hottest year, with the three highest probabilities being for the years 2006 （-47.231%）, 2009 （-40.390%）, and 2010 （-12.376%）. Similarly, with respect to a given year that is among the 10 hottest years, our results show that all the years among the ranks of 1-10 resulting from the Wilcoxon signed-rank test have probabilities above 10%, while the years 2001 and 2012 have probabilities of 3% and 4%.

Interdecadal variability of the large-scale extreme hot event frequency over the middle and lower reaches of the Yangtze River basin and its related atmospheric patterns

Based on daily maximum temperature data from Chinese weather stations for the period 1960- 2013, the characteristics of the interdecadal variability of large-scale extreme hot event （EHE） frequency over the middle and lower reaches of the Yangtze River basin （MLYR） are analyzed. It is found that the frequency of large-scale EHE over the MLYR experiences two significant interdecadal changes, around the early 1970s and early 2000s, having a more-less-more variability shape during the past half century. Furthermore, the EHE frequency interdecadal variability-related atmospheric circulation patterns are diagnosed. The results indicate the western Pacific subtropical high could not be the dominant atmospheric circulation associated with the interdecadal variability of the large-scale EHE frequency over the MLYR. In contrast, the dominant teleconnection pattern over the Eurasian continent, which is represented by the second empirical orthogonal function mode of the 200 hPa geopotential height, is closely related to the interdecadal variability of the EHE frequency over the MLYR. The results of this study deepen our understanding of the variability of the EHE frequency over the MLYR and its possible mechanism.

Comparative Analysis of Extreme High Temperature Weather in the Summers of 2013 and 2003

The characteristics of regional high temperature(HT) weather in 2013 and 2003 and their causes were studied using daily maximum temperature data, National Center for Environmental Prediction(NCEP) reanalysis data, and outgoing longwave radiation(OLR) data. For these two years of HT weather, there were many similar characteristics, such as their long duration, wide range, high intensity, and severe influence. However, there were also three obvious differences: firstly, in 2013, the major area where HT weather occurred was farther north than in 2003; secondly, the HT weather in South China and the southeast area of Jiangnan in 2013 lasted fewer days than in 2003, but in other areas it lasted for more days than in 2003; thirdly, the intensity of the HT weather in 2013 was also stronger in the north and weaker in the south, similar to that of the duration. A strong and stable western Pacific subtropical high(WPSH), a continental warm high, and the distribution of the warm center in the lower troposphere played important roles in the HT weather formation. Several probable causes for the differences are that the cold air was weaker, the WPSH was farther north, and the tropical convective systems were stronger in 2013 than in 2003. Finally, a preliminary cause analysis of the WPSH anomaly was presented.

Changes in Extreme Events as Simulated by a High-Resolution Regional Climate Model for the Next 20-30 Years over China

In this paper, the changes in temperature and precipitation extremes over the next 20-30 years (2021-2050) in relative to the present day (1986-2005) under the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A1B scenario are analyzed based on a high-resolution climate change simulation performed by a regional climate model (the Abdus Salam International Center for Theoretical Physics (ICTP) RegCM3). The extreme indices of summer days (SU), frost days (FD), and growing season length (GSL) for temperature and simple daily intensity index (SDII), number of days with precipitation ≥10 mm d-1 (R10), and consecutive dry days (CDD) for precipitation are used as the indicators of the extremes. The results show that the indices simulated by RegCM3 in the present day show good agreement with the observed. A general increase in SU, a decrease in FD, and an increase in GSL are found to occur in the next 20-30 years over China. A general increase in SDII, an increase in R10 over western China, and a decrease in R10 in north, northeast, and central China are simulated by the model. Changes in CDD are characterized by a decrease in the north and an increase in the south and the Tibetan Plateau.

乙烯裂解炉炉管伸缩囊安装工艺及质量控制

通过阿曼某乙烯项目裂解炉炉管伸缩囊施工,总结其安装工艺及质量控制要点,旨在对全套乙烯裂解炉炉管伸缩囊安装有更好的理解和掌握,为后续承接类似项目工作提供指导。