期刊文献+
共找到1,821篇文章
< 1 2 92 >
每页显示 20 50 100
Effect of building energy efficiency standards on carbon emission efficiency in commercial buildings
1
作者 Xia Wang Qi Ye +1 位作者 Yan Du Mao Zhou 《Chinese Journal of Population,Resources and Environment》 2024年第3期250-257,共8页
The building sector plays a crucial role in the worldwide shift toward achieving net-zero emissions.Building energy efficiency standards(BEESs)are highly effective policies for reducing carbon emissions.Therefore,expl... The building sector plays a crucial role in the worldwide shift toward achieving net-zero emissions.Building energy efficiency standards(BEESs)are highly effective policies for reducing carbon emissions.Therefore,exploring the provincial variations in carbon emission efficiency(CEE)in the building sector and identifying the effect of BEESs on CEE is crucial.This study focuses on commercial buildings in China and applies a difference in differences model to evaluate the impact of BEESs on the CEE of commercial buildings.The slacks-based measure–data envelopment analysis model is employed to assess the CEE of commercial buildings in 30 Chinese provinces from 2000 to 2019.Furthermore,heterogeneous tests are used to explore how climate characteristics and economic conditions affect the efficiency of BEESs.The results indicate that BEESs positively influence the CEE of commercial buildings.Specifically,a 1%increase in the intensity of BEESs causes a 0.1484%increase in the CEE of commercial buildings.Moreover,the impact of BEESs is particularly pronounced in the southern and western provinces.This study provides valuable scientific evidence for governments to enhance BEESs implementation. 展开更多
关键词 Commercial buildings Carbon emissions efficiency Building energy efficiency standards Slack-based measure–data development analysis Difference in differences
下载PDF
Pollutant emission reduction effect through effluent tax,concentration-based effluent standard,or both 被引量:2
2
作者 Kunyu Niu Zhongshan Tian Jie Xue 《Chinese Journal of Population,Resources and Environment》 2016年第2期68-80,共13页
There are numerous studies comparing different kinds of environmental taxes and standards.However,forms of environmental standards focused by former researchers are usually quantitybased limits/standards(e.g.pounds pe... There are numerous studies comparing different kinds of environmental taxes and standards.However,forms of environmental standards focused by former researchers are usually quantitybased limits/standards(e.g.pounds per day or pounds per unit of output).Concentration-based emission standard(e.g.milligrams per liter of wastewater) as one important form of environmental standard has not been given much attention.In this article,comparable estimates of their probable effect on enterprise pollution reduction will be developed for concentrationbased effluent standards,effluent taxes,and a combination of both.A linear simulation model is used to clearly and obviously compare the effects of effluent taxes and concentration-based standards within the same figure.With one detailed application to the paper industry,some enlightenment and conclusions-as well as the general applicability of these principles-are then provided:Under the same effluent tax rate,enterprises,groups,and industries that are cleaner will reduce more pollutants than those that have higher pollutant abatement costs.It is recommended that effluent taxes are set by avoiding cutting it even at one stroke and considering the feasibility of pollution-reducing technology in various industries.It is necessary to reduce MAC of enterprises to better stimulate enterprises' or industries' emission reduction by preferential measures,such as high tax rate coordinated by speeding up the depreciation of environmental protection equipment. 展开更多
关键词 Concentration-based effluent standard effluent tax emission reduction effect(ERE) marginal abatement cost(MAC)
下载PDF
Thinking About the New Atmospheric Pollutant Emission Standard for Thermal Power Plants 被引量:1
3
作者 Sun Weimin Zhang Jie 《Electricity》 2012年第4期46-51,共6页
China's new Atmospheric Pollutant Emission Standard for Thermal Power Plants has been made the most stringent atmospheric pollutant emission limit in the world,with the intensified control of nitrogen oxides in th... China's new Atmospheric Pollutant Emission Standard for Thermal Power Plants has been made the most stringent atmospheric pollutant emission limit in the world,with the intensified control of nitrogen oxides in the air pollutants emitted by thermal power plants,the tightened limit on the emission of sulfur dioxide,and the widened range of control including mercury and other compounds discharge.The adoption of the new standard will considerably impact the survival and development of power plants,even the whole economy of the nation.While implementing all the policies and measures on emission reduction issued by the State to fulfill political,social,and economic responsibilities,China Huadian Corporation,one of the leading state-owned power generation groups,is actively exploring the green and low-carbon path for the sound and rapid development of the group. 展开更多
关键词 environment protection emission standard emission reduction
下载PDF
The Progress of International and National Carbon Emission Management Standardization
4
作者 陈亮 陈健华 +2 位作者 鲍威 孙亮 郭慧婷 《China Standardization》 2014年第4期54-59,共6页
Standardization, as a very effective tool, plays a more and more important supporting role in promoting China's policy implementation in addressing climate change and other issues. This paper summarizes the intern... Standardization, as a very effective tool, plays a more and more important supporting role in promoting China's policy implementation in addressing climate change and other issues. This paper summarizes the international situation and progress, and analyzes the international development tendency of carbon emission management standardization. Correspondingly, the national situation and progress of carbon emission management standardization is reviewed including involvement of international standardization, establishment of national standardization committee, development of national standards and so on. And the policy suggestions are raised to strengthen the standardization work in the fields of addressing climate change during the 12 th Five-Year Plan period. 展开更多
关键词 carbon emission management greenhouse gas climate change standardIZATION
下载PDF
Challenges from the New Emission Standards for SO_2 and NO_X
5
作者 Shen Baozhong Chen Zhen Xu Xiaoming 《Electricity》 2012年第5期55-58,共4页
The Emission Standards of Air Pollutants from Thermal Power Plants (GB 13223-2011) prescribe a stricter limitation to air pollutants than ever before. As set in the new emission standard, the limitations of SO2 and NO... The Emission Standards of Air Pollutants from Thermal Power Plants (GB 13223-2011) prescribe a stricter limitation to air pollutants than ever before. As set in the new emission standard, the limitations of SO2 and NOX for sensitive areas under normal conditions are 50 mg/m3 and 100 mg/m3, respectively. The objective analysis and suggestions are proposed. The recent status and operational experience of desulfurization and denitrification equipment are discussed. From the discussions, thermal power plants face a huge challenge to satisfy the new emission standards. For further reducing of the emission concentrations of SO2 and NOX, three methods were introduced, including: seriously implementing the emission standards, improving treatment equipment, and increasing the efficiencies of desulfurization and denitrification. 展开更多
关键词 power plant emission standard sulfur dioxide nitrogen oxides
下载PDF
On Countermeasures and Suggestions to Control NO_X Emissions from Utility Boilers
6
作者 毕玉森 陈国辉 《Electricity》 2004年第4期41-45,共5页
In combination with low NOX combustion techniques inChina and in view of limits of the Standard of Discharging Atmo-spheric Pollutants from Thermal Power Plants to be published soon,this paper presents corresponding t... In combination with low NOX combustion techniques inChina and in view of limits of the Standard of Discharging Atmo-spheric Pollutants from Thermal Power Plants to be published soon,this paper presents corresponding technical countermeasures andkey subjects to be studied. 展开更多
关键词 NOX combustion technique emission standard
下载PDF
^(18)F-Fluorodeoxyglucose positron emission tomography/computed tomography comparison of gastric lymphoma and gastric carcinoma 被引量:5
7
作者 Xiao-Feng Li Qiang Fu +5 位作者 You-Wen Dong Jian-Jing Liu Xiu-Yu Song Dong Dai Cong Zuo Wen-Gui Xu 《World Journal of Gastroenterology》 SCIE CAS 2016年第34期7787-7796,共10页
AIM To compare ^(18)F-fluorodeoxyglucose positron emission tomography/computed tomography(^(18)F-FDG PET/CT) features in gastric lymphoma and gastric carcinoma.METHODS Patients with newly diagnosed gastric lymphoma or... AIM To compare ^(18)F-fluorodeoxyglucose positron emission tomography/computed tomography(^(18)F-FDG PET/CT) features in gastric lymphoma and gastric carcinoma.METHODS Patients with newly diagnosed gastric lymphoma or gastric carcinoma who underwent ^(18)F-FDG PET/CT prior to treatment were included in this study. We reviewed and analyzed the PET/CT features of gastric wall lesions,including FDG avidity,pattern(focal/diffuse),and intensity [maximal standard uptake value:(SUVmax)]. The correlation of SUVmax with gastricclinicopathological variables was investigated by χ~2 test,and receiver-operating characteristic(ROC) curve analysis was performed to determine the differential diagnostic value of SUVmax-associated parameters in gastric lymphoma and gastric carcinoma. RESULTS Fifty-two patients with gastric lymphoma and 73 with gastric carcinoma were included in this study. Abnormal gastric FDG accumulation was found in 49 patients(94.23%) with gastric lymphoma and 65 patients(89.04%) with gastric carcinoma. Gastric lymphoma patients predominantly presented with type Ⅰ and type Ⅱ lesions,whereas gastric carcinoma patients mainly had type Ⅲ lesions. The SUVmax(13.39 ± 9.24 vs 8.35 ± 5.80,P < 0.001) and SUVmax/THKmax(maximal thickness)(7.96 ± 4.02 vs 4.88 ± 3.32,P < 0.001) were both higher in patients with gastric lymphoma compared with gastric carcinoma. ROC curve analysis suggested a better performance of SUVmax/THKmax in the evaluation of gastric lesions between gastric lymphoma and gastric carcinoma in comparison with that of SUVmax alone.CONCLUSION PET/CT features differ between gastric lymphoma and carcinoma,which can improve PET/CT evaluation of gastric wall lesions and help differentiate gastric lymphoma from gastric carcinoma. 展开更多
关键词 GASTRIC LYMPHOMAS GASTRIC CARCINOMAS 18F-FLUORODEOXYGLUCOSE positron emission tomography/ computed TOMOGRAPHY MAXIMAL standard uptake value MAXIMAL thickness Differential diagnosis
下载PDF
Role of 18F-fluorodeoxyglucose positron emission tomography imaging in surgery for pancreatic cancer 被引量:16
8
作者 Hisao Wakabayashi Yoshihiro Nishiyama +5 位作者 Tsuyoshi Otani Takanori Sano Shinichi Yachida Keiichi Okano Kunihiko Izuishi Yasuyuki Suzuki 《World Journal of Gastroenterology》 SCIE CAS CSCD 2008年第1期64-69,共6页
AIM: To evaluate the role of positron emission tomography using 18F-fluorodeoxyglucose (FDG-PET) in the surgical management of patients with pancreatic cancer, including the diagnosis, staging, and selection of pat... AIM: To evaluate the role of positron emission tomography using 18F-fluorodeoxyglucose (FDG-PET) in the surgical management of patients with pancreatic cancer, including the diagnosis, staging, and selection of patients for the subsequent surgical treatment. METHODS: This study involved 53 patients with proven primary pancreatic cancer. The sensitivity of diagnosing the primary cancer was examined for FDG-PET CT, cytological examination of the bile or pancreatic juice, and the serum levels of carcinoembrionic antigens (CEA) and carbohydrate antigen 19-9 (CA29-9). Next, the accuracy of staging was compared between FDG-PET and CT. Finally, FDG-PET was analyzed semiquantitatively using the standard uptake value (SUV). The impact of the SUV on patient management was evaluated by examining the correlations between the SUV and the histological findings of cancer. RESULTS: The sensitivity of FDG-PET, CT, cytological examination of the bile or pancreatic juice, and the serum levels of CEA and CA19-9 were 92.5%, 88.7%, 46.4%, 37.7% and 69.8%, respectively. In staging, FDG-PET was superior to CT only in diagnosing distant disease (bone metastasis). For local staging, the sensitivity of CT was better than that of FDG-PEr. The SUV did not correlate with the pTNM stage, grades, invasions to the vessels and nerve, or with the size of the tumor. However, there was a statistically significant difference (4.6 ± 2.9 vs 7.8 ± 4.5, P = 0.024) in the SUV between patients with respectable and unresectable disease. CONCLUSION: FDG-PET is thus considered to be useful in the diagnosis of pancreatic cancer. However, regarding the staging of the disease, FDG-PET is not considered to be a sufficiently accurate diagnostic modality. Although the SUV does not correlate with the patho-histological prognostic factors, it may be useful in selecting patients who should undergo subsequent surgical treatment. 展开更多
关键词 Pancreatic cancer Fluorodeoxyglucose positron emission tomography Computed tomography standard uptake value Carcinoembrionic antigens Carbohydrate antigen 19-9 Prognostic factor
下载PDF
Optimization of the Performance of Marine Diesel Engines to Minimize the Formation of SO_x Emissions 被引量:6
9
作者 Mina Tadros Manuel Ventura C.Guedes Soares 《Journal of Marine Science and Application》 CSCD 2020年第3期473-484,共12页
Optimization procedures are required to minimize the amount of fuel consumption and exhaust emissions from marine engines.This study discusses the procedures to optimize the performance of any marine engine implemente... Optimization procedures are required to minimize the amount of fuel consumption and exhaust emissions from marine engines.This study discusses the procedures to optimize the performance of any marine engine implemented in a 0D/1D numerical model in order to achieve lower values of exhaust emissions.From that point,an extension of previous simulation researches is presented to calculate the amount of SOx emissions from two marine diesel engines along their load diagrams based on the percentage of sulfur in the marine fuel used.The variations of SOx emissions are computed in g/k W·h and in parts per million(ppm)as functions of the optimized parameters:brake specific fuel consumption and the amount of air-fuel ratio respectively.Then,a surrogate model-based response surface methodology is used to generate polynomial equations to estimate the amount of SOx emissions as functions of engine speed and load.These developed non-dimensional equations can be further used directly to assess the value of SOx emissions for different percentages of sulfur of the selected or similar engines to be used in different marine applications. 展开更多
关键词 Marine diesel engine standard procedures SO_x emissions Surrogate model Response surface methodology
下载PDF
Nomogram using F-18 fluorodeoxyglucose positron emission tomography/computed tomography for preoperative prediction of lymph node metastasis in gastric cancer 被引量:2
10
作者 Bong-Il Song 《World Journal of Gastrointestinal Oncology》 SCIE CAS 2020年第4期447-456,共10页
BACKGROUND Lymph node(LN)metastasis is an important prognostic factor in patients with gastric cancer(GC).However,the evaluation of LN metastasis status in the preoperative setting is not accurate.Therefore,precise pr... BACKGROUND Lymph node(LN)metastasis is an important prognostic factor in patients with gastric cancer(GC).However,the evaluation of LN metastasis status in the preoperative setting is not accurate.Therefore,precise preoperative prediction of LN metastasis status is crucial for optimal treatment in patients with GC.AIM To develop a preoperative nomogram for LN metastasis using F-18 fluorodeoxyglucose(F-18 FDG)positron emission tomography/computed tomography(PET/CT)and preoperative laboratory test findings in GC.METHODS In this study,the data of 566 GC patients who underwent preoperative F-18 FDG PET/CT and subsequent surgical resection were analyzed.The LN metastasis prediction model was developed in the training cohort and validated in the internal validation cohort.Routine preoperative laboratory tests,including albumin and carbohydrate antigen(CA)19-9 were performed in all patients.Univariate and multivariable logistic regression was performed to validate the preoperative predictive indicators for LN metastasis.RESULTS Of the 566 patients,232(41%)had confirmed histopathologic LN metastasis.Univariate logistic regression revealed that the tumor location,blood hemoglobin,serum albumin levels,neutrophil to lymphocyte ratio,platelet to lymphocyte ratio,CA 19-9,maximum standardized uptake value(SUVmax)of the primary tumor(T_SUVmax),and SUVmax of LN(N_SUVmax)were significantly associated with LN metastasis.In multivariate analysis,T_SUVmax(OR=1.08;95%CI:1.02–1.15;P=0.011)and N_SUVmax(OR=1.49;95%CI:1.19–1.97;P=0.002)were found to be significant predictive factors for LNmetastasis.The LN metastasis prediction model using T_SUVmax,N_SUVmax,serum albumin,and CA 19-9 yielded an area under the curve(AUC)of 0.733(95%CI:0.683–0.784,P=0.025)in the training cohort and AUC of 0.756(95%CI:0.678–0.833,P<0.001)in the test cohort.CONCLUSION T_SUVmax and N_SUVmax measured by preoperative F-18 FDG PET/CT are independent predictive factors for LN metastasis in GC. 展开更多
关键词 Gastric cancer LYMPH node metastasis POSITRON emission tomography/computed tomography FLUORODEOXYGLUCOSE PROGNOSTICATION standardized UPTAKE value
下载PDF
Congenital hyperinsulinism:Role of fluorine-18L-3, 4 hydroxyphenylalanine positron emission tomography scanning 被引量:3
11
作者 Jaya Sujatha Gopal-Kothapani Khalid Hussain 《World Journal of Radiology》 CAS 2014年第6期252-260,共9页
Congenital hyperinsulinism(CHI) is a rare but complex heterogeneous disorder caused by unregulated secre-tion of insulin from the β-cells of the pancreas leading to severe hypoglycaemia and neuroglycopaenia. Swift di... Congenital hyperinsulinism(CHI) is a rare but complex heterogeneous disorder caused by unregulated secre-tion of insulin from the β-cells of the pancreas leading to severe hypoglycaemia and neuroglycopaenia. Swift diagnosis and institution of appropriate management is crucial to prevent or minimise adverse neurodevel-opmental outcome in children with CHI. Histologically there are two major subtypes of CHI, diffuse and focal disease and the management approach will significantly differ depending on the type of the lesion. Patients with medically unresponsive diffuse disease require a near total pancreatectomy, which then leads on to the de-velopment of iatrogenic diabetes mellitus and pancre-atic exocrine insufficiency. However patients with focaldisease only require a limited pancreatectomy to re-move only the focal lesion thus providing complete cure to the patient. Hence the preoperative differentiation of the histological subtypes of CHI becomes paramount in the management of CHI. Fluorine-18L-3, 4-hydroxy-phenylalanine positron emission tomography(18F-DOPA-PET) is now the gold standard for pre-operative differentiation of focal from diffuse disease and locali-sation of the focal lesion. The aim of this review article is to give a clinical overview of CHI, then review the role of dopamine in β-cell physiology and finally discuss the role of 18F-DOPA-PET imaging in the management of CHI. 展开更多
关键词 Congenital hyperinsulinism Fluorine-18L-3 4-hydroxyphenylalanine positron emission tomography Focal congenital hyperinsulinism Diffuse congenital hyperinsulinism Ectopic congenital hyperinsulinism standardized uptake value
下载PDF
Characterization of focal hypermetabolic thyroid incidentaloma: An analysis with F-18 fluorodeoxyglucose positron emission tomography/computed tomography parameters 被引量:1
12
作者 Haejun Lee Yoo Seung Chung +2 位作者 Joon-Hyop Lee Ki-Young Lee Kyung-Hoon Hwang 《World Journal of Clinical Cases》 SCIE 2022年第1期155-165,共11页
BACKGROUND Incidentally found thyroid tumor(thyroid incidentaloma,TI)on F-18 fluorodeoxyglucose(FDG)positron emission tomography-computed tomography(PETCT)is reported in 2.5%-5%of patients being investigated for non-t... BACKGROUND Incidentally found thyroid tumor(thyroid incidentaloma,TI)on F-18 fluorodeoxyglucose(FDG)positron emission tomography-computed tomography(PETCT)is reported in 2.5%-5%of patients being investigated for non-thyroid purposes.Up to 50%of these cases have been diagnosed to be malignant by cytological/histological results.Ultrasonography(US)and fine-needle aspiration cytology are recommended for thyroid nodules with high FDG uptake(hypermetabolism)that are 1 cm or greater in size.It is important to accurately determine whether a suspicious hypermetabolic TI is malignant or benign.AIM To distinguish malignant hypermetabolic TIs from benign disease by analyzing F-18 FDG PET-CT parameters and to identify a cut-off value.METHODS Totally,12761 images of patients who underwent F-18 FDG PET-CT for nonthyroid purposes at our hospital between January 2016 and December 2020 were retrospectively reviewed,and 339 patients[185 men(mean age:68±11.2)and 154 women(mean age:63±15.0)]were found to have abnormal,either focal or diffuse,thyroid FDG uptake.After a thorough review of their medical records,US,and cytological/histological reports,46 eligible patients with focal hypermetabolic TI were included in this study.The TIs were categorized as malignant and benign according to the cytological/histological reports,and four PET parameters[standardized uptake value(SUV)max,SUV_(peak),SUV_(mean),and metabolic tumor volume(MTV)]were measured on FDG PET-CT.Total lesion glycolysis(TLG)was calculated by multiplying the SUV_(mean) by MTV.Both parametric and non-parametric methods were used to compare the five parameters between malignant and benign lesions.Receiver operating characteristic(ROC)curve analysis was performed to identify a cut-off value.RESULTS Each of the 46 patients[12 men(26.1%;mean age:62±13.1 years)and 34 women(73.9%;mean age:60±12.0 years)]with focal hypermetabolic TIs had one focal hypermetabolic TI.Among them,26(56.5%)were malignant and 20(43.5%)were benign.SUV_(max),SUV_(peak),SUV_(mean),and TLG were all higher in malignant lesions than benign ones,but the difference was statistically significant(P=0.012)only for SUV_(max).There was a positive linear correlation(r=0.339)between SUV_(max) and the diagnosis of malignancy.ROC curve analysis for SUV_(max) revealed an area under the curve of 0.702(P<0.05,95%confidence interval:0.550-0.855)and SUV_(max) cut-off of 8.5 with a sensitivity of 0.615 and a specificity of 0.789.CONCLUSION More than half of focal hypermetabolic TIs on F-18 FDG PET-CT were revealed as malignant lesions,and SUV_(max) was the best parameter for discriminating between malignant and benign disease.Unexpected focal hypermetabolic TIs with the SUV_(max) above the cut-off value of 8.5 may have a greater than 70%chance of malignancy;therefore,further active assessment is required. 展开更多
关键词 Thyroid incidentaloma MALIGNANCY Fluorodeoxyglucose positron emission tomography/computed tomography standardized uptake value CUT-OFF
下载PDF
Evaluation of the Implementation of a Low Emission Zone in Lisbon
13
作者 Francisco Ferreira Pedro Gomes +4 位作者 Ana Cristina Carvalho Hugo Tente Joana Monjardino Helena Brás Paulo Pereira 《Journal of Environmental Protection》 2012年第9期1188-1205,共18页
The city of Lisbon, like many others in the EU region, introduced a Low Emission Zone (LEZ) as a tool for improving air quality in its city centre. This kind of emission reduction schemes is always controversial since... The city of Lisbon, like many others in the EU region, introduced a Low Emission Zone (LEZ) as a tool for improving air quality in its city centre. This kind of emission reduction schemes is always controversial since it might lead to significant changes in the daily behaviours of its inhabitants. In order to evaluate the effects of the measure, an estimation of the impact of the introduction of the Lisbon LEZ was performed. Real traffic counting and fleet characterization combined with CORINAR-based emission inventory methodology allowed to estimate the impacts of three different scenarios applied to the “business as usual” condition (current vehicle fleet) ranging from “no circulation from non- compliant vehicles” to an “aggressive fleet renewal”. Results highlight the high percentage of atmospheric emissions of PM10 and NOx that might result from certain fleets like taxis and buses, especially because there was an emphasis in standardized/normalized estimations (emissions per 1000 vehicles) in order to allow different strategic approaches. The total reduction of PM10 emissions associated to each scenario vary between 6 ton.year-1 (scenario 2) and 8 ton.year-1 (scenario 1), or 25% and 34% less emissions. In terms of NOxemission reductions vary between 6 ton.year-1 (scenario 2) and 57 ton.year-1 (scenario 1), or 1% and 7% less emissions. The Lisbon LEZ is therefore much more efficient in reducing PM10 emissions compared to NOx. Major reduction in PM10 and NOx emissions are to be expected with a moderate intervention in the (relatively old) taxi fleet in Lisbon while for passenger cars the impact is limited. However in absolute terms and due to its urban mileage passenger cars should also continue being included in Lisbon LEZ. Simultaneously, an effort in the increase of dedicated lanes for public transport should be made, for further reductions in PM10 and NOx emissions. 展开更多
关键词 Low emission ZONE PM10 NOx EURO standardS
下载PDF
Assessment of incidental focal colorectal uptake by analysis of fluorine-18 fluorodeoxyglucose positron emission tomography parameters
14
作者 Haejun Lee Kyung-Hoon Hwang Kwang An Kwon 《World Journal of Clinical Cases》 SCIE 2022年第17期5634-5645,共12页
BACKGROUND Colon and rectal cancers are among the top five cancers worldwide in terms of their incidence and mortality rates.As the treatment options for cure include surgery even in specific advanced-stage cases,the ... BACKGROUND Colon and rectal cancers are among the top five cancers worldwide in terms of their incidence and mortality rates.As the treatment options for cure include surgery even in specific advanced-stage cases,the early detection of lesions is important for applying active treatment methods.Fluorine-18 fluorodeoxyglucose(F-18 FDG)positron emission tomography/computed tomography(PET/CT)is an established imaging study for many types of cancers;however,physiologic uptake in the gastrointestinal tract is a frequent finding and may interfere with lesion identification.Nevertheless,as unexpectedly observed focal colorectal F-18 FDG uptake may harbor malignant lesions,further examination must not be avoided.AIM To assess the clinical implications of unexpected focal colorectal F-18 FDG uptake by analyzing FDG PET parameters.METHODS A total of 15143 F-18 FDG PET/CT scans performed at our hospital between January 2016 and September 2021 were retrospectively reviewed to identify incidentally observed focal colorectal FDG uptake.Finally,83 regions showing focal colorectal FDG uptake with final histopathological reports from 80 patients(45 men and 35 women with mean ages of 66.9±10.7 years and 63.7±15.3 years,respectively)were eligible for inclusion in the present study.Each focal hypermetabolic colorectal region was classified as malignant,premalignant,or benign according to the histopathological report.PET parameters such as maximum and peak standardized uptake value(SUVmax and SUVpeak),metabolic tumor volume(MTV),mean SUV of the metabolic tumor volume(mSUVmtv),and total lesion glycolysis(TLG)were measured or calculated for the corresponding hypermetabolic regions.Parametric and nonparametric statistical comparisons of these parameters were performed among the three groups.Receiver operating characteristic curves were plotted to identify cut-off values.RESULTS The detection rate of incidental focal colorectal uptake was 0.53%(80/15,143).Of the 83 regions with unexpected focal colorectal hypermetabolism,28.9%(24/83)were malignant,32.5%(27/83)were premalignant,and 38.6%(32/83)were benign.Overall,61.4% of the regions had malignant or premalignant lesions.SUVmax,SUVpeak,and mSUVmtv differentiated malignant and/or premalignant lesions from benign lesions with statistical significance(P<0.05).mSUVmtv3.5 differentiated malignant from benign lesions,with the largest area under the curve(AUC)of 0.792 and a cut-off of 4.9.SUVmax showed the largest AUC of 0.758 with a cut-off value of 7.5 for distinguishing between premalignant and benign lesions.Overall,SUVmax with a cut-off value of 7.6(AUC:0.770,95% confidence interval(CI):0.668-0.872;sensitivity,0.686;specificity,0.688)was a superior parameter for distinguishing between malignant/premalignant and benign lesions or physiologic uptake.No parameters differentiated malignant from premalignant lesions.Moderate or weak positive correlations were observed between the long diameter of the malignant lesions and PET parameters such as SUVpeak and some mSUVmtv.CONCLUSION Approximately two-thirds(61.4%)of incidental focal hypermetabolic colorectal regions were malignant/premalignant lesions,for which SUVmax was an independent diagnostic parameter.Unexpected suspicious focal colorectal FDG uptake should not be avoided and consideration for further evaluation is strongly recommended not to miss the two-thirds. 展开更多
关键词 COLORECTAL INCIDENTAL Fluorine-18 fluorodeoxyglucose Positron emission tomography/computed tomography standardized uptake value
下载PDF
Sulfur Dioxide Emission Control,Blockade and Drainage
15
作者 Wang Zhixuan Jin Wen 《Electricity》 2005年第3期55-57,共3页
This paper presents the present status of sulfur dioxide emission from thermal plants in China, tells the main problems existing in its emission control and finally gives out suggestions to the problems, that is, to c... This paper presents the present status of sulfur dioxide emission from thermal plants in China, tells the main problems existing in its emission control and finally gives out suggestions to the problems, that is, to constitute complete standards and regulations and enhancesupervision accordingly. 展开更多
关键词 sulfur dioxide emission control standard SUPERVISION
下载PDF
Application and Development Trends of Spectral Analysis in Draft of Non-Ferrous Metal Standards in China
16
作者 Lijun Kuai Huachang Li +1 位作者 Jiemin Liu Shufang Tang 《American Journal of Analytical Chemistry》 2023年第6期239-273,共35页
Spectral analysis was a method of identifying substances, determining their chemical composition and calculating their content based on their spectral characteristics. This paper mainly discussed the application of va... Spectral analysis was a method of identifying substances, determining their chemical composition and calculating their content based on their spectral characteristics. This paper mainly discussed the application of various spectroscopic techniques, mainly including atomic absorption spectrometry (AAS) inductively coupled plasma emission spectrometry (ICP-AES) X-ray fluorescence spectroscopy (XRF) atomic fluorescence spectroscopy (AFS) direct reading spectroscopy (OES) glow discharge emission spectroscopy (GD-OSE) laser-induced breakdown spectroscopy (LIBS), in the formulation of non-ferrous metal standards in China. The AAS method was the most widely used single-element microanalysis method among the non-ferrous metal standards. The ICP-AES method was good at significant advantages in the simultaneous detection of multiple elements. The XRF method was increasingly used in the determination of primary and secondary trace elements due to its simple sample preparation and high efficiency. The AFS was mostly detected by single-element trace analysis. OES GD-OES and LIBS were playing an increasingly important role in the new demand area for non-ferrous metals. This paper discussed matrix elimination, sample digestion, sample preparation, instrument categories and other aspects of some standards, and summarized the advantages of spectral analysis and traditional chemical analysis methods. The new methods of future spectroscopic technology had been illustrated in the process of developing non-ferrous metal standards. 展开更多
关键词 Atomic Absorption Spectroscopy Inductively Coupled Plasma emission Spectroscopy X-Ray Fluorescence Spectroscopy Atomic Fluorescence Spectroscopy Direct Reading Spectroscopy Glow Discharge emission Spectroscopy Laser-Induced Breakdown Spectroscopy Non-Ferrous Metals standard Methods Were Formulated
下载PDF
碳中和标准体系建设现状、实践及展望 被引量:1
17
作者 杨博 杨思雨 王思齐 《环境监测管理与技术》 CSCD 北大核心 2024年第1期6-10,22,共6页
通过对国内外现行和正在研制的碳中和相关标准进行梳理和归纳,结合碳中和实现路径中标准的运用实践,探究我国不同行业、不同领域碳中和标准体系建设现状。指出我国的碳中和标准体系建设存在着顶层设计和统筹机制不完善、政策与标准发展... 通过对国内外现行和正在研制的碳中和相关标准进行梳理和归纳,结合碳中和实现路径中标准的运用实践,探究我国不同行业、不同领域碳中和标准体系建设现状。指出我国的碳中和标准体系建设存在着顶层设计和统筹机制不完善、政策与标准发展不协调、技术研发与标准结合不紧密等问题,提出了强化统筹规划和顶层设计、构建标准实施和监管体系、加快制定急需技术标准、建设绿色产品认证制度、构建绿色金融标准体系,以及推进国际交流与合作等标准化工作建议。 展开更多
关键词 碳中和 标准体系 碳排放 温室气体
下载PDF
我国垃圾填埋碳排放核算标准的编制建议
18
作者 何品晶 李晓静 +3 位作者 吕凡 仇俊杰 廖南林 章骅 《中国工程科学》 CSCD 北大核心 2024年第2期174-184,共11页
填埋作为我国主要的垃圾处理方式之一,是碳排放的重要来源;编制我国垃圾填埋碳排放核算标准,将支持碳排放统计核算体系建设,推进碳达峰、碳中和目标进程。本文梳理了国内外垃圾填埋碳排放核算的相关标准和指南研制进展,分析了我国垃圾... 填埋作为我国主要的垃圾处理方式之一,是碳排放的重要来源;编制我国垃圾填埋碳排放核算标准,将支持碳排放统计核算体系建设,推进碳达峰、碳中和目标进程。本文梳理了国内外垃圾填埋碳排放核算的相关标准和指南研制进展,分析了我国垃圾填埋碳排放核算标准编制面临的挑战,在深入讨论相关标准的基准方法、编制重点任务的基础上提出了有关发展建议。研究认为,国际上已有的标准和指南以及提供的缺省值不完全适用于我国垃圾填埋碳排放核算的实际情况,目前我国缺少规范统一的垃圾填埋碳排放核算方法,也缺乏可靠的核算清单数据。为此,针对我国填埋垃圾特征和技术现状,提出了我国垃圾填埋碳排放核算方法、核算范围和清单的建议内容;明晰了我国垃圾填埋碳排放核算标准编制的重点任务,提供了适合我国垃圾填埋场景的清单数据获取方式。后续,可充分考虑地区因素,采用我国特征性数据,以获得更贴合实际情况的垃圾填埋碳排放核算结果,据此开展我国垃圾填埋碳排放核算标准的编制工作。 展开更多
关键词 垃圾填埋 碳排放 标准 核算方法 清单数据
下载PDF
硫磺回收装置烟气碱法脱硫工艺存在问题及解决方案 被引量:1
19
作者 王庆峰 胡久元 《石油与天然气化工》 CAS CSCD 北大核心 2024年第1期36-40,共5页
目的对140 kt/a硫磺回收装置新增烟气碱洗单元的运行情况进行总结,分析烟气碱洗单元运行过程中出现的异常情况,并提出应对措施。方法①总结碱洗单元的运行情况,对操作参数及烟气排放情况进行分析;②将冲洗水由工业水改为除盐水,同时稳... 目的对140 kt/a硫磺回收装置新增烟气碱洗单元的运行情况进行总结,分析烟气碱洗单元运行过程中出现的异常情况,并提出应对措施。方法①总结碱洗单元的运行情况,对操作参数及烟气排放情况进行分析;②将冲洗水由工业水改为除盐水,同时稳定控制碱液pH值,解决了烟气碱洗塔压降增大的问题;③优化工艺操作,对碱洗塔与循环槽连通管线进行改造,解决了碱洗塔液位波动的问题;④保证氧化空气供给,调整碱液pH值,防止急冷塔氨逃逸,解决了含盐废水超标的问题。结果解决了烟气碱洗单元运行过程中出现的问题,该工艺单元于2017年7月建成投运,稳定运行至2022年3月装置大修,连续运行时间超过1700 d。结论实现了装置的长周期稳定运行,烟气中SO_(2)排放稳定达标,远低于排放标准的要求,可为同类装置提供参考。 展开更多
关键词 硫磺回收 烟气 碱法脱硫 SO_(2) 达标排放 含盐废水 GB 31570—2015
下载PDF
中国减污降碳生态环境标准体系研究
20
作者 谭玉菲 王宗爽 +3 位作者 赵国华 李艳萍 江梅 武雪芳 《环境污染与防治》 CAS CSCD 北大核心 2024年第9期1340-1345,1371,共7页
中国现行生态环境标准体系以减污治污为核心,与降碳联系不紧密,支撑碳排放权交易、温室气体排放和监测、减污降碳协同控制技术指南等标准缺乏,难以有效支撑美丽中国建设和“双碳”目标实现。为此,在分析国际温室气体和环境污染物协同管... 中国现行生态环境标准体系以减污治污为核心,与降碳联系不紧密,支撑碳排放权交易、温室气体排放和监测、减污降碳协同控制技术指南等标准缺乏,难以有效支撑美丽中国建设和“双碳”目标实现。为此,在分析国际温室气体和环境污染物协同管控政策标准基础上,结合中国减污降碳管理需求,采用分类层次结构及综合标准化法,构建了支撑“市场+行政”温室气体管理模式的减污降碳生态环境标准体系框架。建议提前对计划纳入碳市场的行业制定配额核算核查等相关碳排放权交易标准,对其他行业研究制定协同控制温室气体的污染物排放标准,并制定相关配套标准支撑全链条减污降碳协同管控。 展开更多
关键词 减污降碳 应对气候变化 温室气体 标准体系 框架结构
下载PDF
上一页 1 2 92 下一页 到第
使用帮助 返回顶部