evaluation
-
Run into the paper statistics, helpless. On Qimo, I saw that Dr.Tong company provided the assistance of thesis statistics, and with the guidance and assistance of the doctor's teacher, I ran smoothly to get the results. Thank Dr.Tong for his high-level service.
Mr. Lin
from: tainan
-
When a doctoral dissertation encounters multiple linear regression, it has always been a difficult point and there is nothing to do. On Google, we can see that the doctor teacher of Dr.Tong statistics company provides statistical running and statistical guidance. The information and requirements to the doctor teacher, with the help of the teacher, smoothly run out the results. Thank you for the help and guidance from the doctor of Dr.Tong statistics company.
Dr. Li
from: taoyuan
-
When I met the difficulties in the statistical analysis of the doctoral thesis questionnaire, I couldn't find a clue. Finally, I saw Dr.Tong's assistance in the statistical analysis of the thesis questionnaire on qimo.com. With the assistance of the doctor, I got the results smoothly. Thank Dr.Tong for his assistance in the statistical analysis of the thesis questionnaire, which solved my urgent problem.
Dr. Li
from: Kaohsiung
-
Previously, a local statistics company in Hong Kong was entrusted, but it failed to do a good job in medical statistics. In my anxiety, I saw the doctor teacher of Dr.Tong statistics company provide statistical running and guidance, and sent the data and requirements to the doctor teacher. With the efforts of the doctor teacher, the analysis results were successfully made. I feel that Taiwan's statistics companies are more professional and the fees are reasonable.
Dr. Li
from: hongkong
-
Thank you for the efficient and high quality service provided by the doctor teacher of Dr.Tong statistics company. Solved my urgent need.
Mr. Lin
from: yunlin
-
When I met the difficulties in the statistical analysis of the pre-test and post-test of the thesis questionnaire, I couldn't solve them all the time. On Qimo, I saw that the doctoral teacher of Dr.Tong statistics company provided the tutoring service of thesis statistics, and sent the information and requirements to the doctoral teacher. With the help and guidance of the teacher, I got the results. Thank you very much for the tutoring service of the doctoral teacher of Dr.Tong statistics company There are two difficulties.
Miss Liu
from: Kaohsiung
-
It is difficult to analyze English papers by SPSS. On Google, we can see that the doctoral teacher of Dr.Tong statistics company provides the paper statistics running and guidance, sends the data and analysis requirements to the teacher, communicates with the teacher, and runs smoothly with the teacher's guidance and help. Thank you very much for the help of the doctor teacher of Dr.Tong statistics company. The teacher is serious, responsible and powerful.
Miss Zeng
from: london
-
It's difficult to analyze Stata data in accounting papers. On Yahoo Qimo, I saw the doctor teacher of Dr.Tong statistics company provide Stata statistical running guidance. The data and requirements were sent to the doctor's teacher. Under the guidance of the doctor's teacher, the Stata code was successfully designed, and the analysis results were also run out. I would like to thank the doctor's teacher of Dr.Tong statistics for his high level guidance and assistance.
Mr. Zhang
from: taizhong
-
Educational papers have quantitative statistics, which is a bit difficult! Helpless, I saw on Yahoo Qimo that Dr. and postdoctoral teachers from Dr.Tong Statistics Company provide doctoral thesis statistics and counseling services. I sent the questionnaire and sample data to the doctor, and with the guidance and assistance of the doctor, I successfully obtained the results and graduated. I am very grateful for the professional guidance of the doctor and postdoctoral teacher from Dr.Tong Statistics Company. The technical expertise, reliable quality, and reasonable fees have saved me a lot of trouble.
Dr. Song
from: Kaohsiung
|
|
|
|
| 2024-01-12 11:16:03 | onclick： | Implementing molecular "surgery", carbon materials family "added new Ding |
 |
|
Xu Wei's team, a professor at Tongji University's School of Materials Science and Engineering, synthesized a ring-shaped pure carbon molecule consisting of 10 or 14 carbon atoms for the first time by "anesthesia" and "surgery".
For the first time, two novel carbon molecular materials (carbon allografts), aromatic cyclic carbon C10 and C14, have been synthesized with precision and have been characterized by their chemical structures.
Surface synthesis strategies and chemical structure characterization of cyclic carbon C10 and C14.Tongji University of Technology
Carbon is a common nonmetallic element, and carbon materials have many forms in nature, and their specific external appearance depends on the number of atoms bonded to each carbon atom around it.When each carbon atom binds to the surrounding four atoms, it forms a hard and transparent material naturally occurring in nature—diamonds; when it binds to the surrounding three atoms, it forms a qualitative soft black graphite.
When each carbon atom binds to only two surrounding atoms, it forms a ring-shaped pure carbon molecule (cyclic carbon, Cn).Because this type of carbon structure is highly reactive, highly unstable, does not occur naturally in nature, and synthetic is extremely challenging.
In addition, in cyclic carbon, the way in which each carbon atom and the surrounding two atoms bond, i.e., cumulative olefin type with equal bond length (continuous double bond) or polyacetylene type (single bond and triple bond alternation).Therefore, the most fundamental problems of their puzzling structure and stability have attracted great interest from experimentalists and theorists.Many teams have tried unsuccessfully to synthesize cyclic carbon, and some gas-phase experiments have shown signs of cyclic carbon, but it is difficult to separate and refine and further characterize their structure.
Until 2019, IBM Labs and Oxford University research teams prepared a single cyclic carbon C18, the first experimental verification of C18 as a single- and triple-bond alternating polyacetylene structure.However, cyclic carbon is a large family, and for smaller cyclic carbon, their synthesis becomes more challenging due to their small size.
In this study, the team innovatively designed two precursor molecules, all-halogenated naphthalene and anthracene.The two molecules were placed on the operating table (sodium chloride film) and "anesthetized" (liquid helium 4.7 K frozen), and then "surgical" (atomic manipulation) to induce complete dehalogenation.Chemical bond resolution atomic force microscopy shows that C10 and C14 have accumulated olefin structures, unlike the previous polyacetylene structures of C18.
The team further found that the two carbon material family members do not have completely identical properties, C10 does not have any bond length alternation, and C14 as a cumulative olefin type C10 to polyacetylene type C18.
"This research work has greatly promoted the development of the cyclic carbon field, and the proposed surface synthesis strategy is expected to become a universal method for the synthesis of cyclic carbon series.""At the same time, the synthesized cyclic carbon is expected to develop into a new type of semiconductor material and have broad application prospects in molecular electronic devices."
|
|
 |
|
|
|
|
|
